hybridfree/eevblog-posts huggingface dataset:
Hameg 203-7 problems - Page 1
Forum section: electronics / repair

author: ThorCW
author_rank: Newbie
timestamp: September 15, 2016, 06:41:27 pm
content: I recently received hameg 203-7 scope and the traces do not show up. Ive checked the power supply and the rails everything seems ok. I did check the lower voltages on the back of the crt I found the vr206 pot was way out of adjustment. Put that back in spec now if the scope is left on for 10 minutes if you cycle the power a trace appears then go right away. The other voltages seems a few volts low but still in spec. Any ideas?

author: ThorCW
author_rank: Newbie
timestamp: September 19, 2016, 05:24:52 pm
content: New revelation in the Hameg scope. I acquired a high voltage probe and measured the high voltage and after the second measurement the traces were there and have not went inop since. I have also unplugged from power and let it sit and the traces come right back. So anyone happen to know the science of this?

author: silverlego3
author_rank: Contributor
timestamp: September 19, 2016, 06:58:49 pm
content: Here is the service manual for that scope,not sure if you had it when you checked the voltage rails.http://data2.manualslib.com/pdf3/57/5634/563302-hameg/hm_203.pdf?056286f123711c821f7e37942a5e52a3

author: ThorCW
author_rank: Newbie
timestamp: September 20, 2016, 01:07:25 am
content: I did have that. The voltages were all within spec but when I touched the lead to pin 3 on the crt board it lit right up and has worked ever since.

author: tronde
author_rank: Frequent Contributor
timestamp: September 20, 2016, 09:08:58 pm
content: You will most likely find some weak solder joints on the CRT socket, or that the contacts in the socket have lost some spring tension.
Fluke 39 LCD screen - barely readable - Page 1
Forum section: electronics / repair

author: electrongeek
author_rank: Contributor
timestamp: September 18, 2016, 02:16:17 pm
content: I have this 20 year old or so Fluke 39 power quality meter that has been working fine for me, until suddenly losing almost all screen contrast. The display is barely readable. Adjusting the screen contrast buttons will take the display from invisible to barely readable. It isn't power, batteries are fresh.Can someone give me a starting point for when I open it up? What has most likely failed? Probably old capacitors, right?I do have access to decent test gear - multimeter, digital scope, adjustable power supply...ThanksChip

author: Gyro
author_rank: Super Contributor
timestamp: September 18, 2016, 06:40:13 pm
content: If the display isn't discoloured then it's probably the Zebra strip that connects the LCD panel (edit: glass) to the PCB. It's normally possible to un-clip or unscrew the LCD housing and give the strip and PCB fingers with IPA.

author: electrongeek
author_rank: Contributor
timestamp: September 18, 2016, 11:18:57 pm
content: Thanks, Gyro. That would fit with a sudden change.
HP8903A Audio Analyzer repair - Page 1
Forum section: electronics / repair

author: mark_maher
author_rank: Newbie
timestamp: September 19, 2016, 10:19:49 pm
content: Hi!I recently picked up an HP8903A Audio Analyzer, which is not measuring AC voltage level properly. I have found a pair of 1/16A glass fuses on the input amplifier board (A2), one of them is blown. I can't find any schematics for this model, and do not want to put another fuse in without understanding what could have caused it (especially as I don't have any 1/16A fuses...) . I also note that there are no fuses on the newer models.... Maybe they are just prone to fatigue?Has anyone got schematics, or experience of this problem?Any advice apreciated!Mark

author: chihaxinh
author_rank: Regular Contributor
timestamp: September 20, 2016, 12:10:43 am
content: hi mark_maherI thing owner equipment make overload vol input device ! Likely measurements in Anode tube in VAS stage !Pls take out and take picture for other member reviewBest regardsNam Nguyen Hai

author: singapol
author_rank: Frequent Contributor
timestamp: September 20, 2016, 02:19:53 am
content: HP8903A service-21Mb 450pg:http://www.schematicsunlimited.com/h/hp-agilenthttp://www.schematicsunlimited.com/h/hp-agilent/hp-8903a-audio-analyzer-serviceHP8903A_errata-http://exodus.poly.edu/~kurt/manuals/manuals/HP%20Agilent/HP%208903A%20Operation.pdfOld 8903A?http://www.electronicspoint.com/threads/hp-8903a-audio-analyzer-schematic.230344/

author: dacman
author_rank: Frequent Contributor
timestamp: September 20, 2016, 11:05:36 pm
content: A2F1 = 1/32 A (or 0.032 A, 250 V). On HIGH signal input line.A2F2 = 1/16 A (or 0.062 A, 250 V). On LOW signal input line.Note that the analyzer has a specified input range of 300 V, whereas the input fuses have a rating of 250 V.Check C2 and C3 on the A3 card (and other aluminum electrolytic capacitors).

author: mark_maher
author_rank: Newbie
timestamp: September 21, 2016, 06:43:40 am
content: Thanks for your replies! The link to the service manual was very helpfull. I changed the fuses, and now the instrument works as it should. Looks like it was an overload from the previous owner..I'll check through the caps as you suggest.Thanks again!
Continuity test vs IC - Page 1
Forum section: electronics / repair

author: TAMHAN
author_rank: Frequent Contributor
timestamp: September 17, 2016, 10:00:32 pm
content: Hello Folks,sorry to be a nuissance here - but I finally found a few minutes to work on the TDS754D again.I had the heroic idea to test some of the soldered contacts of the 71024 RAM ICs using my normal multimeters continuity testing...without thinking.So now I ask for experience: is this a very bad idea and can I give up the attenuator. Or is it low risk in practice? AFAIK, the 2V should not be much of a problem...

