felto Posted April 19, 2006 Report Share Posted April 19, 2006 My computer monitor just went on the frizzs.So I decided to open it up and investigate.I do not see the obvious burnt componentand also checked out the fuse if it was burnt.I put a voltmeter on the output transistor and I get around .6 volts which tells me that itis probably good. Can anyone give me some adviseon what can be wrong with my monitor. I get no powercoming out of the unit when I fire it up. I would really like to fix this because it is a sony monitor and payed alot for it.Any advise will be greatly appreciated. Thanks Quote Link to comment Share on other sites More sharing options...
windoze killa Posted April 20, 2006 Report Share Posted April 20, 2006 You haven't supplied enough info. What do you mean you don't get any power out of it? Do any of the LEDs light up? When it is on place the back of your hand against the screen and see if the hair on the back of your hand stands up, if it does then you have EHT. Can you smell any brown smells? Did it go bang? Any horizontal or vertical lines? Little dot in the centre of the screen? How did you measure .6V on the O/P transistor (if it is one)? Were you measuring the base, emitter or collector?If you can answer some of these we maybe able to help more. Quote Link to comment Share on other sites More sharing options...
SM2GXN Posted April 20, 2006 Report Share Posted April 20, 2006 Just an add to windoze killa excellent post, what brand and model number? Quote Link to comment Share on other sites More sharing options...
felto Posted April 20, 2006 Author Report Share Posted April 20, 2006 It is a Sony monitor and I dont remeber the model no.I do hear it making a sound when it is turns on.The LED power light does not come on when I power it up. The screen remains blank when I power it on. As for the output transistor I do geta .6 volts across collector and emitter when tested.But I get an open between the Base and the Emitter.What is EHT?Let me know if you need more infoThanks again Quote Link to comment Share on other sites More sharing options...
SM2GXN Posted April 20, 2006 Report Share Posted April 20, 2006 EHT= high tension.Some of these horizontal output transistors (HOT) have damper diode built in between collector and emitter that might be the reason why you get .6V, try to swap testleads and if you get same .6 volts the transistor is probably shorted, measure resistance across collector/emitter instead of diode.If the HOT is shorted chance is that the step down converter could be faulty as well, if the coil is shorted you might have to wind one by yourself these are usually not an easy to find spare part ??? Quote Link to comment Share on other sites More sharing options...
windoze killa Posted April 20, 2006 Report Share Posted April 20, 2006 Just to be picky, EHT = Extra High Tension. generally around 26KV for a monitor. A very good reason to be carful when poking around inside. It really hurts. And can leave a little burnt pin hole in your finger. OUCH Quote Link to comment Share on other sites More sharing options...
felto Posted April 21, 2006 Author Report Share Posted April 21, 2006 Step down converter you say.Is that the same as the flyback transformer?Is there an easy way to check this partwithout disconnecting it from the board.As for the HOT what readings should I get out of it. by doing the diode test I think gettingthe .6 volts is sufficient no? What else can I check on the mainboard that wouldlikely be the culprit? Thanks always for your help Quote Link to comment Share on other sites More sharing options...
felto Posted April 21, 2006 Author Report Share Posted April 21, 2006 I forgot to ask you on my last post.What value should I get when checking resistance on collector-emitter junctionof the HOT? Do I set the volt and the highest resistance scale? Let me know Quote Link to comment Share on other sites More sharing options...
SM2GXN Posted April 21, 2006 Report Share Posted April 21, 2006 I don't even know if your monitor has step down converter, a schematic would be a great help, the step down converter supply collector voltage for the HOT, if this converter doesn't work the voltage to the HOT is usually to high and will result in destruction.Use high res scale I think you would get not less than 1Mohm if you get low reading both ways swap transistor.Check the model number otherwise all advises will just be a guess ;D Quote Link to comment Share on other sites More sharing options...
felto Posted April 22, 2006 Author Report Share Posted April 22, 2006 Whats a good site in trying to find a replacement forthe Horizontial Output Transistor?thanks Quote Link to comment Share on other sites More sharing options...
SM2GXN Posted April 22, 2006 Report Share Posted April 22, 2006 Sounds like you figured out that the HOT was the culprit, about you question, it depends on where you live, what kind of transistor is it? Quote Link to comment Share on other sites More sharing options...
felto Posted April 22, 2006 Author Report Share Posted April 22, 2006 New York CityThe part no. for the HOT is C5302hope that helps Quote Link to comment Share on other sites More sharing options...
felto Posted April 22, 2006 Author Report Share Posted April 22, 2006 I have another monitor that has one can I justswap to into this one. The part no. is different andI dont know if these things are interchangeable.Will that work? Quote Link to comment Share on other sites More sharing options...
SM2GXN Posted April 22, 2006 Report Share Posted April 22, 2006 C5302=2SC5302 these are japs :)No you can not just swap to another transistor unless you know it is an true replacement.Check the transistor you got in your spare monitor and let me knowwhat type it is. Quote Link to comment Share on other sites More sharing options...
felto Posted April 23, 2006 Author Report Share Posted April 23, 2006 The Horizontal Output Transistor from my old monitoris part no. DE9704 Quote Link to comment Share on other sites More sharing options...
SM2GXN Posted April 23, 2006 Report Share Posted April 23, 2006 Is DE9704 the marking on your transistor? I'm sorry but never heard of it please check again ;) Quote Link to comment Share on other sites More sharing options...
felto Posted April 24, 2006 Author Report Share Posted April 24, 2006 That part no. is from the working monitoras for the non-working one the part no. is C5302I checked the diode test from C-E junctionand it get a reading of about .4 voltsIs there another test from another junction that I can hookup my meter to? Quote Link to comment Share on other sites More sharing options...
ante Posted April 25, 2006 Report Share Posted April 25, 2006 This is the one: http://wwww.ges.cz/sheet/2/2sc5302.pdf Quote Link to comment Share on other sites More sharing options...
SM2GXN Posted April 25, 2006 Report Share Posted April 25, 2006 Thank's Ante!The 2SC5302 doesn't have any damper diode built in between collector and emitter.If you have unsoldered all legs there should be an infinite resistance between collector and emitter if not then your transistor is smoked, be sure that no legs are in contact with the the pcb traces. Quote Link to comment Share on other sites More sharing options...
felto Posted May 29, 2006 Author Report Share Posted May 29, 2006 Ok I get squelching noise when I turn the monitor onbut no LED light. I also do not get anything on the screen.Let me know if you can helpthanks Quote Link to comment Share on other sites More sharing options...
SM2GXN Posted May 30, 2006 Report Share Posted May 30, 2006 HI felto!Sad to hear that the replacement didn't solve your problem but what do you mean by squelching noise? Quote Link to comment Share on other sites More sharing options...
felto Posted June 9, 2006 Author Report Share Posted June 9, 2006 You know that noise that comes on when turning on the monitor Quote Link to comment Share on other sites More sharing options...
windoze killa Posted June 10, 2006 Report Share Posted June 10, 2006 That noise can be either the deguassing coils or the EHT. If you put the back of your hand against the screen and the hairs stand up then the EHT is working. Quote Link to comment Share on other sites More sharing options...
rybitski Posted June 25, 2006 Report Share Posted June 25, 2006 Sounds like you need a new flux capacitor! Quote Link to comment Share on other sites More sharing options...
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