hybridfree/eevblog-posts huggingface dataset:
Fluke 89IV no continuity beep  - Page 1
Forum section: electronics / repair

author: wguibas
author_rank: Unknown
timestamp: February 02, 2016, 02:54:14 pm
content: Picked up a used fluke 89IV and it seems to work except there is no continuity beep and the sound symbol on the display seems to be flickering very quickly.Could the SMT-12 transducer be bad. I'll have to check it when I get home tonight to see if there is any signal at the speaker.Video of the flicker, tough to see on the videohttps://wayneg.smugmug.com/Eevblog-/i-jJHG3xZ/0/960/20160202_094418-960.mp4

author: ModemHead
author_rank: Frequent Contributor
timestamp: February 02, 2016, 04:53:42 pm
content: Check the setup menu and make sure beep is turned on. The slightly flickering beep annunciator is normal.

author: wguibas
author_rank: Unknown
timestamp: February 02, 2016, 08:23:45 pm
content: Thank you, there was a setting for YES/NO for beep. It now beeps, funny they show the sound icon if it's disabled.
Orion SLED4668 46" LED TV Service Manual - Page 1
Forum section: electronics / repair

author: xokeman
author_rank: Newbie
timestamp: January 22, 2016, 07:57:46 pm
content: I acquired the above mentioned TV for 10$ it turns on SOMETIMES.. Visual inspection looks good I will suck solder and test the caps soon, This Newb is waiting on a solder sucker to come in.http://www.shopjimmy.com/catalogsearch/result/?q=sled4668wshows pictures of what I am working with but I most certainly will add pics if there is interest.Shop Jimmy mentions that replacing an eeprom on the main board may fix this issue.I'd love a service manual but I searched the suggested sites from the sticky and came up empty handed.
Macbook Air backlight repair - Page 1
Forum section: electronics / repair

author: vincearnold
author_rank: Newbie
timestamp: January 22, 2016, 03:18:17 am
content: Hey Guys!I've got a Macbook air in the shop for repair.The display backlight is not functioning, the display is showing a dark picture.There is a suspicious looking component near the display connector, Fuse or capacitor? I can't see a part number or any marking on it.How do I go about testing it? and if so, is it just as simple as soldering in a new one?I've put A multimeter over the component next to it and it shows 20.0?. the component in question does not give a consistent reading.Help would be much appreciatedImages:http://imgur.com/a/pISqb

author: LA7SJA
author_rank: Regular Contributor
timestamp: January 22, 2016, 03:27:38 am
content: For Crapple stuff I go to this gentleman's youtube channelhttps://www.youtube.com/user/rossmanngroupThis some of the things I foundhttps://www.youtube.com/results?search_query=macbook+air+backlight+repairJohan-Fredrik

author: vincearnold
author_rank: Newbie
timestamp: January 22, 2016, 03:54:05 am
content: Ahh yea rossmanngroup has identified the backlight fuse, and I'm getting no connection through it.Guess thats my problem!

author: LA7SJA
author_rank: Regular Contributor
timestamp: January 22, 2016, 04:02:47 am
content: Or at least one of them, pls check for short to ground and the connector before you change the fuse. This fuse don't burn without a reasone.Johan-Fredrik

author: poot36
author_rank: Frequent Contributor
timestamp: January 22, 2016, 06:57:30 am
content: I have heard that the fuze can die if the LCD connector it plugged in when the battery is still connected to the logic board. Other than that it should only die as a result of a short.
8 pin SMD identifcation - Page 1
Forum section: electronics / repair

author: Pscylo
author_rank: Contributor
timestamp: January 21, 2016, 05:47:06 pm
content: Hullo.I've had an HP inkjet printer power supply go pop (waste ink leaked into the Astec/Emerson power module). An 8 pin SMD has clearly been damaged. I can't say I've tried to see if it still works, but if it does I can't see it being long for this world with a good 20% of the face of it now missing.The missing part compounds the problem since I can't read the code on the chip.There's point trying a picture since the writing quality is really quite dubious and you have to catch it at right angle to able to see it, let alone read it.So we have an SO8 (think that's what it's called). All 8 pins are present, though only four appear to be in use.What I can make out from the package:Top line ends in "AA" - there's certainly at least one character before that, though I'm not sure if that's all.Second line - 67*8ML (the seven is about 80% certain, the 8 about the same, I have the bottom half of both characters - the M & L may be a figment of my imagination, but look far too regular to be a trick of the light).Last line - MYC (no doubt here).The nearest I came that looked remotely likely was FAN6755 but they all seem only to have 7 pins. Any ideas? I'm going to try some climbing chalk on the top to see if I can pick out the letters better, but that's what I have for now.

author: Pscylo
author_rank: Contributor
timestamp: January 21, 2016, 10:50:00 pm
content: Think I answered it myself.It looks like a FAN6756ML.Now to find one.
Psion Revo palm pc serial - Page 1
Forum section: electronics / repair

author: ChristofferB
author_rank: Frequent Contributor
timestamp: January 19, 2016, 01:56:44 pm
content: Hey! This is sorta the middle ground between a fix and a mod. I've gotten an old Psion Revo plus aka. Diamond Mako palm pc - 90's pda like thing. It communicates exclusively via serial, but I don't have the "cradle" docking station that has a DB9 out for RS232.It does have a serial connector, for the cradle, which takes RS232 levels, though. Using the MAX3243.But there's no RS232 level output on any of the pins. Soldered a db9 onto them, using this pinout:http://igorkov.org/psion-usb.Now, there are a couple of pins on the cradle connector that's not used - a VCC pin, and one that isn't marked in the pinout. Could be a sense pin, to enable serial functionality, which would explain why it doesn't do anything, but I don't know.So has anyone tried to add serial to this device without the cradle? Does anyone have the full pinout for the docking cradle?Any info or ideas would be useful, as I'm not really getting anywhere myself.--Christoffer