author: singapol
author_rank: Frequent Contributor
timestamp: September 18, 2016, 05:04:28 am
content: Yes, it's low risk in practice as voltage and current in digital DMM is not enough to turn on a diode junction of transistor but be mindful of static electricity from fingers/body or clothing even feet walking on carpet flooring which can range from hundreds to kilo volts.Unless you are work on pcb boards with anti static mat and ESD handstraps which might restrict free movement if you want to take the precautions
Siglent SDM3045X power supply buzzing - Page 1
Forum section: electronics / repair

author: hammy
author_rank: Unknown
timestamp: September 23, 2016, 06:39:44 pm
content: Hiany other SDM3045X owners out there?The power supply of my device is constantly humming, even if it is turned off.I'm just asking out of curiosity. Maybe I got a lemon.Cheershammy

author: hammy
author_rank: Unknown
timestamp: September 23, 2016, 06:54:16 pm
content: I know different techniques to get rid of it.- Soaking the windings of a transformet with superglue- Soaking the stacked metal core U-pieces with superglue- Cable-tie around the windings and/or the metal core- Hot-Glue for coils- foam rubberAny other ideas/tips/tricks?Cheershammy

author: Rasz
author_rank: Super Contributor
timestamp: September 23, 2016, 07:02:53 pm
content: its siglent, probably some rust fell on the pcb and now hums sailor songs

author: hammy
author_rank: Unknown
timestamp: September 23, 2016, 08:38:11 pm
content: It doesn't look that bad.I like the features, and the big display. Ok, my 34401A is another weight class, but the histogram and trend chart are nice features in a DMM for that price.

author: tautech
author_rank: Super Contributor
timestamp: September 25, 2016, 02:00:02 am
content: Quote from: hammy on September 23, 2016, 08:38:11 pmI'm glad you like ithammy.Yes they do hum, thay have an always on linear PSU and a soft switch type On button.One I checked before placing this post, I can hear the transformer from ~100mm away.The demo unit that I've had for nearly 2 years I've never noticed any transformer noise and yours is the first mention I seen of any Siglent SDM3*** PSU hum.

author: hammy
author_rank: Unknown
timestamp: September 25, 2016, 04:08:43 pm
content: Quote from: tautech on September 25, 2016, 02:00:02 am@tautech: Thank you for the cross referenceToday I had a look inside.The transformer ist screwed directly to the case. I put a 2mm foam rubber between transformer and case and now the noise is gone.Beside this:- no rust inside- the smd soldering looks very good- the internal layout/floorplan is well madeI don't know if such transformers are only tested with 110V/60hz and Germany with 230V/50Hz is a corner case.Cheershammy
Yokogawa  DL5140 & DL5180 manuals - Page 1
Forum section: electronics / repair

author: Arctic
author_rank: Newbie
timestamp: September 16, 2016, 11:54:53 pm
content: Hello,I am new here and a newbie in electronics.I recently bought from ebay an old Yokogawa DL5180 digital oscilloscope (specs) with broken display (Sharp LQ9D011K). It came with 2 FET (700943) probes for 200€ (130€ + 70€ shipping). Its not in good shape but its working (with an external monitor via VGA).I really tried to find any manual online ( I checked almost all sites with manuals that are posted in an eevblog thread) but I didn't find any (not even the user manual). I did send some emails to many Yokogawa offices (in Europe) too but I didn't get any answer.Could you help me to find it, may someone have a model from DL51XX series?Thanks a lot,SotirisPS: A very bad thing is that its a 8ch oscilloscope but it use a very strange Jack and not the usual bnc (to connect a simple probe you need adaptor -700946)PS' : I am sorry for my bad english :?

author: dzseki
author_rank: Frequent Contributor
timestamp: September 17, 2016, 07:02:23 am
content: For that price it seems to be a nice score.Yokogawa never released "normal" service manuals, at least not recently. Even if you'd find the manual it will full with vague information, without any really usable circuit details, the replacement parts list consist of the 5-6 board's partnumber that is inside and that's it. The most usable information is how to disassemble the unit, but you'd find out that sonner or later anyway.So the question is if the display is phisically broken or it just does not work?, If it is phisically OK, then check the LCD with a flashlight maybe only the backlight went wrong.Otherwise you can find different small LCD panels on ebay, which may fit insted the original display, and in worst case you fed thet from the VGA output of the scope...
Induction pcb repair - Page 1
Forum section: electronics / repair

author: TomH
author_rank: Newbie
timestamp: September 16, 2016, 10:28:37 am
content: Hi. I have an induction hob on which both pcbs have failed within a month of each other, and two months after replacements have become unavailable. Fortunately I found an ex- display model for sale, so all good, but would like to get the original pcbs repaired for when it happens again. Can anyone here recommend anyone in the Brighton/ Sussex area, who can do this?
Xiron LCD 26HD lcd TV - Page 1
Forum section: electronics / repair

author: thunderbuny
author_rank: Contributor
timestamp: September 15, 2016, 11:24:46 pm
content: Haii got a problem with this tv.the power supp is faulty.it turns on then when you get a picture it goes in to standby again.i cant find annything on the web about is no scematics nothing.is there some one who had that fault too and can tell me were and what part is faulty and save me a lot of time.greets Davy

author: thunderbuny
author_rank: Contributor
timestamp: September 16, 2016, 12:22:21 am
content: ok nevermind just opening the thing up sais it all.4 caps whent poof dayum not even have to get the multimeter out!
Calibration Standards Precision DC Voltmeter DC-100AR - Page 1
Forum section: electronics / repair

