hybridfree/eevblog-posts huggingface dataset:
HP 8165a 5v rail - Page 1
Forum section: electronics / repair

author: Tim T
author_rank: Contributor
timestamp: December 28, 2018, 08:00:38 pm
content: Have been working on and off for a year on an HP 8165a that had too many problems to go into detail (tantalum caps, burned resistors, bad zeners, blown 2N2222a BJT, leaky -5v power supply filter cap), but have gotten it back to being usable and am now looking at smaller problems.A reality check would be appreciated if the +5v power supply filter cap, which is a rather expensive 32000 uF 20v electrolytic, is failing (or something else could be going on). The scope probe is at the rectifier output but before the power transistor.I know what the text book waveform of rectified and filtered AC should look like, and this isn’t it. Putting a 15000uF cap in parallel has no effect. Replacing the rectifier diodes (Motorola 1901) has no effect. The cap measures OK for capacitance, and checking ESR by putting a 200 KHz square wave through the cap and looking at the waveform on a scope didn't raise any obvious red flags - though in my experience those two measures don't necessarily mean much unless the cap is quite bad.Thanks,tim

author: wn1fju
author_rank: Frequent Contributor
timestamp: December 29, 2018, 12:38:41 am
content: I'm seeing about half of what you are. The attached photo was taken with the scope AC coupled - the mean DC voltage measured 7.7V. The probe was putacross C1 (the main 5V supply filter cap). The scope is set to 100 mV/div.Of course, I'm not sure if this matters much since it is the 8V unregulated line. The real point of interest is the actual 5V output after the pass transistors andregulation.

author: Tim T
author_rank: Contributor
timestamp: December 29, 2018, 09:52:09 pm
content: Many thanks for the response. I am mostly interested in understanding why the waveform looks as it does and not a classical rectified AC. Yours is similar to mine, not sure why but that tells me something. Have attached picture of AC coupled sampled at same location (rectifier output).thanks again,tim
R&S SML01 Screen Lines - Page 1
Forum section: electronics / repair

author: xtjacob
author_rank: Newbie
timestamp: January 02, 2019, 04:54:03 pm
content: I've acquired an used SML01 for $90 at a swapfest. The guy I bought it from said the only thing that happened when you turned it on was the fan spun up. Well, after some poking around I noticed the cable running to the screen was kind of loose. After plugging it in the screen came up correctly, but has a couple of lines in. I've been trying to narrow down the problem, but I'm uncertain if the issues lies with the display itself, or something on the mainboard running the screen part. I've seen that you can buy new screen modules online, but they're like $100 and I wanted to narrow down the problem before I spent that kind of money...Made an album here (Used imgur so I didn't have to compress the images):https://imgur.com/a/KISoIUd

author: coromonadalix
author_rank: Super Contributor
timestamp: January 02, 2019, 06:40:53 pm
content: Hitachi SP12N002 specs :http://www.panelook.com/SP12N002_KOE_4.8_LCM_overview_16707.html256x64 pixelsDatasheet :https://datasheet.octopart.com/SP12N002-Hitachi-datasheet-13295826.pdfT6963C Equivalent,you will be able to source the same t6963c 256x64 lcd and adapt it, now they have led backplane instead of CCFLOops the 256x64 is not an standard size it seems ?? 240x64 is very standard256x64 lcd i've found :http://www.mini-box.com/picoLCD-256x64-OEMThe pico lcd as a daughter board to be removed, the board is for usb pc display infos etc...This one seems righthttp://1364811.en.makepolo.com/products/256x64-LCD-Display-with-t6963c-p98535292.html

author: coromonadalix
author_rank: Super Contributor
timestamp: January 02, 2019, 06:55:37 pm
content: The test could be made with an 240x64 with led backlight, sure you will loose 16 pixels in height, but you would be sure it's the display and nothing else ??good luckOOOOOOOOOOOOH a thread here check this out:https://www.eevblog.com/forum/repair/rohde-schwarz-signal-gerator-sml-01-dead-needs-repair/But your lcd is working ... the supply lines should be okay ... back to the lcd ...
Wavetek 3510B/3520 - Page 1
Forum section: electronics / repair

author: Slayer666
author_rank: Newbie
timestamp: September 11, 2018, 02:07:16 am
content: Hello eevblog I am new here and I was wondering if anyone has a wavetek 3510b or a 3520 signal generator.I am looking for the eprom dumps/firmware,preferably the 3520 I screwed up on reprogramming the EPROMsany help would be awesome

author: Slayer666
author_rank: Newbie
timestamp: September 18, 2018, 11:20:46 pm
content: And there is also a website called bitsavers.org that you can upload your eprom dumps in case anyone is interested.thanks again

author: dacman
author_rank: Frequent Contributor
timestamp: September 18, 2018, 11:26:02 pm
content: ko4bb.com has manuals for those units, but not ROMs.

author: Slayer666
author_rank: Newbie
timestamp: September 19, 2018, 07:04:26 am
content: Yeah I have the service manuals for them on cd from Artek manuals but seems like the firmware is impossible to find

author: The Doktor
author_rank: Regular Contributor
timestamp: September 19, 2018, 04:50:34 pm
content: What is the difference between a 3510 and a 3510b? I've got a working 3510, and 2 parts/repair 3510s I've never powered on. Don't know if they're Bs or not.Would a 3510 ROM be helpful?Ed

author: Slayer666
author_rank: Newbie
timestamp: September 19, 2018, 08:19:30 pm
content: I believe the difference is internally not a hole lol of difference ,the b version is more identical too the 3520.If you look on the back of the unit it will say on the model and serial number tag what version it is.im not sure if the original 3510 firmware would work on the B versionDusty

