hybridfree/eevblog-posts huggingface dataset:
Fluke 8000A repair [solved] - Page 1
Forum section: electronics / repair

author: rhb
author_rank: Super Contributor
timestamp: May 13, 2018, 11:37:06 pm
content: I was given this and am doing something silly and attempting to repair it. I've got the manual, though the schematic is a challenge as it doesn't tell you what position the switches are in.It works on all the mA DC ranges. But the 200K, 2000K and 20M ranges don't work, nor do the 20, 200, and 1200 VDC and VAC ranges. Shooting up the switches with tuner cleaner helped, but did not solve everything. I then reworked the range switch solder joints, but still no change.You an get as good a DMM from Harbor Freight for free, so this is more just a grudge match than anything else.Is anyone familiar enough with these to offer any hints or insights?Edit: R1, the 2 W 9.9 M resistor in the input divider is failed open. Checks of Newark, Digikey and Mouser did not turn up a replacement. You're actually supposed to replace R1-R3 as a matched set. So it's just parts.

author: Gyro
author_rank: Super Contributor
timestamp: May 14, 2018, 09:50:37 am
content: The resistor will have a 1200V (or significantly higher) breakdown rating too. A couple of possible alternatives...- A close tolerance HV 9.1M resistor in series with a ~800k padding resistor- An 8M2 in series with 1M8 and a ~30M padding resistor in parallel with the 1M8This sort of thing only turns up in DMMs, a check on ebay for either a resistor or donor might yield something (you might get a matched set that way).

author: rhb
author_rank: Super Contributor
timestamp: May 14, 2018, 01:25:15 pm
content: I'm going to offer it for sale in case someone wants parts for a restoration project.

author: fixitanonymous354
author_rank: Newbie
timestamp: May 15, 2018, 12:45:26 am
content: Something like caddock 1776-8 divider could work if it fits
Agilent/HP 8648 B/C/D Firmware re-programming - Page 1
Forum section: electronics / repair

author: USMC_Spike
author_rank: Regular Contributor
timestamp: November 17, 2017, 08:46:14 pm
content: Hi Gents,Anyone have experience reprogramming the firmwareso that after upgrading one or more boards,that is the upgrade options, on the HP 8648 b/c/dthe unit works and functions properly?I think there might be some folks out there,including me, that could benefit from this.Thanks, ?

author: mmaseda
author_rank: Contributor
timestamp: January 09, 2018, 03:24:00 am
content: Did you ever get a response?

author: Melt-O-Tronic
author_rank: Frequent Contributor
timestamp: January 09, 2018, 03:25:13 am
content: I'm interested in this too.

author: USMC_Spike
author_rank: Regular Contributor
timestamp: May 13, 2018, 09:35:43 am
content: Nope never a response and it is needed.Go figure.

author: SaabFAN
author_rank: Frequent Contributor
timestamp: May 13, 2018, 11:03:48 am
content: What kind of processor is used inside the device?Is the way the CPU talks to the rest of the hardware documented somewhere?If not, it'll be quite difficult to reverse-engineer the functions just from the machine code.

author: LateLesley
author_rank: Frequent Contributor
timestamp: May 13, 2018, 11:27:02 am
content: I did a bit of googling, and you all may be interested inTHISSpecifically, it has a Motherboard Utility, where I think you can pick the options added to your device.
HP 6632B @ BAD INT - Page 1
Forum section: electronics / repair

author: Ussovak
author_rank: Contributor
timestamp: May 10, 2018, 07:55:12 am
content: Been reading eevblog post for a long time and everyone seems to have a solution for everything. This is great. Being my first post, I hope I can finally resolve my problem with a HP 6632B.I bought the unit from ebay and when I received the unit, I powered it up and everything seemed good but I did not test every aspect. I turned the unit off for a couple of hours and when I turned the unit back on, I got nothing, - a completely blank display. I check ac power and of course good. I then turned the unit back off and then on, but this time the entire display was on - meaning every character was nice and bright. But the display just stayed that way until I turned the unit back off. Sometimes when the unit is power cycled, I get just a few characters on the display to show for a short period followed by the words "Bad Int". Then the display goes dark. One of the above mentioned is demonstrated with every power cycle but never consistent.Not sure what "bad Int" means. This is my only clue that the unit may be attempting to tell me something. I can't find any reference to it in the service manual. This still does not explain the previous behavior - or does it?Has anyone seen this before?I checked the transformer wiring to confirm it's wired for 110 vac. This is correct. I also checked all of the rail and bias voltages. They are all correct.Can anyone point me in the right direction?

author: tppc
author_rank: Regular Contributor
timestamp: May 10, 2018, 10:00:55 am
content: Hi,sounds like a problem on the interface assembly which is unfortunately not documented in the service manual.Check the connections between front panel and interface assembly.If you have an oscilloscope, you could check- power suply to the processor- logic levels around the processor- Reset signal- opto isolators...Regards.

author: Ussovak
author_rank: Contributor
timestamp: May 11, 2018, 03:00:20 am
content: Thanks tppcI kind of figured this issue was related to the A2 board somehow. But with really no documents regarding the A2 board itself, it looks hopeless. I'll do my best to check the obvious.

author: Ussovak
author_rank: Contributor
timestamp: May 13, 2018, 04:31:04 am
content: Appears the 40 Mhz oscillator on the A2 board is bad. I have +5v on the input and +5v on the output. The oscillator is a GS-165PHC. I compared this reading with another 6632b A2 unit (no one of mine) and theirs was +5v on the input and +2.5 on the output. I assume this means the crystal on my A2 board is shorted? Can anyone confirm this?Now keep in mind I am measuring with a DMM which is probably a NO NO.
Experiments with an induction hob - Page 1
Forum section: electronics / repair

author: Physikfan
author_rank: Regular Contributor
timestamp: May 12, 2018, 06:44:25 pm
content: After an induction hob does not work properly anymore,I intend to do some experiments with it,to find out what might possibly be broken.I hope to find some interest in this forum.

