480z system disk on ebayu
julesrichardsonuk at yahoo.co.uk
Tue Oct 4 18:19:44 CDT 2005
Tony Duell wrote:
>>Reminds me, I need to fix mine (output module) on my 380Z. Can't
>>remember the details now (and it's a few thousand miles away :) but I'm
>>reasonably sure I remember it blowing the fuse in the PSU on the -12V
>>line when the board was connected, but the machine was fine otherwise.
>>Never got around to fixing it before I left the UK, but I don't imagine
>>there's much on the board to go wrong!
> Well, the -12V line is used to power the emitter load of the 3 output
> transsitors, but said load is 3k3 or something. Most likely, there's a
> shorted decoupling capacitor on the board somewhere if it is blowing the
> -12V fuse.
>>Of course it could be a fault with the RGB board itself I suppose...
> What RGB board? The Hi-Res board has a 8 bit output, that's encoded to
> RGB by 3 resistor DACs on the little board behind the BNC sockets. Isn't
> that the board we're talking about.
Ahh, if that's just RGB between the Hi-res board and the BNC board, then
it likely is just a fault on the BNC board. I'd just wondered if there
was some sort of signal passing back to the hi-res board from the BNC
board such that the actual fault was somewhere in the hi-res board
itself but that it'd work fine without the BNC adapter board plugged in.
Sorting it out is one of the first things on the pile when I get home
(where at least I've got manuals and everything to hand!) as I fixed
various other problems with it, so it'd be nice to have a 100%
operational system again. Heck, I even have the key for it ;)
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