hybridfree/eevblog-posts huggingface dataset:
[PARTIALLY SOLVED] 8593E blank screen - Page 1
Forum section: electronics / repair

author: Daxxin
author_rank: Regular Contributor
timestamp: December 17, 2016, 05:43:44 pm
content: Just fixed psu now switching on screen is blank and getting retrace when switching off , what can be happened?https://youtu.be/a3gV8dq1_4I

author: Daxxin
author_rank: Regular Contributor
timestamp: December 18, 2016, 05:57:21 am
content: here schemas

author: Daxxin
author_rank: Regular Contributor
timestamp: December 18, 2016, 06:58:38 am
content: simple b/w raster or bars generator schematic to test this?

author: Daxxin
author_rank: Regular Contributor
timestamp: December 18, 2016, 04:15:08 pm
content: powering with external ps 12+v remain blank , using Arduino TVout for the signal , switching off no more retraces , measuring signal to B and E of Q44 2sc884 they are sameBE

author: Daxxin
author_rank: Regular Contributor
timestamp: December 18, 2016, 07:13:10 pm
content: no signal coming from processor board

author: Daxxin
author_rank: Regular Contributor
timestamp: December 20, 2016, 05:11:04 am
content: no activity from this graphic chip even from video output theres a enabling pin?

author: Daxxin
author_rank: Regular Contributor
timestamp: December 21, 2016, 07:36:10 pm
content: from service guide 8595E the troubleshooting guide says follow WRUP +5v signal on pin 54 but found it on pin 55 of J1but its ok for other models ..very confused4. Verify the High-Power-Up signal from the A8 power supply bychecking for the +5 V TTL WRUP signal at pin 54 on the A16J1. TheA16J1 connector is on the trace side of the A16 processor/videoNote that if your analyzer is an8590 E-Series, 8591C, or 8594QQAM analyzer, the WRUP signal can be measured on pin 55ofeach card-cage slot on the A15 motherboard. Refer to Figure 4-6for the numbering order of the connector pins on A15J3 throughA15J6

author: Daxxin
author_rank: Regular Contributor
timestamp: December 25, 2016, 04:31:26 pm
content: diode shorten burning resistor sorrounding LM339 disabling HPWRUP signal , pin 54 can measure 5v and it start on with video

author: Daxxin
author_rank: Regular Contributor
timestamp: December 26, 2016, 06:54:08 pm
content: Removed all the 4 eprom to backup forgot to put back i switched power on , front panel relays clicking many times with blank screen ,then i put back eprom's ..suprise video is fine with message error ''FAIL 003.0000000000'' switching off and on again garbled video is backso tried again remove all the eprom's on..off and video back fine again .. thinking volatile memory storing some video params? the onlystoring mem is the dallas for constant variables.

author: Daxxin
author_rank: Regular Contributor
timestamp: January 01, 2017, 12:20:53 pm
content: this system uses cmos ram with dallas ds1259 to retain data CAL etc..as descrind in the service manual chapter "Performing an A16 memory reset"shorting pin 2 and 8 of U104(DS1259) analyzer boot up with correct videoshutting off and on back to garbled video , rom corrupted or ram chip failure?
Hard drive with a broken diode? - Page 1
Forum section: electronics / repair

author: UberStrike88
author_rank: Regular Contributor
timestamp: December 24, 2016, 12:17:57 pm
content: Hello nice people,I have an old hard drive that stopped working and when I took it out of the mashine it had a boldge on a diode, The 2 diodes next to each other have the same part no. But I can't find anything about them on the internet. I know they are from on semiconducters but that's it. Here are the 2 picures and the whole board. The one with the LG. on it has that blodge on it. Anyone has an idea?THe one with LG:The one next to it:And the whole board:Does anyone have an idea with what I can replace the diode?

author: KhronX
author_rank: Frequent Contributor
timestamp: December 24, 2016, 12:35:22 pm
content: Seeing as those are on the 12v and 5v supply lines, you can bet your booty those are a pair of TVS (transient voltage suppressor) diode.https://en.wikipedia.org/wiki/Transient-voltage-suppression_diodeTechnically, the hard-drive should work fine with those removed, but will be left somewhat unprotected in case of any surges on the supplies.

author: UberStrike88
author_rank: Regular Contributor
timestamp: December 24, 2016, 01:13:36 pm
content: Quote from: KhronX on December 24, 2016, 12:35:22 pmAlright thank you mate I will remove them and see if that was my issue or if my psu destroyed something past the diodes.

author: wraper
author_rank: Unknown
timestamp: December 24, 2016, 01:19:49 pm
content: I would advise immediately stop using PSU which was powering this HDD, and as minimum check if electrolytic capacitors inside it are not bulged. Otherwise more damage may follow.

author: KhronX
author_rank: Frequent Contributor
timestamp: December 24, 2016, 01:25:54 pm
content: That's a good point, actuallyQuote from: wraper on December 24, 2016, 01:19:49 pm

author: Inflex
author_rank: Regular Contributor
timestamp: December 31, 2016, 04:57:30 am
content: Was this from an external drive at all (3.5" I'm presuming?).I get a few drives in each year with blown (shorted rather) TVS diodes and they're always from external enclosures.Good advice from Wraper, especially if you do remove the TVS's and it comes good again, last thing you want to do is blow the board with a glitch.Usually I always just clone the data/drive with ddrescue straight to an image and write off the old drive as an overly paranoid precaution
TDS 3012 / TDS 3014 input hybrid module - Page 1
Forum section: electronics / repair

author: whitebear
author_rank: Newbie
timestamp: January 05, 2017, 05:36:50 pm
content: Hi Everyone,just wanted to ask if someone, by chance, has a working hybrid input module for TDS 3012 / TDS 3014 for sale?I've got a 3014 with one of the modules being faulty.
Nikon DSLR Shutter Release IO port, input stuck low - Page 1
Forum section: electronics / repair

