Electronic Circuits Projects Diagrams Free - Repairing Consumer Electronics http://www.electro-tech-online.com/ en Sat, 21 Nov 2009 02:41:29 GMT vBulletin 60 http://static.electro-tech-online.com/images/misc/rss.jpg Electronic Circuits Projects Diagrams Free - Repairing Consumer Electronics http://www.electro-tech-online.com/ help diagnosing Nec lcd monitor http://www.electro-tech-online.com/repairing-consumer-electronics/100290-help-diagnosing-nec-lcd-monitor.html Fri, 20 Nov 2009 23:51:21 GMT hello I have been trying to find a fix for my 17" nec multisync lcd monitor. At startup the v-hold fails to hold, after a few minutes of warm up the v-hold corrects itself, but there are still many horizontal bars flickering across the screen, also I have a single pixel wide line down the left side about 2" in from the side. and last but not least the lower left backlight appears to be flickering. I am assuming I have a problem in the high voltage power supply, I replaced the electrolytic caps that I had spares for, there are still 3 that I didnt have replacements for. I have a capacitor meter on order that should be here in a few days. When I got the monitor it was stone dead, the power supply board appeared that something had been spilled in it, after cleaning off the goo on the board it sort of functions, I would love to get this fixed. What next? If anyone could pinpoint a likely source that would cause all the problems that would be awesome. I included a couple pics so you can see whats going on.

Thanks in advance Caleb :)
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]]> Repairing Consumer Electronics CalebG http://www.electro-tech-online.com/repairing-consumer-electronics/100290-help-diagnosing-nec-lcd-monitor.html optiquest flat screen monitor broke http://www.electro-tech-online.com/repairing-consumer-electronics/100254-optiquest-flat-screen-monitor-broke.html Fri, 20 Nov 2009 01:45:53 GMT model Q7. Screen goes blank after 10-30 minutes. If I turn it off for long enough, it will work again for a while. Sometimes when I turn it back on... model Q7. Screen goes blank after 10-30 minutes. If I turn it off for long enough, it will work again for a while. Sometimes when I turn it back on the image flickers rapidly. I removed the over and the metal shroud over one of the circuit board and set a fan to blow air over it. This did not help.

Ideas?

paul ]]> Repairing Consumer Electronics paulmars http://www.electro-tech-online.com/repairing-consumer-electronics/100254-optiquest-flat-screen-monitor-broke.html Help with Pioneer Audio Receiver please... http://www.electro-tech-online.com/repairing-consumer-electronics/100237-help-pioneer-audio-receiver-please.html Thu, 19 Nov 2009 17:20:12 GMT I posted this a while ago, and didn't get any replies to it, so here goes again!

Hi there folks. My name is Mike and I have recently purchased a Pioneer SX-205 Stereo Receiver that does not power on. I give it 120VAC and press the power button, and nothing happens. I have checked the fuses, and they are good. I get 70-80VAC output from the transformer. I'm not sure what component/s would be bad in order for this unit to not do anything? The only thing that happens when I press the power button is that I can hear a very faint high pitched tone from the main PCB. Very, very faint. Other than that, my desktop light dims a little from applying the load, but nothing else happens... I'm not sure what the transformer is supposed to supply on the output side, but it appears to be good. Any help would be greatly appreciated. I am somewhat new to electronics and am eager to learn all that I can!! Thanks for your time.

UPDATE: I did some more investigating on the main PCB and noticed three small diodes where underneath them the PCB was discolored as if it had been burnt. I removed these three diodes, labeled "A28" or "82A" and tested them, they show an ohm reading in one direction, but not the other, which I'm thinking means they are good? I also removed the small electrolytic capacitor and tested it, and it appears to be good... I'm not sure what these three diodes are used for, and I'm not sure if the PCB being burnt under them is a sign of anything but heat, but I thought I would add it here!

I'm still thoroughly confused by this receiver, and still cannot get it to power up. I get several different DC volt readings across the PCB in different areas... So I'm thinking that the rectifier is good?

I'm looking forward to anyone's input on this matter, It will be greatly appreciated!!

