hybridfree/eevblog-posts huggingface dataset:
Value for money hot air rework station - or alternative - Page 1
Forum section: electronics / repair

author: NOON Design
author_rank: Contributor
timestamp: January 20, 2020, 12:26:32 am
content: Hi, I've been soldering through-hole parts for nearly 40 years now and taken up hand soldering surface mount components (with a magnifying lamp) in the last few years, but have now hit a repair that requires new tools.I have to replace a couple of BUF634 power buffers in TO-263 DDPAK surface mount packages. They're pretty solidly attached to the PCB, so I assume I'll need a hot air station to get them off safely.This is not something I'm going to be doing often, so I don't want to spend a fortune, but I also don't want ultra-cheap disposable crap.Budget is up to maybe AUD$300, I'm in Melbourne, Australia.Recommendations for the best tool/s for the job (with minimal risk to the PCB)?Would also love some pointers to techniques or tutorials to get me started, haven't played with hot air guns before.Cheers!

author: TheMG
author_rank: Frequent Contributor
timestamp: January 20, 2020, 12:47:25 am
content: Quick 861DW.

author: NOON Design
author_rank: Contributor
timestamp: January 20, 2020, 02:06:44 am
content: Thanks. They seem to go for $400 - $500 here, so a bit more than I was hoping to spend. Anything that's a bit cheaper but still worthwhile?

author: DaJMasta
author_rank: Super Contributor
timestamp: January 20, 2020, 03:33:22 am
content: Value for money? One of the 858s. Lots of rebrands, but I've got a WEP 858D and it was like $30 US. Works fine, doesn't take up much space, seems to be fairly even with temperature and airflow settings.Doesn't seem to be the safest thing available(see David's video on a similar unit melting itself), but lots of people have and use them and the failure rate seems relatively low. Been using mine for years and while it's no frills, isn't particularly quiet, and can't put out a crazy amount of heat or airflow.... it really does fine for the majority of SMD work.An alternative for your application could be a PCB preheater, then just using your iron as normal, but I think the flexibility of the hot air station makes it a better investment (and if you get a cheapy like the 858, a much smaller investment).

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: January 20, 2020, 05:55:14 am
content: I've got one of YIHUA 853AAA. It takes more space on the desk but if you have extensive ground plane you may need to preheat the board. It makes removing components much easier.In some applications I think it's really helpful to have a stand. Heating something and having both hands available to do the work... priceless.They are a bit pricey $200.I also have few different versions of 858. It will do the work.
value of the power resistor from a Sonoff powr2 - Page 1
Forum section: electronics / repair

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: September 16, 2021, 08:15:50 pm
content: Dear friends,I have fried my Sonoff PowR2 due to suddend high voltage in a three phases main.The power resistor is no longer readable. I think it is a 10 ohm resistor.Can someone confirm this and tell me the power of this resistor as well as tolerance ?Thanks

author: perieanuo
author_rank: Frequent Contributor
timestamp: September 17, 2021, 08:37:36 am
content: the schematic is all over the net

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: September 17, 2021, 09:29:05 am
content: Thanks a lot.This is exactly what I needeed.I searched the net, but obviously, not enough !Jacques
Vane VP-950 Dynometer - Page 1
Forum section: electronics / repair

author: dalford1987
author_rank: Newbie
timestamp: April 13, 2021, 10:57:09 am
content: Hi All,First post, long shot but does anyone have technical information or know about the Vane VP-950 chassis dynometer. I'm currently repairing one, I have repaired the control PCB before and had some success. I believe I'm getting voltage spikes from the retarder brake on the control PCB many TTL IC's failed. I'm willing to pay for service information, it would make my life easier.Regards,David Alford

author: trobbins
author_rank: Frequent Contributor
timestamp: April 13, 2021, 12:28:38 pm
content: I couldn't get any VANE related technical docs for a VP708 or 7100 - had to reverse engineer all the wiring and pcbs. The operating manual is likely all you can hope for.

author: dalford1987
author_rank: Newbie
timestamp: April 14, 2021, 03:30:17 am
content: Hi,Thanks for reply, yeah I've done a bit of reverse engineering on it. I suspect I might have a wiring issue (rubbed through) somewhere but as its intermittent I was hoping for a circuit/miracle, bit short on them currently 😀

author: crerus75
author_rank: Contributor
timestamp: April 14, 2021, 04:37:10 pm
content: I thought Mainline Dyno inherited the Vane product line years ago and were providing limited support. Have you tried contacting them?

author: dalford1987
author_rank: Newbie
timestamp: April 17, 2021, 07:55:30 am
content: Yes I've contacted mainline but they told me they have no information etc. on the VANE stuff anymore
Varistor selection - Page 1
Forum section: electronics / repair

author: mayor
author_rank: Regular Contributor
timestamp: December 07, 2020, 08:58:43 pm
content: Hello,through my own mistake, I blew up a variable resistor of an unknown value on a board. Here's what the schematic looks like for that part of the circuit (secondary side of a transformer, eventually leading to a 1K resistor at the gate of a mosfet):24ppVAC = 17V RMS, so 20V varistor?I'm not committed to making this repair, but am turning to people with some experience for opinions.Tx
varitronix vi-514-dp display-Any alternatives available? - Page 1
Forum section: electronics / repair

author: djsb
author_rank: Super Contributor
timestamp: December 21, 2019, 04:07:51 pm
content: Hi,I may have to replace the LCD display on an FM tuner. It's a Varitronix vi-514-dp 7 segment LCD 4.5 digit (how is this number of digits determined?). The part number in the service manual is VI515-DP14.5-TC-S-N-12.https://www.pacer.co.uk/Assets/User/1361-VI-514-DP.pdfI'm wondering if there is LCD display currently in production that can be used as a replacement. Any help appreciated.Thanks.David.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 21, 2019, 04:32:15 pm
content: Seems to have them in stock ??https://rs.components-store.com/product/Varitronix-International-Ltd/VI-514-DP-RC-S.htmlhttps://gl.infinite-electronics.hk/product/Varitronix-International-Ltd_VI-514-DP-RC-S.aspxor a search on Ebay give this :https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=4.5+digit+lcd&_sacat=0The first three items ?? substitues but no infos for the pinouts ?