author: sjetmand
author_rank: Newbie
timestamp: December 29, 2016, 05:08:25 pm
content: Hey everyoneI have a simple optocoupler circuit for firing a dslr over hardwire.Most DSLRs can be triggered over either a 2.5mm TRS plug or their own proprietary connector flavor with 3 pins. GND, Focus, and Shutter.You generally have to tie the Focus pin to GND first and then hold Shutter to GND to fire the camera.This optocoupler firing circuit has been problem free for over two hundred cameras. Suddenly, it sporadically fried the input on 3 Nikon cameras in a row (A D7100 and two D7200s).The best I could find, after chopping up the 3rd party shutter release cable was a blob of solder on the Nikon N3 connector that appeared to have been intermittently shorting the Shutter and Focus pins together.I can't for the life of me understand why that would cause this failure, but it's the best I've got because nothing else seems suspect.I've replaced the cable, but am not trying to rule out possible repair of the cameras.They are acting as though the Focus pin is persistently being held to ground. And since it thinks i'm holding the focus button, it disables the LCD, and won't let me do much except a full shutter press. So I can still take pictures. But I can't access the menu system etc.I haven't taken them apart yet because they look like a veritable nightmare to re-assemble, but if someone thought it could be boiled down to replacing a single passive on the main board, I'll give it a go.I'm attaching an image of the main board, from fixyourcamera.org (http://www.fixyourcamera.org/nikon-d7100/) with the area in question highlighted.Also, i've attached a picture of the connector and a different angle of the female jack on a pcb, I haven't worked out the pinout at the rear of the connector.Any help = greatly appreciated.Cheers!

author: voltz
author_rank: Frequent Contributor
timestamp: December 29, 2016, 09:34:53 pm
content: Cant see why shorting the focus pin to shutter release would cause a camera failure. Both pins are basically scanned Input pins. Usually scanned at 25Hz (maybe its 50Hz).. Have you tried putting a scope on each input pin and look for a logic square wave or maybe just a static HI ? If the focus pin is stuck Lo then it could be the protection diode for that pin. Used for static protection.Only other idea might be to try a full camera reset, just in case this is a software issue.

author: TiN
author_rank: Super Contributor
timestamp: December 30, 2016, 04:47:29 am
content: Looks like there are 4 inputs with tinytiny ESD diodes and tinytiny 3-leg trannies coming from connector. Perhaps check those. Or maybe you just borked pullup resistor on focus/shutter lines?Anyhow, be careful with soldering those HDI boards, they are very flimsy

author: sjetmand
author_rank: Newbie
timestamp: December 30, 2016, 09:32:44 pm
content: I guess the only thing to do now is set aside a week and crack it open.
DSO6054A gone wild - Page 1
Forum section: electronics / repair

author: Jwalling
author_rank: Unknown
timestamp: December 29, 2016, 01:30:53 pm
content: Does anyone know what the heck this meter-like thing is on a DSO6054A display and how to get rid of it?I can't seem to clear it off the screen, and it's interfering with the menu buttons. When a menu button is pressed, I get a context sensitive message as expected, but it's instantly cleared so you can't do anything with the scope. It appears to be refreshing hundreds of times per second.

author: HighVoltage
author_rank: Super Contributor
timestamp: December 29, 2016, 01:37:55 pm
content: I don't have a 6000 series but it looks like the brightness dial of the 7000 series.May be the brightness knob is stuck?

author: voltsandjolts
author_rank: Unknown
timestamp: December 29, 2016, 01:39:34 pm
content: Looks like the display intensity (i.e. digital phosphor)On my 6034 that hides automatically a few seconds after adjusting intensity.

author: Jwalling
author_rank: Unknown
timestamp: December 29, 2016, 03:09:28 pm
content: Quote from: voltsandjolts on December 29, 2016, 01:39:34 pmSonofagun!That was it! The encoder appears to be a bit dicked.Thanks a lot!
Onkyo A9711 - Page 1
Forum section: electronics / repair

author: Eugeniac
author_rank: Newbie
timestamp: December 28, 2016, 10:45:57 am
content: Hi every boby,i ha ve a problem with a Onkyo a9711. in fact, afriend give it to me for repair the right channel with the power transistor blown. i change that devices but the short remain until disconnect theP503 connector between driver and power amp.board.somebody have an idea of what happens?thanks in advance.

author: mzacharias
author_rank: Frequent Contributor
timestamp: December 28, 2016, 05:28:16 pm
content: Are the mica insulators installed between the new output transistors and the heat sink?
7.5 Amp panel mount fuse to replace AGC fuse holder. - Page 1
Forum section: electronics / repair

author: electronics-whiz
author_rank: Regular Contributor
timestamp: December 27, 2016, 02:08:47 am
content: I was given A standard electric co. type 500b 7.5 amp 0-140V output Variac. If it's possible without a lot of alterations I would like to pull the current fuse holder and replace it with a 7.5A breaker or resettable fuse.I looked around some, and I see the traditional square type breakers like power strips, UPS use, but this is too tall and would hit the on/off switch.Link:https://www.amazon.com/W23-7-5-W23-X1A1G-7-50-7-5-Circuit-Breaker/dp/B00IHSY4GS/ref=sr_1_25?ie=UTF8&qid=1482797085&sr=8-25&keywords=7.5+amp+breakerThis looks better, but not sure of the brand.https://www.amazon.com/Electrical-Equipment-7-5-Circuit-Breaker-7277-5-7-5/dp/B00IHSVDW6/ref=sr_1_23?ie=UTF8&qid=1482797085&sr=8-23&keywords=7.5+amp+breakerOr is there some kind of a small module I could plug into the variac that has a breaker in it?I assume because the fuse is on the output side I should go with a 240 rated breaker although not sure if 140V would do much to a 120V breaker.Looking at the datasheet on the second one it looks like it is the best choice if it is any good, not sure the specs are metric or english in the datasheet though.The current fuse holder is 1 3/4 inch from the mount flange to the back with 90 degree terminal at end. Looks to be about 1/2 inch diameter Takes a 1 1/4 long) by 1/4 (dia) AGC type tube fuse.I was going to get some fuses for it, but if using a breaker is an option then that's even better. I'd prefer something with some delay so I can start motors, etc on this without it tripping. Not sure if thermal or magnetic breaker would be better for this application.
Aeroflex IFR 3416 Signal Generator (6GHz)  No RF Output &  Error # 522 - Page 1
Forum section: electronics / repair

