hybridfree/eevblog-posts huggingface dataset:
Delta Elektronika SM3540-D - Page 1
Forum section: electronics / repair

author: K3RT
author_rank: Newbie
timestamp: July 04, 2016, 09:41:49 pm
content: Hello, I am new here.I got myself a Delta Elektronika SM3540-D35V/40Apower supply.I am very happy with it overall (never had so powerful power supply), but have one tiny problem with it.The output voltage won't go down to 0V.Even if I turn the V-pot all the way to "0", I get 0,56V on output.Only way to get 0V is when I turn the current limit also to 0A.I have found that there are trim-pots inside to adjust the diplay readings, but they don't affect the actual output.There are some trim-pots also without any markings, but I won't dare to touch them unless I am 100% sure what I am doing.Can anyone please tell me, is there a way to adjust the output to zero?Here is link to a PDF file containing the manuals and schematics:https://ia600208.us.archive.org/32/items/delta_elektronika_delta_elektronika_sm3540-d_power_supply_sm/delta_elektronika_sm3540-d_power_supply_sm.pdf

author: janoc
author_rank: Super Contributor
timestamp: July 04, 2016, 10:03:46 pm
content: That is a pretty heavy duty PSU!I think it may not be actually able to reach true 0V (what do you need that for, actually?) because the control loop would stop working if it didn't sense any output voltage. I would expect that to be mentioned in the manual, though.If you really need small voltage from it, I think the simplest solution would be to add a post regulator

author: K3RT
author_rank: Newbie
timestamp: July 04, 2016, 10:16:26 pm
content: Well, I actually don't need it.When I got it, the diplay readings were bit off, so I calibrated them with my DMM. And then I noticed that the output won't go down to 0V. So I was wondering, if it would just need some fine tuning, or is it a "feature"?It would be nice to have it 100% working as new.

author: RobK_NL
author_rank: Frequent Contributor
timestamp: July 06, 2016, 06:34:19 pm
content: You can always shoot an e-mail to supportdelta-elektronika.nlThey are *very* supportive!
Schematic for ASK Impression A9 LCD projector? - Page 1
Forum section: electronics / repair

author: TerraHertz
author_rank: Super Contributor
timestamp: July 06, 2016, 12:12:34 am
content: This LCD projector was given to me as faulty some years ago. It has a fault in the Green channel, that looks like an electronics failure rather than something with the LCD. It's like an input amplifier has lost all HF response, leaving only very low freq response. Result: the green is severely smeared horizontally.I never could find a schematic. Does anyone know where I might find one?If schematics are still not available, I'll make one more quick attempt to locate the problem, and if no success will disassemble it for fun and to free up space. I was recently given a much nicer and smaller 'broken' projector, that was a very easy fix.User manual is here:http://www.manualslib.com/manual/204907/Ask-Proxima-Impression-A9.html

author: TerraHertz
author_rank: Super Contributor
timestamp: July 06, 2016, 12:18:42 am
content: Quote from: blueskull on July 06, 2016, 12:15:12 amWho said I didn't consider selling it?Besides, group of friends into urbex, and one thing we do is organize movie nights in unusual locations. For which a potentially throw-away projector is best.

author: TerraHertz
author_rank: Super Contributor
timestamp: July 06, 2016, 01:20:00 am
content: Quote from: blueskull on July 06, 2016, 12:26:06 amOK, when I open it, after a few days wait to see if schematics show up. Other things ahead in the queue.It _should_ be easy, since there are three identical paths (RGB). But defeated me last time I tried. I recall they are not laid out identically. Wasn't worth putting in a lot of time.Seehttps://www.eevblog.com/forum/repair/what-was-your-easiest-repair-ever/for why this projector is now in the 'quick fix or scrap' list.
Old 8660 RF generator output low - Page 1
Forum section: electronics / repair

author: joeqsmith
author_rank: Super Contributor
timestamp: July 03, 2016, 09:53:22 pm
content: I bought this old HP 8660 RF generator about 10 years ago. It was listed as working on eBay. After doing an initial checkout, found it had a problem. Once I took it apart, I noticed someone had made a note on it about the problem. Rather than replace the bad parts, they had jumped them out. It has not had any problems since I went over it.I went to use it the other day and the output level was really low. Pulled it apart and checked all the voltages, all good. Checked at the oscillators in the mainframe, all good. Pulled the covers off the RF section and pulled out the board I had repaired way back when. It looked fine. Installed the RF section and it all works.I hate intermittent problems.

author: joeqsmith
author_rank: Super Contributor
timestamp: July 04, 2016, 05:08:41 pm
content: Put it all back together, ran it for a few hours, worked great. Let it cool overnight and fired it back up today and it's been sweeping for several hours with no problems. I suspect a bad contact and re-seating the attenuator control board in the RF section may have corrected it.

author: joeqsmith
author_rank: Super Contributor
timestamp: July 04, 2016, 10:45:17 pm
content: Ran all day. Put it back on the shelf, hooked everything back up. Turned it on. Dead.Reseated the plug-in, dead. Pulled the plug in back apart plugged it in, dead. Reseat all the boards, dead. Looks like it's the connector from the front controlled. Reseated that, bingo.Plastic has not cracked. Contacts look good. Solder looks good. May need to look at something a little newer....

author: tautech
author_rank: Super Contributor
timestamp: July 04, 2016, 11:19:41 pm
content: Quote from: joeqsmith on July 04, 2016, 10:45:17 pmNow you know where to look you could check continuity with a DMM.Do you have a trusted DMM?

