hybridfree/eevblog-posts huggingface dataset:
How replace HA1102r (Overflow/Polarity-LED)?  Or: MAN73a with Decimal point  - Page 1
Forum section: electronics / repair

author: anymouse
author_rank: Newbie
timestamp: March 11, 2016, 08:06:58 pm
content: Currently I try to repair a Kontron DMM 3003 digital Multimeter.It uses a (now defective) HA1102r red LED display for polarity and most-left decimal point.Unfortunatly, this module is obsolete and no-where to find.Does anybody know a possible replacement?It need to have a DIP-14-Layout with the pins along the long sides.Common anode is at pin 1, 3 and 14. Further the needed connections are "+" at 7, "-" at 8 and decimal point at "9". (The two segments for the "1" at 10 and 11 are not used).Size is no matter. As only +/- is used, it does not need to fit the other digits.I don't want to change the PCB to use one of the common polarity modules with pins along the short sides.Currently I found:MAN73A or NTE3065 have the same (or adaptable) layout, but missing the decimal point (at least this is mentioned in the datasheets)MAN73 (without A) may have a decimal point, but is similar hard to findcommon full 7 segment conflict with the "+ / -" on pin 7 / 8. Mostly the center segment is on one of the unconnected places, and pin 7/8 switch some of the lower segementsTIL 304 seems okay, but expensive and rare -- I would need to replace the resistors due to the higher forward voltage (two LEDs per segment).MAN 4630 has the right layout, but is ORANGE instead of RED -- that may conflict with the redI could try to remade the HA-1102R with some small PCB and SMD LEDs -- but that is quite smallish and I have no experience with PCB production.Does anybody have an other option?Or does anybody know, if there are MAN73a or NTE3065 with a decimal point?Thanks, anymouse
Braun Oral B toothbrush (type 4729) coil rewind. Number of turns? - Page 1
Forum section: electronics / repair

author: FrankE
author_rank: Regular Contributor
timestamp: March 18, 2016, 02:54:17 am
content: The coil is trashed on an Oral B battery toothbrush I have. It's 0.2mm OD enameled wire.It looks like there are two sets of coils. Two of the ends go to a common terminal. The other two ends each go to their own terminal on the PCB It's presumably a centre-tapped halfwave tapoff configuration. .The common/ centre tap ends are both intact. One of the +ves I've managed to unwind a turn so can resolder to te PCB. The other +ve arises from an inner lay on the coil and I am unable to unwind a turn to resolderWould anyone happen to know the number of turns on each coil?Sure, I can count the number of turns as I unwind the old coils but there's bound to be a cludge or a snap and I'll end up having to cut the old windings out.The Triumph has a much heftier and clumsy-repairer-proof coil but there's no charger.

author: Macbeth
author_rank: Super Contributor
timestamp: March 18, 2016, 03:01:35 am
content: Scrap it and buy a new one?

author: e-doc
author_rank: Contributor
timestamp: March 18, 2016, 07:11:44 pm
content: https://youtu.be/JJgKfTW53uo

author: FrankE
author_rank: Regular Contributor
timestamp: March 18, 2016, 08:51:57 pm
content: Lost count.Inner lay 3.4mOuter lay 4.2m wound opposite direction.10 minute rewind.

author: ericloewe
author_rank: Unknown
timestamp: March 19, 2016, 04:17:59 pm
content: How would the coil even get damaged in the first place? This story makes no sense.+1 for the "buy a new one" suggestion.

author: MK14
author_rank: Super Contributor
timestamp: March 19, 2016, 04:27:06 pm
content: Quote from: ericloewe on March 19, 2016, 04:17:59 pmI think the coil got damaged, while they were trying to replace a faulty battery. (Speculation).
HV diode test - Page 1
Forum section: electronics / repair

author: jfphp
author_rank: Regular Contributor
timestamp: March 11, 2016, 02:50:04 pm
content: Hello,How can I test HV diode (service of several KV) ? There are alone, not mounted with capacitors. Standart diode test gives no result. If I apply HV to mesure the current I have to float the multimeter beyond the specs... Any idea ? Thank you.

author: bktemp
author_rank: Super Contributor
timestamp: March 11, 2016, 03:04:09 pm
content: Apply a high enough voltage to make it conduct and check if the forward voltage drop is in the expected range. Most high voltage diodes have a forward voltage in the range 5-100V.If it works, apply a high reverse voltage and measure the leakage current. Maybe you should add some protection across the current shunt in case the diode fails at a high voltage.

author: Seekonk
author_rank: Super Contributor
timestamp: March 11, 2016, 03:48:42 pm
content: I tested a microwave oven diode last week and that had stacked a forward voltage of 7.5V. For sure a HV diode will be at least 50V.
IKEA Lamp - Page 1
Forum section: electronics / repair

author: Chappy1978
author_rank: Newbie
timestamp: March 11, 2016, 06:04:35 am
content: Hi All,So I have this awesome IKEA LED lamp and damed expensive, that used to work great. Well now the lamp will go dim and then every so often it will flash like a strobe. So I did what any good techy need would do, I took it a part. Its a cree LED with a flyback converter based on LNK364PN.http://www.mouser.com/ds/2/328/lnk362-364-3310.pdfThe funny part is when I put a magnet on the transformer the lamp works great. Except every time it gets close to something metal well it grabs hold. Eeek! So that idea is kinda sucking. Any thoughts?
Replacement for Sirenza Microdevices SCA-4 MMIC RF AMP - Page 1
Forum section: electronics / repair

author: rastro
author_rank: Frequent Contributor
timestamp: March 10, 2016, 06:02:45 pm
content: Hello,I'm looking for a replacement for this MMIC amplifier:- Sirenza Microdevices SCA-4- SOT-89 Package- DC-4GHz- 20dB Gain- Has markings "H4"The part appears to be obsolete. Needed to repair an R&S SMIQ06B signal generator.-rastro