author: Slayer666
author_rank: Newbie
timestamp: December 20, 2018, 12:27:30 am
content: Well i guess I’ll have to just buy another one to get the eprom dumps

author: The Doktor
author_rank: Regular Contributor
timestamp: December 20, 2018, 03:47:11 am
content: I can give you a regular 3510 dump, if you tell me how to do it. And if there's any chance of it being useful to you.Ed

author: Slayer666
author_rank: Newbie
timestamp: December 23, 2018, 10:11:24 am
content: Thanks for your reply, you would need a eeprom reader/programmer to read the firmware off of each chip.each chip would have to be removed from the unit and plugged into the reader/programmer one at a time, it’s a confusing task if you’ve never done it before, hope this helps somewhat.Thanks Dusty
Tektronix TLA7012 repair question - Page 1
Forum section: electronics / repair

author: drewscruis
author_rank: Newbie
timestamp: December 22, 2018, 05:07:26 am
content: I'm working on a tla7012, the screen was broken and I've found a replacement. My question is how hard would if be to add the touch screen interface to this? I noticed on teardown that the input for the touch screen is there. But trying to figure out what touch screen I would need seems to be a little sketchy, as the service manual only lists the complete assembly. There is 1 listed on ebay, but it shows a bunch of different style connectors and cable length\styles. I figure it would be easier to do this while it's already apart, any input would be greatly appreciated.Sent from my KFSUWI using Tapatalk

author: DaJMasta
author_rank: Super Contributor
timestamp: December 22, 2018, 07:44:34 am
content: What kind of connector does the screen use? Nicer digitizers use capacitive screens, but unless you need gesture/multitouch support, I've seen test equipment with 4 wire resistive screens too.I'd look for something with its own electronics, or with compatible ones available - something that interfaces with USB, for example, would likely to be very easy to integrate into a system and find drivers for, and you don't have to worry about interfacing with the existing board. Adding it is generally just sticking down the sensor panel to the top of the screen with thin double sided tape, fairly straightforward, but it does add some thickness to the screen and the screen needs to be very clean to apply and not get dust. Replacing phone/tablet digitizers goes the same way, so there are lots of tutorial videos that would be similar to the procedure.You could also look for a replacement screen with a digitizer built in, not generally hard to find these days, but means the replacement you've already got doesn't count for much.

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 22, 2018, 11:31:34 am
content: touch screen is separate unit from monitor. your existing touch screen damaged as well? maybe you can revive it or buy unit with same pin count..ymmv

author: drewscruis
author_rank: Newbie
timestamp: December 22, 2018, 11:49:20 am
content: I have to look again but it was either a 5 or 6 pin .100 pitch connector, I'll take a pic when I get home later. I figured that the hardware to drive it was already there and figured I'd try to keep it simple. This machine did not have the touch screen option installed, but it looks to be that the only thing I need is the physical touch screen and the driver for the os.Sent from my SM-N910V using Tapatalk
Tektronix TDS3012B Date & Time slip - Page 1
Forum section: electronics / repair

author: Gangway
author_rank: Contributor
timestamp: December 19, 2018, 03:31:02 am
content: Just asking if anyone knows if this scope has back up battery for date & time. My unit panel mounted, so pain to open up.Cheers

author: tautech
author_rank: Super Contributor
timestamp: December 19, 2018, 04:30:26 am
content: Not looked but the info is probably here:http://w140.com/tek_tds_3000_series_service.pdf

author: Gangway
author_rank: Contributor
timestamp: December 19, 2018, 07:14:17 am
content: Thanks for link, had already scanned this document, but no info or circuit drawings relating to clock source backup.

author: Jwalling
author_rank: Unknown
timestamp: December 19, 2018, 10:26:12 am
content: There is a Dallas DS1742W PDIP with an internal battery. Yours is probably dying.Part is EOL (Dallas/Maxim sucks!)

author: Gangway
author_rank: Contributor
timestamp: December 19, 2018, 12:04:36 pm
content: Thanks JW, that sounds like the issue, 10 year life span. Will have a look in the new year, cheers mate.

author: Gangway
author_rank: Contributor
timestamp: December 19, 2018, 12:47:27 pm
content: JwJust found your previous reports re this bad NLA chip & other excellent articles about modifying it for external battery cell. Had no idea this chip was a known dud. So when the battery goes flat, I guess the cal data goes.

author: voltsandjolts
author_rank: Unknown
timestamp: December 19, 2018, 12:54:12 pm
content: No, cal data will be fine.I have replaced a 3034B BBRAM with a blank device and was all fine - BBRAM just seems to store instrument setup (timebase etc) and date time.

author: Jwalling
author_rank: Unknown
timestamp: December 20, 2018, 10:39:07 am
content: Quote from: Gangway on December 19, 2018, 12:47:27 pmYou won't lose the factory calibration, but you will lose the SPC constants. You'd have to run the SPC before using the scope.

author: TheNewLab
author_rank: Frequent Contributor
timestamp: December 22, 2018, 02:33:10 am
content: here is a YouTube. explains, and does with clever temp solder of a battery so the CMOS never loses the settingsHowever, if date/time does not keep..and the battery is dead..that means calibration..Others on this forum would know more about the latter
Fluke Ti-45-FT Infrared Camera - Page 1
Forum section: electronics / repair

author: Inverted18650
author_rank: Frequent Contributor
timestamp: December 20, 2018, 10:54:18 pm
content: ---Redacted---

author: DaJMasta
author_rank: Super Contributor
timestamp: December 23, 2018, 03:44:30 am
content: Glanced at a listing for one on ebay that had a power adapter pictured, said 24V 3A. Not sure if it's the right one (there were actually 2 in the picture), but if you can find photos of similar units or can find a manual, finding the input voltage for the camera/charger shouldn't be too tricky, at least. Then I'd look around for batteries sold as replacements and look to see if the voltage/capacity is ever specified.
HP proprietary IC replacement  - Page 1
Forum section: electronics / repair