author: Jwillis
author_rank: Super Contributor
timestamp: May 12, 2018, 07:23:04 pm
content: Not sure what make /model you have but I'll wing it.Be interesting to learn what can go wrong since I have one as well. Do you get error codes displayed or is the power totally dead.Start by checking fuses or over heated /burned components.Does the coil looked burned ,check continuity.That's really all I can say without a picture ,wiring diagram,schematic or make and model.
Yamaha EM-300 mixer board troubleshooting  - Page 1
Forum section: electronics / repair

author: Windhand
author_rank: Newbie
timestamp: May 12, 2018, 10:46:58 am
content: Hi all! New to this lovely community and my first post. i'm also a beginner to the world of electronics repair.My band and I recently acquired a Yamaha EM-300 powered mixer board. At first it worked fine then one day there was no sound from the speakers.Sending sound through the 'AUX IN' did produce some barely audible music if the output is turned way up.The other outputs (MON OUT, G-EQ OUT,..), everything before the Power amp, worked fine.Opening the board I first noticed some loose screws, could be they shorted something?I removed them and looked for any signs of a problem. Only thing I could find is this bodged Diode that seemed out of place:Checking theService manualseemed to affirm my thoughts that this is a bodge.My understanding sadly ends there. I shorted the clipped diode to the bodge on and that seemed to jump start something, as now one of the speakers works fine.Could this be the problem? Should I reconnect things according the circuit diagram from the manual?I haven had time yet to check the MA transistors, I did manage to check that bodge diode and it had a FB of 0,3V. Any ideas why this was done?And suggestions on what the next step should be or anything would be very appreciated. Have a great weekend!

author: Andy Watson
author_rank: Super Contributor
timestamp: May 12, 2018, 11:16:53 am
content: There is a relay that connects the signal to the input of both power amps - can you confirm that it is operating? Do you have facilities to measure voltages? If so, check the voltage around TR23/4. Can you identify the diode(s) labels in the bodge - I would guess either D30, D31 or D32.?Do the lamps behind the meters light ? This would confirm that F7 is intact.

author: Windhand
author_rank: Newbie
timestamp: May 12, 2018, 03:15:24 pm
content: Thanks for the reply!I can measure the voltages but it wont be until tomorrow when I can go back to the studio. The lamps behind the meters light up.As far as I can tell, the added diode is an N4007 and judging by the diagram the lower D31 diode is an 1S1555 and the clipped D32 is a 1N34A.I can do some measurements tomorrow and post them here.
New to spectrum analyser is the front end fried? - Page 1
Forum section: electronics / repair

author: Zenwizard
author_rank: Regular Contributor
timestamp: May 12, 2018, 03:32:55 am
content: I am brand new to spectrum analyzers. So please forgive the noobie question. I bought this used and this is the first power up. It looks like it is displaying lots of signal right at DC?. The input is tolerant of a little DC but it really starts working at around 0.15 Mhz. is the front end toasted on this one or is it WAY out of cal? If you roll the pot left the counter jump to 1999.9 so kind of strange. Forgot to mention is it a BK 2630

author: tautech
author_rank: Super Contributor
timestamp: May 12, 2018, 04:38:57 am
content: Welcome to the forum.Well first hit on Google gives some answers:150kHzto 1.05GHz (1050MHz)Datasheet and manual link:http://www.bkprecision.com/products/discontinued/2630-1-05-ghz-spectrum-analyzer-with-tracking-generator.html

author: edpalmer42
author_rank: Super Contributor
timestamp: May 12, 2018, 05:08:45 am
content: That's normal. Most (all?) analog RF spectrum analyzers show a big signal at zero Hz.Rather than try and explain it myself, I'll let the experts do it.https://community.keysight.com/thread/7288Ed

author: Zenwizard
author_rank: Regular Contributor
timestamp: May 12, 2018, 11:59:00 am
content: Thanks for the PDF. Some morning reading with my coffee,. I was was honestly hoping this was user error in reading the device and I did not get a little singed on use gear again. I have had to repair a few things from the lab.
Mains capacitive leakage! - Page 1
Forum section: electronics / repair

author: JS
author_rank: Frequent Contributor
timestamp: May 11, 2018, 10:10:59 pm
content: How much is too much?How much is ok?I've meadured about 15uF today both from neutral and live... Seems a little too much, I didn't took the lamps out but their capacitance shouldn't be going to eart.The section covers an outdoor sector which might have something to do. Rainy days trip the thermomagnetic once and differential protection then, so I shut the section off waiting for nicer days to take a look, now the protections don't trip but I do measure that value which called my attention. I don't know if it was a measurement error as might be quite some noise being picked by the whole line.JS
Attempting to repair a keyboard, but cannot identify the type of rotary encoder - Page 1
Forum section: electronics / repair

author: Razor512
author_rank: Regular Contributor
timestamp: May 11, 2018, 07:40:53 pm
content: I have an old Logitech G510 keyboard which has a failing volume control rotary encoder (volume jumps randomly if trying to adjust, and contact cleaner has not helped much.The issue is that I can't find any company selling this size and shape of encoder.Has anyone come across any that look like this before?I uploaded a few photos of it to imgurhttps://imgur.com/a/ytOabyD

author: Rasz
author_rank: Super Contributor
timestamp: May 11, 2018, 08:17:53 pm
content: https://www.ebay.com/itm/10PCS-Mouse-Encoder-Wheel-Encoder-Repair-Parts-Switch-5mm/271914333594