author: Andy Watson
author_rank: Super Contributor
timestamp: December 21, 2019, 04:50:22 pm
content: Try searching for Display Elektronik - their DE 128 models look similar:https://display-elektronik.de/Drill down: "LCD Products" then "7-segment panels"https://vuec.co.uk/OPTOELECTRONICS/DISPLAYS/LCD_DISPLAYS/LCD_DIGITAL_DISPLAYS/DE128_RS_20_7_5_Display_LCD_digital_STN_Positive_No_of_dig4_5_DE128_RS_20_7_5_V_169098_0.html
Velleman PS603 power supply - Page 1
Forum section: electronics / repair

author: vanders
author_rank: Contributor
timestamp: August 24, 2023, 10:39:56 am
content: Goodafternoon..Still have a old Velleman PS 603 working powersupply.. but now the amp meter is broken..coil somewhere open / no conduct.Maybe someone here has an idea / diagram of which type amp meter is inside.. it is one without a shunt, so it could be somewhere in the micro or milliamps range.If one of the forum members knows, let me know..Thanks in advance.

author: Swake
author_rank: Frequent Contributor
timestamp: August 24, 2023, 02:25:01 pm
content: Use a multimeter to measure it and find out.

author: vanders
author_rank: Contributor
timestamp: August 24, 2023, 08:43:40 pm
content: Goodevening..Thats a good one.. for example 1 at the output with a load, and on the print where the meter is fixed / soldered on the board a second analog one to found out which is the most usefull one..Try tommorow, tnx

author: floobydust
author_rank: Super Contributor
timestamp: August 25, 2023, 03:35:22 am
content: Same schematic PS603 (analog meters) or PS613 (digital panel meters).They are not very strong or well made and need a lot of repairs.
Ventilator repair Drager Pulmolog - Page 1
Forum section: electronics / repair

author: aurelleostean
author_rank: Contributor
timestamp: April 03, 2020, 11:23:42 am
content: Hi to all,I have a very old drager Pulmolog ventilator that i have for some time in the garage, these days of stay at home. I have some parts that i cannot identify if broken or not. Can someone help me with this? the unit worked just fine a year ago.

author: Gyro
author_rank: Super Contributor
timestamp: April 03, 2020, 12:14:44 pm
content: Wow, Spaghetti! I wonder how clean all of those tubes are?(Edit: Although I suspect that they are all pneumatic control lines rather than patient gas though. Even so, that's an incredible unlabeled tangle!)

author: aurelleostean
author_rank: Contributor
timestamp: April 03, 2020, 12:56:59 pm
content: one of the square valves is not working, after an hour of taping the valves i got it to work again. i do not know witch one to blame

author: Gyro
author_rank: Super Contributor
timestamp: April 03, 2020, 01:12:40 pm
content: Unfortunately my pneumatics skills are limited to an old temperamental pick and place machine, years ago, but I suspect that your diagnosis is correct - most likely a rubber diaphragm became 'stuck' to its seating after a year of disuse.I'm sorry, but without documentation I don't see how you're going to be able to narrow it down which valve. The only thing I can suggest is repeated 'power' cycling and gentle exercise in the hope that it will settle down again to normal operation.

author: daisizhou
author_rank: Super Contributor
timestamp: April 05, 2020, 11:40:01 am
content: It is recommended that you conduct a POST test(I looked at the picture and found that your ventilator is very old, I think it should be enough to test the performance of the mechanical seal)You need air source (air + oxygen) and piping + simulated lung (can be replaced with balloons)
Verilux Lamp repair - Page 1
Forum section: electronics / repair

author: jerryk
author_rank: Regular Contributor
timestamp: July 09, 2020, 07:42:52 pm
content: I'm trying to fix a friends Verilux Led Smart Light that just quit working. When circuit board is out of the plastic enclosure pictured below you can get it to turn on by touching the contact springs but it behaves very erratic, blinking, and switching modes on it's own. When I test the controller side of C3 the voltage was very unstable. I removed the capacitor at C3 and now the light performs closer to how it should work. The light stays on, behaves in a stable manner, but only one of the brightness buttons works. When I put the circuit board back in the plastic enclosure the power button works but no other buttons are functional.It seems like I'm on the right track but not sure the problem is solely the capacitor or if there is a malfunction in the microcontroller itself. Any ideas on how I should go about trouble shooting this?The C3 capacitor that I removed measures 5.5 nF. I don't have a replacement for it so I put a 10 nF to see if it would fix the situation. It did not. Any ideas on what kind of microcontroller that is and what the original capacitor should be rated at?Also, I have never dealt with that kind of touch sensitive button setup. It seems based on resistive touch. Any info on this would be appreciated too.Thanks in advance for the help.Jerry
Very Noisy Kikusui PLZ152WA Electronic Load - Page 1
Forum section: electronics / repair

author: sampler1
author_rank: Regular Contributor
timestamp: July 10, 2021, 01:35:18 am
content: I am about to ditch my Kikusui PLZ152WA Electronic Load. It is so noisy !It works well but it's driving me crazy. I thought I would throw this out there and maybe someone might have a solution before I ditch it.Regards to all!