author: JKKDev
author_rank: Regular Contributor
timestamp: December 21, 2018, 12:00:59 pm
content: HeyI'm looking for any pointers to figure out if I could replace this IC with another.The topology can be seenhere. EDIT:the whole board schematic for reference.From the service manual about the theory of operation:Output amplifier A5U2 is a shunt-feedback differential amplifier whose transimpedance converts the current gain of A5U1 (the other proprietary IC on this board) to a voltage gain at the input of the CRT. The CRT's vertical section is the distributed line type with a 330-ohm terminating impedance.What I'm seeing on the board:-delay line coming in to the A5 board has stabile voltage (A5U1 input)-voltage prior to the A5U2 (A5U1 output) is stabile at exactly 28V as stated in manual-voltage after the A5U2 is unstable between 30V and 50V (should be 40V) - nothing connected to the input of the scopeMy question:-Is it reasonable to assume the input current is stable as the voltage doesn't change?-Can I replace this IC with something currently available?Thank you and have a nice day/night

author: jfphp
author_rank: Regular Contributor
timestamp: December 21, 2018, 01:26:07 pm
content: HP Part number ? Scope ? Is it a maintenance problem for a lot of scopes or do you need just one to repair your scope ?

author: JKKDev
author_rank: Regular Contributor
timestamp: December 21, 2018, 02:06:52 pm
content: Quote from: jfphp on December 21, 2018, 01:26:07 pmHP part numbers:A5U1 - 5081 3022A5U2 - 5081 3024 (the one in question)From what I know they are on the vertical output amplifier boards of HP 1715A and 1725A. They might be in others but I haven't looked too closely.I've seen at least a few other threads with a problem with this IC.EDIT: Never mind I just found asolution
Fluke87III motherboard does not turn on. - Page 1
Forum section: electronics / repair

author: ramijosefer
author_rank: Newbie
timestamp: December 19, 2018, 09:58:56 pm
content: Fluke87III motherboard does not turn on.Good afternoon.I bought a new Fluke 87 III Multimeter Plate, without checking, and when I try it it does not turn on the multimeter.I appreciate any guidance from similar experience, AND / or the motherboard scheme of said multimeter.Greetings.

author: Val Babakaev
author_rank: Newbie
timestamp: December 19, 2018, 11:57:11 pm
content: Hi!https://www.eevblog.com/forum/metrology/fluke-87-iii-full-service-manual/

author: retiredcaps
author_rank: Super Contributor
timestamp: December 20, 2018, 06:19:17 am
content: Let me ask the obvious question ... have you tried a brand new fresh 9V battery?

author: ramijosefer
author_rank: Newbie
timestamp: December 20, 2018, 08:34:28 pm
content: If I tried it with a new 9V battery.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 20, 2018, 09:39:19 pm
content: There was a case of power on or off problem, i think it was the mosfets switching the battery on offCheck the attached image from the service manual : 83_85_87smeng0500.pdf]You may have an similar circuit ??

author: mzacharias
author_rank: Frequent Contributor
timestamp: December 20, 2018, 10:02:43 pm
content: Don't rule out an issue with the battery connector. They often develop problems .If you have not already - check the battery voltage at the circuit board and not at the battery itself.
TS100 fails..!! - Page 1
Forum section: electronics / repair

author: cpposteve
author_rank: Regular Contributor
timestamp: December 20, 2018, 09:48:37 pm
content: Hi all.as the title suggests. my ts100 has failed me. i was busy soldering away when it went cold and the screen disapeared. hmmmm i thought..!! checked the battery and that was fine. when i plug it in it starts drawing around 250-300ma. but stcuk as to what to check.wondering if anyone else has had the same issue.many thankssteve
Hameg scopes how to remove voltage (Y) knobs ? - Page 1
Forum section: electronics / repair

author: elettroluis
author_rank: Contributor
timestamp: December 19, 2018, 09:37:09 pm
content: Hi thereI'm cleaning a Hameg 203-6 I got today, I lubricated the switches and rotary controls, all is working fine now and it got rid of the noise but I encountered a strange problem with the two Y (voltage) knobs.Both, and one especially, are a little hard to turn because they are grinding against the frontal plastic panel.I confirmed this by pressing with a thumb on the panel immediately near the rotary switch and turning the knob. It works perfectly.Releasing the pressure makes the knob rub against the plastic.So my questions are ... how can the knobs be removed ? Considering there is the vernier knob too which should be removed first I suppose.And second... it may be possible to reinstall the knobs just a little shy from the plastic surface to avoid the rubbing ?If that's not possible, maybe I could simply use a light sandpaper on the knob's base to remove 1/10 of millimeter to solve the problem.I tried to look for a video where someone is repairing/taking apart an Hameg hoping to actually see how it's done with no success, I'm afraid of pulling and destroy something.Thanks!