author: sfox7076
author_rank: Newbie
timestamp: September 15, 2016, 08:49:41 pm
content: I bought a 1960 made Calibration Standards Precision DC Voltmeter DC-100AR in a pile of stuff for $10. I wanted many of the other items and this was a bonus. When I got it, I opened the case and thought it was in pretty good shape except for some caps that leaked everywhere. It is very well made in that most of the systems are modular and made on turret boards. It has a VTVM setting (though it is transistors and not tubes) and then a differential volt meter section. I recapped the unit except for a power supply can cap that holds a 250uf at 6v and a 1000uf at 10v. The meter was broken (pushed in), so I had to work that out a bit to the point it would move. The meter is I was lucky enough to buy a manual. Sadly, the manual's schematic is not complete in that it identifies the parts, but it doesn't always provide the values. The resistors all match the values in the schematic. Some of the caps are written oddly, but I figured that out. The hard part for me to get are the transistors. Most have numbers I have not seen or do not match those in the unit. The 4 transistors in the supply where the encapsulated 6v chopper (copper can) is are labeled 2n213A or have no obvious marking beyond being made by Sylvania and being germanium. The schematic has 4 2N1302 transistors. I cannot find the data on the 2N213A. There are a few other transistors in the unit. None match the schematic 2N406, etc. Any thoughts on whether I should try to find the replacements in the schematic? I have turned it on and tried it, but it is way too sensitive. Also, any idea how to tell the original value of the NTC thermistor if it is not written on it? Any help would be greatly appreciated.Pictures before work commenced:I have the exterior case, but forgot to snap a picture.All socketed construction. You simply pop the circuit from the octal socket and open up each the case to work on the unit.1 leaked out cap.3 leaked out caps. Notice that the lead on this one bought it.
Help! How to repair flat flex ? - Page 1
Forum section: electronics / repair

author: ali6x944
author_rank: Frequent Contributor
timestamp: September 15, 2016, 01:43:29 pm
content: Hi everyone ,This week I was trying to fix an old CCD-M8E sony 8mm camera, and I found a couple of disconnected wires and a cut in the flat flex...The cut didn't ruin the entire cable , but interrupted a couple of traces... is there a way to repair the traces or to repair the cut ?Please help

author: ali6x944
author_rank: Frequent Contributor
timestamp: September 15, 2016, 01:46:05 pm
content: See photos:https://drive.google.com/folderview?id=0B5vW-k7HbsL4YU04QTVadV9YNlU

author: jonovid
author_rank: Super Contributor
timestamp: September 15, 2016, 02:20:00 pm
content: it can be done and

author: plazma
author_rank: Frequent Contributor
timestamp: September 15, 2016, 02:23:24 pm
content: Looks repairable. I would fix it with thin enameled/magnet wire.

author: ali6x944
author_rank: Frequent Contributor
timestamp: September 15, 2016, 02:34:58 pm
content: Thanx alot
[Fixed] - Repairing a Samsung 940BF - Page 1
Forum section: electronics / repair

author: raul
author_rank: Newbie
timestamp: September 12, 2016, 08:49:48 pm
content: HiI'm repairing a power supply (CCFL inverter circuit) of a Samsung 940BF monitor.I change some caps and a fuse (probably works by now) but i don’t know what is the chip P610 CD6F14 (No luck with google (pt)). This chip have the paths a little baked.Thanks

author: TheBay
author_rank: Unknown
timestamp: September 12, 2016, 08:59:14 pm
content: Here you go:it's a AOP610.http://aosmd.com/pdfs/datasheet/AOP610.pdf

author: wraper
author_rank: Unknown
timestamp: September 12, 2016, 09:05:49 pm
content: Quote from: raul on September 12, 2016, 08:49:48 pmThis is normal, those mosfets run quiet hot and with time PCB darkens in most of the monitors.

author: raul
author_rank: Newbie
timestamp: September 12, 2016, 09:28:13 pm
content: Quote from: TheBay on September 12, 2016, 08:59:14 pmThanks @TheBay. I Will save that and test this chip before i put everything together. Weird, i couldn't find the brand.Quote from: wraper on September 12, 2016, 09:05:49 pmProbably should change that IC before burnout. If i can find one similar. Thanks

author: TheBay
author_rank: Unknown
timestamp: September 12, 2016, 09:31:10 pm
content: Quote from: raul on September 12, 2016, 09:28:13 pmIf the monitor is working leave that IC, as Wraper said that's normal.From looking at the images that's hardly got that warm, I have seen much much worse

author: wraper
author_rank: Unknown
timestamp: September 12, 2016, 09:41:31 pm
content: BTW, if it does not work after replacing the capacitors, check secondary winding of the CCFL transformers, should measure around 1k.

author: raul
author_rank: Newbie
timestamp: September 12, 2016, 10:34:08 pm
content: Quote from: wraper on September 12, 2016, 09:41:31 pmThats useful. Thanks

author: raul
author_rank: Newbie
timestamp: September 15, 2016, 12:09:31 pm
content: HiApparently is fixed. I'm shore it has thepico fuse 3Athat connects to the inverter part (main power supply and the inverter power supply is in the same board but placed in different part) if the motive of a blown fuse are in other side don't know i change some fat caps in the process... will see.Thanks for the intel.
3456a fan to fanless - 3456A-12 - Page 1
Forum section: electronics / repair

author: rigrunner
author_rank: Frequent Contributor
timestamp: September 15, 2016, 03:26:03 am
content: In the 3456A service manual change #10 states: "If the fan is defective and needs to be replaced, retrofit the 3456A to a fanless instrument. Refer to service note 3456A-12 on how to retrofit the instrument"So far i've not been able to locate the service note. Anyone know what the modification involves?
HP Agilent 3458A Digital Multimeter 8½ 8.5 Digit DMM HEWLETT PACKARD Opt Special - Page 1
Forum section: electronics / repair

author: alanambrose
author_rank: Frequent Contributor
timestamp: September 09, 2016, 04:45:24 pm
content: TiN another one for your treatment?http://www.ebay.com/itm/HP-Agilent-3458A-Digital-Multimeter-8-8-5-Digit-DMM-HEWLETT-PACKARD-Opt-Special-/222243889542?_trksid=p2141725.m3641.l6368"The self test did not pass, error codes 202 and 110. Also ACAL errors (209, 210, 104, 114)".Alan

author: TiN
author_rank: Super Contributor
timestamp: September 10, 2016, 04:57:42 pm
content: Yah, now you got all nuts attention around, to throw cash at the monitor...I would be interested in seeing guts of this special option box, but not enough to pay 2k+ for likely.