Thanks.
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]]> Repairing Consumer Electronics sirmikeylikesit http://www.electro-tech-online.com/repairing-consumer-electronics/100237-help-pioneer-audio-receiver-please.html SMD Identification http://www.electro-tech-online.com/repairing-consumer-electronics/100191-smd-identification.html Wed, 18 Nov 2009 14:50:53 GMT Please could you help in identifying the component which has blown on the PCB board (attached file) . I first thought it was a fuse but could not... Please could you help in identifying the component which has blown
on the PCB board (attached file) . I first thought it was a fuse but could not find any that would fit the size (rated at 240vac) I am now thinking it could be
a EMI/RFI component but not sure.The same type of component can be seen below and to the left of the blown one
Thanks
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]]> Repairing Consumer Electronics Dougadam http://www.electro-tech-online.com/repairing-consumer-electronics/100191-smd-identification.html Panasonic rx-ed70 http://www.electro-tech-online.com/repairing-consumer-electronics/100132-panasonic-rx-ed70.html Tue, 17 Nov 2009 12:12:09 GMT I have a Portable Stereo CD System RX-ED70;(PANASONIC) which I powered with a rack of batteries(12v); I happened to reverse the polarity by mistake... I have a Portable Stereo CD System RX-ED70;(PANASONIC) which I powered with a rack of batteries(12v); I happened to reverse the polarity by mistake and the system stopped running. I detected a blown fuse which i have replaced but the system is still not responding; I am new in repairs and I need help. Where do I start? ]]> Repairing Consumer Electronics chukwumezie http://www.electro-tech-online.com/repairing-consumer-electronics/100132-panasonic-rx-ed70.html Hi http://www.electro-tech-online.com/repairing-consumer-electronics/100122-hi.html Tue, 17 Nov 2009 03:54:04 GMT Ok, well, I've always been one to find answers online, and this is the first time I've needed this type of help, but here we go. I have a degree in Mech Eng, so I have a LITTLE Elec Eng experience...ok, I took one Intro to EE class, and admit I don't know a whole lot about electronics, except you shouldn't get them wet. Well, maybe a bit more than that. My parents have a Sylvania LCD Model 6620LCT TV that quit working. Me, being inquisitive, took it apart and found a 4 amp fuse was blown. My dad ran out to check NAPA for a new fuse and came home with a 2 amp one. We tried it anyway, and of course, it blew. Now, rememeber, I'm not the best with electronics, but I like fixing things. My dad suggests we use some aluminum foil to complete the circuit and see if it works at least, and then we can get a good fuse later. I was leary, but we tried it and that proceeded to blow something that then created a smoke cloud. I don't know what the part is, but I contacted sylvania and they sent me to someone who sent me the service manual that lists the parts. Sorry, this is getting long.... I used the part numbers printed on the main circuit board to cross reference the parts list and found it to be a "LINE FILTER 5.0MH 6Y075" At least I hope. I ordered one off funai for $4.35, which seems reasonable enough if I can fix the TV.

Now since I don't really know what I'm doing, before I go and resolder a line filter in and replace the fuse to just blow both again...is there anything else I can check or do? If that doesn't work, how can I diagnose the problem myself? I'll try to provide any photos or information needed.