author: Razor512
author_rank: Regular Contributor
timestamp: May 11, 2018, 09:31:19 pm
content: Thanks, I will give those a try.I will just cut those tabs off and see how well it fits. The shaft seems to be the same size, though the overall width is 0.2mm less, I can put a spacer if needed. That is the closest one physically that I have found so far.I wish they could have gone with an optical encoder since there is more than enough room to fit the hardware needed for it.
Pioneer DJ TAS-1 Toraiz repair - Page 1
Forum section: electronics / repair

author: mjwallin47
author_rank: Newbie
timestamp: May 11, 2018, 05:54:34 pm
content: I'm looking for a repair manual for a Pioneer DJ TAS-1 synthesizer. A encoder that operates the menu display is not working well and probably needs to be replaced. This part is not easy to access and requires total disassembly. I don't want to destroy the thing. A little help would be appreciated.
smps ic identification - Page 1
Forum section: electronics / repair

author: tv tony
author_rank: Newbie
timestamp: May 11, 2018, 12:45:56 pm
content: Hello All,New to this site, been a tv for nearly 45 years. My cooker hob died and I'm stuck, it contains a switch mode psu. The controller is a dual 8 pin, pins 5,6,7 and 8 are deck. Pin 1 is fb, 2 has a resistor down to deck, 3 missing and 4 is to the transformer primary. The missing pin rang a bell (fsd200), but that has pin 7 missing.Any suggestions please, thank you.

author: mariush
author_rank: Super Contributor
timestamp: May 11, 2018, 01:00:13 pm
content: The last cooker thingie I repaired had a VIPER chip (12 or 20, i forget) :http://www.st.com/content/ccc/resource/technical/document/datasheet/3a/e3/ed/c9/0d/16/44/da/CD00084384.pdf/files/CD00084384.pdf/jcr:content/translations/en.CD00084384.pdfSee if yours has same pinout , maybe it's in the VIPER family or a clone.anyways, it was producing 18v for a fan and from there a 5v linear regulator was used for electronics and an 8v linear regulator was used for comparators and opampsthe chip and something else was shot and i couldn't be bothered with it so i repurposed a switching psu from an inkjet printer that was producing 34v and used a 33063 regulator to produce 18v and fixed it.

author: xavier60
author_rank: Super Contributor
timestamp: May 11, 2018, 02:25:58 pm
content: Sounds like a Power Integrations LinkSwitch,https://www.power.com/sites/default/files/product-docs/linkcv_family_datasheet.pdfThe FB accepts AC divided from a winding rather that a DC error signal.But pin 2 is for a VCC ByPass capacitor.
Standard vs Fast Recovery Bridge Rectifier - Page 1
Forum section: electronics / repair

author: forrestc
author_rank: Unknown
timestamp: May 10, 2018, 01:55:35 am
content: I'm repairing a piece of test equipment (HP E4351B), which has a shorted bridge rectifier.The one which is in here is a CRB35F-040P. The 'F' means fast recovery. This particular part has been discontinued, but I can get numerous versions of the same part with "standard recovery" diodes.Since this is a 60Hz power supply (the bridge is connected directly to a non-center-tapped ~120VAC secondary on the main transformer), I'm not sure why one would spec a Fast Recovery rectifier in this application. Especially since it seems to be fairly well filtered with ~3600uF of caps on the DC side.My current plan is to just replace it with a mechanically-identical standard recovery bridge rectifier with at least as good of specs as this one. But before I do, I figured I'd ask to see if there was some esoteric electronic reason why this might be specified the way it is.

author: tautech
author_rank: Super Contributor
timestamp: May 10, 2018, 02:11:16 am
content: Yeah seems weird that fast recovery was used in a linear supply, aren't they noisier ?Yeah I'd be replacing it with an ordinary bridge too.

author: floobydust
author_rank: Super Contributor
timestamp: May 10, 2018, 02:35:38 am
content: I find a fast-recovery rectifier is more important for higher voltages, as slow diode recovery makes more switching noise.Bridge D709, HP 1906-0383 is Taitron RKBPC35-04 35A 400PIV 150nsec trrVanilla KBPC35 I could not find trr, so who knows if it makes a big difference.Agilent E4350B and E4351B Solar Array Simulators Service Manual Addendum A

author: forrestc
author_rank: Unknown
timestamp: May 10, 2018, 03:14:53 am
content: DQuote from: floobydust on May 10, 2018, 02:35:38 amDarn, I missed that document, it's even on the Agilent Website..... Saving for laterAnd RKBC35-04 Seems discontinued as well...

author: David Hess
author_rank: Super Contributor
timestamp: May 10, 2018, 04:49:43 pm
content: Some standard recovery rectifiers suffer from excessive switching noise. If this is an issue, then fast recovery rectifiers can be used or snubbers can be added to the standard recovery rectifiers.

author: floobydust
author_rank: Super Contributor
timestamp: May 10, 2018, 07:01:35 pm
content: I see Agilent/HP has a 0.1uF cap across the transformer secondary, all I find that does is lower the ringing frequency, it's undamped.Better than nothing if slow diodes are used.

author: forrestc
author_rank: Unknown
timestamp: May 11, 2018, 01:12:37 am
content: Well, hopefully I've found a replacement fast diode bridge.... Should be here in a few days.It's interesting that noone makes these anymore even though they generally should be the better solution.

author: David Hess
author_rank: Super Contributor
timestamp: May 11, 2018, 08:04:31 am
content: Tektronix usually did the same thing with a 0.1 microfarad capacitor across the transformer secondary. Some designs place from 220 to 1000 picofarads across each diode which I find works better.
Need help identifying strange looking device (cap, fuse??) - Page 1
Forum section: electronics / repair

author: AlfBaz
author_rank: Super Contributor
timestamp: May 11, 2018, 10:20:40 am
content: I thought we had a sticky thread for this but apparently not, so here's anotherThis board has 2 ohms across the dc bus just before the switching IC.22VAC into some caps, common mode choke, rectifier and large filtering cap.Hanging off the positive side of the cap with the other side heading off back down to the common mode choke area is this device.Any ideas?