author: Jester
author_rank: Frequent Contributor
timestamp: July 10, 2021, 01:52:06 am
content: If you mean audible noise, just change the fan.

author: sampler1
author_rank: Regular Contributor
timestamp: July 15, 2021, 01:00:11 am
content: I actually decided to replace the 100V fan with a 12VDC Fan and a Temp speed controller. Also incorporated a small 12 volt DC supply.Super Quiet now.Regards to all the people who never bother to help out.

author: glano
author_rank: Newbie
timestamp: May 12, 2023, 08:14:12 pm
content: I have a Kikisui PWR401ML PSU with a loud fan.I haven't taken it apart yet to see but wondered if you had any more details on your fix, e.g. parts used, integration, etc.Thanks!
very old variable psu transistor pinout needed - Page 1
Forum section: electronics / repair

author: ME
author_rank: Frequent Contributor
timestamp: May 10, 2025, 02:55:28 pm
content: I have a very old variable psu with an old ME8003 npn TO106 style case , I cant find any pinouts ,can anyone help?, i found its specs but no pinout.

author: Andy Watson
author_rank: Super Contributor
timestamp: May 10, 2025, 03:16:51 pm
content: My Towers Transistor book says it is:NPN, TO105 package, 60V, 800mA, 400mW, hfe 100.It also says that is was manufactured by MicroElectronics Ltd. Here is one of their data books.http://bitsavers.org/components/microElectronicsLtd/It does not list the ME8003, but page 369 gives their package outlines.

author: ME
author_rank: Frequent Contributor
timestamp: May 10, 2025, 04:09:38 pm
content: Many thanks andy , That was a big help,just need to find a sub now,will look at a bc108 as ive a few kicking around in my junkbox.

author: ME
author_rank: Frequent Contributor
timestamp: May 10, 2025, 04:15:22 pm
content: Think i will try a bfy50, they match better than bc109.

author: madires
author_rank: Super Contributor
timestamp: May 10, 2025, 04:29:38 pm
content: If 50V are fine maybe a BC337, otherwise a BC637.

author: ME
author_rank: Frequent Contributor
timestamp: May 11, 2025, 12:36:58 pm
content: would a bdy39 be 0k? , I am trying to use whats in my junkbox.

author: madires
author_rank: Super Contributor
timestamp: May 11, 2025, 01:06:54 pm
content: You're looking for for a jelly bean NPN with a slightly higher current capability (0.8A). BDY39 is power NPN in a TO3 package and could be used as a pass transistor (needs high base current). BFY50 is an RF NPN. Could you please post the circuit diagram? Maybe we're able to narrow down the required specs.

author: ME
author_rank: Frequent Contributor
timestamp: May 11, 2025, 07:40:37 pm
content: Sorry i meant bd139 the pinout doesent matter,heres a pic of the pcb from 1960/70s i guess,it has no model or name. [ Attachment Invalid Or Does Not Exist ]

author: ME
author_rank: Frequent Contributor
timestamp: May 11, 2025, 07:42:38 pm
content: againe.

author: madires
author_rank: Super Contributor
timestamp: May 11, 2025, 07:48:19 pm
content: A BD139 might work.
VFD compatibility for HP/Agilent 6611C, 66309D, 66319D, etc. - Page 1
Forum section: electronics / repair

author: hp3310a
author_rank: Regular Contributor
timestamp: April 25, 2025, 08:30:25 am
content: I'm thinking about purchasing an Agilent 6611C with a rather bad VFD, so a replacement is likely necessary. Looking at the VFDs on ebay I see a lot of different offers for the visually same type of VFD for many different HP/Agilent power supplies, like 6612C, 66319D, 66311B, 6631B and many others.All look the same, same annunciators, digits, number of pins and pin layout. Does someone know if those power supplies in fact use the exact same VFD?

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: April 25, 2025, 09:12:13 am
content: Hi hp3310a,a look at the respective Service-manuals should help.Do you need the display anyways?Will you use the PSU manually or over GPIB/RS232?Good luck

author: hp3310a
author_rank: Regular Contributor
timestamp: April 25, 2025, 10:26:41 am
content: Good suggestion, the service manuals for the 66111A, 66311A/B/D, 66309B/D and the one for 6611C, 6612C, 6613C, 6614C the front panel PCA has got the same part number:Board A3 - Part No. 5063-3430; Front Panel PCAThat *could* mean the VFDs *may* be compatible, unless the circuit details changed while keeping the outside facing interface the same. I believe the 34401a had such a change at some point.I couldn't find a service manual for the 66319D and its cousins.

author: hp3310a
author_rank: Regular Contributor
timestamp: April 26, 2025, 10:43:07 am
content: Yesterday I failed to realize that the PCAs are only the same for early, through-hole 663xx variants and the 6611C. Later SMD variants use a different PCA part number number. Still the VFD might be the same, HP/Agilent/Keysight have a lot of different power supplies with the 66xy(z)abcd naming that apparently all use the same VFD.

