Re: Asteroids Dlx centering

Paul Sommers wrote:

> Gang,
>
> Had a bad 6012 DAC on my Ast Dlx boardset. Replaced it with a AD561JD
> from my Taito PCB (in the second position).

Schematic shows you CAN substitute the 561 for the 6012, BUT there are
others parts that also get installed at the same time.

If you replaced the DAC at posistion B11, for example, a 2.2 Kohm
resistor gets installed at location R122 and .1 uF capacitors at
locations C93 & C81. I would think R92 would have to come out, but
can't prove it.

>
> New DAC is working fine but... picture is too far left.

That might be because of R92, but once again can't prove it.

>
> I've checked the monitor centering without the yoke plugged in as
> described in the Electrohome manual and the dot is dead centre.

All that shows is that centering rings are set for the center of the
tube. If the image is only shifted a little (under half an inch) the
centering rings can be moved to correct for it. There are two centering
rings on the back of the yoke. Turning both the same amount sets the
DIRECTION of the correction, moving them independently of each other
sets the MAGNITUDE of the correction.

>
> I'm now wondering if you need to change BOTH DACS at the same time? Or
> is it something else.

No no no, oh dear God no! Only do that if you want the same problem in
the other channel, too.

>
> Cheers
> MacMan
>
>

---------------------------------------------------------------------------
** 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 Sat Oct 26 18:13:38 2002