author: Tony_G
author_rank: Super Contributor
timestamp: September 10, 2016, 05:28:13 pm
content: They've been trying to sell that for some time - I remember looking at it a couple of weeks before I found my 3458A at Western Digital facility closing auction.I just didn't get a good feel on the unit (can't remember the price though) - I guess desire for these things comes in waves (he says while waiting for FedEx to deliver another 8902A...)TonyG

author: TiN
author_rank: Super Contributor
timestamp: September 13, 2016, 07:42:26 pm
content: Well, some reseller seem to get it.Unlikely that we will see tear-down of this box here

author: Tony_G
author_rank: Super Contributor
timestamp: September 13, 2016, 07:49:33 pm
content: If they use the "no questions, complete refurb repair" option then they paid for around $4600 for a calibrated, manufacturer repaired unit - I guess that isn't too bad, 50% discount off list.TonyG
Help on documentation for Mark Levinson 331 amp. - Page 1
Forum section: electronics / repair

author: CHexclaim
author_rank: Regular Contributor
timestamp: September 17, 2016, 04:44:19 pm
content: Hello everyone,I received for repair an old Mark Levinson number 331 amplifier. As I told the owner, it is very difficult to do a proper repair without the service manual and/or schematic.I've searched online and had no success but maybe I am not looking in the right places. The owner will try to find it too, but, I doubt it.Can anybody help with these?Thank you!!Charlie.

author: singapol
author_rank: Frequent Contributor
timestamp: September 18, 2016, 05:26:00 am
content: If you are an experienced audio power amp tech you would know Mark Levinson does not give out schematics or service manuals even if you ask their official repair centers in US. What's online are much older models of which ML331 is also over 20 yrs, old. Any good/skillful tech can repair such amps without schematic or documentation. A search online will show that ML300 series are prone to power filter electrolytic capacitor failures. Anyway they are due for replacements which is not cheap but only 2 x 50 000 uf. and another smaller pair. Do be careful of big caps! Also because ML331 is operating in class A bias so it's hot so heat will take it's toll on output transistors. There is a difference between restoration and repair as a repairtech I'm sure most would just fix it and throw it back to customer,so it's your choice to do a proper job or risk customer returning back to you for another repair. Is there pride in your workmanship?The closest to a repair manual is a link below although the schematics are not very clear..someone asked fordetails but not sure if he got them from blogger.ML332http://my-mlnoxxx.blogspot.sg/

author: voltz
author_rank: Frequent Contributor
timestamp: September 18, 2016, 06:39:41 am
content: This chap did some work on the ML-331http://playagainaudio.blogspot.co.uk/2013/06/restoring-mark-levinson-no-331-from.htmlSee the posts at the bottom, someone out there has the service manual.Just keep searching. The manual does exist.Cap failure seems common in the 300 series. These guys found replacements:http://audiokarma.org/forums/index.php?threads/mark-levinson-331-cap-failure.582299/

author: CHexclaim
author_rank: Regular Contributor
timestamp: September 18, 2016, 02:21:48 pm
content: Thank you for the help!I will check all links now. I haven't opened the unit yet and I was told that the unit went through another technician before that couldn't fix itThat is not a very good sign.The idea is to do a good repair, not just to make it "work".Thanks again! Charlie.
Staco 3PN1010 Switch  - Page 1
Forum section: electronics / repair

author: Johnny10
author_rank: Frequent Contributor
timestamp: September 12, 2016, 09:47:33 pm
content: I am looking for part number for 140-OFF-120 switch on a Staco Variable Transformer 3PN1010.Thanks

author: Johnny10
author_rank: Frequent Contributor
timestamp: September 12, 2016, 10:59:53 pm
content: OK,So I was tired and I just wanted the answer without trying too hardWhy not use.... Heavy-duty, standard size toggle switch. D.P.D.T., center-off. Rated 15A 125 Vac, 10A 250 Vac. 15/32" threaded bushing. Screw terminals.
Tektronix 2465 power supply - Page 1
Forum section: electronics / repair

author: dan3460
author_rank: Frequent Contributor
timestamp: September 11, 2016, 03:25:26 pm
content: I have been fixing scopes for a while, normally is the power supply. I have been successful until now.After plugging the scope for the first time you get a flash of green but then nothing, no lights on the front, the fan is running.I opened the scope (this is my 4th 2465) and looked at the 2 0.068uf safety caps, both where cracked. As I needed to take the boards out to replace them I replaced all the electrolytic including the 2 big 290uf beside the fan motor.I installed the boards back and still getting the same result. Just a flash of green on the screen and nothing. I don't hear the clicking of the inverter trying to start, but what throws me off is that all voltages on test plug on the main board are ok (there are 9 different voltages there all ok).I scoped the 3 teeth comb that gives power to the inverter board, I was expecting to see a steady voltage but I get the same 60hz +/- 60V on each teeth. So I'm lost as to what to look for.Also there is a voltage reference between pin 4 of T1020 and pin 1 of T1050 that should be 264V over the Reference line. I only get around 140V, also the 12.6V at the collector of Q1062 is around 7V. So thinking that maybe the line voltage selector was bad (as open is the setting for 240V mains) I poke around and I tested the voltage at P204 and P205 I only get 90V. Don't know if that is normal, it seems that the EMI filter is eating 30V.
Help on notebook SMPS repair - Page 1
Forum section: electronics / repair