author: macboy
author_rank: Super Contributor
timestamp: January 21, 2016, 03:00:25 pm
content: is the MAX3243 in the PC or in the cradle? If it is in the cradle, then you will only find logic level UART signals (not RS-232 level) on the pc-to-cradle connector. In fact, connecting RS-232 level signals could kill the thing.
Philips TV Power Board 5VSB Fluctuating  - Page 1
Forum section: electronics / repair

author: DarkZero
author_rank: Regular Contributor
timestamp: January 20, 2016, 08:58:26 am
content: For some time i have been trying to fix this TV with 5VSB oscillating the board is:JSK5190-088 REV:1.1i cant find schematic for this board anywhere on the interneti think that the voltage control is done trough KA431AZ and lM3931 more question should i short PS_ON and 5VSB to turn on the board without actually putting it in TV ?

author: kripton2035
author_rank: Super Contributor
timestamp: January 20, 2016, 11:03:39 am
content: I would first check the chemical capacitors on the board for their esr or bulked state.

author: DarkZero
author_rank: Regular Contributor
timestamp: January 20, 2016, 04:41:08 pm
content: like i said i tried repairing it capacitors are good i disconnected 5VSB from its control circuit i get stable 6.7V unregulated and when i put a load of about 800mA it doesn't drop much, board says that 1A can be drawn from 5VSB
Hot ADCs on Tek 2232 - Page 1
Forum section: electronics / repair

author: Tappy
author_rank: Newbie
timestamp: January 16, 2016, 10:13:26 pm
content: Hello. I'm trying to repair my Tektronix 2322 scope. I've successfully done the focus resistor fix, now I need to fix the other problem. The two hybrid ADC modules (U2200 and U2201) both get very hot (75C) and this is causing gradual vertical drifting of both traces when in digital mode. I've checked the +5v and -5v power rails, which are both spot on.Has anyone out there got any ideas please?

author: c4757p
author_rank: Super Contributor
timestamp: January 16, 2016, 10:34:17 pm
content: Are you sure that's what is causing the drift? If they're otherwise functioning, I don't see any reason to suspect that's a "problem". They most likely run cooler with the case closed (providing the proper ventilation paths), and I would expect them to be fairly high-power devices.

author: Tappy
author_rank: Newbie
timestamp: January 18, 2016, 04:38:33 pm
content: thanks for the reply C4757p. The drift shows up as random bits 'jumping' up to the next level, then all the bits will smooth out at that new, higher level, then the whole thing repeats. The drift reverses if I cooler the modules with freezer spray. I'm sure it never did this a year or so ago. The chips of the modules are mounted on a large ceramic substrate (see photo), so maybe you're right that they are designed to get hot. Thanks.Credit for the photo goes to 'Wolfalex', another contributor on this forum: I hope he doesn't mind me using it here.
220v transformer replacement for Hakko FX-888D - Page 1
Forum section: electronics / repair

author: mko_io
author_rank: Newbie
timestamp: January 17, 2016, 02:25:48 am
content: Hi Everyone,I just burnt my new shinny 888D from sparkfun. I want buy a new fuse and a 220v transformer. Since I'm a newbie to electronic, I don't want to take any risk, Could anyone provide a link for me to buy?I just found out the genuine part is PWB 220V?part no. B3680. But I can't find any online shop provide it and I live in New Zealand I can't find any distributor?And I also find out one from Chinese shopping site:http://world.taobao.com/item/525360791218.htm?fromSite=main&spm=2014.21600712.0.0it looks different, but should fit in the 888D, I just don't know the difference between a good and cheap one, what do you guys think?

author: mij59
author_rank: Frequent Contributor
timestamp: January 17, 2016, 04:22:46 am
content: New shiny ?If it still under warranty send it back.Transformers are very robust devises, are you sure there is a short in the transformer ?

author: miguelvp
author_rank: Super Contributor
timestamp: January 17, 2016, 04:31:33 am
content: Where you soldering something that was powered up?If that's the case the tip of your soldering iron is grounded so most likely is just the fuse that died a horrible death.

author: electrogeek
author_rank: Contributor
timestamp: January 19, 2016, 03:16:44 am
content: Take a close look, I suspect you have a 110v Soldering iron there iirc sparkfun don't carry 240V ones. You may be able to return it, but I don't like your chances, you may have better luck finding a guide and parts to convert it to 240v, I'll have a look later and see if I can find one. When I was looking for an iron in the end I decided it was better to just get the 240v one from the outset, even with the 240V tax and the NZ tax hakko and people seem to like to put on these

author: electrogeek
author_rank: Contributor
timestamp: January 19, 2016, 03:20:51 am
content: Ps no. 1 I got mine from element 14 but you can also get them from synergy electronics in NZ, but yes, both are considerably more costly, if you want to buy the transformer here synergy is probably your best bethttp://www.synergyelectronics.co.nz/store/

author: amc184
author_rank: Regular Contributor
timestamp: January 19, 2016, 06:40:32 am
content: Can you give us a bit more information? What happened that cause it to fail? What makes you think it's the transformer?

author: mij59
author_rank: Frequent Contributor
timestamp: January 19, 2016, 08:17:31 am
content: Quote from: electrogeek on January 19, 2016, 03:16:44 amYes it is a 110 V unit, the text "fuse 250V 0.63A" on the pcb is deleted with a black marker.On my 230V Hakko the 125V text is deleted.