author: hp3310a
author_rank: Regular Contributor
timestamp: July 16, 2025, 05:40:19 pm
content: To answer the original question: Yes, the VFDs for the 33609x-33621x DC sources are compatible with and work fine on my 6611C (presumable also 6612, 6613, 6614 and on a lot of other units).For the record, I bought this:https://www.ebay.com/itm/193879350286
VFD display only working when bent? - Page 1
Forum section: electronics / repair

author: coppercone2
author_rank: Super Contributor
timestamp: April 01, 2021, 08:00:29 pm
content: So I have a old sony audio thing I wanted to fix with a VFD on it. It's 90's tech and I got a new one now that looks similar, but the problem with the old one was that it was only working when I pushed the front panel inWhen I took it apart I redid all the solder joints in the area and some of them in the VFD made quite a bit of noise when they were soldered (like tension being reliefed), but afterwards it would not work at all, before it worked with mild pressure)I threw it out (I don't need 2, the new one is better), but can those complex VFD displays get bad bonds in them that can lead to this symptom? I figure its pretty stiff because its a glass tube but its also thin and long so I don't know if it can be bending inside.Basically it was a job that I set out about 2 hours for before its not worth it and that time expired, so I will just take the transformer and anything interesting in thereIt was making ALOT of noise considering it was just joints being remelted (it almost sounded like tiny tiny wire snapping) so I figured for the 50$ it is on ebay, if I ever want one I can just buy it. It sounded like pink pink pink, you can imagine it sounding like a tiny suspension bridges wires popping off, at least thats what I imagined, it seems like a very bad noise to hear around electronics, because I resoldered big ass chips (dip 80 I think) before in older equipment from the 80's and I never got that kind of noise even though they are similar size. like the noise you get in a movie with water pushing out rivets in a submarine or something big on a wire bridge or something like that, very dramatic

author: helius
author_rank: Super Contributor
timestamp: April 01, 2021, 09:05:32 pm
content: The (directly heated) cathodes in a VFD are "tiny wires" suspended from fingers at the sides. It could be that they snapped when you reflowed the pins, check with a flashlight if they are still there (every pair of fingers will have a wire across the panel).The other possibility is that the vacuum seal was broken, look at the blob(s) in the corner of the front glass, those are barium getters that scavenge gas molecules. When the vacuum is broken and air gets in, they turn from dark silver to white.

author: coppercone2
author_rank: Super Contributor
timestamp: April 01, 2021, 10:27:28 pm
content: ah I will see if I can look at the tube sideways before I throw it away, the transformer is more useful then the whole unit to me right now... i think the new ones have 24bit DAC and some other nice stuff.. its a sony receiverI think it has 3x power op amps too
VFD Multiple Segments on when should be off - - Page 1
Forum section: electronics / repair

author: jjoko
author_rank: Contributor
timestamp: September 10, 2021, 01:16:40 pm
content: Got a Pioneer Disc Player where its VFD has segments glowing where and when it shouldn'tDont know much about VFD's ..been looking for answers but so far stumped!Any help with this would be most appreciated.- Segments do come on as they should when a feature button-switch is selected..but its hard to make out.One leg of the The Filament/Heater Supply Voltage is reading -24Volts DC to ground and the other fluctuating from between -9 and -14Volts DC to ground..The Display Driver Chip is receiving -34Volts DCAlso the Disc Player when on power standby should mean the display is completely off...however there is one segment which is still on!..see picture.the circuit has the heater/filament voltage on all the time as is the supply to the Display Driver Chip - as long as there is mains power.

author: floobydust
author_rank: Super Contributor
timestamp: September 10, 2021, 10:11:47 pm
content: Need a model number to find the schematic.The VFD bias voltage is likely wrong, it needs a negative grid-cathode (filament) voltage to turn off a segment. It might be a problem with driver IC or open electrolytic capacitor for the bias supply.edit: note an open connection to a digit grid will cause the entire digit to be OFF - this is counterintuitive but I find the VFD grid actually acts like a screen (acceleration) grid.

author: jjoko
author_rank: Contributor
timestamp: September 11, 2021, 06:51:48 am
content: Hello FloobyHere is what I can get from a Service Manual ....the Powersupply Circuit feeds the display circuit on CN315.

author: YetAnotherTechie
author_rank: Regular Contributor
timestamp: September 11, 2021, 06:07:00 pm
content: post ac and dc volt readings:across c216across d207verify that the voltages at C315 exist *at the pins* of vfd control chip and vfd. There are several conectors in that path that may be bad.

author: jjoko
author_rank: Contributor
timestamp: September 14, 2021, 05:40:10 am
content: Quote from: YetAnotherTechie on September 11, 2021, 06:07:00 pmThanks for posting YAT - Ive found that the -30Volt VFdisplay Voltage is low at CN315 (pin 2 -24V instead of -30v) ..no other reason other than connector..Going to solder directly the ribbon to the PSU Circuit board - removing CN315.Will then retry..and measure Voltages again if needed...will post again tomorrow.todays Voltage testing:(-30V) VFDisplay Voltage at junction of D207 and R201 was -33.5VDC(-30V) VFDisplay Voltage at CN315, at CN801, at CN805 was all around -24VDCHeater-/Filament Voltage at CN315, at CN801, at CN805 was all around -29VDCHeater+/Filament Voltage at CN315, at CN801, and at CN808 was all around -26.5VDC

author: jjoko
author_rank: Contributor
timestamp: September 14, 2021, 07:59:19 am
content: Went Nuts and soldered the Ribbon at CN315 direct to the board just now - Success !Thanks for the advice - Now its usable again !
VFD rejuvenation USB 5V CD7220 - Page 1
Forum section: electronics / repair

