petehall347
the brandy coffee man
sounds like its proper dead now then .
JVC R-X400 no output and LCD doing some weird things
- Thread starter ExcitableOne
- Start date
ELzekio
Active Member
I remember when I was looking in to repairing a 90s JVC receiver i had the unit on and acidently let the circuit board that had the speaker terminals sit on a metal surface basically shorting every thing out. Needless to say there was a lot of smoke and there was certainly no getting that thing back to life.
ExcitableOne
Active Member
I didn't see any smoke, but I smelled burning silicon, so probably the LCD chips.
ExcitableOne
Active Member
That's what I'm thinking sadly. I guess you learn from being stupid.
petehall347
the brandy coffee man
i manage to do it sometimes and i should know better .
ExcitableOne
Active Member
Yeah, me too. I'm just now getting into the stereo stuff. I've been into electrical engineering in general since 8th grade and have learned a fair bit in the two-three years it's been since then, I honestly forget. But I've shorted stuff out like this plenty of times when I was first starting with powering my first LEDs with a 9v and stuff like that. Shorted and put too much into nearly all 20 of my LEDs that I had at the time. In this case I was rushing and not thinking though.
ExcitableOne
Active Member
Well before I consider this reciever dead I'd like to properly wire it and see if I get any display then that way I'm not scrapping down something I can save and is worth saving.
ExcitableOne
Active Member
I am surprised to say the least. I just tore it all apart, saw no visibly dead components, put it back together and spent more time in the ribbon cables. I then plugged it in and pressed the power button and it worked! Now I get to play around with the preamp to see of I can get some better output from it. Should I check the opamps? Or just the caps? Andything else I should look for?
ExcitableOne
Active Member
Not as it should be, just as it was when I got it. And I will after I fully wake up and eat a thing or two.
GD70
Lunatic Member
Ouch!
May I suggest you just send it to a good tech. I did something similar on my first JVC-7050 power amp, miss aligned a plug and ended up causing a bunch of problems. In hindsight, I would have saved a lot of money if I had just given it to my tech instead of causing more and costly problems.
Good luck!
dr*audio
Fish fingers and custard!
If you are really interested in repairing electronics or studying Engineering, you should learn some electronic theory. The Art Of Electronics is an excellent book, written in conversational English, that tells you basically everything you need to know about electronics. You can download the pdf FREE here: http://www.csun.edu/~acm31201/Old C... of Electronics - P[1]. Horowitz, W. Hill.pdf
ExcitableOne
Active Member
I'll get some pictures later today, and silver. I actually really like how it looks though I don't like the lack of actual dials for the volume.
ExcitableOne
Active Member
It's actually working just as it was before I did that surprisingly. Either way I don't have money to actually get it professionally repaired.
ExcitableOne
Active Member
This is actually a lot of what I've been looking into. While I'm sure I know some stuff in this I know for a fact I do not know nearly as much as I'd like to. I'll definitely look at this once I get a chance. Thanks!
GD70
Lunatic Member
Are there any AKer's in your area that also do tech work?
Aker Tom B has fixed several pieces for me at very reasonable prices.
I'm not trying to dissuade you from digging in and doing it yourself, but I went down that road for a bit, and for me, it ended up being much better with a knowledgeable electronics tech to do it and for the piece to be reliable.
ExcitableOne
Active Member
Yeah I understand, but I bought this knowing I'd have to fix this on purpose. I'd like to get the experience and a new receiver out of this. I'm less concerned about having it and more concerned with fixing it. I understand what you mean though.
GD70
Lunatic Member
Have fun and be careful with the voltage!
ExcitableOne
Active Member
I try to be, doesn't always work though lol. Thank you though.
ExcitableOne
Active Member
Just an update, the zeners for the display are shot. They are causing dimming in the lamps after the relay clicks, and are drawing way too much current through a row of quarter watt resistors. They also discolor to a dark red while they are in and are the thing I smelled whenever I did the ribbon cables wrong From looking at previous AK posts it seems this isn't uncommon and I should put 1 watt zeners in so they don't blow up again. I checked the output transistors again and they appear fine. I can't check the rec out because I don't have access to another amp of any kind right now, or an input to use. And I have pictures!