author: Shock
author_rank: Super Contributor
timestamp: January 19, 2016, 08:24:46 pm
content: The other thread on thishttps://www.eevblog.com/forum/beginners/hakko-fx-888-110v-gt-230v-mod/
Agilent MSO-X 2012A Battery change - Page 1
Forum section: electronics / repair

author: ltktomas
author_rank: Contributor
timestamp: January 15, 2016, 12:05:26 am
content: Hi,I have this oscilloscope and I've just found that with every powering up the time is always the same (22nd October 2015, 8:43 pm). I saw EEVblog #144 where I can see (probably CR2032) backup battery soldered on PCB. Do you also think that the battery is dead ?Another question: I'm going to replace it with a new one. Do I have to solder some temporary power supply instead of that dead battery to not lossing some data in some memory (like some old HP/Agilent which lost calibration data when battery was disconnected) or it doesn't matter in this case ?

author: georges80
author_rank: Frequent Contributor
timestamp: January 15, 2016, 02:47:01 am
content: Bought it new? Comes with a 5 yr warranty...Otherwise, get your meter and measure the battery voltage.cheers,george.

author: ltktomas
author_rank: Contributor
timestamp: January 17, 2016, 07:04:35 pm
content: I've bought it used. So I measured the battery voltage and it's 3.066 VBut the time is still the same (22nd October 2015, 8:43 pm) with every turning on. Any thoughts ?

author: AndyC_772
author_rank: Super Contributor
timestamp: January 17, 2016, 07:39:37 pm
content: Register on Keysight's web site and register your scope. The warranty should be transferable.

author: ltktomas
author_rank: Contributor
timestamp: January 17, 2016, 11:27:41 pm
content: It is repaired. I've disassembled the oscilloscope and found out that the minus pole of the backup battery is loose (probably cold joint).
Hameg 1005 - Front-End repair - Page 1
Forum section: electronics / repair

author: Colin1256
author_rank: Newbie
timestamp: January 15, 2016, 06:03:44 pm
content: Hey everyone,I'm trying to fix up my Hameg 1005 3-Channel 100 MHz Scope, which is unfortunately letting me down a bit.The Channel 2 V/Div switch is very flaky and I'd like to get in there to see what is going on with it and to hopefully fix it (with some contact spray if nothing else).Unfortunately, the front-end is covered by the Time-Base / Trigger-Board and an intermediate board; so there is no easy access.It appears like the front-end can be slid out forward, but I am not certain. It is certainly still catching on to something.What's the best way to get down to this board?Cheers,Colin
10 turn counting dial is crusty or bumpy - Page 1
Forum section: electronics / repair

author: uoficowboy
author_rank: Regular Contributor
timestamp: January 15, 2016, 05:33:16 am
content: I'm working on restoring an active load. It has a 10 turn pot and a 10 turn counting dial labeled "Duodial" made by Beckman Instruments. If I turn it, it moves rather stiffly and sort of bumpily. Very unpleasant. It does have a lock on it that I have in unlocked position (locking it makes it completely stop moving). I removed the dial and the pot itself turns without any issues - the problem definitely seems to be the dial.Anybody have any experience with fixing these things?

author: lowimpedance
author_rank: Super Contributor
timestamp: January 15, 2016, 01:22:40 pm
content: Refer to the thread,https://www.eevblog.com/forum/repair/used-helipot-and-duodial-rb-cleanlube/msg622555/#msg622555About cleaning the same counting dial etc and in which you made the last post !!.Perhaps some useful info

author: EPTech
author_rank: Regular Contributor
timestamp: January 15, 2016, 01:42:44 pm
content: Hi there,I do not recommend opening that up just yet. Soak it in isopropanol and give it a good air burst. repeat that a few times. Regrease with white spray grease, the kind they use to grease plastic moving parts in CD/DVD players and VCR's, yes I am getting old.

author: edpalmer42
author_rank: Super Contributor
timestamp: January 15, 2016, 04:29:12 pm
content: Just a week or so ago I worked on a dial like that. It would bind when I hit the point where the outer number tried to increment. It turned out that it wasn't dirt or crud, it was mechanical. Put the dial down on a flat surface and push hard on the knob. Problem solved. The outer surface piece gets pushed against the inside and binds on the internal mechanism. Pushing down on the knob puts the pieces back into position. The difference between working and binding is only a fraction of a millimeter.Ed
Looking for two parts (low quantity order) - Page 1
Forum section: electronics / repair

author: chromex
author_rank: Contributor
timestamp: January 14, 2016, 10:33:57 pm
content: I am currently trying to repair a Goldstar OS-7020a Osciloscope and i have found two components that need to be remplaced:-2SK304E x 2-LF356J x 2I have search on some sites likewww.chip1stop.combut my order cost 10$ us and the shipping is 40$ us wich is completely crazy!Is there a site where i can buy those components without big shiping fee or high volume order?

author: retiredcaps
author_rank: Super Contributor
timestamp: January 14, 2016, 10:40:05 pm
content: Quote from: chromex on January 14, 2016, 10:33:57 pmIf you drop the suffix letters E and J out of your part numbers above and find equivalents or better by reading the datasheets, digikey.ca shipping is likely $8 and you get your order in 24 to 48 hours.I haven't checked the datasheets for your parts above so my suggestion could be way off?