author: aargee
author_rank: Frequent Contributor
timestamp: May 11, 2018, 12:19:22 pm
content: There is a thread over in General Chat. I’ve seen these before and assumed they were some sort of transient protective devices?

author: Jwillis
author_rank: Super Contributor
timestamp: May 11, 2018, 09:29:53 pm
content: Polyswitch Re-settable Fuse. Unable to find match sorry.

author: AlfBaz
author_rank: Super Contributor
timestamp: May 11, 2018, 11:50:17 pm
content: Thanks guys. I'll start searching under those terms

author: PTR_1275
author_rank: Frequent Contributor
timestamp: May 12, 2018, 12:07:21 am
content: Search Bourns PPTC and you’ll find the seriesEditLooks like a MF-SM030http://www.farnell.com/datasheets/2038620.pdf

author: AlfBaz
author_rank: Super Contributor
timestamp: May 12, 2018, 12:14:57 am
content: That was quick.It's a Bourns MF-SM Series PTC resettable 0.3A Fuse (030 = 0.3)Bis the Bourns logo and H5 is the date codehttp://au.element14.com/bourns/sm100-2/multifuse-smd-1-1a/dp/9350225?st=resetable%20fuseThanks againedit - PTR_1275, you beat me to it

author: AlfBaz
author_rank: Super Contributor
timestamp: May 12, 2018, 12:22:33 am
content: It is a sticky thread over in General ChatWhat's this please?
Replacing  Variable knob of tektronix tps 2024 (2200 series) - Page 1
Forum section: electronics / repair

author: sean87
author_rank: Regular Contributor
timestamp: May 10, 2018, 05:45:09 pm
content: Hi all,A while back I bought a TEK scope, very nice one...unfortunately after house moving one of its knobs is broken and lost somewhere...to my bad lock, it's the horizontal position knob....I have no idea what to do now. I have never opened this scope as I am afraid to break this wonderful piece of technology and smoke my hard earned spent moneyany ideas??? Is there any replacement on the market (counterfeit is ok or even something that can rotate as!!!). I am in the middle of a very crucial project and I need that thing to rotate as soon as possiblePlease if you have any experience with this kind of scopes please tell me what can I do to move that horizontal position again! is it a huge effort to open the scope and do something about it? e.g. a temporary solution ?!Here are some pictures attached.
Help Pls! Replacement power supply board/Magnavox LED TV didn't work, no power - Page 1
Forum section: electronics / repair

author: Tricia0723
author_rank: Newbie
timestamp: May 19, 2018, 10:46:03 am
content: I have no knowledge of electronics, let me say from the get go! But, I'm tenacious enough to research, order parts and give almost anything a try. I did successfully replace the "other board" on a different TV (where all the ports are), so it only emboldened me to order a power supply board and replace the existing a smaller, older TV. The red standby light will stay on, but TV won't power up anymore after intermittently working. I was advised to replace the PSB. Apparently, that's not the problem, and I really don't know what else to try. TVs don't grow on trees, so I really hope someone can suggest a simple fix. It seems a common problem. Thank you all!
Unkonwn component in smart battery controller - Page 1
Forum section: electronics / repair

author: nuno
author_rank: Frequent Contributor
timestamp: May 08, 2018, 01:55:10 am
content: Anyone knows what is this component marked in the image? This is an ACER notebook battery controller. If they somehow follow the main chip's reference design (ti bq20z95), it should be an "electrically blowable fuse" (a fuse with an "fuse" control line). The 2 chips underneath are FETs.

author: nuno
author_rank: Frequent Contributor
timestamp: May 08, 2018, 03:04:39 am
content: I bit the bullet and took it out of the board. Underneath it saysSEFUSED6T34Abut no results at all turn up on google. I think I'll just bypass it and have my PC battery back since the cells are good and the controller responds on the SMBus...

author: nuno
author_rank: Frequent Contributor
timestamp: May 08, 2018, 03:22:20 am
content: Pfuuuuu, found it...https://www.schott.com/epackaging/english/cutoff/sh_type/d6.htmlD6 TypeSeries: D6T, D6X, D6WXThe D6-type uses a ceramic material for the body (cap and base) andintegrates a resistor as a heater inside the thermal cutoff. Hence, the D6-typecan be activated either when the abnormal temperature increase is caused bythe external environment, or when it is a result of the heat generated by theelectrical circuit within the device. This provides a second protection for theelectrical equipment in which the D6-type is installed.The D6-type is available for 12A and 15A (DC).
Replacing Chip in watson 10-am PSU - Page 1
Forum section: electronics / repair

author: Sel
author_rank: Contributor
timestamp: May 07, 2018, 12:30:31 pm
content: I while back I bought second hand Watson PSU and it's been fine until Yesterday.When I first turned it on with nothing connected to terminals it came on with a loud click but seemed to work fine.I used it for an hour or two only a few seconds at a time with very low load and no shorts.Later when I tried to run a small motor there was a little crackle and smoke came out of the psu.Opened it up and noticed that the NEC C324C chip was sparking if I pushed on one of the legs. It is burnt at the chip not a dry joint to the board.Now the PSU still work but I have no voltage control it's stuck at max 20volts (rec 13.5) but reads zero on the meter, the Amps read as normal 0-20.There's no other obvious fault, when checking theNEC C324Cchip online it tells me it's a Quad op Amp.Do I have to replace it with an exact match or could I use aLM324 DIP-14as these are a little cheaper and easier to get?Any help please.