author: hakonon
author_rank: Newbie
timestamp: November 04, 2023, 11:30:04 pm
content: Salvaged this old POS display with a dim vacuum fluorescent display in it. This is USB 5V version, fully DC.Been reading about these VFD rejuvenations possibilities.I tried supplying around 11,5v DC from some old computer PSU do the outermost pins some seconds a few times.Only a couple of the segment display areas from top left lit up, no general improvement in brightness.I was under impression those filament lines/grids should start glowing instead.Should I try more voltage to those same pins? I have no clue really.This USB version is really easy to program with python.I was thinking some chatgpt api app for fun, or maybe a guitar tuner or smth.
VGA monitor detection, simple way - Page 1
Forum section: electronics / repair

author: luis garcia
author_rank: Regular Contributor
timestamp: May 29, 2023, 10:32:48 pm
content: Hi,in order to detect a monitor on VGA connector in a way as simple as possible, i have used the old method of setting to ground pins 4 and 11.Apparently these should be enough to detect a monitor 1024x768 capable. Or at least it was many years ago.I have also to ground pins 6,7,8 and 10. Pin 5 is Gnd.However, when I connect this VGA connector to my PC VGA out, it detects no monitor.The graphics card is an old Nvidia with HDMI and VGA outputs. It is not the latest graphics card but it is not too old either.Do these relatively new graphics cards, detect 1024x768 monitors using this pin configuration, as old VGA cards did?

author: fzabkar
author_rank: Super Contributor
timestamp: May 29, 2023, 11:28:12 pm
content: You need to install 75-ohm resistors between the RGB pins and their respective grounds. The graphics card looks for these terminations.

author: luis garcia
author_rank: Regular Contributor
timestamp: May 30, 2023, 06:56:18 am
content: It works! Thanks fzabkar!

author: spostma
author_rank: Regular Contributor
timestamp: May 30, 2023, 08:38:22 pm
content: old monitors have 3 ID pins (4, 11, 12), one of which is grounded inside the monitor (see very end of linked page)Newer monitors ground ID0/pin 11, and have an I2C DDC on pins 12 and 15 for plug-and-play and monitor control functions.details seehttps://pinoutguide.com/Video/VGA15_pinout.shtml
Viavi CellAdvisor JD785A failing self-test - Page 1
Forum section: electronics / repair

author: nielsm
author_rank: Newbie
timestamp: November 10, 2020, 10:32:53 am
content: I am a radio amateur and recently purchased a used JD785A CellAdvisor Base Station Analyzer.The unit appears to have developed a fault in spectrum analyzer mode. Noise levels are within specification but signal detection levels are 30-40db below where they should be. I have attached a screen shot of the self-test showing a problem with the RF Board.I have not been performing any high power measurements which may have damaged the RF board so I'm not sure why this has happened.Anyone got any ideas/suggestions on what to try next?Thanks in advance.Niels

author: trentender
author_rank: Contributor
timestamp: November 23, 2023, 07:08:54 pm
content: I have a similar problem-did you have any luck solving the problem?
Victrola multi-player - No audio - Page 1
Forum section: electronics / repair

author: kokopelli75
author_rank: Newbie
timestamp: January 11, 2025, 10:01:44 pm
content: Hello!My mother has a Victrola Navigator multi-function player that stopped working after a storm. I checked out what I could - all player functions appear to work, but there is no audio output in either the speakers or the headphone jack. I suspect (with my limited knowledge) that the amplifier part of the device is toast. Photo of the suspected board is attached. There's separate boards for front display, record player, etc. This board has a section for power regulation and a section for amp. There's a UTC7266 7+7W dual bridge amplifier IC and a CSC2314F sound processor IC on the board. Visually, nothing is obvious. No caps look bad or bulging, no cooked resistors. Power regulators are providing voltages in range. Any thoughts on what I can check to identify the bad component(s)? Unfortunately, I'm limited to a multi-meter for test equipment. It's also a royal pain to take the board out, since there are so many multi-pin connectors on it. Lastly, I contacted the company, but they don't offer replacement parts.Thanks![edit: updated image]

author: kokopelli75
author_rank: Newbie
timestamp: January 12, 2025, 11:15:44 pm
content: Quick update, I did get datasheets for amp IC and sound processor.Voltage on amp input is appropriate, and injecting noise on the inputs produced sound on the speakers. So... perhaps the sound processor IC is fried?

author: Dougmc
author_rank: Contributor
timestamp: January 13, 2025, 01:58:31 am
content: Post info on sound processee.A cheap signal tracer would help u .

author: kokopelli75
author_rank: Newbie
timestamp: January 13, 2025, 06:03:42 pm
content: Sound Processor is CSC2314F. I only found a Chinese datasheet, but had google translate it. See attached.I jumped one of the radio inputs on the board directly to the amp IC input, and it sounded loud on the speakers. The volume control was ineffective, so the problem is definitely between the audio inputs and the amp chip.Voltage regulators seem ok. There are two op-amp chips, but I see 0V on both Vcc pins, which seems bad.
Victror (Ruoshui) VC4091C  LCR meter not working - Page 1
Forum section: electronics / repair

author: madstudio
author_rank: Newbie
timestamp: February 10, 2025, 05:04:32 pm
content: Hello guys, I tried to contact the tech. support of the manufacturer but there is not much help. TBH I really don't understand why they don't give the support, at least the spare mainboard. Can anybody help fixing this guy?Unit is powering up, it goes to the menu but it acts like the input is in short. I attached the display and the mainboard pics. Voltages seems to be OK.Thanks!