author: rickells
author_rank: Regular Contributor
timestamp: January 01, 2017, 11:52:37 pm
content: hi,I just acquired an Aeroflex IFR 3416 6GHz Signal Generator with an ERROR #522 and No RF output !This is an Aeroflex Marconi IFR 3410 series (3410 - 3416).Just started examining the unit and need some help:-- Don't know how to disassemble to get to the RF PCB board (sandwich) , any ideas ??--- How does one run the unit, powered On but disassembled so that one can view the LED's on the RF PCB ??-- Can't find the Service Manual online and sure can't afford the $400 price that Cobham wants for it.The Operating manual, is on-line, has a simple block diagram, but little Service info.If someone can email me the Service Manual for the IFR 3410 to 3416, it would be much appreciated.My #522 ERROR says "power supply problem; hint: RF board."The Operating manual gives no clue.All 9 Power LED's are Green, all 9 PCB fuses are good, and the one large in-line fuse is good.My Supply voltages are a little low (0.2 to 0.5 V) in some instances: Not sure of the significance.+11.81 V+ 3.35- 11.51+ 6.49+11.28+11.26+ 4.93+ 6.48+26.86I can see ~ 8 Red Led's that are On, (steady On) in the RF PCB (sandwiched between the top cpu/PS/GPIB boards on Top, & the large metal sealed RF unit on the bottom. The 8 Red Led's seem to be grouped Front: (4), (3), (1) : Back.I have no idea what the proper disassembly sequence is to get to the RF PCB, nor how to open the Sealed RF unit correctly (many screws).There is also a Red Blinking "Led D7+" "Boot 0" on one of the top (CPU ?) boards (PCB barcode# 44830/367 01043 09) near IC 34, which seems to be a regulator IC of some kind. It is blinking in some sort of lengthy Morse code blinks (Short-Long-Short-Short, etc.) I have not easily been able to determine its complete sequence yet, but will soon. All utility key-press functions appear to work correctly, and display/cpu functions appear to work.The large RF metal package on the bottom is quite hot to the touch in several places:Possibly some short or issue inside?Bottom Temperature position locations:Back1 2 34 5 67 8 9FrontPositions #2,3, 5,6 are very hot to the touch.Any hints for next steps & Service Manual .pdf would help.Thank you
what the name of this - Page 1
Forum section: electronics / repair

author: Daxxin
author_rank: Regular Contributor
timestamp: December 22, 2016, 08:12:11 pm
content: looking for replace this , what the name of this guide to connect db d-sub pcb connectors m/f ?

author: PaulAm
author_rank: Frequent Contributor
timestamp: December 25, 2016, 06:16:21 pm
content: Look for d-sub stud
Fluke 189 Fuse Clip replacement - Page 1
Forum section: electronics / repair

author: lushMAFIA
author_rank: Newbie
timestamp: December 20, 2016, 07:26:03 pm
content: Hello everyone.I have a fluke 189 that needs a new fuse clip for the 11A fuse part# 803293I found this parthttps://www.zoro.com/mersenferraz-shawmut-fuse-clip-15a-14-in-panel-600vac-sdc6/i/G2370663/Not too sure about that one just yet.Can anyone point me in the right direction?Bottom right clip. This picture is not of my unit.

author: Fisher77
author_rank: Regular Contributor
timestamp: December 20, 2016, 10:18:09 pm
content: Mouser has 2 differnt numbers. Dont know which one is the one you need.http://www.mouser.com/ProductDetail/Eaton/659524/?qs=%2fha2pyFadujw8Ef53fEcDTPnRTICTmO7sMtKN0mOa2A%3dhttp://www.mouser.com/ProductDetail/Eaton/707190/?qs=%2fha2pyFaduhnx5XPV%252bCi2LUIanZg%252bpYhhJ9IbtogCP0%3dProlly best to call fluke to find out which one 1-800-443-5853

author: retiredcaps
author_rank: Super Contributor
timestamp: December 20, 2016, 11:28:32 pm
content: At $1.15 and 54 cents each, I would get both.

author: lushMAFIA
author_rank: Newbie
timestamp: December 21, 2016, 01:16:58 am
content: Purchased a couple of each. Thanks guys. Ill let you know how it goes.$7.99 to ship.....

author: Fisher77
author_rank: Regular Contributor
timestamp: December 21, 2016, 02:24:21 am
content: Quote from: lushMAFIA on December 21, 2016, 01:16:58 amYep the shipping is the ass kicker, but Mouser was the only place I found that you could purchase individuals. Newark, and Digikey both had a minimum purchase of 1,000.

author: lushMAFIA
author_rank: Newbie
timestamp: December 21, 2016, 10:09:40 pm
content: I will have to say that they are super quick! Ordered yesterday, used standard UPS shipping and they'll be here tomorrow.