author: joeqsmith
author_rank: Super Contributor
timestamp: July 05, 2016, 12:42:52 am
content: As cheap as the modern scopes are and as advanced as the handheld meters have become, RF signal generators must be too specialized. I can't find a 1M - 4GHz, low phase noise, -130 to 10dB, with some basic modulation and an Ethernet interface from UNI-T for $50. Where is that deal??Stupid thing. I can't get it to fail now. May be time for a complete cleaning of that RF section.
Hitachi VM-C30E VHS-C video camcorder 1987 - Page 1
Forum section: electronics / repair

author: DjoleMac
author_rank: Newbie
timestamp: July 04, 2016, 10:23:12 am
content: Hi, i recently found this old camcorder in basement it's from my dad, When i charged battery and turn on camcorder all functions are working except picture in viewfinder. I don't have cassette, is that problem or malfunctioned? The camera is left unused 25 years and when is prepared for storage then it worked.Best regards!
HP 34401A dmm repair -- general schematics question - Page 1
Forum section: electronics / repair

author: iXod
author_rank: Frequent Contributor
timestamp: July 04, 2016, 12:12:18 am
content: Pins 12 and 13 have a little triangle next to the pin number; pins 1, 2, 15, 16 have what looks like an "n"; 3 and 14 have an "x".What's the meaning of these marks?Thanks.

author: Dr. Frank
author_rank: Super Contributor
timestamp: July 04, 2016, 06:39:44 am
content: Quote from: iXod on July 04, 2016, 12:12:18 amThese triangles usually denote digital inverting inputs; in the AD7524 datasheet, it's /Chip Select and /Write.These small 'n' may denote a guard ring around all these 4 analogue pins, but that's my speculation only. Never noticed that before.I'll have a look into the original, 1990 vintage schematics, which look a bit different.Frank
neded help identifying this burnt mosfet. - Page 1
Forum section: electronics / repair

author: mookie1590
author_rank: Contributor
timestamp: July 03, 2016, 08:53:09 pm
content: I'm trying to find this mosfet and I have had no luck, the numbers are burnt but I pulled some under my microscope and trying to cast a shadow, worked a little. The top row has a Texas instrument symbol and then 48(xxxx?) and maybe an m next to the 48, but I'm not sure. so the first 2 numbers are 48, what is past that, idk. so 48(xxxx?) the bottom row is gsd1850(xxxx?) these are the only numbers I could pull, the rest was burned and boiled away. it came from a porter cable 20v drill, model number pcc600 type one.TO-220 PackageWould post zoomed in picture but how can I with a max of 2mb total for atachments, that is stupid.Guess this is the correct forum location? Don't see a forum for identifying burnt parts.Also it had a diode sb15100, can't find anywhere to buy this diode as it's discontinued.Thank you!

author: mookie1590
author_rank: Contributor
timestamp: July 03, 2016, 09:05:53 pm
content: Quote from: blueskull on July 03, 2016, 08:57:59 pmNice, I googled the numbers and could not find anyything. You're good or I'm retarded, I'll go for the both, lol.http://g01.a.alicdn.com/kf/HTB1sDTmJpXXXXXcaXXXq6xXFXXXH/CSD18502KCS-18502KCS-font-b-MOSFET-b-font-N-CH-40V-font-b-100A-b-font-TO220.jpgfound this image and this looks close, with the 28m not 48m. Still those nuumbers don't matter as it just goes in a drill and that just means I know what I need now. a 40v n channel. Of course I'll do plenty of research before buying, I don't care about wasting the dollar or two, but the time for shipping. Thanks man! Now I have something to go on.
Balance accuracy problem on a Thunder Power TP820CD LiPo charger - Page 1
Forum section: electronics / repair

author: ilium007
author_rank: Frequent Contributor
timestamp: July 04, 2016, 02:54:32 am
content: Hi guys - I have a decent (supposedly) quality dual port LiPo battery charger. I mainly use it to charge 3 cell LiPo's but have found cell#1 on port 2 is always balanced lower. I have calibrated both ports with a decent meter (to the mV).The charger is a Thunder Power TP820CD. I have had a look inside and I know that this charger is essentially two discrete chargers. I can see the two banks of through hole 10 ohm 1% load resistors (for discharge as well as balancing ?? I am not sure) and a bunch of surface mount resistors used in the voltage divider parts of the circuit.I am thinking that the low resultant cell voltage on cell#1 is because (maybe) the resistor tolerances are not so great. I was thinking that if I could narrow down the locations of the resistors used in measuring the individual cell voltages I could replace them with lower tolerance items.I have attached a pic of the board. Port two is on the right hand side and the balance lead plug is the white external connector on the right side. The uppermost pin (pin 1 in picture) is ground and the next pin down (pin 2 in picture) is cell#1. I haven't taken the board out of the case and given it will be a multilayer board I assume that because I can't see the trace for cell 1 it may be underneath.The battery packs are in series so cell 1 voltage is measured between pin 1 and pin 2, cell 2 voltage measured between pin 2 and pin 3 etc.Not sure if it's worth investigating but thought it would be fun to give it a go. Happy to pull the board all the way and get pics of the PCD traces.I don't know 100% how the circuit works but the LiPo charger has a built in balancer the compares each cell voltage and attempts to keep them balanced. This charger can handle an 8 cell battery, looking at the board there are opamps there that I assume are being used as comparators ? Each side (left / right) has its own discrete set of balancer components.Can anyone help !! I would like to keep this charger and given cell balancing on port #1 (left side) is spot on I know it has the potential (no pun intended) to be a good unit.