author: rfeecs
author_rank: Frequent Contributor
timestamp: March 10, 2016, 07:11:41 pm
content: Some possiblilities:http://www.nxp.com/files/rf_if/doc/data_sheet/MMG3012NT1.pdfhttp://www.rfmd.com/store/downloads/dl/file/id/30281/sbb5089z_data_sheet.pdfhttp://www.rfmd.com/store/downloads/dl/file/id/28579/sga6589z_data_sheet.pdfAll are in stock at Digikey.
GOS-653G with power but no trace - Page 1
Forum section: electronics / repair

author: crazyjim30
author_rank: Contributor
timestamp: March 10, 2016, 05:27:42 am
content: So my first oscilloscope arrived today. Before leaving for work, I had a quick look under the hood. I didn't spot any obvious damage (bulging/leaky caps, cut/damaged cables, etc. I plugged it in, hit the power button, and waited a few minutes for it to warm up. It has power. The light is on. No green line after several minutes. I plugged the probe in, switched on Ch. 1, and hooked the probe up to the calibration tab. No square wave. Nothing at all. I'm hoping I just didn't have a switch in the right position. Step 1 is to download the manual tomorrow. I'm currently at work so I'll be unable to provide instant feedback, but suggestions are welcome. I've had some limited experience with the digital oscilloscopes at school, but this is quite different . Be gentle. I'm a noob.Sent from my SM-G900V using Tapatalk

author: ataradov
author_rank: Super Contributor
timestamp: March 10, 2016, 05:45:35 am
content: Play with trigger and vertical position settings.

author: vk6zgo
author_rank: Super Contributor
timestamp: March 10, 2016, 06:00:51 am
content: Yes,if the triggering is set to "Normal" & it isn't triggered,you won't see a trace.Try "Auto"trigger.Also check the 'Intensity" control--if it is wound off,again no line.

author: crazyjim30
author_rank: Contributor
timestamp: March 10, 2016, 06:13:11 am
content: Thanks. I'll try that in the morning. And before someone catches my photography error: the probe is in the Ch. 2 BNC, not the Ch. 1 BNC. I switched channels at some point while swearing and "troubleshooting".Sent from my SM-G900V using Tapatalk

author: ataradov
author_rank: Super Contributor
timestamp: March 10, 2016, 06:14:21 am
content: Your scope is set up for Ch 2 anyway

author: crazyjim30
author_rank: Contributor
timestamp: March 10, 2016, 06:35:45 am
content: Yeah. I got that much right. Switch matches connector. I made an embarrassing error that way several months ago. 10 minutes of cursing at my uncooperative lab setup only to discover....wrong channel! I try to learn from my mistakes.Sent from my SM-G900V using Tapatalk

author: oldway
author_rank: Super Contributor
timestamp: March 10, 2016, 08:01:10 am
content: You need to read the user manual first.http://www.gwinstek.com/en-global/products/Oscilloscopes/Analog_Oscilloscopes/GOS-653G_GOS-652G

author: crazyjim30
author_rank: Contributor
timestamp: March 10, 2016, 11:57:39 am
content: Thank you to all. I adjusted the intensity, played with the vertical position a bit, and turned the triggering to "auto". IT LIVES!!!! Now on to reading the manual.Sent from my SM-G900V using Tapatalk
5" black and white tube TV PK-4184 - looking for composite input - Page 1
Forum section: electronics / repair

author: bubba198
author_rank: Contributor
timestamp: March 06, 2016, 07:45:32 pm
content: Hi everyone,I've got 5" black and white tube TV model PK-4184 and I'm looking for composite input? The TV doesn't have one, it only has an old style analog tuner which is useless now days. The main and only IC running the TV is D2915CP. The PCB has markings TV502PCB. It's a Chinese thing built in early 2000s.I've looked at the data sheet of that IC and many schematics of similar but NOT identical TVs and I'm still unsure whether it's possible to capture a trace or something like that so I can feed it composite signal, which is my ultimate objective.It seems that pin 5 is the holly grail but the TVs that do have composite inputs also have bunch of other parts sitting in between pin 5 and the tube driver and those things aren't present in my TV. Any advice would be appreciated!Thank you

author: Paul Moir
author_rank: Frequent Contributor
timestamp: March 07, 2016, 01:41:56 am
content: It might help to know that there is the very similair KA2915 for which you can get a datasheet:http://www.promelec.ru/pdf/ka2915.pdfWhile hunting that down I noticed someone had rigged a composite input:http://www.bidouille.org/hack/minitv(some interesting info in the comments at the bottom)

author: bubba198
author_rank: Contributor
timestamp: March 11, 2016, 06:06:19 pm
content: that's exactly what I was looking for, pin 5 was always a suspect but now I know that it simply needs to be inverted. thank you!
Replacement CRT for a Sony KV-27HFR TV - Page 1
Forum section: electronics / repair

author: Gerardo
author_rank: Newbie
timestamp: March 19, 2016, 10:39:27 pm
content: Hello.Does anyone know which model of CRT can be a used as a replacement for a Sony TV model KV-27HFR ?. I don't have the data of the CRT. However I know it's the original one since it was never before replaced.Any help will be great. Thanks.

author: vk6zgo
author_rank: Super Contributor
timestamp: March 20, 2016, 03:27:00 am
content: Sony were pretty conservative with their 27" TVs & Picture Monitors.From memory,the tubes in all the 27" stuff were interchangeable,from the big old wood pattern TVs with AV inputs ---can't remember their model number,to the KX27 "Profeel" Picture Monitor series.I seem to remember us having a few KV-27HFRs which I'm fairly sure shared the tube type with the Profeel & others,but I can't actually remember replacing the pix tube in one.As a TV Studio,we made a lot of use of the services of a CRT "regunner" for all but the most "critical" monitors.I guess such an occupation would be as extinct as "buggy whip maker" these days!

