2 Jaguar consoles with problems 1: no sound 2: black screen - any ideas?

[Chandler]

hi all

 

i have a couple of jags with issues and would really like to sort them as they look like new!

 

1: console 1: works fine but no sound! any ideas where i should start to look?

 

2: console 2: black screen when switched on with cartridge inserted, power LED ok, so dead board?

 

thanks..

[Zerosquare]

1: check REG1.

 

2: could be a lot of things, hard to tell without more info.

[Chandler]

ok the jag with no sound is repaired! it was REG 1

 

so what info do you need for jag no: 2?

 

it has a dark grey / black screen with some small vertical moving lines

 

green led on jag is on and working game inserted, no sound

[Zerosquare]

I would check the "easy" things first : voltage, resets signals, clocks, that kind of things. If everything looks OK, check the address and data buses and their control signals (it could be a broken track or defective buffer) ; you'll need an oscilloscope and lots of patience for that.

 

Unfortunately the boot process needs a lot of things to run (Tom, Jerry, 68k, DRAM, ROM), so the fact that it doesn't boot doesn't tell much.