author: KungFuJosh
author_rank: Super Contributor
timestamp: February 10, 2025, 11:01:20 pm
content: In the most hilarious EEVblog style, Martin and Mike responded to the other thread for you now that you created this one. 😉Martin included a link to the part, which is rated to 125C, but maybe isn't supposed to be as warm as it is. 🤷

author: madstudio
author_rank: Newbie
timestamp: February 16, 2025, 08:14:46 pm
content: Quote from: KungFuJosh on February 10, 2025, 11:01:20 pmI replaced the U100 (CD74HC4053PWR) and unit works again! Thanks a lot for the support. Cheers!

author: madstudio
author_rank: Newbie
timestamp: March 03, 2025, 09:35:28 pm
content: Hi all. As I reported, unit woks again after the U100 replacement but I have an issue with measuring the inductance. For the known values meter measures close enaugh but after few seconds value drops for approx 30% and whatever I do it shows that wrong value. Callibration does not help. It seems that something else is damaged but I have no clue what. Can you gues what?
Video: Attempting to fix an SVI 328 but SOOOO many problems! - Page 1
Forum section: electronics / repair

author: llopis
author_rank: Contributor
timestamp: April 03, 2020, 05:31:02 pm
content: I normally don't post my repair videos here, but I thought you'd get a kick out of this one because it's mind boggling how many things are wrong with this poor computer.
Video Recorder Panasonic AG-6200 Instable image - Page 1
Forum section: electronics / repair

author: decoder_82
author_rank: Regular Contributor
timestamp: November 16, 2022, 09:15:26 am
content: Hello,I am trying to fix a video recorder Panasonic AG-6200.The symptoms are shown here:https://imgur.com/a/4YZE8pjBasically the image is not stable.What I did: cleaning of the video heads but it didn't improve the image stability.Anyone has seen similar issue on a VCR ?Thanks in advance

author: Manolo Mos
author_rank: Contributor
timestamp: November 16, 2022, 01:31:03 pm
content: Hi! I don't know this model, but this fail is common in other similar models, like AG-7330, AG-7350. This fault is due to bad electrolytic capacitors in Servo CTL Head Ic. You replace the caps, and the fault is repaired.In this video talks about the same fault in a similar Panasonic video. Best regardsAt minute 30 aprox

author: decoder_82
author_rank: Regular Contributor
timestamp: November 17, 2022, 05:34:46 am
content: Thanks for the reply. Indeed both electronic and mechanical problems are possible here.I will have a look on the caps as indeed the device is quite old. Might also be tape alignment issue from what I read.
Viewsonic XG2703-GS horizontal lines all over the display - Page 1
Forum section: electronics / repair

author: negodidentina
author_rank: Newbie
timestamp: September 28, 2021, 03:08:18 pm
content: Hello members of eevblog. I have a viewsonic xg2703-GS monitor that has seen quite a few years of usage. It's one of those monitors, 27inch with 144hz and 1440p. This one offers G-Sync as well. Due to unknown reason, a couple of weeks ago, horizontal lines started to appear on the screen. After testing singled out the problem to be the monitor itself and not my GPU or display cable. I'm typing this on that same system with a spare monitor.It's almost a year after my warranty has expired so when I contacted Viewsonic all they can do was looking up the parts numbers for my specific monitor so I can order replacements. I tried ordering parts but apparently Viewsonic US does not ship outside the US. So they told me to contact their branch that according to the support staff "supposed" to help me in this case. Viewsonic Netherlands replied me by saying that the responsibility to help me sits with the seller and not them. My seller was Amazon.I've looked at repair shops in my location and none does pcb repairs. All they offer is parts replacement which I can safely say I can do that myself.At this point I've decided to try and repair it myself. But I have no knowledge of pcb repairs, so I'll be starting at 0. I will include a couple of attachments to see if anyone can tell me what the problem is. Also I have no tools to diagnose a faulty pcb. My budget is not too high, probably with a new multimeter plus additional tools should sit around the 300 ballpark. Can someone recommend me the required tools to fix this monitor?

author: tunk
author_rank: Super Contributor
timestamp: September 28, 2021, 03:40:59 pm
content: Probably won't make any difference - could you try to reseat the PCB with the heatsink a few times?Ditto for the cable that goes to it (both ends).

author: negodidentina
author_rank: Newbie
timestamp: September 28, 2021, 05:53:50 pm
content: Hi, Tunk. Thank you for the suggestion. I just have tried that. The pcb with the heatsink is the gsync module. I have removed it and reseated it back in place a couple of times but the symptom of my monitor remains.
vintage components on ebay. - Page 1
Forum section: electronics / repair

author: bigpimp347
author_rank: Newbie
timestamp: February 27, 2023, 06:42:30 pm
content: found this sellerseems to have found a massive load of vintage stuff from Pye/Philips/Siemens/Neohm/GEC/Plessey and loads more..a lot of old VR and such.i messaged them and they have thousands of IC's and TTL, Logics and such, RF and other related items..maybe worth a message or a look, they said they are selling a lot of vintage components back to china where they want quality vintage items for restorations..ironic..!!https://www.ebay.co.uk/sch/i.html?item=255990686757&rt=nc&_trksid=p2047675.m3561.l2562&_ssn=electro-niknaks

author: coromonadalix
author_rank: Super Contributor
timestamp: February 28, 2023, 12:09:45 am
content: Dont want to spoil the "fun" but the pricing is vintage indeedover priced a bit to my taste

author: james_s
author_rank: Super Contributor
timestamp: February 28, 2023, 04:08:04 am
content: LOL 5 quid + shipping for some junk electrolytic capacitorshttps://www.ebay.co.uk/itm/255971883288?They might have some gems in the mix but there's clearly some old junk too.

