Tempest - those 4 (1495) chips

westal_sage

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Does anyone know the functions that each of these chips is responsible for? I understand that at least one of them handles vertical pincushion control - do I have that part right? Thanks!
 
Two are responsible for both vertical and horizontal pincushion control. The other two handle the rest of the digital to analog video output. They are a common failure point on Atari vector games, resulting in everything from no video to mirrored video.
 
Thanks Maxstang! Do you happen to know which 2 handle the pincushion? See I have a very bad vertical pincushion going on, so I ordered 4 of these chips.

Rather than replace all 4, I'd like to replace only the 2 that handle pincushion - and perhaps even 1 if I get lucky and try replacing 1 of the 2 and it fixes the problem. Know what I mean?
 
And when I say vertical pincushion, I mean the top and bottom are curved inward. The left and right are nice straight edges.
 
Thanks Maxstang! Do you happen to know which 2 handle the pincushion? See I have a very bad vertical pincushion going on, so I ordered 4 of these chips.

Rather than replace all 4, I'd like to replace only the 2 that handle pincushion - and perhaps even 1 if I get lucky and try replacing 1 of the 2 and it fixes the problem. Know what I mean?

Where abouts are you going to get these from please :)
 
Thanks Talon! Dezbaz, I ordered these from futurlec.com - $6 each. You can go there and do a search on MC1495L. Although for all I know they can be found elsewhere for cheaper.
 
Finally got A/B12 replaced with a new 1495 (with new socket) and Woohoo! it fixed my hideous Y pincushioning beautifully. I didn't put the cap back on that was soldered across 2 pins on the chip - seems great so far without it.

I also did some convergence adjustments and got things dialed in to where the monitor looks quite fantastic!
 
Nice to hear you got it back up and running. The cap you mention is most likely not needed. They put those on some of the 1495's to clean up the signal a bit. If you don't see a problem then there probably isn't .
 
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