author: Fisher77
author_rank: Regular Contributor
timestamp: December 24, 2016, 05:47:33 pm
content: Quote from: lushMAFIA on December 21, 2016, 10:09:40 pmThat is the one thing about Mouser, they don't mess around. They get on the order quick. i have placed an order before, and 20 minutes later get an email that it is ready to ship. The advantage I have ordering from them is I only live 350 miles away from their warehouse. I can get away with using the economy shipping, and usually have my order delivered in 2 days.
Xantrex Inverter - Normal Behaviour? - Page 1
Forum section: electronics / repair

author: edpalmer42
author_rank: Super Contributor
timestamp: December 02, 2016, 06:34:15 pm
content: I picked up a used Xantrex Xpower 1000 inverter. Typical 12V to 115 Vac @ 1000 W modified square wave inverter.Everything seems to be working, but I noticed one odd thing. When it warms up enough for the fan to kick in, the waveform changes; the non-zero part of the modified square wave gets slightly shorter and the zero time gets longer so the frequency doesn't change. A scope shows that the peak voltage isn't changing. A non-true RMS DMM shows the change as a significant voltage drop from 120V to 110V. The output voltage is speced at 115 Vac +-5% so both 120V and 110V are within spec.This is the first time I've played with anything like this. Does this sound like normal behaviour?Thanks,Ed

author: arclight
author_rank: Contributor
timestamp: December 27, 2016, 03:26:54 am
content: Their output waveform will change based on the type of load you apply. For instance, a transformer-style microwave oven will cause it to smooth out significantly. I'd look at what is happening when the fan comes on (i.e. refrigerator kicking on, fans, etc).Arclight

author: edpalmer42
author_rank: Super Contributor
timestamp: December 27, 2016, 05:55:05 am
content: In order to get things warmed up so that the fan would start, I was using a heating element from an electric stove (~43R) to apply about 300W of load. The waveform didn't change until the fan started up.
I need help with a sony/tektronix awg2041 arbitrary waveform generator - Page 1
Forum section: electronics / repair

author: toolnuts
author_rank: Contributor
timestamp: December 18, 2016, 04:11:24 am
content: Hello,Newby here - first time on this forum.I bought an tek arb off ebay, and it has a problem with square waves. on the non-invertedoutput a 10Mhz square wave has a chunk out of the corner of the rising edge/corner, and the decendingedge/corner. I suspected a high frequency problem so I downloaded the service manual and looked upthe procedure for calibrating the HIFREQ, but the the one R253, and C251, and C253 made no differenceat all.One problem it said to use the waveforms off the calibration and verification floppy, and I don'thave that floppy. Would any of you be able to send me a copy of that floppy.Since I didn't have the floppy, I used the pulse function from the Function Generator.I can't find a component level schematic for this device. I called Tek but they said we don't have one any more.Would any of you have a floppy or any advice on how to tackle this problem?I looked at the inverted and non-inverted signal at their respective caps and they look the same,but the non-inverted ouput lookes like PacMan took a nibble out of the rising edge corner andthe falling edge corner. The inverted output look OK, but with some mild overshoot. Mightbe to high a gain somewhere.Any help would be greatly appreciated.Best Regards,Paul Hoffman

author: tautech
author_rank: Super Contributor
timestamp: December 20, 2016, 07:44:57 am
content: Welcome to the forum.Some pics from your scope would help.You can upload them by placing the file in Attachments, the + below the Reply text box.

author: toolnuts
author_rank: Contributor
timestamp: December 21, 2016, 12:16:28 am
content: Here is a scope shot of the square wave (see attachment)

author: tggzzz
author_rank: Super Contributor
timestamp: December 21, 2016, 12:23:39 am
content: What is the source impedance, the cable length, the cable impedance and the terminating impedance? If you assume the velocity of light in the cable is 200e6m/s, what is the length corresponding to the duration of the "rising edge corner"? Compare that to the cable length.I'll bet there is an impedance mismatch.

author: tautech
author_rank: Super Contributor
timestamp: December 21, 2016, 12:55:31 am
content: Is that a 50input indicator on the display ?Without schematics I'd just trace the signal path back through the output stages until you find where the corruption appears, then check all componentry in that area.Another thought, have you checked how clean the PSU supply is in this AWG ?

author: toolnuts
author_rank: Contributor
timestamp: December 23, 2016, 09:05:50 pm
content: Hello all,To answer one question - it's 50 ohm on both ends.It's not very easy to trace out on a 6 or 7 layer board, with all surface mount components, andcomponents mounted on both sides of the board.The inverting output is fine. If I had a schematic I might be able to tell, what in thepath of the non-inverting output might be causing the bandwidth choke.Regards,Paul
BWD 246A Twin Power Supply - Page 1
Forum section: electronics / repair

author: hpxref
author_rank: Newbie
timestamp: December 23, 2016, 03:37:03 am
content: Had three of these through my hands recently for repair/adjustment, including my own one and would invite comments from members who may have experience with these units.Only one of them had actual faults (s/C 2N3055's and shattered Crowbar high VCe voltage regen scr drive transistors.The others just needed setting up as per the manual.However one unit was totally unstable, bursting into oscillation shorty after switch on (Voltage meter goes hard over on #1 and cant turn Vout knob down past half scale with V control)Looking at the others , both working into proper 5Amp resistive loads, I noticed that at least one is just on the verge of instabilitythough needs a CRO on the output to see this, just a small, narrow burst of Rf which does not seem to affect the user controls or calibration.But it seems that BWD had BIG problems in taming instability in all these units??For example there are quality low esr "styroseal" caps soldered underneath the main board which appear to be in different places on each 246A looked at, and not shown in the schematicEven weirder is a long blue Teflon covered wire which snakes out from under the 2N3055 emitter resistor board and returns again via being snagged under one of those extra polystyrene caps several inches down the main board!All three of the units have this which seems to have been a desperate attempt at taming rogue oscillations in the factory.Ive fitted A few Ferrite beads which seems to suppress most tendencies to oscillateWould anyone care to comment on the peculiarities of this model?When working they are fine, low ripple and noise and, given their age, give good service., but are HEAVY !!!Ive had two slaved in parallel and that worked OK.Only trouble ive had with mine was in powering a highly reactive switched inductive load (Kettering type) which made adjustments impossible as the ripple was finding its way into the reg. feedback and rendering it useless, cured by adding an external power diode in series with the 246A output. I don't think the 245's reverse diode across the output (14Amp rated) was fast enough to fully absorb the negative swing caused by the coil turning off.The crowbar circuit was probably meant to be set to just above the output selected, but is not a reliable circuit. BWD mentions it only to be set to trip at 36v via the rear pot. It does work this way but can be set off by load transients fed back to the output terminals. There is an OFF switch on the pot to defeat the crowbar and I suspect most users had this set to OFFCan anyone shed more light on the BWD 24x series?John