author: Shock
author_rank: Super Contributor
timestamp: March 20, 2016, 04:40:44 am
content: Quote from: Gerardo on March 19, 2016, 10:39:27 pmLook up the service manual and start there. If you haven't used this website before you have to wait till the "This file is downloadable free of charge: Get Manual" comes up and then click on "Get Manual"http://elektrotanya.com/sony_kv-27hfr_20hfr.pdf/download.html
BOSE ACOUSTIMASS 8 SERIES II POWERED SUBWOOFER - Page 1
Forum section: electronics / repair

author: macross
author_rank: Contributor
timestamp: March 09, 2016, 07:39:10 pm
content: So my friend asked me if i could repair his "BOSE ACOUSTIMASS 8 SERIES II POWERED SUBWOOFER". It has two broken pots, but i'm having a hard time identifying those pots. They have seven legs + two from the outer case. I think they are 2x50k pots, but i'm not sure. Maybe someone can identify them?

author: Addicted2AnalogTek
author_rank: Frequent Contributor
timestamp: March 10, 2016, 03:07:26 am
content: "B103" typically means 10Kohm.What leads you to believe they are 50Kohm?I have a PS 28 III / AV18 Bose Lifestyle system that I'll be tearing into at some point.. When I was looking around for schematics for the Series III systems, I couldn't find them, but the Bose Series II schematics are readily available. Just look around. There's a database of service manuals somewhere that I saw them in. If I find the link to the site, I'll drop it here for you.
Old RCA transistor house number  - Page 1
Forum section: electronics / repair

author: PaulAm
author_rank: Frequent Contributor
timestamp: March 07, 2016, 04:44:04 pm
content: I'm replacing some 2n2207 germanium transistors in a piece of antique gear and I ended up with some house numbered RCA transistors.I can't find these numbers anywhere. I've put them on a curve tracer and they look good, but it would be nice to see RCA's specs on them.Does anyone have a clue on what these are or how to interpret the numbers? Sometimes there was an implied prefix, but I'm drawing a blank on this one.Across the top is 7 0132 00Across the bottom is 7451The RCA logo on them is consistent with mid sixties or later.

author: vk6zgo
author_rank: Super Contributor
timestamp: March 09, 2016, 01:19:51 am
content: The three set of numbers looks vaguely Tektronix (or GM).Where do the 2N2207's come in?Are you hoping to replace them with the unknown ones?Or vice versa?

author: PaulAm
author_rank: Frequent Contributor
timestamp: March 09, 2016, 04:55:52 pm
content: I'm working on an antique Tek 321a and most of the transistors are Tek lableled 2n2207s. Neither the Tek nor the 2n2207 transistors are easily available, so I'm looking for replacements. These were billed as 2n2207 replacements and I have some GT321Vs coming from Latvia as well.Turns out there's no urgency on this. The scope initially wouldn't deflect below the crt centerline, but after replacing a bunch of failed electrolytics, it came back to life.Still would be nice to identify the RCA reference.
HP Agilent E4418B Power Meter keypad flex circuit E4418-20007 needed - Page 1
Forum section: electronics / repair

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: March 01, 2016, 01:15:54 pm
content: Hi guys, i need an HP Agilent E4418B Power Meter keypad flex circuit E4418-20007Mine stopped working.

author: kada
author_rank: Contributor
timestamp: March 03, 2016, 02:39:52 pm
content: Hello,I also need this one.My flex keypad stopped working too.The new part number is E4418-66502 (taken from Keysight site).

author: kada
author_rank: Contributor
timestamp: March 09, 2016, 02:18:08 pm
content: After receiving $183 quote from Keysight for flex keypad I definitely decided to do it myself.First of all I bought the thinnestpush-buttonsI was able to find. It is only 0.8mm thin.I decided to mill 1.5mm PCB on my CNC-engraver and after it to reduce thickness down to 0.7mm by back side milling.PCB MillingResults:I also glued rubber circles taken from old remote controller to rubber keypad pushers for better force transfer to push-buttons.I was not satisfied with result since after keyboard assembly some push-button was pressed and did not released due to the increased length of rubber keypad pushers and push-buttons thickness.So I decided to cut pushers of rubber keypad and re-glue the rubber circles.Now all keys works excellent with little more pressing force comparing to original keyboard.In addition there is a tactile effect which improved ergonomics of the keyboard.I also included Altium Designer 15 project of the PCB for those who decide to do it.
Help with Vintage Teac V-35 tape deck - Page 1
Forum section: electronics / repair

author: gooseEL34
author_rank: Regular Contributor
timestamp: March 06, 2016, 07:06:30 pm
content: Hey guys-I was wondering if someone could offer a suggestion. I grabbed a goodwill cassette deck (Teac V-35). When I plug it in, the motor continuously runs. None of the buttons will stop it (Stop, Pause, FF, Rewind, etc).Here is a pic of the motor in questionhttps://www.flickr.com/photos/140022773@N08/shares/05gx70The drive belt has long turned to goo. No obvious burned components on the PCB nor any electrolyitics that are spewing their guts.Thanks for any tips...

author: karoru
author_rank: Regular Contributor
timestamp: March 06, 2016, 10:14:48 pm
content: Are you sure that motor even has the "stop" circuitry? I've seen many vintage tape decks that had motor just wired straight to power supply (or via some motor controller chip, often on separate PCB), without any ability to disconnect it while unit is on. I don't see V-35 manual available online, but on elektrotanya there's V-9000 from similar era and there the motor is just connected straight to 10V rail.