author: Prime
author_rank: Regular Contributor
timestamp: July 08, 2016, 02:44:49 pm
content: Hi,I can't comment on the individual charger designs - I haven't pulled enough of them apart but yes, there should be a compare method. They could either be check the cell voltages against a comparator or reading the cell voltages with the ADC. My guess is that the comparators are for safety and the analog input of the micro is doing the level checking. My reason for saying this is that the LCD displays cell voltage.I'd trace the measurement circuits back until you find some form of voltage divider or current limiting resistor on the measurement circuit. You'll probably find an out of spec resistor or bad soldering.

author: ilium007
author_rank: Frequent Contributor
timestamp: July 08, 2016, 03:14:45 pm
content: Thanks. I'll open it back up tomorrow and post some more pics.
Anyone have an Amrel SPS series DC power supply handy? Need some Cap info - Page 1
Forum section: electronics / repair

author: almstsobur
author_rank: Contributor
timestamp: June 26, 2016, 09:13:03 pm
content: This particular power supply is a model year 2006 SPS600-2-0020, but I think most SPS rack supplies in the range will have similar circuitry. I fixed the power supply, but I have a buldging capacitor that needs to be addressed. Problem is, it looks like someone has already been shit-rigging the area in question, it's a mish-mosh of caps, brands and values and I am not sure any are correct. The one marked in red is the one that is bulging, but I could use the value of the ones marked in blue as well if possible, please.I have scoured the web for a schematic, parts list or service manual, no luck. Amrel power supplies division was sold to Ametek in 2010 I think. I sent an email to Ametek and they were far from helpful, in fact quite "dick-ish"Any help much appreciated C117 & C120-126 are the ones I really need the value for.Thank You!

author: almstsobur
author_rank: Contributor
timestamp: June 30, 2016, 09:52:14 pm
content: No one? Maybe a guru can tell me what I'm looking at here? Is this a filter section? Any idea the ramifications of the wrong capacitance in this section? If I just pop in some 1000uf caps?Thank You.

author: SeanB
author_rank: Super Contributor
timestamp: July 03, 2016, 02:16:08 pm
content: Reasonably low power SMPS, so pretty much any value from 470uF to 1000uF of the appropriate voltage 105C low ESR capacitor will do there. However I would change all of them as well, unless they are the original Matsushita ( Panasonic) ones. Just make sure the ripple current rating is high enough, from the rectifier diodes anything over 1500mA would do.

author: almstsobur
author_rank: Contributor
timestamp: July 03, 2016, 07:31:25 pm
content: I plan to do them all, I don't see any Panasonic's, but that's likely what I will put in. The price was right at $45 and the repair was inexpensive as well. Don't know how often I will need it, but its nice to have a higher voltage unit in the rack at that cost. Thank you, I appreciate the information.
Fluke 99B Scopemeter Series II - Problem with FlukeView and download of Screens - Page 1
Forum section: electronics / repair

author: Candid
author_rank: Regular Contributor
timestamp: July 03, 2016, 01:32:46 pm
content: Yes I know. A very old product and old Softwareversion but maybe someone had the same problem and has a hint for me.I have a Fluke 99B Scopemeter Series II 100MHz. I managed to install FlukeView 3 on different virtual machines WindowsXP SP2 and Windows 7 32Bit. I use the RS232-Interface with an RS232 to USB Bridge. All drives are installed and working fine. I can connect to the good old baby and do all things (show online measuremt values, load curves and saved data...) except a download of a screen. On every install (32Bit WindowsXP or Windows 7 under VirtualBox or VMWare Fusion on a PC or my Mac) I have the exact same problem when I want to download a Screen. The transfer starts and runs till 18% and then I get a connection error.Maybe someone had the same problem and found a solution.
Marconi 2305 Repair - Page 1
Forum section: electronics / repair

author: TheDefpom
author_rank: Frequent Contributor
timestamp: July 07, 2016, 10:29:04 pm
content: Hi Guys and Gals,I thought I would just post a recent repair I did for a Marconi Modulation Meter, which I picked up from eBay as a faulty unit, I found a few issues with it, but I got it all fixed.I put a video up on YouTube showing the issues I found, one of which was due to good old Tantalum capacitors failing.

author: jkf1000
author_rank: Regular Contributor
timestamp: July 07, 2016, 11:33:47 pm
content: Thanks for posting the video. I know when I purchased my 2305 quite a few months back there was very little information out there. Mine was advertised as sold as seen and untested but fortunately it is working perfectly so far, all I have had to do is new LEDs throughout, and remove and re-seat the lefthand LCD to clear a bit of oxidation on the contacts. Very useful bit of kit, just a bit on the large size. Karl

author: TheDefpom
author_rank: Frequent Contributor
timestamp: July 08, 2016, 05:41:53 am
content: I found a service manual online before I purchased it, so I had that to refer to also, although in reality it wasn't what allowed me to fix it, just looking around and testing/reseating things allowed me to narrow it down.The manual was only helpful to test the power supply outputs.I would if uploaded it here too, but the forum doesn't allow a 3MB file upload.

author: tautech
author_rank: Super Contributor
timestamp: July 08, 2016, 06:24:29 am
content: Quote from: TheDefpom on July 08, 2016, 05:41:53 amYou can post up a link to it Scott, those that find this thread in the future will be thankful.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: July 08, 2016, 07:02:46 am
content: I find two manuals online:The first seems complete, the second appears to be missing all the detailed drawings etc.http://www.fracassi.net/iw2ntf/manuali/Marconi%20Instruments%202305.pdfhttp://exodus.poly.edu/~kurt/manuals/manuals/Other/MARCONI%202035.pdf
Hameg HMO352x HMO3522 - Page 1
Forum section: electronics / repair

author: ino5on
author_rank: Newbie
timestamp: June 30, 2016, 08:16:18 am
content: Hello to allMy Hameg HMO3522 did shut down while doing nothing and won't turn on again.Does anyone has the schematic / service manual ?Thanks for your help.