author: tautech
author_rank: Super Contributor
timestamp: December 23, 2016, 04:28:50 am
content: What seems to be the last remaining resource for their manuals is Kevin Chanthttp://www.kevinchant.com/bwd.htmlFor your PSU:http://www.kevinchant.com/uploads/7/1/0/8/7108231/bwd_246a_instrument_handbook_sc.pdf
HP/AGILENT 70950A OSA plug in - Page 1
Forum section: electronics / repair

author: jfphp
author_rank: Regular Contributor
timestamp: December 22, 2016, 09:22:34 pm
content: Hello,Did anybody try to repair this optical Spectrum analyzer plug in for the MMS/70K system ? Is there any CLIP available ? I have a slit failure. Thank you
How to power up 6V 6W leds - Page 1
Forum section: electronics / repair

author: rajeshnayak789
author_rank: Newbie
timestamp: December 22, 2016, 02:48:32 pm
content: I have these stuffs and they are kinda 2-3 years old and unused since something went wrong in the circuit. Now I am looking forward to fix these things. Apart from that I would like to know about how to chose proper battery for specific led devices. These are things that I have atm.transformer,battery,switch and led.Sent from my AO5510 using Tapatalk
Samsung UA32H4000AW LED TV Backlight Very Dim  - Page 1
Forum section: electronics / repair

author: quad
author_rank: Regular Contributor
timestamp: December 08, 2016, 11:46:01 pm
content: Hi,My Samsung 32" UA32H4000AW LED TV - backlight is very very dim, can still see moving images on the TV but barely.I couldn't find a schematic online, the board number is L32S0_EHS - BN44-00696BWhat I've tried:EDIT: I think I messed up my testing points. Retested with 3+ to 3- etc.Measured the power to LED strips (top right connector on power supply board), labelled CNL802. The output rating listed is 76V @ 450mAWith TV switched on, and LED strips plugged in:3+ -> 17.45 V2+ -> 14.8 V1+ -> 61.5 VWith TV switched on, and LED strips unplugged:3+ -> 0 V (in the mVs)2+ -> 0 V (in the mVs)1+ -> 0 V (in the mVs)All measurements taken with the negative probe connected to the corresponding "-" point e.g. 3+ to 3-. 2+ to 2-And TV switched on, LED strips unplugged, this time measuring 3+,2+,1+ to chassis3+ -> 130 V2+ -> 0 V1+ -> 0 VSo I think it's a power supply board issue.Any ideas? ThanksHigh res photos:Back of TV:https://postimg.org/image/eq68hb75r/Front of power board:https://postimg.org/image/b4m3q2tt5/Back of power board:https://postimg.org/image/kemcz2ly1/

author: KhronX
author_rank: Frequent Contributor
timestamp: December 22, 2016, 01:13:57 pm
content: You might want to check if both rectifier diodes are ok (you'll need to desolder one end of one of them, to be able to test them separately), DM854C and DM856C. Possibly D9151C as well.That being said, i don't 100% trust CM856 and the one above it, either (the 250v electrolytic capacitors next to the above-mentioned diodes.It looks like they've included a handy current shunt, to measure the total LED current as well. See that red polypropylene(?) cap between L9151CS and CNL802? On the back of the board, between TP1 and TP2 there's a parallel pair of 2resistors, so measuring across those on the mV scale will give you a mA figure.
zurich dps-1512m power supply - Page 1
Forum section: electronics / repair

author: Nemo1956
author_rank: Contributor
timestamp: December 07, 2016, 02:19:50 am
content: Has anyone done a repair on one of these power supplies?Mine has gone tits up and will not regulate the voltage. I set it to 13.8 volts bub as soon as I put a load on to it at just 3 amps the voltage will drop to 7.2 volts.Anyone got a schematic for this unit?

author: Nemo1956
author_rank: Contributor
timestamp: December 21, 2016, 02:10:37 am
content: Just let you all know I have repaired this power supply now. The fault was a electrolytic capacitor that had gone intermittent internally.Never had that before.Interesting fault. It would work then not work, but found that by moving the components with a light tap I closed it down to one cap. Each time I moved it, it would ether work or not work. I just re soldered it to begin with but that made no difference. So I replaced it. Now its working correctly all the time. I tested the cap and found again when I moved the + lead it would stop working as a capacitor.I've have had bad solder joints before but not and internal intermittent connection on a capacitor.Interesting.
TDS430A Attenuator replacement - Page 1
Forum section: electronics / repair

author: dan3460
author_rank: Frequent Contributor
timestamp: December 15, 2016, 02:06:50 am
content: I got this scope a few day ago and today I started to work on it. Took me almos 2 hours to clean this thing, it looked like was left on a barn and had a ton of dust. I took the cover, made sure that power supply looked ok and also checked the lytics on the main board, every thing looks ok. I fired up the scope came to life but had 1 fail - Acq/Attn. I followed the troubleshooting procedure and it say to replace the acquisition board, which I suspected.Started to search for the problem, channel 2 I can get full signal. So I wired my signal generator to put the same signal into both channels so I can compare the path as I don't think there is a full schematics for this thing out there. I also setup both channel at the same amplitud, 1V and the signal was a square 3Vpp.Probing the path in both channels I came to a place where was different, actually was signal on channel 2 but nothing on channel one. It is right at the end of the path trough the attenuator, looking at the attenuators from the bottom and counting the pins from back to front is pin #2. On Channel 2 is a signal about 150mv in amplitude, in channel 1 is a flat line about -250mV. I pushed a square wave about 300 mVpp into pin#2 and the scope displays a square wave on channel 1. So clearly is the attenuator, more specific the hybrid sitting there. So my questions are:1- Can the hybrid be replaced?2- Can something be put together to replace the hybrid?3- Can I use an attenuator from other 400 series of scopes, on ebay is a cheap 420?Suggestions welcomed.

