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JVC R-X400 no output and LCD doing some weird things

dr*audio said:
You're not going to get any audio until you fix the -15V supply, , and if the switching ICs are bad you better find out now. If they are not available you are wasting your time.
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The aux input works. And I was getting some audio without the -15v, just distorted.
 
I got the lights and zeners for the backlight. They fit and I actually like them. I'll post a picture.
 

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redk9258 said:
Did you ever get this thing working?
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Hey! I was just coming here to ask abut this. if you're still active, I have good and bad news. It is not currently working, the problem I am current trying to address is the lack of a 15v supply. Id say its a hopeless effort but I have gotten the paper version of the service manual so I have schematics and block diagrams and parts lists and everything. I'm also much more knowledgeable in electronics now, so I think with a bit of effort I can get this up and running. I think its all just in the power supply. Anyway, if you're still around I could definitely use some help. Also sorry I didn't respond quickly, I usually get emails about replys.
 
petehall347 said:
i vaguely remember this . i have also learnt more about these things.
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Nice to see someone. I may have learned some more but i still do the same dumb ****. I managed to short the power supply board out again and I lost the main negative power rail. The power rails (47v) come off a separate board though, and its pretty simple, so it should be an easy fix. Ill get some pictures of the power supply schematic in a second.
 
no rush for me right now .. random swollen foot thing going on . typical symptoms dont fit with the experts but i think i know otherwise .. need to drink less . . worked last night . was fine all day .
sorry was just saying will be on form soon as i can .
 
petehall347 said:
no rush for me right now .. random swollen foot thing going on . typical symptoms dont fit with the experts but i think i know otherwise .. need to drink less . . worked last night . was fine all day .
sorry was just saying will be on form soon as i can .
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aww that sucks man. I figured i could sit back on one of these summer nights and get something done thats besides my focus right now. Ive been learning abut building distortion pedals for guitars and ive been trying to get a little business going.
 
redk9258 said:
Ok great!
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did a little hunting around the schematic. found that either r856 isnt dropping to 40.9v rail down to 18.7v, or somethings faulted in d851 that causes a direct short to ground. ill test the resistor and see if the diodes hot after i upload those pdfs. if this is the problem though then the entire 15v rail should come back alive.
 
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