Gravitar and signature analysis..

hi all.

 the gravitar pcb i spoke about in my last post did not have a bad chip
thingie... swapped from a good major havoc and it did the same thing..

anyhow, i then sat down to play with the catbox for the first time.. what a
hunk of junk. the one i have here is intermittently switching itself off,
and appears to read out the wrong signatures, maybe a display problem...

so i used the catbox to generate the NOP and used my HP5006a analyser, much
better, proper sigs..

now.. i tried to put the HP onto the VG circuit instead of the MPU to try
match the sigs on the gravitar schems.. I grounded the /SA pin to put the VG
into its own loop for sig analysis.

I found the SACLK to hook the clock up, but being a bit new to this i have
no idea where to put the start/stop.. i'm aware the start stop has to kind
of be put on each chip under test, or on the enables for a circuit section,
however, in order to match up the sigs with the ones on atari's schem
package, i need to put them exactly where atari did. Now, try as i might, i
could find no info on where to hook these to get the sigs.. the schems and
manual are scarily silent on this matter, despite providing test points and
stuff on the pcb.

i can't be the first person to run into this problem, anyone tried it out
before and got sucess?

thanks..

Andy Welburn
www.andys-arcade.com

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Received on Thu May 22 12:05:09 2003