Thanks in advance...if nothing, I'm hoping to learn a bit. :-) ]]> Repairing Consumer Electronics Crafty42 http://www.electro-tech-online.com/repairing-consumer-electronics/100122-hi.html Testing an RS232 device http://www.electro-tech-online.com/repairing-consumer-electronics/100085-testing-rs232-device.html Sun, 15 Nov 2009 22:26:50 GMT I have this RS232 device that isn't working, and I don't know if it is a hardware or software problem. Is there a 5‚¢ solution to testing the receive conductor for activity? I don't have an oscilloscope, but I do have a multimeter. Obviously, however, it is designed to expect AC signals to be no more than 60Hz, not 115200bps. :(
The device is an IR receiver, FWIW. I think all the energy it produces comes from the transducer, and doesn't cheat the hardware flow control lines out of power, like mice used to. It certainly doesn't have a battery and I don't plug it into the wall. ]]> Repairing Consumer Electronics Angus http://www.electro-tech-online.com/repairing-consumer-electronics/100085-testing-rs232-device.html Lab-Volt 791 Oscilloscope http://www.electro-tech-online.com/repairing-consumer-electronics/100079-lab-volt-791-oscilloscope.html Sun, 15 Nov 2009 19:31:05 GMT I have an old Lab-Volt 791 Oscilloscope that I purchased several years ago at a garage sale. It worked for a few months, but eventually the trace... I have an old Lab-Volt 791 Oscilloscope that I purchased several years ago at a garage sale. It worked for a few months, but eventually the trace stopped scrolling horizontally, so I just have a dot. I can change the location of the dot with the horizontal and vertical controls, so assume that the display is working ok. I have had a look inside, and can not see anything suspicious looking, but I am no electronics genius and I wouldn't know where to start looking.

I have access to a nice digital fluke meter, so I could test the Lab-volt, if I knew what to test and what to look for.

If anyone on this forum has any experience with this type of scope I'd really appreciate some suggestions.

Cheers. ]]> Repairing Consumer Electronics tomloader http://www.electro-tech-online.com/repairing-consumer-electronics/100079-lab-volt-791-oscilloscope.html Disabling Automatic Test Page Printing HP 932C http://www.electro-tech-online.com/repairing-consumer-electronics/100078-disabling-automatic-test-page-printing-hp-932c.html Sun, 15 Nov 2009 18:00:44 GMT Does anybody know of a way of disabling the printing of a test page "feature" that automatically occurs when replacing an ink cartridge on an HP 932C inkjet printer? I recently replaced the cartridge (with power left on: I've heard that if I had powered down before replacing the cartridge it would not automatically want to print a test page) and after every print job it tries to print a test page. I keep deleting the (test page) files in the print spooler but apparently the printer keeps sending a "test page print" command to the spooler and will continue to do so until it prints a test page. It appears that there is possibly a nonvolatile memory location inside the printer that "remembers" whether or not a test page has been printed after cartridge replacement (if done with power left on).


HP claims that it is extremely important, critical for operation, etc., etc. that the test page be printed, however, I'd like it to be my option when to print a test page, not the option of the seller of ($5,000 + per gallon) printer ink. Especially when the printer prints just fine without the so called "alignment" and "calibration" that is supposed to happen when dumping a load of ink on a test page.

I'm thinking that I could install an old cartridge, let it burn up a lot of (nonexisitant) ink printing a test page and then swap in the new cartridge with it powered down. However, I already pitched the old cartridge before I realized this little nuisance was going to persist and don't have that option right now.