author: kripton2035
author_rank: Super Contributor
timestamp: June 30, 2016, 10:27:03 am
content: you can ask the hameg support on their web site - they are very helpful.isn't it still under warranty ?

author: ino5on
author_rank: Newbie
timestamp: June 30, 2016, 10:33:31 am
content: no more warrantyand rode & schwarz won't send me the service manual, I should send it in. But why spend a lot of money, if I could fix it my self.

author: nctnico
author_rank: Super Contributor
timestamp: June 30, 2016, 11:14:31 am
content: You could check the fuses and the power supply IF you have experience with repairing these kind of circuits.

author: ino5on
author_rank: Newbie
timestamp: June 30, 2016, 11:28:06 am
content: I can measure the voltage behind the rectifier (german Gleichrichter) but there is no more voltage at the transformer (german Übertrager)

author: kripton2035
author_rank: Super Contributor
timestamp: June 30, 2016, 11:43:25 am
content: http://www.repairfaq.org/sam/smpsfaq.htm#smpssfmoddon't forget to read the safety measures before ...

author: ino5on
author_rank: Newbie
timestamp: June 30, 2016, 11:56:24 am
content: I got an FI SwitchJust kiddingIt seems I have a lot to read

author: nctnico
author_rank: Super Contributor
timestamp: June 30, 2016, 07:22:58 pm
content: If you have the SMSP removed from the scope perhaps you could make some high-res pictures and post them somewhere with a link here. What often helps is to identify the switcher chip used and then look for a datasheet or even better an application note with a circuit which closely matches the PSU at hand. The datasheet is likely to also help to give a detailed description of the chip and how the circuit works.There are many checks you can do before actually applying mains voltage to the PSU with all the asociated dangers.

author: kripton2035
author_rank: Super Contributor
timestamp: July 01, 2016, 05:59:18 am
content: Quote from: ino5on on June 30, 2016, 11:56:24 amfixing smps is quite easy in the long run (but lot of the time is it worth fixing or replacing ?)but I've never been able to fix smps with PFC that are far more difficult to understand.
Looking for connector name - help to identify pcb crimp connector  - Page 1
Forum section: electronics / repair

author: marc22
author_rank: Newbie
timestamp: April 13, 2016, 02:24:30 pm
content: Hello,I'm looking for name of this connector?Can anyone recognize it?I spend some time searching google for "pcb connector" but no luck, looks like molex, but it is smaller...Any ideas?regards

author: krivx
author_rank: Frequent Contributor
timestamp: April 13, 2016, 02:32:41 pm
content: Looks a bit like JST XH

author: marc22
author_rank: Newbie
timestamp: April 13, 2016, 04:24:47 pm
content: It's looks like You are close to solve mistery.Not XH - because pin spacing is to big in this type.I think it's 1.25 pin spacingHere seller have dimensions on picture and match mine:http://www.ebay.com/itm/Micro-JST-1-25-T-1-5-Pin-Connector-plug-with-Wire-x-10-sets-/111380527960

author: mngiggle
author_rank: Contributor
timestamp: April 13, 2016, 06:34:58 pm
content: Molex PicoBlade may also be a close match.

author: marc22
author_rank: Newbie
timestamp: June 28, 2016, 07:50:27 pm
content: Hello,I'm back and got right connector.It was sold by RC shop at description "PicoBlade Molex Mini Micro JST 5pin 1.25mm" fit's perfect.Here picture how it looksThank You for answers and i hope it will help someone.

author: wyx
author_rank: Newbie
timestamp: June 30, 2016, 07:23:42 am
content: It seems like a RC battery charging connector. Search for a li-po battery 5s charging connector.
HP 34401A pcb rev and firmware version history? - Page 1
Forum section: electronics / repair

author: iXod
author_rank: Frequent Contributor
timestamp: July 05, 2016, 04:06:09 am
content: Just beginning the repair of my 34401A and wondering how high the pcb revs go and what the latest shipping firmware version was. A web search turned up nada.Thanks,iXHP-branded 34401A, Rev D. pcb; f/w 11-05-02
Tenma 72-5000 frequency counter sensitivity problem - Page 1
Forum section: electronics / repair

author: Radio Tech
author_rank: Frequent Contributor
timestamp: June 29, 2016, 01:11:56 pm
content: A while back I picked up this counter for free. A few days ago I tried using it for the first time. Was aligning a radio and it would not lock onto the oscillator, grabbed my old B&K 1801 and no problem.Yesterday I decided to test the counter and see what the problem is. Connecting my SG at full throttle (20K) to input A it read the 100MHz signal. At 15k it falls off. Tried the same on input B and it falls off at 10K. This thing is deafer than I am.Just looking over the board it appears to be two different circuits for A & B. With the same problem. My guess is the two signal paths comes together further in the circuit and this is where the problem is. Without a schematic I am shooting in the dark. Anyone seen this issue before?
HP PS-3701-1 failure - Page 1
Forum section: electronics / repair

author: rodrigopires
author_rank: Regular Contributor
timestamp: June 28, 2016, 10:39:16 pm
content: Hi everyone! So a few months ago i picked two power supply's (HP PS-3701-1) from the junk yard for a really great deal and they work amazing! One i left as is, but the other i soldered some wires to the output pins, just to have a better way to connect something to it. After that, the PS started to have iregular voltages, like as i terned it on, i would go to 4v, 6v, than 12v, as before it went right to 12v. After some time it stopped to work at all. When i plug it in it goes right to 12V and the to Ov. I think the overcurrent protection circuit is being activated but i dont know why. After this i desoldered the wires but it is still the same thing, goes normal as i plug in and then to OV, while the 5v channel work fine. Also i cant find any schematics online for this PS. Any ideas on what is goin on and what can i do?Thanks!
Spindle Motor PWM Controller  - Page 1
Forum section: electronics / repair