author: chromex
author_rank: Contributor
timestamp: January 14, 2016, 10:57:31 pm
content: Quote from: retiredcaps on January 14, 2016, 10:40:05 pmEDIT:It looks like i found only the Texas Instruments LF356N/NOPB remplacement but no2SK304E, this last one is harder to find

author: retiredcaps
author_rank: Super Contributor
timestamp: January 14, 2016, 11:07:07 pm
content: If you really need LF356J, aliexpress.com has two for $6.54 CDN (or $1 USD) + free shipping.http://www.aliexpress.com/w/wholesale-LF356j.html?site=glo&SortType=price_asc&g=y&SearchText=LF356j&initiative_id=SB_20160114150447&shipCountry=CA&needQuery=n&isFreeShip=yPS. Canadians will know my reference above wrt to the exchange rate with our loonie under 70 cents presently.

author: chromex
author_rank: Contributor
timestamp: January 15, 2016, 03:22:56 am
content: Quote from: retiredcaps on January 14, 2016, 11:07:07 pmNice! Tnx for the share!

author: retiredcaps
author_rank: Super Contributor
timestamp: January 15, 2016, 07:49:32 am
content: Quote from: chromex on January 14, 2016, 10:57:31 pmDidn't see the edit after I posted, but after about 2 hours of searching, this is the best I could find. There was a listing on aliexpress for it, but now it is defunct/expired? However, there was a cache copy so maybe you can contact the seller and ask him/her to relist?http://webcache.googleusercontent.com/search?q=cache:c8UOKWQelcYJ:www.aliexpress.com/store/product/Free-shippin-5pcs-lot-2SK304E-SPA-2SK304E-K304-transistor-original-authentic/1918854_32524631308.html+&cd=2&hl=en&ct=clnk&gl=caSeller ishttp://www.aliexpress.com/store/1918854I have no affiliation with aliexpress or seller. Understand that stuff from aliexpress sellers shipped to Canada could take anywhere from 30 to 60 days. However, in post #1, you wanted no big shipping fees or high volume orders.
Help on erratic bahaviour on AOC TV - Page 1
Forum section: electronics / repair

author: CHexclaim
author_rank: Regular Contributor
timestamp: January 12, 2016, 08:20:20 pm
content: Dear all,First of all I always appreciate the feedback people give me when I ask for help on the forum and thank you all for that.The issue I am having now is with an AOC L42H961 TV. It works fine but after some time it trips the earth leakage protector in the power panel on the house. I think it can be a leaky capacitor in the power supply but if anybody has any similar experience or a service manual it will be of great help.Thanks, CH!

author: kfitch42
author_rank: Frequent Contributor
timestamp: January 12, 2016, 08:38:52 pm
content: Well, if it is really the earth leakage protection that is tripping, then (I think) you would need something shorting to earth (the grounded case?) for that to happen. A capacitor that is failing shorted would normally cause an overcurrent trip. In either case the first thing to do is open her up (and discharge capacitors) and have a look around. Is anything: loose? discolored? bulging? or just look plain fishy?Until you post something more substantial (like pics) I don't think we can help very much.

author: Seekonk
author_rank: Super Contributor
timestamp: January 12, 2016, 08:52:41 pm
content: Does it have an earth ground (many TV are just two wire power) or antenna/cable attached. It needs some ground path to trip the circuit. If not internal arcing of a component can sometimes trip it.

author: CHexclaim
author_rank: Regular Contributor
timestamp: January 13, 2016, 05:17:35 am
content: I am expecting to open the unit tomorrow. I haven't been able to do so yet.I did unplug everything from the TV and it still trips the protection. The TV has an earth pin that if isolated, the protection does not trip (obviously).I was thinking about filter capacitors to earth in the front end of the PS being leaky. I will look these or something loose or broken. I will update with my findings.Thanks. CH!

author: wraper
author_rank: Unknown
timestamp: January 13, 2016, 06:22:04 pm
content: There are not many parts to leak: 1. most likely two of Y class capacitors (blue color), 2. transformer, 3. optocoupler(s) - though very unlikely, 4. inlet connector (though it will leak only of contaminated or have burned (carbonized for some reason).Except those, that could be only PCB contamination with some crap. For example, electrolyte which leaked from some cap. Or some foreign conductive object on the PCB.BTW, try different power cable or measure it as it could be faulty too. Anyway, it would be a good idea to measure a resistance from live wires to the earth. Also do not forget that PSU PCB carry high voltage electrolytic capacitor(s) which most likely will hold the charge even after the TV is disconnected from the mains voltage.
2215a oscilloscope No trace - Page 1
Forum section: electronics / repair

author: ifrrated
author_rank: Newbie
timestamp: January 12, 2016, 04:09:11 pm
content: Hi:I have a 2215A scope with no trace. Beam finder works ok. All trigger settings appear correct.Printing out service manual today.Any suggestions as to where to start? is this a common fail?Thank you

author: anachrocomputer
author_rank: Regular Contributor
timestamp: January 12, 2016, 04:17:26 pm
content: First step, as always, is to check the power supply voltages. A bad or missing power supply voltage will send the CRT beam off the screen, and hence give the symptom that you report.

author: tautech
author_rank: Super Contributor
timestamp: January 13, 2016, 07:57:51 am
content: Quote from: ifrrated on January 12, 2016, 04:09:11 pmYou might need this too:http://www.sphere.bc.ca/test/tek-parts/troubleshooting-scopes.pdf
Marshall Bass Guitar Amplifier MB450H schematics - Page 1
Forum section: electronics / repair

author: sirNemanjapro
author_rank: Newbie
timestamp: January 07, 2016, 09:18:57 pm
content: I'm having a problem with this Marshall MB450H amp. It seems that there is something wrong with the power line coming to the tube (ECC83 pre-amp valve (Classic channel)), not the tube itself. I've replaced the parts that I've could and knew, but the problem remains.Can anyone please share a scheme for MB450H or at least point me where to look?orIf possible I would like just a scheme for pre-amp for ECC83.The problem is that the signal is coming through, but it's very weak.