author: RobertGogol
author_rank: Unknown
timestamp: March 06, 2016, 10:27:23 pm
content: Hi,every deck in my life has continuously running motor connected with capstan by drive belt.I think this is ok.

author: gooseEL34
author_rank: Regular Contributor
timestamp: March 07, 2016, 04:42:20 pm
content: Thanks guys!!!
Flax Ribbon Cable Repair - Any Solution for this? - Page 1
Forum section: electronics / repair

author: zaoka
author_rank: Frequent Contributor
timestamp: March 07, 2016, 10:40:21 pm
content: Does anybody have working solution of how to fix bad ribbon flax connection when there is a bad connection between PCB board and cable?I used latex tubing to create pressure, however, its not reliable way to fix it...Here is how it looks like:Thanks

author: Agent24
author_rank: Regular Contributor
timestamp: March 08, 2016, 01:54:34 am
content: Expensive (k$) hot bar rework machine, or try to do it manually with a hot bar tip for your handheld soldering iron. Good luck.http://electronics.stackexchange.com/questions/3086/hot-bar-manual-solderhttp://www.flexdude.com/Back%20Issues/FCN11-00A.PDFhttp://p1repair.com/blog/lcd-repair-missing-lines/http://www.aliexpress.com/item/Copper-lcd-cable-welding-tools-lcd-cable-hot-head-soldering-iron-tips-30W-40W-60W-thermocompression/1305949702.html

author: sorenkir
author_rank: Regular Contributor
timestamp: March 08, 2016, 05:43:35 am
content: Dave has already tried that:https://www.eevblog.com/2015/10/14/eevblog-808-fluke-196-scopemeter-repair/Michel.

author: RobertBG
author_rank: Regular Contributor
timestamp: March 08, 2016, 06:41:42 am
content: I've had some luck just carefully using a solder iron and reheating them.But its hit or miss,it either works all the time or not at all depending on what it is.

author: SAUL BRITTO
author_rank: Frequent Contributor
timestamp: March 08, 2016, 09:14:24 pm
content: If you don't understand portuguese just look:
Iskra Unimer 3 - repair and mod for external power - Page 1
Forum section: electronics / repair

author: Thilo78
author_rank: Regular Contributor
timestamp: March 05, 2016, 05:09:43 pm
content: Hey guys,I finally came around to open up the Unimer 3, that I inherited from my father.It featured several problems:- Corroded battery contacts due to leaky batteries- Corroded fuse holder- Wrong and/or slow readingsRepairing it was a bit problematic due to lack of documentation. The only thing I found was a schematic diagram.No markings on the board whatsoever, but at least a few pieces of information on the components themselves.After quite a bit of measuring I put together a map of the components. Might prove itself useful to others trying to revive an Iskra.The actual problem came from a lifted trace in the positive path to the movement. I repaired that with a piece of tinned copper wire.I replaced the fuse holders with new ones, but couldn't get new battery terminals. So I opted for external power supply.On top of the case, I positioned two 2mm jacks and wired them to the battery connections.Thus, I can plug in a battery pack if I need to do resistance measurements, and don't need to worry about leaky batteries.

author: Thilo78
author_rank: Regular Contributor
timestamp: March 05, 2016, 05:17:14 pm
content: btw: One of the pictures shows the Unimer 3 next to my Goerz Unigor A43.They really look alike, but the Unimer is a bit smaller.
NAD 6050C - Page 1
Forum section: electronics / repair

author: rahandford
author_rank: Regular Contributor
timestamp: March 03, 2016, 08:37:50 am
content: I am currently repairing a NAD 6050C cassette mechanism and I am trying to find a replacement play idler (idler tyre) for this unit. Does anyone know where I can obtain such parts? Can I use a generic part and if so how do I go about sizing? The fault that I have is that if I put the unit into play/FR/FF nothing happens, but if I push on the idler (by about 1mm) all is OK. Is there a mechanism adjustment for that? I have tried putting the existing tyre on at an angle (and that works) but the speed is so far out I can not bring it back into range. Any help or advice would be very much appreciated.Thank you.

author: mzacharias
author_rank: Frequent Contributor
timestamp: March 04, 2016, 11:38:52 pm
content: If the idler isn't too far gone (falling apart, etc) it's often possible to clean them, maybe use some "rubber re-grip" and clean the motor pulley and any other drive surfaces. Many times this will restore service for years.
Anyone here an expert at deciphering Kontron / JumpTEC part numbers? - Page 1
Forum section: electronics / repair

author: cvanc
author_rank: Frequent Contributor
timestamp: March 04, 2016, 03:45:31 am
content: I've got an old PC/104 module I'm trying to replace, part number 01028-0000-30-2. I can't find any stock of the exact same P/N (if you can, you would be my hero!!). But I can find 01028-nnnn-nn-n, where some or all of the trailing digits vary. I can not for the life of me sort out what these suffixes mean. It's possible some of these permutations might work for me but I have no way of knowing.Surely there is a pattern to Kontron part numbers, right? Does anyone know the secret here? Thanks.

author: Smith
author_rank: Frequent Contributor
timestamp: March 06, 2016, 08:56:19 am
content: Have you contacted Kontron directly? I had some contact with them previously, and they where quite helpfull.
tggzzz>> - Page 1
Forum section: electronics / repair

author: SAUL BRITTO
author_rank: Frequent Contributor
timestamp: March 04, 2016, 02:46:24 pm
content: tggz if you are not satisfied with my presence at this forum and happens to be an administrator feel free to block my profile I'm sorry but I hate censorship (It's better) and stupid reproaches.