author: cryptlabs
author_rank: Contributor
timestamp: June 29, 2016, 01:13:30 pm
content: Hello,I have a PWM Controller to control a CNC motor. Everytime i try to start the controller by pluging in DC power to it the fuse blows.The fuse is rated to 5amp from the factory.Everything is connected correctly, im not sure why this is happening.Any help would be appreciated.Regards

author: EPTech
author_rank: Regular Contributor
timestamp: June 29, 2016, 08:42:59 pm
content: Hi there,Use a multimeter in continuity or ohms mode and measure between each pin marked S, D and G. Those are the pins that go to the power MOSFET's on the heat sink. There should not be any short between them, that is for each FET. There may be a short however between the FET's as they may use a common power rail. But on the FET's themselves ther should not be any short. Let us know.Happy hunting.
USB charging and data buses - Page 1
Forum section: electronics / repair

author: gore
author_rank: Regular Contributor
timestamp: June 28, 2016, 12:14:52 pm
content: Hello,I couldn't find a clear answer to this. I want to charge a camera off of a bicycle 6V 3W generator. I've wired up a simple AC-DC regulator, which works, but not every device charges up with only the Vbus / GND connected on the USB. How should I wire up the D+ D- buses? A resistor divider of some kind, perhaps? The specific device I want to charge draws around 400mA.

author: WaveFunction
author_rank: Newbie
timestamp: June 28, 2016, 01:07:39 pm
content: Many devices check to see if the data lines are shorted together. If the resistance is less than 200ohms then you get up to 500mA charging.However, newer Apple devices do things a different way. They check the voltage on the two data lines. You need 2V on both lines for 500mA charging, or 2.8V on D- and 2V on D+ for 1A charging.Seethisfor more info.

author: gore
author_rank: Regular Contributor
timestamp: June 28, 2016, 01:29:10 pm
content: Looks like I will do just fine by shorting the D+/D-. Thanks for the input!
Smd transistor test and JBL speaker repair. - Page 1
Forum section: electronics / repair

author: sspj9
author_rank: Contributor
timestamp: June 26, 2016, 01:16:55 pm
content: This board is from a JBL bluetooth speaker, wjere the comtrol buttons are. I beleive it is faulty as all leds ligjt with the d-mm on continuity however the leds on the left (were the power button is located dont ligjt up (on top and bottom of button) the device is faulty since as i swich on the power button the leds light up though immediately turnoff as i release the button (it tries to power up but doesn't) is this a sign of a short?, battery is charged well , its in good condition. I suspect the smd transistor as shown (S2A written on) what is tbis model and how do i test if it is faulty or not?Any ideas on what else might be causing the problem? I even checked the main board though no signs of shorts from the smd capsThanks

author: poot36
author_rank: Frequent Contributor
timestamp: June 27, 2016, 04:26:00 am
content: You can test it like two diodes. If it is shorted it will show 0V if not anywhere between 0.3V and 0.7V on diode test.
Fluke 8060A capacitor list and general restoration? - Page 1
Forum section: electronics / repair

author: cvanc
author_rank: Frequent Contributor
timestamp: June 25, 2016, 02:15:10 pm
content: Hi all-Finally getting around to re-capping and restoring my 8060As. I know there are several old threads here about this but I'm not finding a BOM for all new electrolytics. Pretty sure I've seen such a list here before? If anyone can point me to it I'd appreciate it - I hate reinventing wheels... thanks!

author: retiredcaps
author_rank: Super Contributor
timestamp: June 25, 2016, 04:54:34 pm
content: Modemhead's bloghttp://mrmodemhead.com/blog/fluke-8060a-repair/Look for July 29, 2013 reply with digikey part numbers.My only comment about modemhead's selection is he chose 85C caps whereas I would have chosen 105C when possible. In a handheld multimeter at room temperature, I doubt the difference in 85Cand 105C will matter over a 20 year period.Nichicon, Rubycon, Panasonic and United Chemicon would be my choices.

author: cvanc
author_rank: Frequent Contributor
timestamp: June 26, 2016, 08:53:36 pm
content: Ah, thank you! That's what I remembered... much appreciated!
telefunken solarize the images 17mb25-3 v1 060309 - Page 1
Forum section: electronics / repair

author: albott
author_rank: Newbie
timestamp: July 03, 2016, 02:47:16 pm
content: Hi,i've a problem with a telefunken tv that solarize the images.In a first step i've changed the ic (CM1671B) on the t-con board (V260B1-XC11) with negative result.After that, i've seen that with teletext, the problem does not occur. So the problem isn't the t-con board.The problem occour also with hdmi input (xbox360).Can anyone help me?Here, you cand find the service manual of the board (mb25):http://alessiobotticelli.com/manuali/MB25_SERVICE_MANUAL.pdfThx in advance
Soldering station the tip won't (barely) heat up anymore. - Page 1
Forum section: electronics / repair

author: vgamesx2
author_rank: Regular Contributor
timestamp: June 26, 2016, 07:18:58 am
content: Hi, I have a bakon 950d soldering station which stopped heating, I'm guessing it's the transformer dying? I'm asking because I'm not all that experienced...I at least know it isn't the tip, since that's seemingly what killed (or finished off) my iron, basically I had been using a tiny 1.6mm tip (T12 tip btw) since I got the thing, so I got fed up with its low thermal mass and recently got a new 3.2mm tip (well it's probably a clone, it only cost like $4) inserted it and even though it was warm I couldn't even melt solder, switched back to old 1.6mm tip and still nothing. Great...Suggestions?