author: Anks
author_rank: Frequent Contributor
timestamp: January 07, 2016, 10:25:35 pm
content: When you say weak were are you measuring and what are the voltages on the pins of the ecc83

author: fleuroman
author_rank: Contributor
timestamp: January 13, 2016, 07:05:27 am
content: try youtubing Daves world of fun stuff, contact him and ask if he might know where you can get schematics for it, he mainly does base guitars but I've seen him do a few amps
KEITHLEY 136 - Page 1
Forum section: electronics / repair

author: kardacz
author_rank: Contributor
timestamp: January 15, 2016, 05:29:15 pm
content: Good evening; I seek the scheme of Keithley 136. Someone should you itThank you for your help!

author: kardacz
author_rank: Contributor
timestamp: January 16, 2016, 10:35:27 am
content: oups! SOS!

author: rastro
author_rank: Frequent Contributor
timestamp: January 16, 2016, 06:00:48 pm
content: Looks like someone at the Radio Museum has posted an article on this DMM along with some excerpts from the manual.http://www.radiomuseum.org/r/keithley_digital_multimeter_136.htmlYou might try to contact him through the Radio Museum web page...-rastro

author: kardacz
author_rank: Contributor
timestamp: January 19, 2016, 05:32:09 pm
content: Good evening; I do not see the diagram! ??

author: PedroDaGr8
author_rank: Super Contributor
timestamp: January 20, 2016, 12:22:34 am
content: Quote from: kardacz on January 19, 2016, 05:32:09 pmHe advised you to contact this person to see if they have the schematic. The schematic itself is not posted.
Keithley 2000 - Self diag fault 402.2 - Resistor ID? - Page 1
Forum section: electronics / repair

author: Macbeth
author_rank: Super Contributor
timestamp: September 02, 2015, 08:57:58 pm
content: Recently got a Keithley 2000 which consistently failed it's VAC test 402.2 in the self diag. I also found its AC volt measurement were around 4% out, while the DC is pretty much bang on within 0-2 counts with my chinese Hao Qi Xin volt ref.I'm posting this because at least 2 others on the internet have had the same fault but not appeared to resolve it or document resolving it. Also, I wouldn't mind part identification too.I pretty quickly found SOT23 resistor network R110 was reading 1.6k instead of 1k (in-circuit) on one if its resistors. There is another one of these devices nearby, R133 which read 1040 ohms in circuit.The repair manual has a descriptionRES NET, 9K-1K, MICRO DIVIDERand Keithley part numberTF-246-2. As can be seen in the pic, its only identifier isA4EAnyone have any idea what it is? The best I can come up with is Vishay MPMT10019001.Before I get the right part I decided to bodge the existing high 1k6 junction with the closest to get it to 1k I had on hand - a 3k3 0805 in parallel.It appears to have fixed it. Measures 1070 ohms in circuit and I have ran the VAC tests in a loop for an hour - no problem.I still have a 4% out on 10VAC range readings, so I guess a DIY recal is in order on the VAC only. When I get the proper part I may get a real calibration/adjustment.

author: ketil b
author_rank: Regular Contributor
timestamp: September 02, 2015, 11:39:51 pm
content: HiI had a similar problem but with R133 winch is the same part. It meant that U112 had a gain of about 8 instead of 10I replaced it with a Vishay Thin Film MPM Divider,thanksketil

author: Macbeth
author_rank: Super Contributor
timestamp: September 03, 2015, 07:32:40 pm
content: Thanks. Confirmed what I thought it was. I've calibrated the low AC ranges up to 10V using my sig gen. I don't have 100 VAC or higher to play with. The high range seems to read ok (240 VAC makes an easy test) and all my low ranges now match up with my other meters and scope give or take a few counts.Have added the proper part to my digi-key/mouser want list to be ordered when it eventually tops £50

author: Macbeth
author_rank: Super Contributor
timestamp: January 12, 2016, 10:03:08 pm
content: Necro update:Vishay MPMT10019001 is the wrong part as it has the 9k/1k the wrong way aroundThe correct part isMPMT90011001as I found to Vishays cost thanks to their sample serviceIt also seems thenewer Keithley 2000 metershave a totally different (through hole?) SIL package instead. Perhaps the older SOT SMD's were not up to snuff?
Flashlight repair - Page 1
Forum section: electronics / repair

author: girolamoo
author_rank: Newbie
timestamp: January 12, 2016, 09:27:31 am
content: Is it possible to repair a broken flashlight? I payed over 100$ for it...

author: Srbel
author_rank: Frequent Contributor
timestamp: January 12, 2016, 09:41:51 am
content: Open it up, and see what is wrong with it.
Looking for Owon HDS-1021M components help - Page 1
Forum section: electronics / repair

author: electRic2772
author_rank: Newbie
timestamp: January 11, 2016, 04:02:31 am
content: Hello. This is my first post on the forum, so I apologize in advance for any breaches of etiquette. I have been going through posts for the past few days to try to make sure no one has already covered this question.I have an Owon HDS1021M DMM/Oscilloscope and it has been a pretty handy meter. I loved Mikeselectricstuff's EXCELLENT videos on the HDS3102M, and all the information in that thread. And, as Mike and a few others so excellently pointed out, the protection circuitry needs much improvement.Does anyone out there own an HDS1021M and could tell me what the OEM components are for the F1 fuse and the Q33 component that is in-line with the fuse? The Q33 component has a 200 ohm resistor in parallel with it, and if anyone knows the purpose of this component, please chime in as well.I committed the cardinal sin of carelessness and clumsiness and let one of my probes cross the wrong lead while using the ammeter function, and found out the vents at the bottom really are for letting the blue smoke out. I gave both the fuse (F1) and the U33 in-line with it, a more than light toasting. When I asked Owon tech support about the components, they said I would need a whole new mainboard (even though several functions were still working just fine) at the tune of $150 US. When I told them that was an outrageous solution for replacing 2 small SMD components, they assured some functions would continue to work.Thank you in advance for any help!!