author: dav
author_rank: Regular Contributor
timestamp: September 11, 2016, 02:03:35 pm
content: Hi friends,my notebook power supply died (no output).Fuse, bridge rectifier, transformer and capacitors are ok.This one seems fine , too (Vgs>0, no resistance between drain and source).KHB 7D0N65Fhttp://www.datasheetlib.com/datasheet/191987/khb7d0n65f2_kec-korea-electronics-corporation.htmlI doubt on this:SBT100-16http://www.mouser.com/catalog/specsheets/onsemiconductor_SBT100-16LS.pdfMy 87V measured a forward voltage of 0.175V (while the datasheet indicates 0.82 to 0.88V)What do you think?Otherwise I have to check the small SMD resistors and caps on the back side of the board.
Yaesu FT-221R with no audio - Page 1
Forum section: electronics / repair

author: apelly
author_rank: Unknown
timestamp: September 08, 2016, 04:59:23 am
content: It'll take me some time to actually get to fixing this, but I'll start this thread so I've got somewhere to make notes as I go. Annoyingly I don't haveanyof my T&M gear with me where I'm living at the moment.The seller claimed he'd tested it and it transmits fine. There is no receive audio. That is all I know. The seller did say they hadn't had a go at fixing it. I had a very brief look inside, and at first glance I am the first person in there, so that's something.I found a service manual without too much drama, but it's 13MB, so can't post it here. Don't have the link on hand right now.An that absence of better advice I think I'll turn my hand to making or acquiring an extender board to aid with diagnostics. Before I go searching and measuring, does anyone happen to have any docco on the connector specs for boards in this thing?It's also missing the clips that hold the lid on. Does anyone know what they looked like?

author: Flump
author_rank: Frequent Contributor
timestamp: September 08, 2016, 07:04:16 pm
content: I would check the obvious 1stTest with head phones / check socketResistance across the Speaker coilSquelch full on ?

author: PA0PBZ
author_rank: Super Contributor
timestamp: September 08, 2016, 07:26:39 pm
content: Calling it deaf and then saying there is no audio makes it hard to guess what you are talking about. Deaf usually means that the sensitivity sucks and you have to apply a large signal to hear anything but noise, but no audio implies that you don't even have noise. Please be a little more specific.

author: klunkerbus
author_rank: Unknown
timestamp: September 08, 2016, 07:57:28 pm
content: A major indicator for me would be whether or not the s-meter kicks up at all as you tune around with some form of antenna connected. Seeing an active s-meter would suggest most of the receiver is likely fine. No s-meter movement opens up front end possibilities.I had a weak-output receiver once that I sold rather than troubleshoot. The buyer told me all it took to fix it was to clean the volume pot.EDIT: I'm not familiar with that radio, but also make sure it isn't something simple like the signal not being routed/connected to the speaker. Some radios support speakers in an OEM power supply and take some jumpering to get the signal going elsewhere.

author: apelly
author_rank: Unknown
timestamp: September 08, 2016, 09:29:43 pm
content: Thanks for the tips guys.Quote from: PA0PBZ on September 08, 2016, 07:26:39 pmI know. I'm only working on what I've been told at this stage. I haven't turned the radio on yet so I don't have any more information.I changed the thread subject anyway. Sorry for the antagonisation.
Circuit diagrams for HP 54602B oscilloscope? - Page 1
Forum section: electronics / repair

author: e-doc
author_rank: Contributor
timestamp: September 08, 2016, 03:11:23 pm
content: I'm looking for circuit diagrams for HP 54602B oscilloscope (or other of 5600 series), can anybody help?

author: pelule
author_rank: Frequent Contributor
timestamp: September 08, 2016, 03:24:33 pm
content: You may find it at the great host of KO4BB. I would recommend to denote his activities.www.ko4bb.comLink:http://www.ko4bb.com/manuals/84.57.76.160/HP_54600-Series_User_and_Service_Manual.pdf

author: JFJ
author_rank: Regular Contributor
timestamp: September 08, 2016, 05:48:50 pm
content: Agilent/Keysight have only released a Component Level Information Package (CLIP) for the 54600A/54601A oscilloscopes. It may still prove useful, because some of the circuitry in other 54600 series oscilloscopes is similar. You can download the package from Keysight's web site:http://www.keysight.com/main/editorial.jspx?cc=GB&lc=eng&ckey=1517718&nid=-536900196.536898053.00&id=1517718The circuit diagrams are spread over lots of individual pages, but a stitched together version is available here:http://www.ko4bb.com/manuals/92.18.50.6/HP_54601A_Digital_Storage_Oscilloscope_Schematics.pdf(edit: direct link doesn't work)http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=HP_Agilent/HP_54601_Digital_Storage_OscilloscopeIf you can't find what you're looking for (e.g. there's no schematic for the power supply in the CLIP) then describing the fault here, might find a solution from a forum member who has already dealt with the same problem.

author: e-doc
author_rank: Contributor
timestamp: September 12, 2016, 08:20:02 am
content: Thank you!
Chauvin Arnoux CA6513 Megohmmeter. Anyone have picture or schematic ?  - Page 1
Forum section: electronics / repair

author: matthieu.e
author_rank: Regular Contributor
timestamp: September 04, 2016, 10:46:04 am
content: Hi,I am trying to fix a Chauvin Arnoux CA6513 Megohmmeter. The previous owner has already opened it, so I am not sure of what have been done on it.I am looking for schematic and high resolution pictures. I was not able to find it on google. Thankshttp://www.chauvin-arnoux.com/sites/default/files/D00QBN50_24.PDF

author: matthieu.e
author_rank: Regular Contributor
timestamp: September 04, 2016, 04:08:16 pm
content: Here are the pictures of my unit. I know there is some corrosion on the bottom PCB but it seems to be OK.