author: tggzzz
author_rank: Super Contributor
timestamp: March 04, 2016, 03:01:13 pm
content: Quote from: SAUL BRITTO on March 04, 2016, 02:46:24 pmDon't be silly. I'm trying to help you get better answers to your problems. There's a relevant English proverb "you can lead a horse to water, but you can't make it drink".As for "persecution", well I appreciate English probably isn't your first language.

author: SAUL BRITTO
author_rank: Frequent Contributor
timestamp: March 04, 2016, 03:09:21 pm
content: Quote from: tggzzz on March 04, 2016, 03:01:13 pmeither my first or my second what I said is worth. Na minha língua nativa há um outro provérbio: Jamais queira fazer de cachorro gente! This is my first language,portuguese! I SPEAK PORTUGUESE.you speak Portuguese?

author: SAUL BRITTO
author_rank: Frequent Contributor
timestamp: March 04, 2016, 03:33:20 pm
content: There is a good dictation in my coutry: Elogie em público e corrija em particular. Um líder corrige sem ofender e orienta sem humilhar.Praise in public and correct in particular. A leader without offending corrects and guides without humiliating.

author: Simon
author_rank: Unknown
timestamp: March 04, 2016, 05:48:29 pm
content: Quote from: SAUL BRITTO on March 04, 2016, 02:46:24 pmDon't worry, I can take the pleasure if you wish. This is not how a forum is used. If you have a problem you report the post or PM/email a moderator.
VOM or VTVM precision resistor trimmers - Page 1
Forum section: electronics / repair

author: FlyingHacker
author_rank: Frequent Contributor
timestamp: March 03, 2016, 11:10:42 pm
content: Just curious... Why wouldn't you include trimmer pots in VOM and VTVMs for the precision resistors for Ohms or Volts?For volts I guess it is a matter of power/heat? But for ohm readings?Just curious. Anyone ever seen this? Sometimes you find a meter that is just a little bit out, and it would be nice to be able to tune it rather than simply replace the resistor.
Rigol DS1052E repair question - Page 1
Forum section: electronics / repair

author: Vytautas
author_rank: Regular Contributor
timestamp: March 02, 2016, 10:09:43 pm
content: Hello,could anybody help me with repairing my DS1052E scope? Some time ago, it started going crazy. At first it started showing signs of working normally in long memory mode only. In normal mode, the waveform was not possible to contract in the horizontal scale, as it would freeze when trying to see more of the waveform on the screen, and had to be expanded to start sampling again. Then, after a few minutes of work, when it warms up, it goes crazy (shows whatever) or freezes totally. I tried to blow cold air on the FPGA and when it cools down, it would start working again. I tried resoldering the FPGA a few times, the problems did not go away. Now, I ordered and soldered a new FPGA, but the problems are not gone, even though I monitored the process very carefully (preheated the board, used leaded balls, and a careful temperature control, it never exceeded 220 Celsius, and the FPGA nicely sat in place). Is the FPGA still the culprit, or should I look somewhere else? Got tired already with this stubborn thing. Could anybody help me, please? Going to sleep today, its late, and I am frustrated.

author: lowimpedance
author_rank: Super Contributor
timestamp: March 02, 2016, 11:05:01 pm
content: As it appears thermal I assume you have checked the fan is running at the correct speed? etc. And (not being familiar with the main PCB) is there any local voltage regulators etc that are playing up due to dodgy bypass caps !.I also have a faint recolection that some reversed enginneered schematics are some where on the forum too, might be useful.see here:https://www.eevblog.com/forum/blog/rigol-ds1052e-nasty-surprise!/msg56070/#msg56070

author: Vytautas
author_rank: Regular Contributor
timestamp: March 03, 2016, 11:52:04 am
content: Hello again.Thanks for reply. I tried to check some things.First, I checked the voltage supply for the EL1881 video sync separator (marked 102). According to the reverse engineered schematics supplied online, this supply should be +5V. It reads 3.3V there though.Another thing. When soldering the Altera FPGA, the "DEE" component, marked "1" was moved out of place by accident. I soldered it back the way shown in the picture, which I downloaded from a teardown. But now I noticed that the "DEE" marked "2" is upside down in my scope compared to this image! How could this be, if I had never touched it and the scope was bought new?! And what is the DEE? Could not google it out.Thank you.

author: PA0PBZ
author_rank: Super Contributor
timestamp: March 03, 2016, 12:27:57 pm
content: As far as I can see 102 is a resistor array , not the EL1881, so what the voltage at the pin should be remains uncertain.The parts marked DEE are also resistor arrays, probably 4 resistors across, so the orientation makes no difference.
Test Equipment Plastic Parts - Page 1
Forum section: electronics / repair

author: deepskyridge
author_rank: Regular Contributor
timestamp: March 02, 2016, 07:00:34 pm
content: I have a HP 3478A Multimeter that works in all respects, but it has a broken cap on the end of the power switch shaft.The shaft and switch are fine but the cap is missing.I thought about taking the one off the Front/Rear terminal switch but would rather not.Any idea where I could fine one.I have searched EBAY repeatedly without luck.ThanksGary

author: Richard Head
author_rank: Frequent Contributor
timestamp: March 02, 2016, 07:24:19 pm
content: If you have no success finding one you could try to get one 3d printed.Incidentally, have an HP437B RF power meter that uses the identical button. Probably used on plenty of HP instruments from that era.