author: Chris56000
author_rank: Frequent Contributor
timestamp: December 19, 2018, 10:55:34 pm
content: Hi!On older Hameg Oscilloscopes, the variable knobs in the centre of the Y volt/div and TB time/div switches are collet knobs, fixed by a clamp arrangement!If you run a fingernail gently around the edge of the inner knobs, you'll find the little red or green caps will lift out of the knobs, revealing a Philips screw you then slacken anti-clockwise to release the inner variable knob, which will allow the outer knob to be removed - it just pushes on.Chris Williams

author: elettroluis
author_rank: Contributor
timestamp: December 19, 2018, 11:38:07 pm
content: Doh !Nice to know !Thank you Chris, I'll try it tomorrow

author: elettroluis
author_rank: Contributor
timestamp: December 20, 2018, 07:17:27 pm
content: I was able to re-positioning the knobs a couple of mm. from the panel and now they turn smoothly.Under the variable knob there is a white plastic disc, and below that there is a nut keeping the Volt/div. knob in place.In case someone else will have the same question in the future, here are some pictures.
Help needed to identify thermistor value in failed Avaya PSU - Page 1
Forum section: electronics / repair

author: alanb
author_rank: Frequent Contributor
timestamp: December 18, 2018, 10:50:12 am
content: I'm repairing the failed PSU in an Avaya IP office 500. The inrush limiting thermistor appears to have failed, the markings are S.10 K275. Can any one tell me what the resistance value when cold should be or alternatively the equivalent part number on Farnell or RS websites?Thanks in advanceAlan

author: perieanuo
author_rank: Frequent Contributor
timestamp: December 18, 2018, 08:18:18 pm
content: I'll have to check but view the code you're sure it's the PTC inrush?For me that code is the parallel varistor 275V that protect from over voltageEnvoyé de mon iPad en utilisant Tapatalk

author: alanb
author_rank: Frequent Contributor
timestamp: December 18, 2018, 08:22:38 pm
content: The code is correct but it is possible that I've wrongly traced how it is connected. I don't have the psu with me so I won't be able to check until tomorrow.

author: perieanuo
author_rank: Frequent Contributor
timestamp: December 18, 2018, 10:12:08 pm
content: http://www.produktinfo.conrad.com/datenblaetter/500000-524999/500592-da-01-en-Scheiben_Varistor_S10K275.pdfRemove it and check the fuse and bridge and chopper transistor then power on.you had an voltage spike or some 380V on your psEnvoyé de mon iPad en utilisant Tapatalk

author: alanb
author_rank: Frequent Contributor
timestamp: December 19, 2018, 08:48:12 am
content: Thank you Perieanuo, you are correct. It is the a Varistor for over voltage protection.Unfortunately this is not the cause of the fault so I need to continue fault finding on this psu.
Metalwork for Tektronix 7854 - Page 1
Forum section: electronics / repair

author: perdrix
author_rank: Frequent Contributor
timestamp: December 19, 2018, 04:10:58 am
content: I just acquired another 7854 (Wot? Not another 'scope?).In its previous history someone has removed the bottom and side covers from the power supply (200-1262-00, 200-1906-00, 200-1263-01). Also used in the 7834, 7934 and 7104.Does anyone have these parts available (ideally in Europe)? Or a spare 7854 PSU?Meantime I'll continue struggling to remove C154 (which has leaked) from the power supply (rusted screws).Dave
Please help ID this chip? - Page 1
Forum section: electronics / repair

author: TrippySquidsman
author_rank: Newbie
timestamp: December 17, 2018, 10:24:29 pm
content: Hi guys and gals, hoping for some help here. Three of these chips on the motherboard of my MSI laptop and the one pictured in the center of the pics is the troublemaker.Some power-type chip. 4309 RQ91T. It's sitting right after the power jack (alongside a partner as seen in first pic)- there's another one down near the battery connection too.It seems to be dead, an internal short or something. Gets nice and toasty with minimal power so I'm hoping that's all that is stopping the board from working.However I can't find a single clue about what it is, google returns nothing relevant and a replacement board is upwards of AU$800 so I'm desperately hoping that I can replace the chip and maybe luck will be on my side.Thanks for any assistance!

author: wraper
author_rank: Unknown
timestamp: December 17, 2018, 10:30:30 pm
content: SM4309PSK MOSFEThttp://www.sinopowersemi.com/temp/SM4309PSK_datasheet.pdf

author: TrippySquidsman
author_rank: Newbie
timestamp: December 17, 2018, 10:32:55 pm
content: You're amazing, thanks very muchHow'd you find it so quickly?

author: wraper
author_rank: Unknown
timestamp: December 17, 2018, 10:42:01 pm
content: Just googled '4309 mosfet'.

author: oPossum
author_rank: Super Contributor
timestamp: December 17, 2018, 10:43:00 pm
content: It matches the pinout of a SO-8 MOSFET. Pins 1,2 and 3 connected together. Pins 5,6,7, and 8 connected together.Search for 4309 MOSFET.

author: perieanuo
author_rank: Frequent Contributor
timestamp: December 18, 2018, 08:20:47 pm
content: Mosfet, if you see 4 pins together on one side,3 pins together on the other one even if you're not a genius you realize it's a transistor and what else but a mosfet used as commutingEnvoyé de mon iPad en utilisant Tapatalk
Ersa Icon 1 - Page 1
Forum section: electronics / repair

author: Theboel
author_rank: Frequent Contributor
timestamp: December 17, 2018, 11:28:18 pm
content: Hello All,I got two ersa icon 1 without solder head (ersa I tool) but when I looking for the solder head I realized the cost for solder head send to my country is unbelievable high.so I thinking about use more common head solder with 24v supply. any of the EEV member here have experience have done this "mod"its easy to find the head solder with 24v supply but I have doubt about the temperature sensing and movement sensing if any of you have idea please let me know.Thank YouAnton

author: Rasz
author_rank: Super Contributor
timestamp: December 18, 2018, 12:36:02 pm
content: if its anything like nano it will have tons of electronics in the hand piece = not reusable with generic irons = sell and buy something else, because the only thing you could salvage would be transformer

author: branadic
author_rank: Super Contributor
timestamp: December 18, 2018, 05:01:50 pm
content: You can sell one unit and buy a new i-Tool 150W (0100CDJ).https://www.ersa-shop.com/ersa-l%C3%B6tkolben-itool-150w-p-224.html-branadic-
Ultrasonic Sensor for Car Interior - Page 1
Forum section: electronics / repair