author: Samogon
author_rank: Frequent Contributor
timestamp: May 07, 2018, 04:36:29 pm
content: Cheaper than 40 cents? Shipment would be 3-5$

author: wraper
author_rank: Unknown
timestamp: May 07, 2018, 05:01:55 pm
content: There is no need to get particularly uPC324 and you can use LM324 as uPC324 is just a yet another flavor of LM324. It does not have LM letters as most other 324 only because NEC used uPC for their analog ICs and uPD for digital.

author: Sel
author_rank: Contributor
timestamp: May 07, 2018, 11:04:40 pm
content: Excellent thanks for the information, I just wasn't sure.
Tektronix 2467B display issues help - Page 1
Forum section: electronics / repair

author: Lightbeing
author_rank: Newbie
timestamp: May 06, 2018, 03:35:47 pm
content: Hello,Just bought a Tektronix 2476B scope and have found a couple of issues so would be very grateful for any help.1 - There are a set of flickering dots in two raws showing at the top and bottom of the screen display.2- When the measure button is selected. The display readout brightness becomes overwhelmingly bright across the whole screen and the brightness becomes uncontrollable by the readout intensity knob apart from turning the measurement off.Many thanks for your help!

author: GerryBags
author_rank: Frequent Contributor
timestamp: May 06, 2018, 06:44:53 pm
content: Hi there, I think you too may have leaky SMD electrolytic capacitors on the control board A5. I had a look at the display troubleshooting chart in the SM, and the ICs it recommends checking (those around U2980 on A5) are near the cap on the left hand side of the board, and is between it and the air outlet.Have a look at this thread (https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/), the 2465B and 2467B have the A5 control boards in common and share a service manual. I'm just fixing a display issue on my 2465B which I've traced to the other side of A5 but the same issue: leaky SMD caps and corroded pins. I have a 2467B that doesn't have this issue yet, but I'm going to change the caps on it's control board at the same time. I've also been adivised to change the NVRAM that holds the cal data, this is also covered in that thread.I think your first step is to have a look at the A5 board, particularly around the electrolytic capacitors near the top of the board. I found that taking a high-res picture of the area allowed me to see things that were beyond my naked eyes, and then you can post it here, too!That extremely useful thread also has links to lots of resources you will find useful, too, you will definitely want the full Service Manual if you haven't got it already.edit to add link to thread I've been raving about

author: Lightbeing
author_rank: Newbie
timestamp: May 07, 2018, 06:21:16 pm
content: Hi Gerry. Thank you for your message and the tips. It was my first time here on the eevblog forum and first time owning a real scope. Well I’m only 57 years young lol.Here is another video showing the issues perhaps more clearlyhttps://www.bitchute.com/video/7w8h3k1Ntc2NThe person i bought the scope from is willing to take it back as it was sold fully working but i am in two minds as to whether I should return it or keep it and repair it.I will definitely be posting photos if I end up keeping it and have the courage to take this gem apart.Thanks!

author: Testtech
author_rank: Regular Contributor
timestamp: May 07, 2018, 10:05:36 pm
content: It might be leaking SMD caps on the control board, if the serial number is B05xxxx or greater. Or, the CRT Bias pot is too far advanced.If it is leaky caps, there are several posts regarding remediation.Be careful with the Microchannel plate crt, it can be damaged by excessive intensity.
Help identifiying these burnt resistors - Page 1
Forum section: electronics / repair

author: OVERPOPULATION
author_rank: Newbie
timestamp: May 06, 2018, 11:54:11 pm
content: For a set of Logitech speakers Z906 resistors R79 and R80. Both are identical and both are fried. I ask because im unsure about the colors. I went to a local electronic components shop and the guy was unsure also. I think light is better on the pictures. Ive found ppl saying they are 5,6Ohm but found also some contradictory.

author: dacman
author_rank: Frequent Contributor
timestamp: May 07, 2018, 02:40:34 am
content: 5.8 Ohm 5%, which is not a common value. 5.6 Ohm is a common value.

author: LateLesley
author_rank: Frequent Contributor
timestamp: May 07, 2018, 05:11:55 pm
content: I actually think they look like yellow gray gold gold, which would make them 4.8, But if the first band is green then it will be 5.8.either way, a 4.7or 5.6respectively would probably do. Looks like they've been used as fuseable resistors, So the next question would be why they burnt up.http://resistor.cherryjourney.pt/

author: Cyberdragon
author_rank: Super Contributor
timestamp: May 07, 2018, 05:40:50 pm
content: I think they were 5.6, they're burnt so blue probably turned gray.EDIT: They could also be yellow green gold, 4.5.

author: Twoflower
author_rank: Frequent Contributor
timestamp: May 07, 2018, 07:16:50 pm
content: I know a nice forum that repairs lots of stuff (I highlighted the interesting part):Quote from: Daniel RR on July 28, 2017, 11:15:42 amHere'sthe full thread.
repair of the intensity control on a tektrionx 317 scope - Page 1
Forum section: electronics / repair

author: KV8E
author_rank: Newbie
timestamp: April 29, 2018, 08:35:00 pm
content: I have a Tektronix 317 scope. the scope works fine except the intensity control has no effect on trace brightness. I have checked the voltages and the 400v unregulated supply is running at 450-460v. the other supply voltages r very close to correct. the voltage across the brightness control pot goes from +40v to 0v with the pot at the most cw position. seems to me the voltage must go - to dim the trace. other than this the scope works fine. any help on this problem??

author: mzacharias
author_rank: Frequent Contributor
timestamp: May 03, 2018, 11:23:54 am
content: https://elektrotanya.com/showresult?what=TEKTRONIX%20317&kategoria=&kat2=schematicsPage 85 of the PDF is where I would start.