author: alanambrose
author_rank: Frequent Contributor
timestamp: March 02, 2016, 08:59:49 pm
content: Yep, check the keysight site in case anything in production still uses the part. (Get the part number from the docs.) I just bought some key caps for a 3458a (which is still in production) - but, for instance, the same ones are used on the 3245a (which is not). Easy and <$10. Else find a CAD person, bribe with beer (the CAD should take < 1/2 hour) and send the stl file to shapeways or imaterialise. You might want to order the part in a couple of different materials to see which one matches the best. However, small parts are cheap, say <$5 in one off.Alan

author: vinicius.jlantunes
author_rank: Regular Contributor
timestamp: March 02, 2016, 09:13:57 pm
content: Definitely worth to check with Keysight if they have it.Maybe I was lucky, but once I bought an used power supply and the front panel was broken during transportation. I sent an email to Keysight and a support engineer found a spare panel in the US and had it shipped to the local Keysight office here in Brazil which then sold it to me at a very reasonable price. The engineer said it was not typical for them to do this (more typical would be for me to send the equipment to them and they fix it), but as it was a "hard to get" part and replacing the panel was easy, they were willing to help me.I was impressed!In short - shoot them an email with the part number (you can get it from service manual) and if they have it they will likely help you. Great service in my experience.EDIT: typo

author: DonDoucette
author_rank: Newbie
timestamp: March 02, 2016, 09:29:52 pm
content: I have been researching a 3D printer for just this reason. I have for many years discarded things because something like a switch cap or know have broken.
Dremel 395 Type 4 Variable Speed Switch Faulty - Page 1
Forum section: electronics / repair

author: mstoer
author_rank: Contributor
timestamp: March 06, 2016, 07:47:00 pm
content: I have an older Dremel (had for over 20 years now). The variable speed quit and it just runs full out once you slide switch to 5 (maximum). I've opened it up many times, initially cleaning the contact surfaces of the switch and lately been trying to figure out what parts are in the circuit. The photo shows the PCB (small ceramic slab, approx 11mmx25mm) and lucky me, they potted one component. The newer Dremel switch PCBs seem to have a slightly different design/layout and they don't pot the components. I'm guessing there is a diac (not a diode), a capacitor and under the black blob maybe a triac? Has anyone tried to repair one of these? Any suggestions on how to remove the potting compound?I do have a new Dremel, but I'd like to fix this on if I can.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: March 06, 2016, 09:45:30 pm
content: Quote from: mstoer on March 06, 2016, 07:47:00 pmAlmost definitely; they seem to just use a glorified light dimmer speed control. It's a little hard to tell, but is there three wires going into it? The top one looks like it might just go beside the blob.Anyway, since it's dead, why not grind it off with the other dremel to see what's going on.Interesting other repair:http://danjovic.blogspot.ca/2013/11/reparando-o-controlador-da-dremel.htmlPerhaps doing a direct die improves thermal conductivity to the ceramic.

author: mstoer
author_rank: Contributor
timestamp: March 06, 2016, 10:13:13 pm
content: Here is a closer view. I started to scrape away at the epoxy with a scalpel and hit the other half of the metal that looks like some kind of hold-down. It does not look like the tab on a typical SMD component. The ceramic is only 0.64mm (0.025") thick, so I'm trying to be careful not to break it. The cap is a 1206 for size comparison. There are 3 traces leading away from the epoxy in the direction of the cap. The right most one goes to the cap, the middle one to the diac and the left one to the black "T".If I don't get any scraping I'll try the other dremel I guess.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: March 06, 2016, 11:02:54 pm
content: Thanks,To me it makes sense that the "hold-down" (which it may very well also be) is the MT1 contact rather than using a wirebond. It seems to fit with the typical speed control schematic.
Kester 285 vs 44 flux for repair - Page 1
Forum section: electronics / repair

author: PaulAm
author_rank: Frequent Contributor
timestamp: March 02, 2016, 03:51:09 pm
content: I'm working on an old Tek scope with the ceramic tie points and I need to get some silver bearing solder for repair.Normally, I would use a Kester 44 rosin core, but I found a cheap supplier for Kester 285 sn10pb88ag02. Anyone have any experience with the 285 flux?Kester's description sounds OK, but ...thanks

author: nanofrog
author_rank: Super Contributor
timestamp: March 02, 2016, 06:04:39 pm
content: The flux in 285 solder wire is the same as 186 liquid flux, so it's rated as RMA (comes close to RA, but not quite; the flux in 44 solder wire or the 1544 liquid are more aggressive). Beyond 44 in activity level, there's 48 (most aggressive RA they offer, and IIRC, you do need to clean it).FWIW, I use Sn62Pb36Ag2 as it's eutectic (aka 62/36/2).You can get it in small quantities from RadioShack (add a more aggressive liquid flux should you need it).62/36/2, .022" diameter, 1.5oz rosin core(out of stock online, but may find some in a store)62/36/2, .015" diameter, 1.0oz rosin coreIt just says rosin, but I suspect it's at least RMA.I picked up a couple more rolls of the .022" when a local RadioShack closed down here, so I'm probably set for life (still have most of one I bought back in the early '90's).I also have Kester 186 and 1544 liquid flux on hand.

author: Orange
author_rank: Frequent Contributor
timestamp: March 02, 2016, 06:14:45 pm
content: Quote from: PaulAm on March 02, 2016, 03:51:09 pmSN10PB88AG2 has a very high melting point (268..290 Celcius) so it is not suitable for your purpose. Better get an SN62 solder.