author: NivagSwerdna
author_rank: Super Contributor
timestamp: December 15, 2018, 06:16:43 pm
content: Someonebroke the interior sensor on my Renault Espace today and I'm trying to work out exactly what the part is...In the Espace there are at least two ultrasonic interior sensors (one on each side at the back), might be some further forward as well... not sure about that.Anyway this device when taken out of its housing is 9.8mm diameter and 7.1mm high so quite like MUS-40S or MUS-40E?Are these either Transmitters (presumably to flood the cabin) or Receivers (to detect pertubations)? How can I work out if I have a damaged Transmitter or Receiver?Should I replace the pair?Thanks in advance

author: SeanB
author_rank: Super Contributor
timestamp: December 15, 2018, 06:45:18 pm
content: Probably will work with either, so just buy the transmitter and put it in, it will at least work there as either transmitter or receiver, with only slightly less sensitivity if you have it wrong.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: December 15, 2018, 07:04:46 pm
content: I found a picture of MA40S4S on ebay which seems to look almost identical to mine but has a red dot. Do you think red dot means sender? or does polarity matter with these and it marks +ve?"S" for Sender? j = September 2003?(Excuse the ignorance... never used these before)

author: fzabkar
author_rank: Super Contributor
timestamp: December 16, 2018, 04:58:18 am
content: https://www.murata.com/en-us/products/productdata/8797589340190/MASPOPSE.pdf?1450668610000https://www.murata.com/en-us/products/productdata/8797589274654/MASPOPRE.pdf?1450668610000The S part is a transmitter (sender) while the R part is a receiver.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: December 17, 2018, 11:08:30 am
content: Do these things have polarity? What is the intention of the red dot on these EBAY ones (which I don't have on my damaged one)?

author: fzabkar
author_rank: Super Contributor
timestamp: December 17, 2018, 07:06:25 pm
content: The datasheet states that you should not apply a DC voltage to avoid migration, so the device cannot be polarised.
TV power connector repair - Page 1
Forum section: electronics / repair

author: mintsoft
author_rank: Contributor
timestamp: December 14, 2018, 11:34:29 pm
content: Hey,I'm attempting to repair my parents TV at the moment, there's a physical connector issue with the DC jack I think as I can hear it crackling and it's very sensitive to movement of the power supply.It's not a normal socket however, I think it's a 7mm female socket, PCB mount, however it's vertically mounted on the PCB (see attached for photo). I've been unable to locate a replacement component from my usual list (rapid, rs, farnell) however I assume I don't know the magic words to put in the search! Does anyone know where I could source a (UK preferred) replacement socket?The TV in question is an LG 29MT31S if that's of any use.Thanks,Rob

author: Shock
author_rank: Super Contributor
timestamp: December 15, 2018, 12:14:50 am
content: First hit I got was this, but confirm it's the exact same thing.https://www.aliexpress.com/item/10pcs-lot-New-DC-Power-Jack-Connector-for-LG-E1945CWA-monitor-driver-board-etc-3-pin/32477313791.html

author: coromonadalix
author_rank: Super Contributor
timestamp: December 15, 2018, 01:53:15 pm
content: Seems the good one ?Maybe take some rings diameters and inside hole measurements and ask the seller ?

author: mintsoft
author_rank: Contributor
timestamp: December 16, 2018, 11:50:30 pm
content: Yeah definitely looks like it; I've ordered some. I was hoping they'd be standard so I could source them from somewhere UK based. I guess that's just not the way things are built these days
a funny/strange   transistor failure - Page 1
Forum section: electronics / repair

author: madao
author_rank: Frequent Contributor
timestamp: December 16, 2018, 04:18:42 pm
content: HiI have a little trouble with Tektronix 568 + 230. Nixie show wrong after a bit time.https://youtu.be/SKMouqQ_ZWYSetting of curve tracer: 10V horz, 1mA vert.This transistor is silicium, type 2N3877.Massive thermal runaway with only 30mW power.best regardsmatt

author: duak
author_rank: Super Contributor
timestamp: December 16, 2018, 07:18:07 pm
content: I have found a few transistors that develop collector to base leakage that looks similar to what you observe. Leakage increases at high temperatures and so as the transistor gets wamer, the collector current increases and the temperature increases and so on. The transistor should be replaced but you may find that a resistor between the base and emitter to divert the leakage current may help. I don't have the circuit so I can't say what value, but I would try 2K2.That transistor is quite old and the processing or manufacture is not as good as more modern devices.Cheers,

author: madao
author_rank: Frequent Contributor
timestamp: December 16, 2018, 07:33:17 pm
content: correct, leakage between collector and base is reason for thermal runaway.This transistor are driving by RTL logic-gatter, it should not be a problem. I'll replacing soon all 2N3877 by MPSA06. Why, because it is third failure of nixie drive transistor. (all three transistor have same failure)best regardsmatt
Please help with circuit parts - Page 1
Forum section: electronics / repair

author: Berserk
author_rank: Contributor
timestamp: December 15, 2018, 09:32:07 pm
content: Hello, please can anyone help to identify some burned circuit part in sсheme on F103CBT6?Board from electrical scooter ninebot was probably damaged due water short circuit in the connection between board and wheel, current state of board blinking red diode.Photo of burned part of a board, sot23 marking A7I - probably bav99, other sod123 marking 3Mᶸ some zener diode?

author: Wimberleytech
author_rank: Super Contributor
timestamp: December 16, 2018, 01:14:11 am
content: https://www.st.com/en/microcontrollers/stm32f103c8.htmlLooks like a bipolar or mosfet with something else. Trace the connections to the micro linked above and see if there are any clues.
Compenent reference  - Page 1
Forum section: electronics / repair

author: yalect
author_rank: Regular Contributor
timestamp: December 13, 2018, 10:19:59 pm
content: Hi, I would like to ask you if you can tell me the reference number of this part because it's damgedThank you

author: yalect
author_rank: Regular Contributor
timestamp: December 14, 2018, 10:30:57 pm
content: Thank youDatasheet if that possible for marvell maufacture.