author: tautech
author_rank: Super Contributor
timestamp: January 11, 2016, 04:20:51 am
content: Welcome to the forum.The minor mistake you made was this would have been better in the Repair board.However, no biggie and good luck with your repair.There will be members that can give the info you seek, be patient.

author: electRic2772
author_rank: Newbie
timestamp: January 11, 2016, 04:31:07 am
content: Tautech, thank you so much for the heads-up and understanding. Since the post is new would it be best to go ahead and delete it from Test Equipment and re-start in Repair? Thanks again!!

author: tautech
author_rank: Super Contributor
timestamp: January 11, 2016, 04:53:06 am
content: Quote from: electRic2772 on January 11, 2016, 04:31:07 amNo problem, we can clean the thread later. I'll ask Dave to move it. Just wait for now.

author: electRic2772
author_rank: Newbie
timestamp: January 11, 2016, 05:03:14 am
content: Thank you again!!
Agilent ESG (e4423b) series diagnostic screen - Page 1
Forum section: electronics / repair

author: ce_lab
author_rank: Newbie
timestamp: January 08, 2016, 11:48:14 pm
content: In the Agilent ESG series signal generator, u106 eeprom (AT28C256E) on the motherboard holds the values shown on the diagnostic info screen. [Utility > Instrument Info/Help Mode > Diagnostic Info]At 0x4B00-03 is the backlight hours * 3600, 0x0582-83 is attenuator count, etc. But altering these values does not change what is shown on the display. My guess is that u108 flash memory (LH28F032) is where these values are read from.Does anyone know how to alter the values shown on the diagnostic info screen?

author: MarkL
author_rank: Unknown
timestamp: January 10, 2016, 11:23:53 pm
content: Because they are updated so often, it could also be that those values are stored in battery backed SRAM, and then checkpointed to the EEPROM periodically.If so, you might have to update the EEPROM *and* remove the battery to force it to use the EEPROM value.I'm sure there's a hidden command to reset one or both of the values. Disassembly of the the binary would probably reveal how to do it.You could also ask on the Keysight Signal Sources forum:http://www.keysight.com/owc_discussions/category.jspa?categoryID=41
Tektronix TDS 684B Signal Path Compensation (SPC) Error - Page 1
Forum section: electronics / repair

author: seancsnm
author_rank: Regular Contributor
timestamp: January 17, 2016, 05:42:58 pm
content: I just picked up this scope at auction and powered it on. It threw a signal path compensation error but after running a full signal path compensation through the utility menu, no errors are being thrown when the scope powers up. Should I stop here?I did just a bit of reading up on these scopes and it looks like earlier versions (like the tds 600) have serious cap issues but the later versions fixed these issues for the most part. Still, I'm wondering if I should go ahead and try to do a cap overhaul on the scope just to prevent future problems.I've been running a similar scope (TDS 640A) from a similar origin (same local auction) fairly heavily for over a year now with zero problems - I just plugged it in and started using it. So I think I'll probably be ok if I just start using it, but I'm also a tad bit nervous that I need to do some maintenance on it to be safe.

author: AndyC_772
author_rank: Super Contributor
timestamp: January 17, 2016, 07:32:23 pm
content: Open it up, check the processor and acquisition boards to see what type of caps they have.If they've got electrolytics, replace them and be prepared to find and fix further damage. Later boards have tantalum caps which are fine.
LCD Backlight IC  - Page 1
Forum section: electronics / repair

author: jmajtyka76
author_rank: Newbie
timestamp: January 27, 2016, 04:34:42 pm
content: Hello I repairing a Flir b60, the lcd backlight is not working I have checked voltages to the IC/Driver. The flat flex is fine tested good, I have traced the following error to this IC/Driver, I know its part of the led driver but I don't know who makes it if anyone can identify this part I appreciate you help.James M.

author: Buriedcode
author_rank: Super Contributor
timestamp: January 27, 2016, 10:41:36 pm
content: http://www.futurel.bg/datasheets/4/HV9903.pdfSupertex chip, apparently they were acquired by microchip. I couldn't find a datasheet from a 'nice' site, the copy from mouser gave an error

author: jmajtyka76
author_rank: Newbie
timestamp: January 28, 2016, 03:34:48 am
content: Thank you, the data sheet will help me to find a suitable replacement...
Power +8000 hot air/soldering station (+YH850V6 based air controller) - Page 1
Forum section: electronics / repair

author: neex
author_rank: Newbie
timestamp: January 09, 2016, 06:06:37 am
content: Good evening everyone,I have also jumped on the cheap/cheerful hot air station bandwagon and had a question about the pump voltage control... The unit I have is a Power 8000 which appears to share the same hot air controller as many other clones: YH850V6. My question is that I was wondering if anyone else with a similar unit could confirm that the 3 gang pot for "AIR" is actually wired with only two terms almost like a rheostat? My pot appears to do very little in the way of controlling pump voltage. The controller has inputs for both the grn and yel wire on the pot and they're marked "AIR VOL 1" (3 wires... RWB) and "AIR VOL 2" (2 wires... YG). I believe that the pot up front is meant to vary the pump speed through the AIR VOL 1 circuit but I'm not sure if there's anything oddball to be concerned with here and was hoping someone might know.Is the triac without the heatsink the regulator for pump voltage???Thanks in advance.
Tek TDS3000B series hangs at splash screen. - Page 1
Forum section: electronics / repair