author: PaulAm
author_rank: Frequent Contributor
timestamp: March 02, 2016, 08:27:54 pm
content: Good point. Thanks for the replies
Successfully repaired an instek FG-8015G - Page 1
Forum section: electronics / repair

author: Ferroto
author_rank: Frequent Contributor
timestamp: March 01, 2016, 03:45:19 pm
content: So awhile ago I purchased a used function gen from ebay. It was sold from a seller that said he got it with a bunch of instruments labeled as nonworking or defective it had a big old sticker on it saying défectueux (defective) but it was 30 bucks and located in Canada so I figured I'd take a crack at repairing it.When I got it home I turned it on and nothing at the output however the pulse output still worked. so i took the cover off. I discovered that the board was worked on by someone else. It was easy to see where because the rest of the board was wave soldered.Bodge City!! I especially like that resistor on stilts. You can probably smell those resistors through the internet to. I was the one who removed Q506 srry I don't have any pictures from before I started working on it.Both Q506 and Q505 were getting hot up to round 90deg Celsius. So I decided to desolder them both and test them out of circuit Q505 was shorted internally fellas.Now according to the datasheet the Q506 was supposed to be a 2n2905 (NPN) and Q505 was supposed to be a 2n2219 (PNP) and both are wired up in a class AB type configuration and are the final amplifier stage before the output. However when I hammered the heatsinks off both I made a shocking discovery. They were both 2n2219'sthey also both had fresh solder on them which means they were replaced by the previous owner.So I replaced both transistors, reused the heatsinks, adjusted the voltage rails (I was messing with the voltage adjust trying to correct a voltage drop caused by a shorted transistor.) and now it works perfectly.Here's the schematic for those interested.

author: mij59
author_rank: Frequent Contributor
timestamp: March 01, 2016, 04:26:41 pm
content: The unit is quite old, you might want to check the filter caps C101 and C103, in my GFG 8015G they only lasted 25 years.

author: Eng_hassan85
author_rank: Newbie
timestamp: March 01, 2016, 10:22:21 pm
content: Good Work .. Keep it up

author: preludelinux
author_rank: Newbie
timestamp: March 02, 2016, 05:30:52 am
content: Sure can smell the burnt components. good job with the fix and finding the other persons mistake. i wonder what happened to cause the last person to repair the unit like that. usually i always get a bad feeling once i find out someone has tried.

author: Ferroto
author_rank: Frequent Contributor
timestamp: March 02, 2016, 12:57:30 pm
content: Quote from: preludelinux on March 02, 2016, 05:30:52 amBest I can figure is voltage was fed into the output terminals. two of the resistors fried were 1/2 watt 100 ohm's in parallel at the output for 1 watt 50 ohm effectively.
HP E3611A output problems - Page 1
Forum section: electronics / repair

author: OiD
author_rank: Regular Contributor
timestamp: March 02, 2016, 09:15:09 am
content: Hi,I have a couple of HP 3611A power supplies at work, one of them seems to work okay but the other one is a nightmare to set the voltage. For example, I would try to set the output at 20V, adjust the voltage and watch the display slowly reach 20V... and continue getting higher and higher, adjust the voltage lower and watch the display slowly reach 20V... and continue getting lower... after about 5 or 6 iterations I might have the display showing 20V but that could be between 3-6minutes of time adjusting the voltage.Any Ideas? I've popped it open and looks okay. Don't have a multi-meter handy to check anything thoughA quick look at the schematic and I don't know where to start checking. First I'll find a multi-miter i guess...

author: Whales
author_rank: Super Contributor
timestamp: March 02, 2016, 09:18:36 am
content: Perhaps the pot is travelling past its normal end stop point. The contact is now 'floating'. Does it behave fine when turned to a few degrees shy of maximum?

author: johm
author_rank: Contributor
timestamp: March 02, 2016, 12:17:14 pm
content: Got exactly the same problem on an E3616A, check the voltage ripple, it should be less than 200mV. In my case it reached up to 1.2V ripple and a constantly increasing or decreasing voltage. I tracked down the problem to a leaky cap on the constant voltage control circuit, the one on the feedback loop.I suggest you check the reference and preregulator voltages and particularly their ripple.Then perform a visual check / ESR of output caps and feedback caps.Try loading the power supply and see if the problem is diminished.

author: OiD
author_rank: Regular Contributor
timestamp: March 02, 2016, 01:12:19 pm
content: Hi again, I opened it up and tested it again... now it's stable.... maybe somethings lose, they don't get treated very well... I'll check the regulators as well, got a bit of work to do now.Whales, I mentioned 20V as an example, it happened at all voltages. Even at the end of the pot travel.Thanks for the insight, I'll post back later if possible.
Successful repair to LG RZ-15LA32 LCD TV - Page 1
Forum section: electronics / repair

author: anachrocomputer
author_rank: Regular Contributor
timestamp: February 29, 2016, 01:51:27 pm
content: I found an LCD TV in the scrap pile at the Hackspace the other day, an LG model RZ-15LA32. It was manufactured in 2004, and has a full set of inputs: RF (UHF), SCART, composite PAL, S-Video and VGA. I didn't find the remote, but I thought I'd test it out anyway, for use with 8-bit microcomputers and video games. Anyway, it didn't work. All I got was a white screen, which showed that the backlight was OK but the input stages weren't. There was no on-screen display (OSD) and no sign of either a blue screen (input out-of-range) or a 'snow' image (RF input).I opened it up, expecting bad capacitors:https://www.flickr.com/photos/anachrocomputer/25233735352But the capacitors were OK. I identified various chips, the NICAM processor, the VGA input chip, the LVDS driver, the audio power amp, and so on. Then I spotted the main chip the generates the (missing) OSD, an SDA555FXL (no relation to the 555 timer!). It's in a 52-pin, 0.07-inch pitch DIL package, and socketed. The chip looked a bit suspicious to me:https://www.flickr.com/photos/anachrocomputer/24725256823To my total surprise, after I had gently lifted the chip in the socket and re-seated it, the TV worked! It must've been a bad contact in the socket. I was able to reassemble the TV and get it connected up to a laptop as a VGA display. Tonight, I'll test the composite video (PAL) and SCART connections with a BBC Micro!The TV working, showing the OSD:https://www.flickr.com/photos/anachrocomputer/25352000805