author: fzabkar
author_rank: Super Contributor
timestamp: December 15, 2018, 09:06:26 pm
content: If there is a serial flash memory at U12, then it would be easier to transfer this part to a replacement PCB. OTOH, if U12 is unpopulated, then you will be in trouble because the ROM firmware and "adaptive" data are stored within the embedded flash of the MCU.hddoracle.com and hddguru.com are good sources of information and firmware tools.Seehttp://www.hddoracle.com/viewtopic.php?f=56&t=2600
Philips MMS 222/00 stereo speakers issue - Page 1
Forum section: electronics / repair

author: dav
author_rank: Regular Contributor
timestamp: December 09, 2018, 12:12:26 pm
content: This set of speakers is making me crazy!It's a PC stereo speakers with internal 220V power supply, a switch and a green LED.Amplifier circuit is based on TA8227P.First of all I cannot shut down the speakers with the switch (LED is always on).Audio via the right speaker is good, but left speaker just makes a 100Hz noise.The TA8227 is very hot, expecially pushing the switch.I know, the trash is the easiest way, but I want to learnChannel 1 of the TA8227 is connected to the left speaker, Channel 2 to the right.Regarding typical voltages on TA8227 pins (from datasheet), I have different values.Powering via an external 9V DC power supply:TERMINAL 1 2 3 4 5 6 7 8 9 10 11 12Vcc2 OUT1 BS1 GND NF1 IN1 IN2 NF2 RIPPLE BS2 OUT2 Vcc1TYPICAL: 9 4.5 8.7 GND 0.7 0.03 0.03 0.7 5.0 8.7 4.5 9ME: 5.6 8.9 7.0 GND 1.38 0.03 0.03 0.59 3.3 5.26 2.77 9 (w. power button NOT pressed)ME: 8.9 8.9 8.7 GND 1.35 0.03 0.03 0.57 4.9 8.5 4.5 9 (w. power button pressed)

author: dav
author_rank: Regular Contributor
timestamp: December 09, 2018, 12:26:52 pm
content: Based on the attached pic, input signals on both channels (IN1 & IN2) seem to be fine.Powering with an external power supply, the 100Hz noise on the left speaker disappears, but audio is very very very low.I already replaced C9, C11, C15, C17 with brand new caps, but nothing.I also tried to send IN-2 signal to IN1 input but nothing to do: OUT1 is always very very very low.(I lifted both C7 and C8 negative terminals and applied IN-2 to C7 negative terminal)I also don't undestand why I wasn't able to remove the 100Hz noise on the left speaker after replacing C17. It disappears only when powering with the external power supply.Thanks to anyone will help me.

author: Chris56000
author_rank: Frequent Contributor
timestamp: December 10, 2018, 12:15:43 am
content: Hi!Your fault is indicative of a partial failure in one half of the TA8227 output amplifier IC!This device contains two separate amplifier sections with a common ripple compensation/standby arrangement common to both internally with each section's output providing each channel's drive to the appropriate loudspeaker.A partial failure in either section will load the speaker unit's internal power supply resulting in a larger than normal 100Hz sawtooth ripple on the power–supply LT line which the remaining good half of the device will amplify, causing the hum and buzz you're troubled with!This is also why the speakers don't appear to go silent on the power switch, because the faulty amplifier section is not shutting down as it should!Replace the TA8227 with a new one and you should be well on your way to enjoyable listening, but please post back if still stuck!Chris Williams

author: dav
author_rank: Regular Contributor
timestamp: December 14, 2018, 07:55:44 pm
content: Thank you.I ordered a brand new TA8227.
Memory card for Injection machine - Page 1
Forum section: electronics / repair

author: digsys
author_rank: Unknown
timestamp: December 14, 2018, 02:05:04 am
content: Has anyone ever come across one of these type CF? memory cards? I've literally searched the planet and found nothing.It is form a 8+ yr old Nissei Injection moulder that I'm fixing. Even their supplier can't get them any more. I can't believe they're custom made!?They're slightly larger than a PCMCIA card and wafer thin. I'm guessing only 16-64MB in size

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 14, 2018, 02:44:43 am
content: just want to get +1 diamond level up in google foo belt... if its worth it... google key: "32 pins m card"... ymmv...https://en.wikipedia.org/wiki/Bee_Cardhttps://www.ebay.com/itm/MITSUBISHI-PLASTICS-BEE-CARD-OTP-ROM-RARE-COLLECTIBLE/302313051762?hash=item4663431672:g:ETUAAOSwH09ZFEVT:rk:1:pf:0https://www.ebay.com/itm/Mitsubishi-BEE-CARD-EEP-ROM/153230864213?hash=item23ad456f55:g:fAEAAOSwORxb0HKR:rk:2:pf:0

author: digsys
author_rank: Unknown
timestamp: December 14, 2018, 05:23:57 am
content: Quote from: MechatrommerAwesome !! The force must be with you :-) .. I tried everything, even picture match. Any secrets you can share ? :-) I need that force ..