author: tautech
author_rank: Super Contributor
timestamp: June 26, 2016, 08:14:53 am
content: There's some info in this thread that should help you sort out where the problem is:https://www.eevblog.com/forum/repair/need-help-identifying-heating-element-of-a-hakko-936b-clone/

author: vgamesx2
author_rank: Regular Contributor
timestamp: June 26, 2016, 08:29:21 am
content: Please correct me if I'm wrong, but isn't the heating element integrated into the tip itself on T12/T15 tips?

author: tautech
author_rank: Super Contributor
timestamp: June 26, 2016, 08:35:22 am
content: Quote from: vgamesx2 on June 26, 2016, 08:29:21 amSorry I'm not familiar with your iron so if I've led you up the wrong path.Good luck with your quest for answers.

author: Wirehead
author_rank: Regular Contributor
timestamp: June 26, 2016, 09:57:16 am
content: In some review I read the following:"However in mine the temperature was badly calibrated. It was showing 250C (P1) while the tip is only 160, I used the pot on the board, and was able to calibrate it properly. Now at 250C it is around 250, and at 300 it is 300."Could you try that? Use a thermocouple that came with a multimeter for this

author: Rasz
author_rank: Super Contributor
timestamp: June 26, 2016, 03:02:02 pm
content: bakon 950d, isnt that pretty much a repurposed laptop power supply with small t12 controller added?open it up and measure voltages

author: vgamesx2
author_rank: Regular Contributor
timestamp: June 26, 2016, 08:03:47 pm
content: Quote from: Wirehead on June 26, 2016, 09:57:16 amI had it set to it's highest temperature 450C and was getting nothing out of it, I think that's a little more serious than being poorly of calibrated.Quote from: Rasz on June 26, 2016, 03:02:02 pmHeh, yeah it looks like a laptop psu with a controller, alright I'll try poking it.I was thinking it was the transformer because it's fairly small for a 75W iron.
Tripplite 2200RMXL2U, functional, but clicking relay. - Page 1
Forum section: electronics / repair

author: electronics-whiz
author_rank: Regular Contributor
timestamp: June 26, 2016, 04:43:24 am
content: I got this old UPS from my work, we had 2 of this model with bad batteries, we ordered one new pack to see if we could get one of them running. This one was questionable but tried it even with full charge this is wat it does and not sure why. If you plug it in it's fine, unplug it with good full battery it goes to UPS mode so that's good. But when you go to unplug it and shut it down it will not shut down and what sounds like a relay will not stop clicking until the battery power is cut to it.I did open it up to look for visual damage, smell of burnt electronics. Got nothing but I did notice this: They used some relays in it that appear to be for load transfer or controlling the outputs. They have large spade terminals on the top of these relays with connections to the transformer and the outlets. I did notice one white wire was turned a light shade of brown like it got hot. I checked all the internal connections and that spade connector to that relay was loos, I squezed it down some with a pliers to try and fix that which helped, but it still clicks.I'm not sure if maybe it got hit by a surge, the heating of the wire somehow damaged that relay, or if there is some other issue. Part of me would like to fix this as it seems to be a fairly nice UPS unit. However, I also don't know if I should be trusting something like this not to go up in flames one day. It could be nice for a home rack or lab, but that is not critical either so UPS is not a huge deal. Maybe could turn into a power inverter, but still not sure i'd trust it for that.Any ideas or suggestions what I should do with this thing? thanks.
Unidentified SMD connected from pin #1 of balanced audio input XLR-3 to GND - Page 1
Forum section: electronics / repair

author: peteb2
author_rank: Regular Contributor
timestamp: June 24, 2016, 11:03:02 am
content: Anyone able to I.D. this component please? One (PA102) has ruptured and now permanently open circuit meaning the input hums should mic i/p be selected.. The red coloured body has the symbol 'T' . There is no schematic for the board available, only a roadmap and these two components are marked with an ! .... meaning they are specific.I don't think it's a fuse or one of those self-repairing fuses. I prefer not to just bridge the OC one as this is an expensive hi-end Panasonic camera. I hope to be able to just buy a few of these components from say Element 14, Mouser etc... The only other option is to replace with a new populated PCB which will take weeks and cost the earth!Anyone every seen such a thing?

author: bktemp
author_rank: Super Contributor
timestamp: June 24, 2016, 11:33:06 am
content: Looks like a fuse. It could be TE 1206SFV1.60FM/065-2:http://www.te.com/commerce/DocumentDelivery/DDEController?Action=showdoc&DocId=Specification+Or+Standard%7FSCD28861%7FA%7Fpdf%7FEnglish%7FENG_SS_SCD28861_A.pdf%7FRF4316-000

author: Someone
author_rank: Super Contributor
timestamp: June 24, 2016, 11:40:46 am
content: Reference figure 7 here:http://www.rane.com/note165.htmlIts a fuse to limit current in the local ground/inductor.