author: Assafl
author_rank: Frequent Contributor
timestamp: September 07, 2016, 02:25:47 pm
content: Do the French not get tickled and amused by 500V? Only 1000V deserves a French d'Exclamation de Point (exclamation point)?Apart from that I am missing a coil. How do the French ramp up to 1000V without a transformer of sorts? (or wine)
Tektronics 2213 Scope Repair - Page 1
Forum section: electronics / repair

author: RonnieEEVBlog
author_rank: Newbie
timestamp: September 03, 2016, 02:36:09 pm
content: Hi,I recently purchased a Tektronics scope 2213 60MHZ from Ebay. While testing it, I noticed that when both the channels are active, the display becomes very dim and starts flickering. But if I watch each channel separately, it works fine.Does any one know what is going on here and is it safe to open the hood and look inside when power is disconnected, when you have zero experience ?Regards,Ronnie

author: oldway
author_rank: Super Contributor
timestamp: September 03, 2016, 03:51:19 pm
content: Welcome op EEVBLOG.That's TEKTRONIX and not TEKTRONICS.Don't open the hood of your oscilloscope, there is probably no fault, only a wrong operating. (alternate selected instead of chopp)Read first the user manual to learn how to operate it.http://user.physics.unc.edu/~sean/Phys351/techresource/docs/2213%20User%20Manual.pdf

author: RonnieEEVBlog
author_rank: Newbie
timestamp: September 03, 2016, 03:59:10 pm
content: Hi,I checked that. My settings are as follows Vertical Mode: BOTH & ALT & under trigger its is VERT MODE.Regards,Ronnie

author: oldway
author_rank: Super Contributor
timestamp: September 03, 2016, 05:05:24 pm
content: Please read the instruction manual first .....

author: tautech
author_rank: Super Contributor
timestamp: September 03, 2016, 08:38:51 pm
content: Quote from: RonnieEEVBlog on September 03, 2016, 02:36:09 pmYou can but with zero experience what do you expect to see?Truth is without considerable experience you'll see nothing.There are a few things that can bite even powered down and from what you describe there may be nothing wrong with it only the way you're using it.Oldway's advice is sound, RTFM.Basic manual advice will include nominal settings to observe a waveform, the best to play with initially is the 1 KHz square wave from the probe calibration output.After becoming comfortable with the cal output then a low voltage AC, say from an AC wallwart (never straight mains) will give a sinewave.Just printing the basic setting part of the manual is handy for scope newbies like you.Enjoy and be careful.BTW hunt out Daves vid on "how not to blow up your scope"

author: David Hess
author_rank: Super Contributor
timestamp: September 05, 2016, 05:49:04 am
content: Quote from: RonnieEEVBlog on September 03, 2016, 03:59:10 pmWell, there's your problem. Read the manual.If ALT sweep and VERT trigger is used, then the oscilloscope will do alternate triggering which is tricky to use and only applies for specialized applications.Either use CHOP mode or set the trigger to channel 1 or channel 2 when displaying both channels.
Someone with a HAMEG 303-6 - Page 1
Forum section: electronics / repair

author: PartialDischarge
author_rank: Super Contributor
timestamp: September 04, 2016, 10:39:23 am
content: Just got a HM303-6 and the seller told me it had a problem in one channel but forgot that the timebase was also screwed. With the service manual of the303-5I was able to repair the channel (a JFET gone bad), but the timebase seems to have 2 missing components, one of them is a cap, whose value I've been test-guessing,but there seemed to be other not shown in the 303-5 schematics.So anyone with a303-6is willing to open it quick to look what these 2 components are and maybe their values???The timebase board is readily visible after the cover is removed.Thanks

author: tronde
author_rank: Frequent Contributor
timestamp: September 04, 2016, 04:20:31 pm
content: Schematics / PCB for time base board attached.
Toshiba Satellite A210-133 - screen turning off - Page 1
Forum section: electronics / repair

author: Srbel
author_rank: Frequent Contributor
timestamp: September 03, 2016, 06:14:36 pm
content: Today it finally started to fail. A few times in the last 15 minutes it happened. The screen is on, and all of the sudden, it just turns off (picture disappears). Backlight is still on.Now it works again (I am typing this on it). But I think it will just get worse and worse, and will fail completely.Last time it happened, I had seen a picture disappearing (black screen) and in that moment (half a second) a few thin horizontal lines appear in the middle, and then just completely black screen.I have tried pressing the edges surrounding the screen, and it did nothing.I don't think it it the LCD cable or connector, because in that case I would probably have some picture left.I think that it is the GPU, or some capacitor on the GPU power supply rail.The problem is that this laptop is held more by super-glue than by screws, and if I disassemble it again, I don’t think I will be able to assemble it again (like I barely managed to do last time). So, I need to be certain that I could repair it, or it will not be worth it to disassemble it.

author: spilihps
author_rank: Regular Contributor
timestamp: September 04, 2016, 10:31:16 am
content: Does it have a external VGA port that you can hook up a screen to. To see if the problem follows or not.That could help you atleast narrow it down a bit?