author: KV8E
author_rank: Newbie
timestamp: May 06, 2018, 08:08:52 pm
content: think I have and answer to my intensity control problem. the rectifier tube v824 may be bad. I ordered replacements and will put it in when they arrive. will keep all informed of process. kv8e doug
Kelvin Hughes Husun 55 repair - Page 1
Forum section: electronics / repair

author: Ice-Tea
author_rank: Super Contributor
timestamp: May 04, 2018, 09:44:41 am
content: So, I was given one of those for repair, a marine VHF. Well over 30 years old and, well, surprise, it doesn't work anymore. At least not well. Especially sending seems to be hit-and-miss. My first guess was bone-dry electrolytes but at least at first sight seems to be OK.Second guess was the TX/RX relay but that seems to work as well. I'm now focussing on a damaged pushbutton (weird, because I can't find the debris of it but it is certainly seriously damaged....) Problem is, I don't know what it is supposed to do... Anyone know what the D/Watch button is supposed to do?

author: PA0PBZ
author_rank: Super Contributor
timestamp: May 04, 2018, 11:03:31 am
content: I think D/Watch is Dual Watch, monitor 2 channels, one will be the emergency channel 16.What kind of hit-miss are you looking at?

author: Ice-Tea
author_rank: Super Contributor
timestamp: May 04, 2018, 11:34:49 am
content: Ah! That makes sense!Well, sometimes it transmits. Sometimes not. So I figured sticky relay, doesn't seem to be an issue though...Not sure how the D/W switch would cause to many issues with the transmit path :

author: PA0PBZ
author_rank: Super Contributor
timestamp: May 04, 2018, 11:37:34 am
content: So how does it not transmit? I guess you are using the PTT button on the microphone? Does it not react at all on that button or does it just not produce output? Does the TX led light up?

author: Ice-Tea
author_rank: Super Contributor
timestamp: May 04, 2018, 11:41:52 am
content: Excellent questions. Unfortunately, I just got the unit, haven't seen it work or fail in its original setting. And I didn't get the antenna so I'm pretty limited in the testing I can do untill I get my hands on an antenna.

author: PA0PBZ
author_rank: Super Contributor
timestamp: May 04, 2018, 12:09:59 pm
content: An antenna would be a bad idea, what you need is a dummy load and a wattmeter. I'm not sure about your local regulations but here you need some kind of license to operate these things, and really you don't want to random transmit around a bit, not even knowing it the transmitter is on the right frequency.

author: Ice-Tea
author_rank: Super Contributor
timestamp: May 04, 2018, 07:02:39 pm
content: I can hook it up to a CMU200, so I got that coveredMy dad has a license (and, well, the antenna) so if needs be I can bullshit my way out of this. I have a portable VHF as well which could serve as a test receiver.Sure, the CMU would do the job but setting it up properly would be much more fun. Also, if the unit goes in 20W mode the CMU is gone. Hmm, better take a CRTU then...
Mystery Diode? - Page 1
Forum section: electronics / repair

author: SirAlucard
author_rank: Regular Contributor
timestamp: May 03, 2018, 06:23:03 pm
content: Hey all, I'm at a loss in identifying this SMD component. It's found right near a USB connection of a device I'm repairing. It's labeled as D1 unfortunately it's the only D that has 6 pads. Somehow the majority of the chip got broke off and the only identifying thing on it is a "K". The dimensions of the chip are ~2.9mm X ~1.6mm X ~.95mm and From what I can tell the center pin pointed out in the photo below is ground. If anyone can lead me in the right direction into getting this chip replaced. It'd be greatly appreciated.

author: helius
author_rank: Super Contributor
timestamp: May 03, 2018, 06:35:21 pm
content: That will be an ESD suppression/TVS diode marketed for USB applications. NXP, ON Semi, ST, and TI all make these and the pinouts should be compatible.

author: PA0PBZ
author_rank: Super Contributor
timestamp: May 03, 2018, 06:47:15 pm
content: Quote from: helius on May 03, 2018, 06:35:21 pmYes, have a look here:http://www.littelfuse.com/products/tvs-diode-arrays.aspx

author: SirAlucard
author_rank: Regular Contributor
timestamp: May 03, 2018, 09:14:09 pm
content: Here's a bit more info that I could figure out. These are the pin-outs from the USB to this chip.

author: SirAlucard
author_rank: Regular Contributor
timestamp: May 04, 2018, 01:48:07 am
content: So I found this by ON Semi, it nearly perfectly matches the one I took out.https://www.mouser.com/datasheet/2/308/NUP2114-D-120263.pdfHowever couldn't find any from the other manufacturers.
Buck Regulator SMD code BX6L - can anyone identify what it is? - Page 1
Forum section: electronics / repair

author: dicky96
author_rank: Regular Contributor
timestamp: April 27, 2018, 12:50:31 pm
content: Hi folksI'm looking for a replacement partSMD Code BX6LIt's a buck regulator in SOT23-6 pin packageCan anyone identify that? Google is not being my friendCheersRich

author: dicky96
author_rank: Regular Contributor
timestamp: May 02, 2018, 06:01:21 pm
content: Just in case it helps anyone else..... SMD Code BX6L is SY8009B. Apparently. I got that info from another repair forum and have ordered some so will see if they work.Rich

author: lordvader88
author_rank: Frequent Contributor
timestamp: May 03, 2018, 04:37:48 pm
content: We're lucky they put any code on them, I don't think they like us repairing stuff
NEC 1024 uPB403D - Page 1
Forum section: electronics / repair

author: billysdomain
author_rank: Contributor
timestamp: May 03, 2018, 12:14:55 pm
content: Hi,I am repairing a unit which seems to have a non-working bit of battery backup'd CMOS RAM, its an old unit, the device is a 16pinNEC uPB403Dwith1024marked on it (attached pic)I cant seem to find anything regarding this IC, can anyone offer any suggestions for a replacement? or a datasheet perhaps?Many thanks