author: peteb2
author_rank: Regular Contributor
timestamp: June 25, 2016, 06:46:38 am
content: Gentlemen... a million thankyous!
Does someone know Ibanez/Boss JFET switching well? - Page 1
Forum section: electronics / repair

author: gooseEL34
author_rank: Regular Contributor
timestamp: June 23, 2016, 08:23:42 pm
content: Hey folksWorking on a guitar effect pedal that uses JFET switching. Was wondering if anyone can help me out. Schematic is herehttp://www.freestompboxes.org/download/file.php?id=11624Issue: pedal passes AC input signal only when engaged in the effect-ON state.So far I believe I have troubleshot the issue. This pedal uses a JFET as a series switch and the source and drain are never connecting on the unaffected signal path.I was going to just pull and replace but I began to look at the circuit and began to wonder how it works. I am no EE and essentially have a rudimentary knowledge of circuits but mostly audio (guitar amp). I can read a schematic, solder and use an oscilloscope to trace a signal to troubleshoot no output.That being said, I am weak on most other EE areas so no super tech answers please.basically my audio path is good at the source. This is a 9v system run off a battery or wall adaptor. I find 4.3vDC on both the Source and Drain (which makes sense). The circuit designed to switch the gate voltage from 8v to 0.5v (service manual specs) works and I get those readings at the junction between the 1meg resistor and diode (MA150) that are in series with the gate.So my JFET is not making the source to drain connection. Easy answer was to pull and replace but I got to wondering how the diode there is being used...can someone explain?I assume it is there (based on its orientation) to stop DC voltage from getting on the gate. I read that the diode was there to let the gate "float" where it will but I don't get that. How does presenting either 8v or 0.5 volts on the other side of that diode cause the gate to open or close since the diode stops the gate from seeing that voltage?JFET in question is the one in the lower right corner of the schematic D106. I get 7.6v and 0.6v at test point labeled CP9 as per service manual. I assume that is enough to open and close the gate when S and D are at 4.5vDC.Also the service manual seems to indicate that with the controls set as directed I should be able to use the trim pot VR101 to adjust so that there are 0 volts on pints 10 and 12 of the IC. With pot fully rotated I gain only get it down to 0.8v DC. Is this issue related? Will having 0.8 volts there harm anything?Item is an audio signal compressor

author: Anks
author_rank: Frequent Contributor
timestamp: June 23, 2016, 08:50:35 pm
content: Can't download the schematic could you not post it up here

author: Andy Watson
author_rank: Super Contributor
timestamp: June 23, 2016, 08:53:33 pm
content: Quote from: gooseEL34 on June 23, 2016, 08:23:42 pmMay be it is there, but ..."You are not authorised to download this attachment."QuoteIf those are the voltages on the legs of the FET and it's not passing any signal between drain and source, it's probably dead.
Vox v125 center tapped pot  - Page 1
Forum section: electronics / repair

author: Anks
author_rank: Frequent Contributor
timestamp: June 23, 2016, 10:13:42 am
content: I got an old vox v125 bass amp that I just got back to good health and someone at the rehearsal room decided to plonk there amplifier on top of mine and smashed the 250hz pot into the inside of the amp (trust me there was some stern words).Now onto the problem I can only find center tapped pots from mouser etc that are for pcb mounting so can't be bolted to the chassis and also it will have to fit the chicken head knob. It's a weird setup for an amplifier like this using inductors.I'll attach the schematics as someone may have an idea that can use a standard pot without shifting the cut boost points of the eq.I've also just got the pots out but I'm thinking its a goner.All help much appreciatedKris

author: Anks
author_rank: Frequent Contributor
timestamp: June 23, 2016, 10:49:20 am
content: well i took the pot apart and bent the wiper back and reassembled but it seems rough compared to the other pots.is there a missing part (see attached picture)it measures fine so i suppose it will have to do untill it completely fails and then ill have to find another.
Fixing Nvidia GPU - Page 1
Forum section: electronics / repair

author: Interocitor
author_rank: Newbie
timestamp: June 21, 2016, 01:24:52 am
content: So I have an ASUS GTX 670 DC2 on my hands. I bought it expecting it to be an easy fix but it turns out the previous owner abused it quite a lot.The connectors and LEDs show signs of having been in an oven. An electrolytic cap seems to have lifted. Either someone was trying to desolder it or there was some arcing/heat damage. The area surrounding the leads was covered with a hard brown residue (maybe flux). There was no thermal paste between the heat sink and die. Screws were missing. There were no insulators to keep the backplate nuts from scratching the board.The first thing I did was baking it. Monitored the temperature and used no-clean flux. Put it back together but the screen stayed black.The next thing I did was inspecting the components. One of the 0805 caps was cracked and measured shorted. I tested the PCIe fuse and it was defective. I scraped the cap of the board and bridged the fuse and now the card boots fine. Before I replace the fuse and put the card in my main PC to test it I want to know a few things:Why did the fuse blow?Is the 0805 cap just for bypassing?What are the symptoms of defective electrolytic caps in graphics cards?Is there a danger to the motherboard from a graphics card that is known to blow its fuses?Go easy on me. I'm just just a newbie.

author: System Error Message
author_rank: Frequent Contributor
timestamp: June 23, 2016, 10:20:00 am
content: please read the OP's post he has already fixed it and wants to know why it happen. my guess would be lightning/surge/bad PSU that failed while the card was in use.
PHILLIPS dsr 7141/22 satellite receiver - Page 1
Forum section: electronics / repair

author: Quase
author_rank: Newbie
timestamp: June 22, 2016, 05:48:22 pm
content: Hello,I am repairing an satellite receiver and can't identify an sod23-6 package on the board.It's where the dc voltage enters the unit.I want to ask of anyone know what component is or look via the board layout what it could by.I think it is an voltage regulator but i am not sure. The SMD code on the chip is AT3A but the lastcharacter is not readable.Regards,Quase.
8050A Transformer - Page 1
Forum section: electronics / repair