author: coromonadalix
author_rank: Super Contributor
timestamp: December 14, 2018, 06:25:19 am
content: woah !! never saw this pinout ...https://en.wikipedia.org/wiki/Bee_Card

author: Mechatrommer
author_rank: Super Contributor
timestamp: December 14, 2018, 11:47:09 am
content: Quote from: digsys on December 14, 2018, 05:23:57 ammaybe the trick is not being too nitpick about particular feature or the name of it. if i have to i will key in the weight or dimension of that thing if i have the info in google foo no matter how silly the keyword is... lucky i counted the pins number and i saw some pictures later on
Fluke PM3380A Problem with Text Position - Page 1
Forum section: electronics / repair

author: Retired2
author_rank: Contributor
timestamp: December 13, 2018, 05:47:12 pm
content: I am wondering if anyone could help me. When I press Text button the display in text is misaligned with the buttons on the right. It is raised about 1/2 inch high. Is there any adjustment that could be made? All other functions appear OK.
HP 1715A PSU repair - Page 1
Forum section: electronics / repair

author: JKKDev
author_rank: Regular Contributor
timestamp: December 11, 2018, 06:54:13 pm
content: It's me againI just got my HP 1715A scope and since the ad stated tested and not working I decided to peak under the curtain before I even attempted to connect it to the mains voltage.It didn't take more than a solid minute to spot a nicely charred pair of diodes. Looking at the schematic its a pair of diodes on the 5V rail used as a bridge rectifier across a center tapped transformer winding. As I was probing for the connections that were supposed to be present on said 5V rail (at this point 9.2V before regulation) I realized it was short circuited to the chassies. Since the only 2 connections on this trace were a 2600 uF cap and a power transistor I checked and sure enough the cap was shorted out.Is it reasonable to assume that the cap shorted out and blew the diodes or should I still be concerned with what's going on down the 5V rail? (Ofc I'll check but I'd rather have another persons opinion on this)Also on this topic... Since I'll have to replace the cap I was wondering what to get? (sure same type, same rating, 105°C) I can't seem to find any caps with this type of layout anymore. Should I just plop another elco in and wire the leads to the appropriate terminals? (the cap is one of those yellowish gray ones on this) Should I also replace all the caps on the PSU board? (I think the answere is yes but I'd rather ask) EDIT: I did find the Epcos axial ones but the price is something else. 4-5x the price of the radial ones.Another thing... The diodes are according to the manual some 400V 750mA power ones but since they operate on a 9.2V AC line I was thinking of inserting some 1N4001 just to test the PSU (no connection to the other parts of the scope so no actual current draw). Am I gonna have another explosion xD?Thank you for all the help and have a nice day/night

author: coromonadalix
author_rank: Super Contributor
timestamp: December 11, 2018, 11:40:50 pm
content: in4001 should do the job but check after the diodes if you have low impedance, shorts ... if everything is fine after the cap change, i think you can try to power it up again ?service manual :https://literature.cdn.keysight.com/litweb/pdf/01715-90903.pdf?id=1863106Not sure about the schematics quality ? maybe you have it already

author: JKKDev
author_rank: Regular Contributor
timestamp: December 12, 2018, 10:32:33 am
content: Quote from: coromonadalix on December 11, 2018, 11:40:50 pmSince I was already ordering all the caps for the PSU I decided to add the diodes aswell. I got some 1N4004 which I hope will do the job just fine. I already have the service manual and as you said some of the schematics are garbage but it's better than nothingAt this point I'm just praying that the transformer wasn't too abused by the fault (fuse on the primary is intact but who knows it might have been swapped...)
Looking for Sangean ATX-800A (or Realistic DX-370) SW radio service manual - Page 1
Forum section: electronics / repair

author: cdev
author_rank: Super Contributor
timestamp: December 11, 2018, 08:18:13 pm
content: Hello,I've had this small Realistic AM/FM+shortwave radio for a long time and its a really good performer for something of its kind, but its really showing its age. It has an issue now with the frequency synthesizer tuning on shortwave. It could be an aging capacitor, but all the ones that Ive been able to non-destructively test so far (the low hanging fruit) have tested close enough to their marked values to not be immediately suspect.So I am looking for the manufacturers' service manual.The radio is really a Sangean product as it was made by Sangean for Radio Shack - I bought it in 1988 or possibly early 1989, and its described as having "the hardware of an ATS-800A with the firmware from an ATS-800". It was an excellent radio for casual shortwave listening before this issue developed. (the synthesizer won't stop scanning sometimes on shortwave, it works fine on AM and FM)Anyway, it is both a great performer for something of its size, and it has sentimental value for me.
Hakko FM-202 compatible with FM-2028 iron - Page 1
Forum section: electronics / repair

author: Sparky_Freak
author_rank: Contributor
timestamp: December 12, 2018, 04:25:46 am
content: Just wondering if anyone out there has tried to use the FM-2028 iron will work with the FM-202 station and how does one go about getting it to work . I took one up on eBay all I need is a iron and the key card ( lockout card) but I can no longer buy the original iron

author: Rasz
author_rank: Super Contributor
timestamp: December 12, 2018, 08:44:42 am
content: you just plug it in? its officially supported
HP54602b checksum error - Page 1
Forum section: electronics / repair

author: johndczerwinski
author_rank: Newbie
timestamp: December 12, 2018, 03:27:55 pm
content: Hi,I have an HP54602b (150 Mhz/4-channel oscilloscope) that's now getting checksum errors and having lock issues with NTSC signals (see below and attached).Error messages:"Vertical cal factors failied checksum test - defaults loaded""Horizontal cal factors failed checksum test - defaults loaded"Doing some reading, it looks to be the NVSRAM chip, so I'm thinking of doing the following:- Buying a new NVSRAM- program chip with an RAM image I found on the Keysight page- Open up the HP54602b, after discharging the CRT- Un-solder old chip- Solder new chipAm I missing anything? Do I need to re-calibrate the entire device?

author: nsd_c
author_rank: Contributor
timestamp: December 14, 2018, 09:03:17 am
content: Just curious, where did you find a RAM image on Keysight's website? I don't have any actual vested interest, just curious. I have a 54621D, but this is rather different from the older 54602.Also, I don't know if you've found this yet or not, but there are full schematics for the 54600 and 54601 in what HP called a "component level information package," available fromhere. (That link isn't actually working for me at the moment, but an alternative would be thesescanned copies of the schematics.)By the way, I have seen usersreport success in hacking batteries into the existing NVRAM.