author: Rerouter
author_rank: Super Contributor
timestamp: May 03, 2018, 12:36:06 pm
content: this looks to be a link to the datasheet,http://www.ic37.com/NEC/UPB40_datasheet_7318505/UPB40_5.html

author: billysdomain
author_rank: Contributor
timestamp: May 03, 2018, 12:39:43 pm
content: Great one, thanks
FUNCTIONS GENERATOR CA 910 - Page 1
Forum section: electronics / repair

author: lionelkjh
author_rank: Frequent Contributor
timestamp: April 25, 2018, 10:49:44 am
content: Hello everyone! I am looking for the value of 2 resistances for a CHAUVIN ARNOUX CA910 frequency generator. Here are their references: R414, R410. This frequency generator is now repaired because his former owner had tinkered with it. Another question: the fuse of origin (125mA for France) jumped occasionally for no apparent reason. I measured the consumption with an external amperemetre and it indicated me about 110mA. When you start the gbf, the consumption can reach 180mA. In my opinion, the fuse was calculated too accurately on its peak consumption at startup. I specify that the fuse was well timed. So for the moment, I put a fuse of 250mA timed. I took some pictures of my generator: waiting for your answers! Have a good day

author: lionelkjh
author_rank: Frequent Contributor
timestamp: April 25, 2018, 10:52:11 am
content: the following

author: lionelkjh
author_rank: Frequent Contributor
timestamp: April 25, 2018, 10:54:08 am
content: the following

author: lionelkjh
author_rank: Frequent Contributor
timestamp: April 27, 2018, 06:09:43 am
content: help

author: lionelkjh
author_rank: Frequent Contributor
timestamp: April 28, 2018, 07:25:52 am
content: NOTE: This message has been deleted by the forum moderator Simon for being against the forum rules and/or at the discretion of the moderator as being in the best interests of the forum community and the nature of the thread.If you believe this to be in error, please contact the moderator involved.An optional additional explanation is:

author: lionelkjh
author_rank: Frequent Contributor
timestamp: May 01, 2018, 08:56:35 am
content: NOTE: This message has been deleted by the forum moderator Simon for being against the forum rules and/or at the discretion of the moderator as being in the best interests of the forum community and the nature of the thread.If you believe this to be in error, please contact the moderator involved.An optional additional explanation is:

author: Simon
author_rank: Unknown
timestamp: May 02, 2018, 06:56:04 am
content: English only please.
Tektronix type 581 A scope. - Page 1
Forum section: electronics / repair

author: InductorbackEMF
author_rank: Regular Contributor
timestamp: April 29, 2018, 02:13:35 am
content: Hi,having some rather head scratching moments today i got a type 581 A scope that of course needs to be recaped ectEither way i powered it on (i checked there was no deadshort capacitors ect) and to my both joy and then heartbreak the "trace" lit up.Sounds good until the spot was unaffected by any of the controls and not staying still. after looking around i found the voltage levels was a bit high, and some low aka 500v was 490 225 was 215 ect but that should not effect the sweep/ramp generator of the scope if anyone knows where to find the ramp generator output to the CRT so i can check as the manual does not help much in this regard thanks. Alex

author: InductorbackEMF
author_rank: Regular Contributor
timestamp: April 29, 2018, 02:14:06 am
content: http://w140.com/581a_by_matt.pdfThe scopes manual.

author: tautech
author_rank: Super Contributor
timestamp: April 29, 2018, 09:35:34 am
content: If you can catch Martin.M's attention he should be able to point you in the right direction.https://www.eevblog.com/forum/testgear/vintage-tek-restoration-pictures-by-martin/

author: Testtech
author_rank: Regular Contributor
timestamp: April 29, 2018, 02:50:57 pm
content: You have a plugin installed, right?

author: InductorbackEMF
author_rank: Regular Contributor
timestamp: April 30, 2018, 06:22:32 am
content: Yes i have the plugin installed,anyway now there is some other things going haywire as well. Once i have it closer to getting all the caps done i will post pictures.

author: InductorbackEMF
author_rank: Regular Contributor
timestamp: May 01, 2018, 10:36:45 am
content: Hi,found out the reason the guy who had the scope last put a much larger 6au6 tube in due to this it got knocked out of the socket when installing it!Here is a video of ithttps://www.youtube.com/watch?v=05tJeCqedLM&feature=youtu.be
HP8642B Signal Generator what are these missing parts? - Page 1
Forum section: electronics / repair

author: Johnny10
author_rank: Frequent Contributor
timestamp: April 30, 2018, 05:53:04 pm
content: Just bought a HP8642B Signal generator and after working the front panel I cannot get a signal out of the thing.I can set controls and such.So I opened unit and looking around I noticed missing parts.Looking over tear down photos online I see pictures of the parts but not sure what they are.

author: Johnny10
author_rank: Frequent Contributor
timestamp: April 30, 2018, 06:02:27 pm
content: Errors : Looks like error is from missing A19 J1 and J2 parts.

author: vtp
author_rank: Regular Contributor
timestamp: April 30, 2018, 09:02:54 pm
content: Someone stole its attenuators.33321SC and 33321SD with proper control voltage may be suitable replacements. Amplitude accuracy will be off though, calibration includes the original attenuators.
Philips Pulse generator PM 5716 - Need service manual - Page 1
Forum section: electronics / repair

author: txescientist
author_rank: Regular Contributor
timestamp: May 01, 2017, 01:12:38 pm
content: Hi,Does anyone have a service manual or schematic for the Philips Pulse generator PM 5716?Best regards, Milos.

author: usergen
author_rank: Newbie
timestamp: April 29, 2018, 10:08:29 pm
content: Hello Milos,did you find it? Looking for it me too and not found anywhere so far.Does anybody know more?best regards.