Anybody have any ideas or workarounds besides letting it print a test page of dubious value (unless of course you're an HP shareholder:rolleyes:)? ]]> Repairing Consumer Electronics fordo http://www.electro-tech-online.com/repairing-consumer-electronics/100078-disabling-automatic-test-page-printing-hp-932c.html help with a lexar 1gb jumpdrive http://www.electro-tech-online.com/repairing-consumer-electronics/100052-help-lexar-1gb-jumpdrive.html Sat, 14 Nov 2009 19:50:36 GMT it heats up but is not on screen... whom has schamatics it heats up but is not on screen... whom has schamatics ]]> Repairing Consumer Electronics Gregboy http://www.electro-tech-online.com/repairing-consumer-electronics/100052-help-lexar-1gb-jumpdrive.html help fix sterio receiver http://www.electro-tech-online.com/repairing-consumer-electronics/100010-help-fix-sterio-receiver.html Fri, 13 Nov 2009 18:10:00 GMT while listening to sterio receiver yamaha rx-v661 the receiver went dead. Electronic technition did a evaluation and thought it was one whole... while listening to sterio receiver yamaha rx-v661 the receiver went dead. Electronic technition did a evaluation and thought it was one whole channell that went out. I was told it would be expensive to repair, so I thought I would try to repair it myself. I enjoy working with electronics, but I have no experience. Could you please help. Thank you ahead. ]]> Repairing Consumer Electronics Ed Goodberlet http://www.electro-tech-online.com/repairing-consumer-electronics/100010-help-fix-sterio-receiver.html AC, DC power supply http://www.electro-tech-online.com/repairing-consumer-electronics/99992-ac-dc-power-supply.html Fri, 13 Nov 2009 08:45:33 GMT I need to power a Bill Changer acceptor. This is just the part the accepts the bills. It requires +5VDC, +12VDC, -12VDC AND 6VAC. These voltages... I need to power a Bill Changer acceptor. This is just the part the accepts the bills. It requires +5VDC, +12VDC, -12VDC AND 6VAC. These voltages all have the same single ground wire. How do I recreate this on my bench? I can do the DC with my bench power supply and I have a separate AC power supply but how do I get them together so that I can power up these acceptor? I am a little confused on this one.
Thanks
Russ ]]> Repairing Consumer Electronics uriahsky http://www.electro-tech-online.com/repairing-consumer-electronics/99992-ac-dc-power-supply.html EVGA 256-P1-N399-LX GeForce 6200 256MB 64-bit GDDR2 PCI Video Card http://www.electro-tech-online.com/repairing-consumer-electronics/99988-evga-256-p1-n399-lx-geforce-6200-256mb-64-bit-gddr2-pci-video-card.html Fri, 13 Nov 2009 05:59:45 GMT i need some help identifying a missing piece from my video card and some help on how to get a replacement. its a surface mount piece labled on the... i need some help identifying a missing piece from my video card and some help on how to get a replacement. its a surface mount piece labled on the board as lb12 .heres a picture Newegg.com - Computer Parts, PC Components, Laptop Computers, Digital Cameras and more!
go to the backside picture and look just below the push pin for the heatsink and to the left of the bar code sticker [you have to zoom in all the way to see it] i have all the tools to resolder it if i knew what it was and where to get one.

i think it might be a diode but i really am not sure enough to try it in my computer. ]]> Repairing Consumer Electronics johnathon007 http://www.electro-tech-online.com/repairing-consumer-electronics/99988-evga-256-p1-n399-lx-geforce-6200-256mb-64-bit-gddr2-pci-video-card.html Pansonic TV FX21A Power supply not regulating http://www.electro-tech-online.com/repairing-consumer-electronics/99979-pansonic-tv-fx21a-power-supply-not-regulating.html Thu, 12 Nov 2009 20:35:05 GMT Hi Can someone help me with this power supply the output voltage is too high. It is 180v can someone help with diagram.:) Hi Can someone help me with this power supply the output voltage is too high. It is 180v can someone help with diagram.:) ]]> Repairing Consumer Electronics G.E.C http://www.electro-tech-online.com/repairing-consumer-electronics/99979-pansonic-tv-fx21a-power-supply-not-regulating.html <![CDATA[Help troubleshoot Sharp 12" display on running treadmill]]> http://www.electro-tech-online.com/repairing-consumer-electronics/99968-help-troubleshoot-sharp-12-display-running-treadmill.html Thu, 12 Nov 2009 17:11:00 GMT Hi!

The display on our "treadmill running machine" has stopped displaying graphics and I need some help to troubleshoot before eventually buying an new display.

I would really like to find out whether its the display thats mailfunctioning or any circuit before the display connector. (the programs seems to be functioning, but nothing shows in the display).

I have found the following connection table for the "Sharp LM32P07" display:

PIN No. FUNCTION PIN No. FUNCTION
1 Vo - -16.5V
2 VEE - -24V
3 D3 9 P0
4 D2 10 P1
5 D1 11 P2
6 D0 12 P3
7 NC - -
8 VSS 3 GND
9 VDD 5 VCC
10 CP2 35 SHFCLK
11 CP1 38 LP
12 S 36 FLM

Does anyone know if its possible to use any standard interfaces on an laptop or workstation computer to test the graphics functions on the display? Or any other ideas?

Regards
Marcus (sweden) ]]> Repairing Consumer Electronics tartex http://www.electro-tech-online.com/repairing-consumer-electronics/99968-help-troubleshoot-sharp-12-display-running-treadmill.html