author: johndczerwinski
author_rank: Newbie
timestamp: December 14, 2018, 04:29:42 pm
content: Thanks for the information!I got it from the Drivers, Software & Firmware portion of the support site a while ago. Just looked and don't seem to be able to find it again.In case anyone else is looking for it, I've attached it. FYI... It's for the HP54602A and not B
Hello, my AB panel-view HMI plus 600, only the comm green light comes ON  - Page 1
Forum section: electronics / repair

author: nyame
author_rank: Regular Contributor
timestamp: December 11, 2018, 02:05:27 pm
content: Hello, my AB panel-view plus 600 HMI touch screen, only the comm green light comes ON when powered and it does not go OFF, the main touch screen of the HMI does not come ONwill appreciate any technical guidance on how to solve this issue i need it to power up fullythanks
Non polarised cap replacement suitable for audio - Page 1
Forum section: electronics / repair

author: Hawke
author_rank: Contributor
timestamp: December 09, 2018, 08:50:15 pm
content: Looking for a replacement of np caps in crossovers. The NP caps in my speakers have taken a dump after 25 years so they lasted a while. I was just going to replace them but started thinking about other longer lasting caps. Problem is they are used for frequency response. I'm sure someone has hit this problem before so before banging my head looking at data sheets I thought I would ask. What if any replacements would offer longevity whilst still doing the job on the crossovers.

author: commongrounder
author_rank: Frequent Contributor
timestamp: December 09, 2018, 08:55:47 pm
content: If there is space, you can replace them with film capacitors of the same value and voltage rating. They will be much larger than the electrolytics, but will last longer. Be prepared for sticker shock, though. A number of companies make them targeted at the crossover market.

author: Hawke
author_rank: Contributor
timestamp: December 09, 2018, 09:21:24 pm
content: Thankyou for the reply. You're not wrong about sticker shock I googled just the film caps first they all were cheap but add audio to the Google search and it's all dollar signs. Big ones. I found this article where someone has tested a good range of caps for audio it's an interesting read. CheersHere's the link incase anyone is interested.https://www.diyaudio.com/forums/parts/117452-polar-electrolytic-vs-polypropylene-film-capacitors.html

author: Tim88
author_rank: Regular Contributor
timestamp: December 11, 2018, 07:30:13 am
content: I use Nichicon UFG bipolars.Whoops, I meant DB-GB Series.
Push-button switches to rotary selector - Page 1
Forum section: electronics / repair

author: OhMagoo
author_rank: Newbie
timestamp: December 10, 2018, 05:35:03 am
content: Hi all!New guy here, seeking help to convert 4 push-button switches into one rotary selector switch. This is on an old Craig H340, which has (imo) a very ugly set of 4 selector switches for the different inputs.http://img4.imagetitan.com/img.php?image=19_craig_h340_switch.jpgWhen a switch is off, it's two poles to the left will be connected to it's two poles in the middle(output). When the switch is pressed into the on position, of course the two middle poles connect to it's poles on the right (input). All output appears to go out through the middle poles on the tape switch.Im having a hard time to wrap my head around how to convert this to a single 4 position rotary selector switch. Any help would be much appreciated!

author: z01z
author_rank: Regular Contributor
timestamp: December 10, 2018, 12:44:02 pm
content: If you replace each switch with a DPDT relay, you could simply use the rotary switch to energize one of the relay coils.

author: OhMagoo
author_rank: Newbie
timestamp: December 11, 2018, 05:28:36 am
content: Quote from: z01z on December 10, 2018, 12:44:02 pmNow thats something I would not have thought of. Thank you very much z01z!
Field (near ?) probe identification. - Page 1
Forum section: electronics / repair

author: jfphp
author_rank: Regular Contributor
timestamp: December 09, 2018, 06:47:17 pm
content: Hello,I am facing a puzzling probe with no manufaturer/type. Is it a near field probe ? How can I determine the frequency range ?Thank you

author: philpem
author_rank: Frequent Contributor
timestamp: December 11, 2018, 01:52:05 am
content: Looks like one of the old Chase EMC (later Schaffner) near-field probes.

author: coppercone2
author_rank: Super Contributor
timestamp: December 11, 2018, 02:23:57 am
content: what kind of design is that?Why is there a bunch of ferrite on the coax?what is actually going on there? is that a pulled back antenna (bare wire) with impedance matching balun? whats the PCB do?
Need help finding a microcontroller please - Page 1
Forum section: electronics / repair

author: RandyDarkshade
author_rank: Contributor
timestamp: December 10, 2018, 05:37:52 pm
content: Been awhile since I have been on the forums. Anyway my stepdad, while working on his model railway has accidentally blown the microcontroller for his level crossing gates. It has 12F675 i/p 23 55k M1437 on it and I can not seem to find an exact match as there seem to be many variations of the 12F675. Is there an equivelant controller we could use? Or have I been looking in the wrong places?Thanks in advance.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: December 10, 2018, 05:52:10 pm
content: https://www.microchip.com/wwwproducts/en/PIC12F675Still in productionhttps://uk.farnell.com/microchip/pic12f675-i-p/mcu-8bit-pic12-20mhz-dip-8/dp/9759018I = Industrial Temp Range... P = PDIP

author: ataradov
author_rank: Super Contributor
timestamp: December 10, 2018, 05:53:54 pm
content: "12F675" is the important part. Find the one in the same package and you should be good. Provided you have the firmware file.Other numbers define assembly site and date, this one was made on the week 37 of 2014. But this makes no difference to functionality.