author: Srbel
author_rank: Frequent Contributor
timestamp: September 04, 2016, 02:59:24 pm
content: It does have it. I will try it next time it happens.
Wistron PV-01 mobo power cycling - Page 1
Forum section: electronics / repair

author: AtanasP
author_rank: Newbie
timestamp: September 04, 2016, 10:09:23 am
content: Hello everyone,I have a pretty bad and hard to recognizing problem with Wistron PV-01 mobo from Probook 4520s.The mobo powerups without CPU for maybe 1 second and then shutdowns. With CPU powerups for 15 seconds and then shutdown without getting POST screen or something. And then it startups again after 5 seconds and same thing is happening. The consumption was around 35 W from the adapter.The adapter is OK, on battery is the same thing.The bios battery is showing 3.04 V - which is OK.There's no overheating anywhere, with or without heatsink, the same things is happening.All voltages and power schematics are checked. All of the voltages are appering while it's on and there's no problem with any of them. All of the mosfets are checked. There's no short anywhere.I have checked it with two CPUs, many RAMs and what so ever.The last symptom of the laptop before failure was screen flickering and then suddenly restart.Even when it shutoffs, there is always 19.34V on DCBATTOUT /the main power bus/.So, there's not problem with power rails anywhere. The problem is more complicated and I can't get it.
Sony CMT-G2BNiP Service Manual? - Page 1
Forum section: electronics / repair

author: GTASA
author_rank: Newbie
timestamp: September 03, 2016, 10:24:58 pm
content: Hello,Does some kind of Service Manual for this thing exists ?I have a Problem with the FM reciver, it cuts off every few minutes.Thank you

author: amyk
author_rank: Super Contributor
timestamp: September 04, 2016, 01:25:58 am
content: Could it be a market relabeling of the HCD-G2BNiP, which does have a service manual available?http://elektrotanya.com/sony_hcd-g2bnip_hcd-g2nip_ver.1.1.pdf/download.html
NEC FM Transmitter F300DHF IPA Repair - MOSFET Replacement - Page 1
Forum section: electronics / repair

author: Oddcoffee
author_rank: Newbie
timestamp: August 31, 2016, 06:25:09 am
content: Hi all,On my bench currently is a F300DHF IPA from a NEC FBN series FM transmitter. The main power mosfets test crook and i'm having absolutely nill luck trying to source some replacements as they're no longer manufactured. I can't seem to find equivalents or substitutes, even. The best I can find is supposedly NOS stock with no info on HK inventory and alibaba (no thank you). Part number is 2SK524.The data sheet doesn't give me much to work on although the basics are there (attached), was wondering if anyone can point me in the right direction?Cheers,

author: dave_k
author_rank: Frequent Contributor
timestamp: August 31, 2016, 12:21:25 pm
content: Those NEC transistors are basically unobtanium! My suggestion would be to gut the IPA and replace it with a BLF278 300W FM pallet.I have performed a similar modification to a 600W IPA module from a NEC FBN-11K20E transmitter.The module is preceded by a 6dB pad (to match the output level of the exciter better to the input level required by the pallet). The original circulators were removed as the pallet will tolerate a 3 to 1 load mismatch, however the original reflected power alarm circuit was retained, which controls the bias supply to the pallet.For added protection a shorted 1/4 wave stub was also added to the input of the tube cavity, to prevent any tube flash overs from damaging the pallet (it acts as a DC short, but is transparent at FM frequency).Here is a link for a suitable 300W pallet:http://broadcastconcepts.com/BLF278-300W.html
Voltcraft DPS-4005PFC Firmware or HEX files needed - Page 1
Forum section: electronics / repair

author: cat87
author_rank: Regular Contributor
timestamp: January 26, 2015, 08:31:00 am
content: Hello everyone, I recently acquired a Voltcraft DPS-4005PFC 0-40V, 0-5A power supply which unfortunately is missing the 2 micro-controllers inside, the W78C32B-40 from Windbond and the Atmel AT89C51. I want to see if there's any life left in it and maybe get it back to full functioning condition, so if anyone has some idea where I might find the HEX files (if they exist somewhere in the Internet) for these two chips, please tell me, because after a few days of searching I found nothing promising.Also I found that my power supply is a close relative of the Instek PSP-405, if this helps.If all else fails, I'll spin my own power supply out of this. An Arduino or a micro (or two) might get the job done.Thank you

author: Yansi
author_rank: Super Contributor
timestamp: August 31, 2016, 05:27:00 pm
content: Hello, still in search for the firmware?I have currently Voltcraft 4005 without PFC, but as far as I am concerned, that shouldn't matter, as the PFC has nothing in common with the MCUs, I guess.
HP 3490A Fixed - Page 1
Forum section: electronics / repair

author: 13
author_rank: Contributor
timestamp: August 30, 2016, 02:40:37 am
content: Hi,I recently fixed up my old HP 3490a multimeter after spending a few months of trouble shooting. So here's a word of advice for others. Check that every dip chip is fully seated in the socket! I have spent countless hours of effort on trying to get my meter to work only to find out that it was just a dip package flapping in the breeze. Also if you haveg a HP 3490 make sure to not touch any of the AC side you'll mess it up. Oh well, time to calibrate it.Cheers,13

author: bitseeker
author_rank: Super Contributor
timestamp: August 30, 2016, 04:54:05 am
content: Yes, every repair is a new adventure.

author: HighVoltage
author_rank: Super Contributor
timestamp: August 30, 2016, 07:20:05 am
content: It is easy to overlook something simple.The good thing is, you repaired it successfully and learned from it.I have been really enjoying the repair of many instruments over the last few years.And have spent countless hours, doing so.
HP6010A 200V 17A 1kW Power Supply Repair - Page 1
Forum section: electronics / repair