author: Jwalling
author_rank: Unknown
timestamp: January 06, 2016, 06:50:22 pm
content: I have a TDS3054B scope on my bench that hangs at the initial splash screen. I suspect that it may be trashed firmware, but I suppose it could be most anything. I tried using the (alleged) method for a hard reset I found inhttp://www1.tek.com/forum/viewtopic.php?f=5&t=6124by holding down the B Trigger button, but that didn't help any. The (crappy) service manual was not of any use, what a surprise!Hoping someone might have a bit more insight into this series of scopes.Thanks.Jay

author: cncjerry
author_rank: Unknown
timestamp: January 07, 2016, 03:49:48 am
content: I assume that if you had any optional keys in that unit you have removed them during the test. It's loading firmware right after the splash screen and checks the optional firmware keys right around there.

author: Jwalling
author_rank: Unknown
timestamp: January 07, 2016, 11:51:19 am
content: Quote from: cncjerry on January 07, 2016, 03:49:48 amYup - tried with the 2 keys removed. Didn't make a difference. Thanks.Jay

author: cncjerry
author_rank: Unknown
timestamp: January 07, 2016, 03:28:48 pm
content: Never looked inside mine, knock on wood, but if this was a computer I would be reseating/replacing the memory.

author: HighVoltage
author_rank: Super Contributor
timestamp: January 07, 2016, 04:11:16 pm
content: Test the power supply first inside the scope.About 5 years ago I had two of these scope fail because of a single resistor in the PSU.I remember how surprised I was to find such a cheap PSU in these scopes.

author: Jwalling
author_rank: Unknown
timestamp: January 07, 2016, 05:51:58 pm
content: Quote from: cncjerry on January 07, 2016, 03:28:48 pmMemory is very fine pitched TSOP synchronous DRAM. Somehow I don't think I'd be successful.Quote from: HighVoltage on January 07, 2016, 04:11:16 pmPower supply is fine in this one. No drop-outs or excessive ripple. I guess I was hoping that the scope had a recovery mode for the flash.Thanks all.Jay

author: RR
author_rank: Contributor
timestamp: January 07, 2016, 07:38:49 pm
content: Did you tried RS232? Or maybe there is some internal debug port that can spill out some boot info.
HP/Agilent 6632B shows 'OUT OF RANGE' when entering voltage calibration point P2 - Page 1
Forum section: electronics / repair

author: TDQ7050
author_rank: Newbie
timestamp: January 06, 2016, 09:13:35 pm
content: Hello,I am using two (Agilent)6632B power suppliesand recently wanted to perform a voltage calibration since displayed & actual voltage were not fully matching.I did that from the panel, and all went well on the first power supply, but on the second one I'm encountering a strange effect:The delta between displayed and actual voltage is quite large, and if I enter 10.000 Volt at the keypad the 6632B just displays 9.768V(!) and I'm actually just getting an output of 9.688V. So it's not only far off but it doesn't even display the 10.000V that I've entered. I thought that has to do with the long overdue calibration.When performing the calibration, the 6632B goes into CAL mode without problems, I can select P1 and enter the measured voltage for this calibration point, but when I enter the value for P2 and confirm with <ENTER> I'm always getting an 'OUT OF RANGE' message and the calibration aborts. What's wrong here? Is someting wrong with the A2 board? I have tried to reset the device, but the error message keeps coming whenever I'm entering the P2 value.Unfortunately I have no possibility to try it via GPIB.Considering something on the A2 board is defective, could I just scrap a board from another HP/Agilent/Keysight 6632B and replace it in my power supply?Thanks for help,Markus
Anritsu 69269A signal generator blown filter/rectifier board - Page 1
Forum section: electronics / repair

author: ravig
author_rank: Newbie
timestamp: January 05, 2016, 06:31:47 pm
content: Hello,Does any one have schematics or know the DC output voltage from the A21 board from a anritsu 69269A signal generator. The A21 board simply takes the AC line voltage /filters it and rectifies it. I am guessing that the DC voltage is simply line rectified. I want to be sure.. I need to spin a PCB to replace this board since I cannot find a replacement board from anritsu, ebay etc....The part should be the same for the family of generators that are 692XXA types...Appreciate it!!Ravi###rapidrf@gmail.com(remove the three hashes to email .. done to avoid the spambots)

author: tautech
author_rank: Super Contributor
timestamp: January 05, 2016, 07:43:11 pm
content: Might be here:http://bee.mif.pg.gda.pl/ciasteczkowypotwor/Anritsu/
Repair: Proscan 32LA30Q power board info needed. - Page 1
Forum section: electronics / repair

author: zrunner
author_rank: Newbie
timestamp: January 04, 2016, 11:18:25 pm
content: The chip resistorR117somehow was popped off during repair. Its part of the 5 volt regulator circuit and causes crowbar zener Z7 to short from overvoltage. Can someone please provide the value of this resistor.Board part number is SBGD-200-3HP-5.
Chip board repair - Page 1
Forum section: electronics / repair

author: @rt
author_rank: Super Contributor
timestamp: January 04, 2016, 05:32:59 am
content: Hi GuysI’m looking for suggestions on what the next course of action for attempting repair on this board should be.It measures 12 Ohms across it’s power supply, measured across any of it's six electrolytic capacitors.Of course the caps themselves are the first suspects so I have replaced all six,and that’s all I’ve done so far. The measurement is still the same.On powerup, most of it’s chips heat up quite hot to touch. which might suggest they are not getting a supply,but why the measurement close to a short across the supply?I’m reluctant to power it without having found something else wrong, as the programmable chips areirreplaceable and any left working can be used as spares for another unit (which I do have a working one).paid $500 on eBay for this thing :rolleyes:Cheers, Art.