author: jonpaul
author_rank: Super Contributor
timestamp: February 28, 2023, 04:15:12 am
content: Freight tax customs cost means only practical for UK buyer'sSeller needs a BVRS boot saleJon

author: bdunham7
author_rank: Super Contributor
timestamp: February 28, 2023, 04:26:41 am
content: If they are willing to sort and list all those in a manner which is readily searcheable on eBay, they are doing a very good service for anyone that happens to need one of those specialized parts. Sure, some of their listings are 'nope', but all it takes is one hit to save the day.

author: james_s
author_rank: Super Contributor
timestamp: February 28, 2023, 08:42:24 am
content: If they're going to try to sell random electrolytics they'd be better off putting the whole lot of those up together. It's only specific unique parts that are going to be worth selling in small batches.
Vintage Conar 255 Oscilloscope repair - Page 1
Forum section: electronics / repair

author: jk99345
author_rank: Newbie
timestamp: August 24, 2024, 11:10:10 pm
content: Hello,I picked up this old scope for cheap at a hamfest recently, it seems to be mostly functional with a few issues. The trace seems to be slightly rotated (which I can probably adjust easily with the trace rotation), but the trace is also slightly jagged rather than a straight line. I also get huge spikes (as shown in the second image) when adjusting the volts/cm knob. I assume this could be due to the switch, so I will try to clean off the contacts and inspect the solder joints.Thanks

author: jk99345
author_rank: Newbie
timestamp: August 24, 2024, 11:11:58 pm
content: The manual for this oscilloscope can be found here:https://bama.edebris.com/download/conar/255/255.pdf
Vintage Fan Capacitor Replace - Page 1
Forum section: electronics / repair

author: Webserfer
author_rank: Newbie
timestamp: July 08, 2020, 12:18:51 pm
content: So I recently got my hands on this beautiful Mitsubishi fan, oiled and it runs smoother than any brand new fan I've had.My problem is I found the capacitor was from the 60s and knew it'd need replacing (had a cap from 53 do this in a sewing machine already) so I pulled 2 caps from (within 5 years) old fans. Installed 2 in parallel to give the 2uf rating.Problem is when I was done the fan would barely spin, thought it was because they were in parallel but I cut one out and it got worse.Had to reinstall the old cap for now but don't feel comfortable leaving it on alone, bought it for white noise when I sleep but don't trust it.I assume theirs something I'm missing about the capacitor type or something? The replacement caps were rated 1uf each and were similar voltage ratings, (small black square caps out of somet cheap fans). One cap was from a working (but just damaged) fan so the replacements should of been fine.I assume this cap isn't safe to keep using or is it some special kind? Where would I find a genuine replacement that'd work if/when I do replace it while avoiding knockoffs?Thanks to anyone for any help.
Vintage HP Oscilloscope 1220A - No power. - Page 1
Forum section: electronics / repair

author: michalism
author_rank: Regular Contributor
timestamp: January 25, 2021, 12:24:23 pm
content: Hello all, and happy new year!I took my chances and bought this old oscilloscope on an Ebay auction. The seller clearly mentioned that it is not powering up, but it was only 10 Euros, and I was the only bidder, so here we are now.The first thing I checked when I received the unit, was to measure the resistance of the two power pins, and sure enough, I get no reading, so I guess the primary of the transformer is fried.I will take the cover off, and see if there's some kind of a thermal fuse that may be tripped off, but apart from that, do you have any other ideas?Is there a way to save this unit, or should I just donete it to a museum?thanks in advance!Michalis

author: michalism
author_rank: Regular Contributor
timestamp: January 25, 2021, 01:55:22 pm
content: I pulled the tranformer out of the chassis, and tried to take a better look at things. Took some pictures also.I was under the impression that the power from the IEC connector goes directly into the primary, but this does not seem to be the case. Based on the schematic, and my primitive investigation, the power is fed to the primary of the transformer after it goes through the main power switch, a capacitor, and the voltage selector switch. Here's the relative page from the service manualNow, when I opened up the unit, I saw two connectors attached to the tranformer. The smaller one, takes the line votage from the power connector and the voltage selector switch, and takes it to the main power sitch at the front. The second connector leaves the transformer and goes to the main board.So, repeating the measurment of the primary with the power switch at the "ON" position, I do get a resistance value around 50 Ohms, which I suppose is ok.Some more pictures in case they help.