author: TAMHAN
author_rank: Frequent Contributor
timestamp: December 15, 2016, 04:22:56 pm
content: Hello,for this kind of detail questions, the Yahoo Group of Tek owners AFAIK is better. There are a lot of Ex Tek guys there...

author: dan3460
author_rank: Frequent Contributor
timestamp: December 16, 2016, 11:46:22 am
content: I posted the question on the Tek group but I have not gotten any answers. My urgent question at this point is if a attenuator from a 420 would work on this scope? The 420 is a 100 MHz scope (I think) and this one is 400 Mhz.

author: voltsandjolts
author_rank: Unknown
timestamp: December 18, 2016, 07:55:39 pm
content: FWIW I have replaced an input hybrid on a TDS3034B and it worked - so, no verification of the input ASIC serial number by the main board.For 70 bucks this has got to be worth a try?http://www.ebay.com/itm/Tektronix-TDS420a-circuit-board-assy-attenuator-671-3595-00-/322350570742?hash=item4b0d975cf6:g:UkgAAOSwZVlXn~lZ

author: dan3460
author_rank: Frequent Contributor
timestamp: December 19, 2016, 12:33:55 pm
content: I have a TDS420A that I purchased for $25. My main concern is not that it will work, is that the design of the attenuator will not take 400MHz. I just wanted to get assurance before I go taking the attenuator from the 420 (200 Mhz) and putting it on the 430, there is a lot of pins to de-solder.
Hantek DSO5072P - Page 1
Forum section: electronics / repair

author: Bernardo Lucas
author_rank: Newbie
timestamp: December 20, 2016, 10:38:27 pm
content: HelloI have a Hantek DSO5072P oscilloscope. Initially I had a problem with the backlight that I was able to repair. At this juncture where the backlight was faulty the whole oscilloscope functioned normally. But now he has another problem after being accidentally turned off while starting. It was all uncalled and unconfigured, when I try to calibrate it always goes wrong. Can someone help me with my problem?I think that if I did a full reset and loaded firmware again the problem was solved, but I do not know how I can do it or if it is possible.
E3634A repair and need firmware - Page 1
Forum section: electronics / repair

author: vtp
author_rank: Regular Contributor
timestamp: December 18, 2016, 11:35:13 am
content: Would anyone happen to have later than version 1.6 firmware for the Agilent E3634A PSU?According to the crappy BOM in KS parts site there should be later available from somewhere, but certainly not from KS according to my experience with them. For some products their support seem to suck.I have a couple of these in pieces in cardboard boxes and would like to update the FW on the same go as they get repaired otherwise. Blown current shunt, melted pass transistors, blown opamps etc...

author: carl_lab
author_rank: Frequent Contributor
timestamp: December 18, 2016, 01:37:14 pm
content: What's the benefit of the "newer" firmware?I worked with different E36xx and never noticed a problem by firmware bugs...

author: vtp
author_rank: Regular Contributor
timestamp: December 18, 2016, 04:10:28 pm
content: One unit had a broken rotary encoder. It did not take too long to find out what appears to be identical replacement for the original ALPS encoder.Bourns PEC16-4015F-N0024 seem to fit perfectly and is available from Mouser and Digikey for a whopping $1 or so each.One thing to note is that the Bourns encoder came with a large washer. I left the washer between the encoder and front panel plastics to make it keep the folding tabs on the encoder body together. I suspect there is some play in the mechanics which allows the shaft support to wiggle and then break the whole encoder. Not it looks to be nice and snug fit.Looking at the schematics has made me wonder what was the idea of putting crowbar behind the expensive current shunt. Pass transistors short -> OVP crowbar on -> eventually very crispy current shunt. The crowbar does not even blow mains fuse and there is no fuse after the mains transformer to blow.
Old fluke scopemeter with LI-ION battery - Page 1
Forum section: electronics / repair

author: dtmf
author_rank: Newbie
timestamp: October 02, 2016, 02:15:08 pm
content: What You Need:1.Power bank box for 1$2.Inductor3.1000uF+100nF capacitors.4.18650 or other li-ion battery5.cell phone charger

author: lamello
author_rank: Contributor
timestamp: October 02, 2016, 03:54:52 pm
content: Hello,I like the idea, but I don't understand what to do.Could you give some extra info?Tia spock

author: SeanB
author_rank: Super Contributor
timestamp: October 02, 2016, 04:46:00 pm
content: Take the 18650 cell out of the power bank and fit in the battery compartment. Then take the power bank end and remove the USB A socket that you would normally plug your USB device into. Then use the inductor and capacitors to make a LC power line filter on the charge PCB. Cut the end of the power bank off and fit into the scopemeter in place of part of the battery compartment door, so you can plug in a regular micro USB phone charger ( any semi decent one, just has to provide 5V at 500mA) to charge the cell. The original 4V8 4 cell power pack connectors are now connected across the capacitor you added, so the scopemeter now runs off this filtered 5V supply from the power bank.Charge the unit with the cell charger and when full you unplug and use as normal. Runtime will be somewhat longer, but there will be no real low battery indication, it will just turn off after the cell protection disconnects the load.

