Re: G08 deflection custom chip

On Mon, 29 Jul 2002 11:55:40 -0400, "Mark Jenison" <jenison@enteract.com> wrote:

>Hi all,
>
>I ran into 2 bad custom chips on g08 deflection boards this weekend. Anyone
>have some junk deflection boards I can scrounge off of?
>
>>From what I understand, this chip contains 2 error amplifiers and a
>pincushion corrector. Is there anything aftermarket that could be
>used/modified?
>
>Anyone done any research on these towards developing a replacement chip?

If it helps, we've designed a replacement circuit for the MC1495 pincushion
correction circuit. It uses the LM13700 as the 4 quadrant multiplier and seems
to work rather well. It replaces two MC1495's with one LM13700 and a dual op
amp (TL082), and corrects for 1 axis (which is all that Atari corrected for,
since there aren't any monitors that need Y pincushioning correction.)

It's a start, and LM13700s are readily available.

-Zonn

(For the record I'd like to thank Al Kossow for finding this chip. We searched
the full database of National and found nothing. But in a 1998 Vectorlist post
Al mentions this chip. Going back to the National site I found the datasheet
which talks about its use as a 4 quadrant multiplier. It must mean something
when searching the vectorlist gives you more information on National's products
than searching National's website. :-)
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Received on Mon Jul 29 14:18:49 2002