Re: G08 deflection custom chip

From: Zonn <zonn_at_zonn.com>
Date: Mon Jul 29 2002 - 17:02:33 EDT

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. :-)
---------------------------------------------------------------------------
** To UNSUBSCRIBE from vectorlist, send a message with "UNSUBSCRIBE" in the
** message body to vectorlist-request@synthcom.com. Please direct other
** questions, comments, or problems to vectorlist-owner@synthcom.com.
Received on Mon Jul 29 14:18:49 2002

This archive was generated by hypermail 2.1.8 : Fri Aug 01 2003 - 00:34:06 EDT