author: dtmf
author_rank: Newbie
timestamp: October 02, 2016, 07:42:07 pm
content: SeanB is 100% right.I use 2x 2500 mAh in paralel (removed from android tablets).

author: lamello
author_rank: Contributor
timestamp: October 10, 2016, 12:16:09 pm
content: Thanks for the info.Just one question. With this modification, can i still use the 15Volt adapter?TIA lamello

author: SeanB
author_rank: Super Contributor
timestamp: October 10, 2016, 08:30:01 pm
content: No, you have to use a cellphone charger, the charge circuit will not work with voltage applied to what is nominally the 5V output.

author: lamello
author_rank: Contributor
timestamp: October 10, 2016, 09:31:21 pm
content: Thanks SeanB,I understand that the recharger in the pm97 will not charge the li-ion battery.But my question was about safety. Can there be a hazard, like a fire li-ion battery, if the 15 volt adapter is connected?TIA lamello

author: dtmf
author_rank: Newbie
timestamp: December 24, 2016, 08:03:58 pm
content: China power bank with universal IC FM6316 is bad idea. Burned after few hours.Next attemptTwo independent modules: charger and DC/DC step UP with MT3608 (2A output)

author: Samogon
author_rank: Frequent Contributor
timestamp: December 25, 2016, 05:57:09 pm
content: Why just dont use new battery?
Solartron 7150 input impedance - Page 1
Forum section: electronics / repair

author: wn1fju
author_rank: Frequent Contributor
timestamp: December 17, 2016, 06:53:30 pm
content: I just got a Solartron 7150W. Even though the front panel says 7150, the nameplate on the back has the "W." I don't know what that means.Here's the puzzlement: I was under the assumption that the input impedance on VDC is supposed to be >10G on the 0.2V and 2V ranges, and 10M on the 20V, 200V, ... ranges (maybe this is my mistake!). But my input impedance is 10M on ALL ranges. I verified this by putting 1V through a 10M resistor into the unit and got a 0.5V reading. So naturally I suspected the relay that switches in the attenuator was stuck. But the relay checked out OK, so I suspected the ULN2003 driver. But that also checked out OK. The ULN2003 is driven directly by the HD68P01 microprocessor and so I suspected a stuck line. But the voltage on the line goes from TTL high to low when I switch the 7150 away from DCV mode. So the line isn't stuck. The meter is simply being directed to leave the attenuator in at all times (so on low ranges, it is in parallel with another closed relay directly putting the input into the FET amplifier).I cannot believe that the program is corrupted, since everything including the cal procedures, work fine. It's almost like it's supposed to work this way. Is this what the "W" in 7150W might mean? Does a normal 7150 have 10M input impedance on all DCV ranges?

author: wn1fju
author_rank: Frequent Contributor
timestamp: December 17, 2016, 08:44:01 pm
content: Oops, never mind. The >10G input impedance on the 0.2V and 2V ranges is for the 7150plus version. The straight 7150 says 10M for VDC without distinction as to the ranges. So it's supposed to work that way. Pretty lame.
power designs 6050b manual  - Page 1
Forum section: electronics / repair

author: crazyhog
author_rank: Regular Contributor
timestamp: November 29, 2016, 12:26:13 pm
content: Does anyone have a copy of Power Designs 6050B power supply service manual and schematic? I'm trying to repair my 6050b. I couldn't find a free copy on the web. The ebay equipment manual sellers are charging quite a bit. The price of 2 manuals is closed enough to buy another PS.Thanks.

author: mc172
author_rank: Frequent Contributor
timestamp: November 29, 2016, 12:34:00 pm
content: Does this help?http://techobsessed.net/power-designs-manuals-and-schematics/

author: crazyhog
author_rank: Regular Contributor
timestamp: November 29, 2016, 12:46:49 pm
content: No, unfortunately its no good. Each Power Designs variants is very different from the previous one. I've already studied the schematics of 6050, 6050A and a partial and poorly photographed 6050B (my). They all have major differences. Much time was spent on google and bing and still no luck.Thanks.

author: dan3460
author_rank: Frequent Contributor
timestamp: November 29, 2016, 04:21:59 pm
content: It is really hard to find schematics for power design. I have a unit, don't remember the number, that I spent a couple of days trolling the internet for schematics. I could not get nothing close. Then I tried to reverse engineer but there are a lot of parts going up and down of the board, spent several hours working on that and I gave up. Now the unit is sitting on a shelf.Does anyone knows if Power Design, had a repository of the schematics somewhere? Maybe is an old timer that worked there that remembers? Maybe those can be rescued.

author: crazyhog
author_rank: Regular Contributor
timestamp: December 19, 2016, 01:07:28 am
content: Found the schematic for 6050B. Leaving a copy here in case anyone is interested.
Emag 20HC ultrasonic cleaner - Page 1
Forum section: electronics / repair

author: pingodeluxe
author_rank: Newbie
timestamp: December 16, 2016, 07:30:42 pm
content: Hi,I have a Emag 20HC which is broken.Before it broke, it had a fuzzy sound after it was turned off, as if something was boiling inside of it.Is there someone who know what is can be ?/Pingo
01005 resistor kits - Page 1
Forum section: electronics / repair

author: orbiter
author_rank: Frequent Contributor
timestamp: December 16, 2016, 12:38:52 pm
content: Anyone got any sources for 01005 resistor & capacitor kits please? I can find them on RS butthere's an 11 week lead time on them.Thank you

author: rob77
author_rank: Super Contributor
timestamp: December 16, 2016, 01:10:30 pm
content: 01005 for manual assembly/prototyping ? i think you must be kiddingat least i wouldn't go to anything below 0402 for manual work. i hate even the 0402 but was forced to go for such small decoupling caps in my latest project.