author: Srbel
author_rank: Frequent Contributor
timestamp: January 04, 2016, 07:07:10 am
content: Get one chip out of the socket, then measure the resistance of the supply rail again. If it still shows low ohms, remove next chip, until you find which one is shorted.

author: @rt
author_rank: Super Contributor
timestamp: January 04, 2016, 07:10:46 am
content: Yeah I’ve already begun that... since the board looks clean,and after electrolytics, there’s really only decoupling caps and chips leftIf it’s a chip that isn’t socketed I suppose that’s a good thing since it will be replaceable.

author: @rt
author_rank: Super Contributor
timestamp: January 04, 2016, 07:35:58 am
content: It was the Altera, so bad news for the unit, but thanks for the reply.
Repair : Nikkor 28-70/2.8D, stuck focus ring. [Fixed] - Page 1
Forum section: electronics / repair

author: TiN
author_rank: Super Contributor
timestamp: January 03, 2016, 08:50:22 am
content: Hope all are well and happy in 2016. Let's do something new this time, instead of old rusty HP gear or leaky Keithley's...Some might saw my used eBay DSLR shenanigans. Well, even though it's sorta offtopic for most folks here, let's take a look inside Nikkor 28-70/2.8D Pro-grade zoom.I got it 2 years ago used from bay, and used almost daily since then. Last few months it got an issue with focusing, having focusing stuck at ~3m level. Even in manual, if I turn the focus ring it got stuck same place, producing scratching/squealing sounds. If try 5-10 times, it get past sticking point and I can set lens to infinity. But then going back - same issue. It was sorta okay before and was rather lazy to open it up, suspecting issue with SWM motor, which are expensive to replace (300$ for module, usually more). But yesterday I was trying to shoot starscape at night and it was really stuck, got me angry. That means unavoidable teardown, which is commited today.Interested to see what makes this 1K$ lens tickle?

author: SeanB
author_rank: Super Contributor
timestamp: January 03, 2016, 09:40:51 am
content: Yes, with the high res shots as well. I am guessing a worn internal barrel as opposed to the motor being faulty.

author: TiN
author_rank: Super Contributor
timestamp: January 03, 2016, 05:06:26 pm
content: Timelapse 4K:Full articleSorry, no full teardown, as repair was as simple, as adding few bits of dual-sided scotch tape to fix loose FPC board.Easiest repair ever!

author: SeanB
author_rank: Super Contributor
timestamp: January 03, 2016, 06:00:35 pm
content: Nice that it was that easy, and the FPC itself was undamaged from the rubbing against the inner walls.
Leader LBO-520 Oscilloscope repair help - Page 1
Forum section: electronics / repair

author: YoshiKnuuckles
author_rank: Contributor
timestamp: January 07, 2016, 07:43:14 pm
content: Well, I'm back at it again trying to fix this old scope. I have the service and owners manuals, and I've read over the Tektronix scope troubleshooting guide. I believe something is wrong with the vertical amplifier or vertical pre-amplifier.I've dragged it in to my school's lab to work on it (they have the equipment I need to do so,) and I'm about to leave for the day so I won't be able to do anything else till tomorrow.What I've done so far:-Tested the voltage rails, they all appear to be OK.-Started the calibration procedure, which went well until I reached the step titled "MATCHING adjustment of Delay Line." I was able to get it calibrated, and gained a clue to this scope's fault, which I took a video of.https://youtu.be/ClHPE3mwp4QThe waveform looks ok other than the amplitude being ~0.5 CM off when at the top half of the display(I'm guessing the vertical gain is off? That's the next step in calibration,) but as it is moved to the bottom it distorts and collapses in on itself. I'm feeding in a ~100Khz square wave at about 80mVp-p from an HP 3312A Function Generator, and have the proper waveform displayed on one of the school's scopes. Both probes are set to a 1x attenuation ratio.I know the scope still needs a lot of calibration, but I'd like to figure out what is causing the fault before I continue, as I'll likely have to recalibrate it all over again afterwards. Any ideas or suggestions on what to check when I get here tomorrow would be wonderful.

author: oldway
author_rank: Super Contributor
timestamp: January 08, 2016, 09:41:51 am
content: This is clearly a failure.Never attempt to calibrate a faulty scope: it must be repaired before any calibration attempt.This failure does exist on one or on both channels?

author: YoshiKnuuckles
author_rank: Contributor
timestamp: January 08, 2016, 03:09:04 pm
content: The failure exists on both channels. The scope appears to be functioning properly other than the fault I've shown. I'm admittedly a beginner, hence why I didn't realize to find the fault first! I was simply following the service manual.

author: YoshiKnuuckles
author_rank: Contributor
timestamp: January 08, 2016, 03:59:29 pm
content: Looked it over when I got to the college this morning, and found that the Vertical Final amplifier is missing transistor Q315, which looks like it was desoldered from the board!Taking a look at the schematic for the scope, it shows that it is supposed to be there, and is a 2SC1012A transistor. Hmm. This might explain a lot.Datasheets for 2SC1012A:http://www.datasheetarchive.com/2SC1012A-datasheet.htmlHaving a bit of trouble finding an equivalent part. This one looks to be the closest I could find that is available:http://www.digikey.com/product-detail/en/2SC2258/2SC2258-ND/279299I found that part through one of the equivalent transistor datasheets. Wondering if I'd be ok with that one.