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: September 04, 2016, 12:41:35 am
content: Hi group,Another HP 1kW Power Supply repair.This power supply is similar to the HP6035A that I repaired in this thread:https://www.eevblog.com/forum/testgear/hp6035a-500v-5a-1kw-power-supply-repair/msg697835/#msg697835There were three parts to this repair.1) The front panel Current Potentiometer.The 10 turn 5k Ohm potentiometer, R100, was open circuit:This was replaced by a Bourns 3590S-2-502L2) The down programmerThe 6010A, and the similar power supplies, have a down programmer. This is used to discharge the output, if the output is turned down. This is a lot faster than waiting for the bleed resistors.Quite often this circuit is damaged if the power supply is used to charge batteries. The power supply will try and discharge the batteries if the output is set lower than the battery voltage.R20, a 1.2 Ohm fusible resistor was open circuit. This was replaced.3) MOSFET inverterVisual examination of the MOSFET indicated that they were damaged. This picture shows the MOSFETs that were removed:On the left MOSFET and the one next to it, you can see the discolouration on the can. This happens if there has been a plasma inside the can.De-capping the MOSFETsI made a fixture so that can de-cap the MOSFETs quickly in a metal lathe. Here is a picture of MOSFET ready for de-capping:Confirmed killConfirmed kill x4All four of the MOSFETs were dead.In addition to changing the MOSFETs, fuse F1 and F2 had to be replaced. These are Littelfuse PICOFUSE II 251 series 1/8A (125mA)With these repairs the power supply worked again.Regards,Jay_Diddy_B
Flooded electric motor and gearbox - Page 1
Forum section: electronics / repair

author: daedalus13
author_rank: Newbie
timestamp: August 28, 2016, 04:59:29 pm
content: Hello all,As some of you may know it flooded pretty bad here in Louisiana over the past few weeks, and I have been helping alot of family and friends clear out their homes. While doing so yesterday, I came across a flooded pride mobility scooter. I have been wanting these motors and controls for a long time for an rc lawnmower project. all of the electronics boards are corroded I believe the chair was underwater for 5 days. the gear box looks sealed and packed with grease and the motors have surface rust. What are the chances the motors are even salvageable, and if they are what are the best practices for restoring them. Thank you for any and all help, I just wanna know if its even worth my time.

author: Ian.M
author_rank: Super Contributor
timestamp: August 28, 2016, 06:18:35 pm
content: It depends - if there was any voltage on the motors, electrolytic corrosion will have trashed them, otherwise if the battery was isolated there is a pretty good chance they are salvageable if you strip them down, wash thoroughly with clean water, dry in a warm place for a week and clean up commutator and shaft surfaces. Lubricate the bearings and reassemble for a quick test and if they run, strip them down again if there was any rust on the armature and stator cores to clean it up and finish with a coat of rust converter, avoiding the windings before reassembly. Non-sealed ball bearings will almost certainly need replacement - if they feel even slightly gritty, change them.

author: amyk
author_rank: Super Contributor
timestamp: August 29, 2016, 02:55:33 am
content: Even if they're not perfectly salvageable,

author: Jeroen3
author_rank: Super Contributor
timestamp: August 29, 2016, 04:33:03 am
content: Dissassemble, megger, clean, dry (oven 120c several hours), megger(, rewind the stator), reassemble.Low chance it will run now.

author: helius
author_rank: Super Contributor
timestamp: August 29, 2016, 04:49:03 am
content: http://crcindustries.com/ei/water-damage-guide.aspxhas some good advice. The products they make appear to be widely used by flood recovery teams.
Broken MG882K-1WHD camera - Page 1
Forum section: electronics / repair

author: lilljocke
author_rank: Newbie
timestamp: August 28, 2016, 05:52:46 pm
content: HelloI'm trying to repair a MG882K-1WHD camera, i don't know what happened to it but it won't turn on. It seems to work with the external input. I measured some voltages and I discovered a shorted SOT-23 device that has "1350" written to it. The camera powers up when i short 2 pins on it. I can't find "1350" in any SMD code lists. Anyone who knows what it can be?

author: retiredcaps
author_rank: Super Contributor
timestamp: August 28, 2016, 05:54:37 pm
content: A clear focused picture and its surrounding components may give us a clue?

author: lilljocke
author_rank: Newbie
timestamp: August 28, 2016, 06:15:32 pm
content: Thanks for the quick reply.Here is an image of the board. Yeah I ripped off the pad when I removed the component ops :S

author: amyk
author_rank: Super Contributor
timestamp: August 29, 2016, 03:03:07 am
content: That would appear to be aP-Channel MOSFET.
LG LCD TV - extremely bright picture when TV warms up - Page 1
Forum section: electronics / repair

author: Delta
author_rank: Super Contributor
timestamp: August 23, 2016, 07:46:44 pm
content: A TV in a local boozer is on the blink. It's a 42" LG, not the newest. It turns on OK, and displays a perfect picture, but after 10-15 minutes the picture "whites out". I say "whites out", but is more like the brightness has been turned up to an extreme level. You can still see the picture, it's just really really bright.What could be causing this? Is it (economically) repairable? (I'm not sure if a replacement T-CON board is available)Thanks!

author: Cyberdragon
author_rank: Super Contributor
timestamp: August 23, 2016, 08:31:32 pm
content: Could be a bad connection either to or on the backlight board causing it to loose the PWM brightness signal and default to full. Check the cable and solder joints (poke them with something non-conductive when on). Is it an LED backlight or a CCFL tube type?

author: Rasz
author_rank: Super Contributor
timestamp: August 28, 2016, 07:41:29 pm
content: you cant 'white out' lcd wityh a backlightits a glass/tcon problem

author: BMack
author_rank: Regular Contributor
timestamp: August 29, 2016, 02:09:29 am
content: I think you mean solarized. If that is the case I'd say it's either the panel or the T-con, it could be the power supply. First, flex the tv a little bit, if it fixes the picture it's a bad panel. If not check the voltage going to the T-con, is it stable? Check with the T-con plugged in and without it plugged in. I expect you'll be replacing the T-con. You can monitor it for hot chips and check components but check for the part cost first, normally we replace T-cons because it's not worth the hassle to fix it on the component level.

author: amyk
author_rank: Super Contributor
timestamp: August 29, 2016, 02:49:47 am
content: That sounds like a gamma buffer failure. Do they happen to be AS15/AS19 in this TV?Fromhttps://www.eevblog.com/forum/chat/why-might-these-ics-be-failing/Quote