author: tautech
author_rank: Super Contributor
timestamp: April 29, 2018, 11:48:55 pm
content: This might be of the same series:http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=Philips/PM5786_125MHz_Pulse_GeneratorPM 5715 is listed here:http://www.ebaman.com/index.php/component/remository/ELECTRONICS/Test-Equipment/Fluke-Philips/Generators/orderby,2/page,2/?Itemid=0Both these repositories are listed here:https://www.eevblog.com/forum/repair/repair-documents-and-links-sticky-me-please-mods/Google sometimes won't find manuals but checking some of the good repositories in the link above generally provides results. Another trick is because Phillips were acquired by Fluke they are often in a common Fluke/Phillips listing.

author: txescientist
author_rank: Regular Contributor
timestamp: April 30, 2018, 07:47:39 am
content: Hi,usergen: did not find the manual, but at the end did not needed it after all.tautech: thank you very much for the reply, the manuals are useful. Not exactly for mine, but certainty a great read for understandinghow it wokrs...

author: usergen
author_rank: Newbie
timestamp: April 30, 2018, 08:43:27 am
content: thanks a lot tautech and Milos, in case I'll find the proper link I'll post it here.
Does anyone know how to extend time of backlight of Brymen multimer (eg.BM829S)? - Page 1
Forum section: electronics / repair

author: chemik22
author_rank: Newbie
timestamp: April 26, 2018, 05:10:30 pm
content: Hi,I have small issue with my Multimer Brymen BM867S/BM829S. The time of backlight is only 32s and it is the thing which annoys me in this very good tool.Does anyone know how to make hardware/software "hack" it to extend the time ?Best,Tomasz

author: lordvader88
author_rank: Frequent Contributor
timestamp: April 26, 2018, 07:08:27 pm
content: On el-cheapo meters there's some external cap used for the timing, no idea on this 1, I own a BM869. I'm tempted to get a 2nd 1 for the price/quality/etc, as a 2nd good DMM.I'm not going to mod this 1, but I'm powering it off a UPS 12V rechargable battery w/ a LM317 on my desk

author: coromonadalix
author_rank: Super Contributor
timestamp: April 26, 2018, 10:27:19 pm
content: the main chip datasheet hasn't been found ...

author: chemik22
author_rank: Newbie
timestamp: April 27, 2018, 11:01:20 am
content: So I guess it is not so easy task.. I know that the timer issue (backlight of only 32s) occur in the couple different multimetrs eg. BM867/869, BM828, BM525 etc...Anyway if anyone know how to hack it for any kind of the Brymen multimetr pleas let me know !probably it woud be easly transformable to the whole family of Brymen multimetr...

author: coromonadalix
author_rank: Super Contributor
timestamp: April 27, 2018, 08:33:33 pm
content: why not ask brymen, sure it will void any warranty, maybe they will answer how to do a mod, if its possible

author: chemik22
author_rank: Newbie
timestamp: April 28, 2018, 10:04:34 am
content: I asked Brymen before posted here and answer was like: "There is not enough ROM memory to insert such function, we know that this issue is problematic, in the next generation of multimetrs we solve this problem"... Well not nice answer...

author: lordvader88
author_rank: Frequent Contributor
timestamp: April 29, 2018, 02:17:02 am
content: Well have u tried tracing back from the light ?I added 3mm LEDs to a Vici VC99, but my improvised defuser didn't work, so I tried SMD LEDs and at least with the low 5-10mA current I used, they where useless even without a diffuser.So for now it has wonI shall go play Star Craft 2 WofL instead

author: coromonadalix
author_rank: Super Contributor
timestamp: April 30, 2018, 07:24:12 am
content: there was a capacitive touch backlight project with an Uni-T meter on this forum ... maybe you could do something like it ??
Update: Keithley 175 Overvoltage during Calibration - Page 1
Forum section: electronics / repair

author: zaphi
author_rank: Newbie
timestamp: April 24, 2018, 09:34:57 am
content: Hi,I made a stupid mistakeI step through the Calibration of DC 1,9V to 950V and repeated this in AC :-( of course this was not a good idea.I got some strange noise out of the Keithley and the Fluke Calibrator get an overload error.now I am getting only strange readings.any idea which component I should check fist?a Schematic can be found herhttps://www.utwente.nl/en/tnw/slt/documentation/Equipment/GeneralEquipment/keithley175.pdfhope for some suggestionsbest regards form GermanyTobias

author: coromonadalix
author_rank: Super Contributor
timestamp: April 24, 2018, 11:02:24 am
content: i would check page 63 every input components from the volt ohms amp section

author: zaphi
author_rank: Newbie
timestamp: April 24, 2018, 05:03:42 pm
content: did some further investigations.After opening the case and inspecting the components i did not find any burn marks or visual damaged parts :-(If i power up the unit in mega ohms mode with open circuit it starts at 15 mega ohm and clim up till arround 20 mega ohms...shorting the terminals result in arround 2 ohms Looks like Switch range and Auto ranging is working.i read about troubleshooting mode in the manual but i can not anderstand it fully. Entering troublshooting works fin but what should i check?

author: zaphi
author_rank: Newbie
timestamp: April 25, 2018, 06:43:39 pm
content: Quote from: zaphi on April 25, 2018, 06:39:52 pmGesendet von iPhone mit Tapatalk

author: zaphi
author_rank: Newbie
timestamp: April 29, 2018, 03:34:28 pm
content: finaly i traced down U103 is working fin. the - 7V rail was draged down bei U105 a TLC271CP after changing the -2V refferenc is rock solid again. But now i have a reading off -1.2V in the 20v range open circuit. If i supply 19V i get a reading of 17.8 the REL function is working fin. Any ideas how i can get rid of this offset?Changed so far:all CD4053LM393NTL061CP