author: mentaldemise
author_rank: Regular Contributor
timestamp: June 25, 2016, 09:05:46 pm
content: Does anyone know a US trasnformer I can get for the 8050A?Preface:I bought two broken on Ebay. They both seem to have an issue with the transformer. I guess it could be the rectifier. One that has the battery option works just fine if I provide it 2.4V to each battery terminal. Not when I provide 5 to just one. This requires that I use two channels of my power supply. I believe this uses a DC-DC converter and by passes the AC->DC side of the power supply. The other without the battery option on it I removed the transformer. If i put my dual supply in series and provide +12 and -12 the meter works fine if I connect the common to ground on the board.The internet has led me to believe that I need a center tap 15-0-15 transformer. The center tap for the US transformer is not connected as can be seen in the image. The red circle is where center tap is hooked up for non-120. The two wires that are soldered in are going to a dual power supply with it in series for +/- 12Any suggestions or help would be great! They both work and only one of the sections of one of the LCDs is bad!!! *the one with the battery option actually measures 2V low but the other is accurate to other meters I have.

author: vgamesx2
author_rank: Regular Contributor
timestamp: June 26, 2016, 07:30:49 am
content: If I may, might I suggest to grab a power brick of whatever voltage and a little DC converter set to 2.4V instead? I dunno, its what I'd do anyway.Also, I don't understand why you need to use both channels on your power supply... Why can't you just attach it to one terminal, then tack on a lead or an alligator clip from there to the other terminal?

author: bitseeker
author_rank: Super Contributor
timestamp: June 26, 2016, 07:40:27 am
content: Since you questioned the rectifier's condition, did you check it? It's not uncommon for them to short out. In other words, check the transformer on its own and then the rectification section on its own to isolate and narrow down the source of the fault(s).

author: mentaldemise
author_rank: Regular Contributor
timestamp: June 26, 2016, 10:53:41 pm
content: Well, checked the transformer, 12V AC out. Checked the rectifier, just under 12V DC out. Guess I'll start pulling and testing caps now.

author: bitseeker
author_rank: Super Contributor
timestamp: June 27, 2016, 02:53:52 am
content: Yeah, 12V DC out sounds low. Was the rectifier still connected to the circuitry after it? Something pulling the voltage down.Note that you don't have to completely remove the caps, just free one side. Do you have an ESR meter? Checking capacitance only gives you part of the picture, which might look OK.
repair Casio 465 sound tone bank - Page 1
Forum section: electronics / repair

author: Anora
author_rank: Newbie
timestamp: December 27, 2014, 05:49:27 pm
content: I have been attempting to repair a Casio 465 sound tone bank, its refusing to turn on, I have verified all the resistor values and cap values and there all good, nothing appears to be burn but when i did first open it i did smell like something did burn, there's a few thing i haven't varied has I have not found a service Manuel for the board inside. This would not be the first time a repair a device, but it is the first time I ask for help.Thanks in advance for any help

author: HalfSpace
author_rank: Regular Contributor
timestamp: December 27, 2014, 08:56:14 pm
content: Hi Anora,What is the model number of the keyboard? 465 sound tone bank is just the series.Some of the Casio keyboards used a power control IC like LA5668 for power switching/regulation between battery and AC plug pack, this or something like it may be the problem.Maybe a photo of the PCB would help us to point you in the right direction.HalfSpace

author: Anora
author_rank: Newbie
timestamp: June 21, 2016, 10:29:50 am
content: oh damn i had forgotten about this i think the model is CT-636 not much on this for identification
Tektronix 2465A only uses a tiny part of the display area - Page 1
Forum section: electronics / repair

author: sprok
author_rank: Contributor
timestamp: June 20, 2016, 05:52:11 pm
content: .

author: lukier
author_rank: Unknown
timestamp: June 20, 2016, 06:03:50 pm
content: It looks like the beam finder button is stuck. Normally pressing beam finder produces this kind of image.Of course power supply problems and horizontal & vertical deflection settings might also squeeze the image like that so it is always worth to check voltages & ripple on the main board (I forgot the designator for this test connector, it is in the service manual and somewhere in the big thread on 2467B).

author: lukier
author_rank: Unknown
timestamp: June 20, 2016, 08:15:36 pm
content: Quote from: sprok on June 20, 2016, 07:50:32 pmNow I would be interested in the answer to that problem. Some time ago I bought 2467 (2465A with MCP CRT), replaced all the electrolytic caps on the PSU (except big input HVDC ones) board (A2/A3), most of the electrolytics on the main board (A1) and I think two electrolytics on the CPU board (A5, not the SMD version with bad tantalums as in 2467B). The voltages are now ok. I've also replaced the fan (dating from 1987) and Keeper lithium battery.The scope roughly works, traces are fairly sharp considering the age of the MCP CRT, but I have the same issue with LEDs flashing with every button press or when I turn some knobs (for example turning readout intensity on/off). Sometimes even the scope reboots itself. I have no idea what might cause that strange behavior, some undervoltage watchdog?The only information I found on this very problem is here:https://forum.tek.com/viewtopic.php?t=138353where it says:QuoteWhich is of not much help as I've already replaced > 90% of the caps

author: Skimask
author_rank: Super Contributor
timestamp: June 20, 2016, 10:37:58 pm
content: Quote from: sprok on June 20, 2016, 10:32:45 pmThey may very well have been glued on. I just rebuilt a 2445 where more than one of the 'outer knobs' were glued on...since I broke them taking them off. The knobs that don't have set screws have 2 pieces, the outer piece that you grab attaches to an inner piece which goes on the shaft of the pot/encoder/whatever. You can buy sets of replacement knobs on ebay easily enough. I tried 3D printing a few. They came out 'OK' but not good enough.