author: orbiter
author_rank: Frequent Contributor
timestamp: December 16, 2016, 01:17:47 pm
content: I use them for iPhone repair and getting a bit fed up with wasting time buying donor boards to remove them from.. A kit or two would be far quicker.Sent from my HTC One using Tapatalk

author: rob77
author_rank: Super Contributor
timestamp: December 16, 2016, 01:24:36 pm
content: Quote from: orbiter on December 16, 2016, 01:17:47 pmthen i would just buy the values present on the boards..it won't be too many values - BOMs are always optimized for the least different components possible.however those 01005 resistors are pretty expensive compared to the standard stuff... and for example farnell doesn't even stock them in europe and you have to pay the 25$ fee for shipping from US.

author: orbiter
author_rank: Frequent Contributor
timestamp: December 16, 2016, 02:30:26 pm
content: It would be great if say the different iPhone models used perhaps only a few component values between them, but they differ quite a lot over the 9 modelsthey have. On the iPhone 6 alone there are 16 different resistor values.I think due to the prices of the 01005 style components donor boards are going to be on the cards for some time yetThanks anyway though
Basic Push/Pull amplifier question - Page 1
Forum section: electronics / repair

author: synth-dude
author_rank: Contributor
timestamp: December 16, 2016, 11:22:05 am
content: Hi,I'm fixing up this Audio amp for my brother, symptoms are distorted output, I've worked out via the pre-outs the pre-amp sections are working ok, problem lies in the power amps.I've downloaded the schematic (see below), and it has a push pull power amp stage, with a few filters and things in the final stage.This question isn't really about this amp per se, but rather all push pull amps, why do they have a phase inverters (differential pairs) on the input? I'm guessing this isn't a simple answer, I've looked everywhere online (Googled many different sources) but I cant find a good explanation. Talking Electronics has a great discussion on transistors, and even has a 60W push/pull amp with inverter in their examples, but sadly no explanation what the inverter does, and how it works.Any ideas?Cheers,Chris

author: KhronX
author_rank: Frequent Contributor
timestamp: December 16, 2016, 11:36:39 am
content: What you call "inverter", and what is actually / indeed a differential pair, is one of the main building blocks of amplifiers and operational amplifiers.I'm no expert on the topic, but that stage is what compares the input signal with the signal fed back from the output.https://en.wikipedia.org/wiki/Operational_amplifier#Closed_loophttps://en.wikipedia.org/wiki/Differential_amplifier#Long-tailed_pairDouglas Self has a pretty extensive description and explanation in his "Audio Power Amplifier Handbook".I hope it won't be terribly illegal or harmful to add a few quotes here."The input stage of an amplifi er performs the critical duty of subtracting the feedback signalfrom the input, to generate the error signal that drives the output. It is almost invariably adifferential transconductance stage; a voltage-difference input results in a current output that isessentially insensitive to the voltage at the output port.""Using a single input transistor ( Figure 4.3a ) may seem attractive, where the amplifi er is capacitor-coupled or has a separate DC servo; it at least promises strict economy. However, any costsaving would be trivial, and the snag is that this singleton confi guration has no way to cancelthe second harmonics generated in copious quantities by its strongly curved exponential V in / I outcharacteristic  . The result is shown in Figure 4.2 , curve B, where the distortion is much higher,though rising at the slower rate of 12 dB/octave."

author: Kleinstein
author_rank: Super Contributor
timestamp: December 16, 2016, 01:25:31 pm
content: Most audio amps have the differential pair at the input, because this is the obvious choice to amplify the difference from input and feedback. However there are a few amps that don't use it, but use a circuit more like a current feedback OP. So have the feedback to the emitter.
Frequency counter Philips pm 6662 - Page 1
Forum section: electronics / repair

author: SatanDream
author_rank: Newbie
timestamp: December 15, 2016, 08:45:33 am
content: Hi, allUnfortunately I made a false manipulation with an hf transceiverTwo hs components.I seek the schema or the reference of the two components.Thank you for Help

author: yngndrw
author_rank: Regular Contributor
timestamp: December 15, 2016, 01:14:35 pm
content: Hi Rémy,From a photo I have on my phone, it looks like the resistor is 68 Ohms and the capacitor next to it is 10nF - I'll confirm when I get home and open it up.Thanks,-Andrew.

author: SatanDream
author_rank: Newbie
timestamp: December 15, 2016, 01:29:38 pm
content: Hi, AndrewA big big thank youBest regard

author: PA0PBZ
author_rank: Super Contributor
timestamp: December 15, 2016, 02:21:43 pm
content: In the mean time:http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=Philips/PM6652_6654_Frequency_Counter

author: SatanDream
author_rank: Newbie
timestamp: December 15, 2016, 02:43:18 pm
content: Quote from: PA0PBZ on December 15, 2016, 02:21:43 pmThank you but it is for pm6652Best regard

author: PA0PBZ
author_rank: Super Contributor
timestamp: December 15, 2016, 04:04:14 pm
content: Quote from: SatanDream on December 15, 2016, 02:43:18 pmOops...

author: yngndrw
author_rank: Regular Contributor
timestamp: December 15, 2016, 08:01:27 pm
content: Just opened it up to check, it's definitely a 68 Ohm resistor.As for the capacitor, it says "10n K" on the top and has some text on the face towards the front of the counter, but I could read it without removing the whole board. It looks like the face with the text on it is the opposite side that burnt on yours so you should be able to read all of that. There's no text on the burnt side.Hope that helps.

author: SatanDream
author_rank: Newbie
timestamp: December 16, 2016, 06:46:31 am
content: Quote from: yngndrw on December 15, 2016, 08:01:27 pmHi,Thank you for your kind assistance,I was unable to find the service Manual.For the resistance I will have to find the W, the capacitor normally 250v 10nf.I will return to the forum to indicate the right values.Best regard