author: michalism
author_rank: Regular Contributor
timestamp: January 25, 2021, 04:39:26 pm
content: ok...News update...The oscilloscope is working fine...Haven't changed anything; I just put the transformer back in the chassis, and powered the unit up to start measuring voltages and do some troubleshooting.Once I turned the power on, the power led lit, which was a pleasant surprise since that was not the case this morning...I checked the 4 power lines (-/+ 12V, +95V and +220V) and they're all fine...so I waited a little and after a while the green dot showed up to my delight!Still, I need to run a few tests to make sure everything is ok, but at least the main functions are there.Thanks for the attention
Vintage Keithley Model 440 Picoammeter Repair/Restoration - Page 1
Forum section: electronics / repair

author: danielbriggs
author_rank: Regular Contributor
timestamp: September 12, 2019, 06:14:46 pm
content: Hi all,Prompted from my other thread in B/S/T to purchase a Nixie tube for this, here is a thread for the repair / "restoration" (might be more applicable!) of a very old Keithley Model 440 Picoammeter.First off... I have absolutely no idea what I'm going to do with this; I only bought it for the lovely display and repair journey. So if anyone can suggest a worthy use, let me know.The unit has cleaned up quite well so far.Based on the now removed asset tags, it appeared to have been bought/owned by AVX Semiconductor.Currently the "Hundreds" Nixie tube is dead. Verified by swapping the H/T/U tubes around, fault follows the tube. All drive electronics of the 3x on the card work well.The "±" indicator works.I currently haven't ascertained if the "1" Thousands tube works, but is not the same as the H/T/U. On my list to investigate.The Nixie tubes are NL-841's.It appears to be a RTS-14 base.http://danielbriggs.co.uk/NL-841.pdfhttp://www.swissnixie.com/tubes/NL841RCA/I have a sensibly priced NOS replacement on its was from USA old aviation surplus place; it should be here in a week or so, so fingers crossed that's the glorious display back and working with the correct parts.After then I'm swapping the mains flex as the 1970's one is breaking down / disintegrating and is bordering on dangerous.Once the display is functional fully again I'm planning to calibrate it, and run some tiny currents through it to see what it says on each range. Any pointers? I do not have a SMU or picoampere source currently.Now for the first batch of pics:Note the amazing range switch and 100GΩ resistor! [I've been careful not to touch any component, as have read things that scared me like "the resistance of a fingerprint"]Manual:http://danielbriggs.co.uk/Keithley440.pdfWell, hope that's of interest.All the best,Dan

author: SilverSolder
author_rank: Super Contributor
timestamp: September 12, 2019, 07:59:37 pm
content: Looks in beautiful shape! Gotta love old tech...

author: Gyro
author_rank: Super Contributor
timestamp: September 12, 2019, 08:55:54 pm
content: I love the old stuff too.Good instinct on the fingerprints, you want to keep everything in the frontend scrupulously clean.At least it has nice cheap input connectors, not the modern Triax stuff. It looks to have a decent level of input overload protection but it would still be pretty sad to accidentally damage the matched input FETs - hopefully that calibration note on the 100pA range isn't significant and just indicates a bit of contamination somewhere.

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: September 13, 2019, 03:40:06 pm
content: The meter portion is the same as other Keithley multimeters... I have 160 with the same exact driver. I believe 164 has the same as seen in Marco Reps video here:
Vintage multimeter test leads - where to find? - Page 1
Forum section: electronics / repair

author: Peabody
author_rank: Super Contributor
timestamp: August 10, 2022, 05:40:53 pm
content: I have a Monarch MT-222 analog multimeter. Mind you - this is a genuine Monarch MT-222, not some cheap imitation. Two jewels! Anyway, over the years I've had to rework the DUT end of the leads several times, but would really like to just get new leads. The problem is that the meter ends of the leads are very small pins. They are about 1/16 inch, a little less than 2mm. Everything I see online is either shrouded, or banana plug, and much bigger. Does anyone know where I might find the right leads, and what would be the correct term to search for? This meter dates back at least to the 70's, and is no longer my primary analog meter. But I would like to restore it to a useful condition, and would rather avoid splicing if I can. The AA says best if used before 2002, so I probably will replace that, although at 1.48V it's just broken in. But otherwise I just need to get leads that work.

author: james_s
author_rank: Super Contributor
timestamp: August 10, 2022, 07:31:09 pm
content: Are they like these?https://www.amazon.com/JFtech-Bullet-Banana-Connector-Female/dp/B08F1XYPWFI used connectors of this type to connect small brushless motors to the speed controller in RC planes.

author: bdunham7
author_rank: Super Contributor
timestamp: August 10, 2022, 07:59:23 pm
content: Probemaster has these with 0.080" pins. Does that work?

author: tooki
author_rank: Super Contributor
timestamp: August 11, 2022, 06:10:20 am
content: Quote from: Peabody on August 10, 2022, 05:40:53 pmNo-load voltage? Then it’s already going bad. Given the age, leakage is a likely outcome, and given how cheap AA batteries are, just replace them.

author: Peabody
author_rank: Super Contributor
timestamp: August 11, 2022, 02:18:47 pm
content: I think the Probemaster leads would work. But at $22 plus shipping, I could just buy a new meter as good as this one. So I guess I'll rework the ones I've got, and try to implement some better strain relief.As for the battery, I think I will use this meter for current and voltage, mainly current, so it won't need a battery at all.

author: tooki
author_rank: Super Contributor
timestamp: August 11, 2022, 04:05:46 pm
content: Quote from: Peabody on August 11, 2022, 02:18:47 pmWhich will come with awful probes that are worth exactly what you paid for them. Probe Master probes are worth every cent, they’re just lovely to use.Of course, Probe Master isn’t the only company that makes pin style multimeter probes. Or you could get whatever probes you like and replace the banana plugs with pin plugs. Or keep the banana plugs and use an adapter. You could also modify the meter to replace the pin sockets with banana jacks. There are so many options.

author: james_s
author_rank: Super Contributor
timestamp: August 11, 2022, 06:20:03 pm
content: Quote from: Peabody on August 11, 2022, 02:18:47 pmHow much is your time worth? $22 is not much money these days, the McDonalds near me is hiring starting at $17/hr. Seems fairly reasonable for a set of good quality test leads.