A1200 tv signal problem ???

[jimmyboy]

Bought a a1200 at the "big amiga bash" along with some other bits and pieces. But the a1200 seems to have a problem. When i turn it on i get a very dark screen. The boot sequence/start screen is very dark and i can make out the floppy disk which is just light grey, the rest is so dark i can barely see anything. Ive tried using the RF lead with constant tv tuning and ive tried the RCA way.

Does anyone have any ideas? Has anyone else encountered this?? :-?

[jimmyboy]

Just stipped it down. Board is version 1A. Looks like its had a bodge job done it aswell, a bit of home modding soldering some legs on a chip together  :-(



pic 1

pic 2

Anyone seen this done? Could it be the problem ??

[Castellen]

Pic 1 shows pins 1 and 2 connected together, which is fine as they are both video ground pins.

Pic 2 shows pins 20 and 21 (both video ground) connected to what looks like pin 16 (also video ground).  At a guess this is to fix a PCB tracking fault?
I can't remember all the production faults with the rev 1A board off the top of my head.

Get another photo of the other end of the wire link.  It almost looks like pins 16 and 17 are joined together?  This would cause a video problem as pin 17 is for an external compensation network.