author: Wor3d
author_rank: Contributor
timestamp: March 01, 2016, 11:41:56 am
content: Good job! Stuff that I often overlookMaybe the TV just fell down and "yeeaaa, its crushed"
Service Manuals for Some Old Marantz Gear - Page 1
Forum section: electronics / repair

author: nathanpc
author_rank: Unknown
timestamp: February 28, 2016, 05:18:47 pm
content: Recently I friend of mine found a very old Marantz system his father had, since he was going to dump the whole thing he contacted me first to know if I wanted it and of course I picked up everything, the only problem I have now is that I could only find the service manuals for the CD-52 mkII CD player and the PM54 amplifier, but the tape deck, tuner, and graphic equalizer all need some work, so if anyone could point me to the service manual or at least a schematic for the following items it would be really appreciated:EQ-20D Graphic EqualizerSD255 Cassete DeckST360L TunerThanks in advance,Nathan

author: tautech
author_rank: Super Contributor
timestamp: February 28, 2016, 07:08:18 pm
content: Did you check these manual repositories ?http://www.ebaman.com/index.php/remository/Home-Electronics/Audio/MARANTZ/http://www.schematicsunlimited.com/m/marantz

author: nathanpc
author_rank: Unknown
timestamp: February 28, 2016, 07:23:04 pm
content: Yes, I did quite a lot of googling and wasn't able to find anything for those listed above.

author: PaulAm
author_rank: Frequent Contributor
timestamp: February 28, 2016, 08:59:36 pm
content: This is a good site for Marantz information, although I couldn't find anything for those specific models.http://www.hifiengine.com/manual_library/marantz/Maybe you can find a related model that will have something close enough to be useful. You have to register to download.I did find complete schematics and service manuals for my 2245 thoughIt might be worth a post there to see if anyone has a pointer to what you need.

author: nathanpc
author_rank: Unknown
timestamp: March 01, 2016, 10:13:47 am
content: Fromthis russian forum/url] I was able to download a massive ISO file that contained the schematic for the SD255 tape deck, now all I need is to find the one for the tuner and graphic equalizer. I've attached the schematic so no one has to download the same massive ISO.
898D+ Solder Station Repair - Page 1
Forum section: electronics / repair

author: danadak
author_rank: Super Contributor
timestamp: February 25, 2016, 11:23:55 pm
content: I purchased one last Sept, using iron side of station. Then yesterday usedhot air, worked for ~ 1 hour, although fan speed control would not work.Then hot iron fan failed, overheating in the process. Now totally dysfunctional.Anyone have a schematic ? Its a no brand knockoff, so I am guessing it followsthe OEM version(s). I have already poked around trying to troubleshoot buta schematic would be quite useful.Regards, Dana.

author: bitseeker
author_rank: Super Contributor
timestamp: February 26, 2016, 05:26:03 am
content: Since a lot of these kinds of things can have many variations, it's a good idea to post some photos of the PCB(s), etc. to help folks orient to the device you're inquiring about.

author: danadak
author_rank: Super Contributor
timestamp: February 26, 2016, 09:11:06 pm
content: A couple of picsRegards, Dana.

author: nogood
author_rank: Contributor
timestamp: February 27, 2016, 05:16:47 am
content: Is that red stuff on the connectors and IC melted cable isolation or just some sort of paint ?edit: nvm, I noticed it on the front panel too... glue, duhh

author: KL27x
author_rank: Super Contributor
timestamp: February 28, 2016, 01:06:19 am
content: 5V rail: Do the displays turn on? Do they show what they're supposed to? If not then you're probably screwed. Check the voltage on the control board rail.If it's 0V or 5V, then maybe you're ok. Proceed to look for a loose wire or a cold solder joint. If it's 0V, check the output of the transformer. Check the 5V regulator.If you get high voltage on the 5V line, then your whole control end is probably fried.If the 5v rail and the displays are good, look at the power FET/TRIAC and w/e is driving them. If those are fine, check for any problems on the sensor/voltage feedback lines.Just start at the logical spots. You don't need a schematic to look for the common and/or practically fixable problems.

author: danadak
author_rank: Super Contributor
timestamp: February 29, 2016, 09:43:53 pm
content: The red stuff is just glue to hold stuff in place.The 5V rail is good, solder iron side of station works, shows temp ramping on display and thenlevel off so control loop OK (I assume micro uses essentially same code base for both sides).What I do not see is 24 Vdc at fan, when it was working fan was always on when switch thrown.I did check fan, its hosed.Contacted vendor, trying to get schematic out of them, to see how 24 Vdc is developed. Tryingto avoid creating a schematic from scratch, looks like I have wasted enough time maybe Ishould give up and do that. I detect vendor thinks his schematic part of the nuclear triad armsrace top secrets. People get real weird when they use 2 Rs and an NPN and a load R and createa 1 transistor amp, they think that is a top secret. I have same problem with an amplified subwoofer, oem will not provide schematic. Idiots.Thanks guys for the replies, I will get off my lazy arse and create a schematic from scratch. Ugh.Regards, Dana.
Identify push button from some Sony Video Console Thingy - Page 1
Forum section: electronics / repair

author: Hole
author_rank: Contributor
timestamp: March 08, 2016, 05:39:40 pm
content: Hi!I rescued some parts from a non working Sony Video Mixer Board. These are illuminated push buttons, I assume two-color. I desoldered one button and looked a bit into the schematic, see attached images. As far as I see everything is multiplexed.Resistor on board is 15 ohms, so I tried it with 1k. Adding 5 V nothing happend, adding 12 V it glowed some time and then it died.I don't want to kill more of those button for experiments.... Anyone out there to identify this push button and some data how to use it?Thanks!