Still having trouble with Red Baron display

Hi all,
I'm working on a Red Baron board set that only displays in the bottom half
of the monitor (on a monitor and in a cabinet that both work fine with a
good Battlezone boardset).

So far I have replaced the following on the main board:
2114s at A1 and A2, B1 and B2, C1 and C2, D1 and D2
7915 at VR1
7805 at VR2
2N3904 at Q2
2N3906 at Q3 (replaced with 2N5401)
6012s at A9 and D9 (replaced with DAC312s)
TL082s at A10 and D10
LF13201s at B10 and D11
LM319s at B12 and D12
TL084 at C11
I've also lifted and checked most of the resistors and all of the diodes in
that area of the board. I've checked the board interconnect cable and
resoldered all the interconnect pins on both boards. I've pulled, cleaned,
and reseated every socketed chip on both boards.

On the aux board I've replaced 7815 at VR2, 7915 at VR1, and the 74LS175 at
H0.

Still having the same display problem. The only thing I've managed to
accomplish is to create a ROM error at C0 on the aux board that wasn't there
when I started.

I'm starting to think I'm not just barking up the wrong tree, I'm in the
wrong forest.....
Any pointers on where to look next? Any suggestions at all? I'm really at a
loss here.
Thanks!
Lewis

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Received on Fri Oct 5 16:51:42 2001