Re: WG6100 X is wacky

On Sun, 2 May 1999, Jim Sulzer wrote:

> Vector Gurus,
>
> I've just finished a WG6100 recap & LV2000 installation and fired up my
> Space Duel. Unfortunately, it looks like I've got a boogered up X signal
> coming from my main board. Occasionally it settles down, the spot killer
> turns off and I can see some vectors & a picture but most of the time it's
> way out of range +/-10V and it jumps all over the place. On the main board,
> the Y output looks good and I compared the respective X and Y voltages all
> the way back to the DACs and the X still looks proportionally greater. Any
> ideas on what to look at or where to go? I haven't broken out the scope yet
> but I may have to get down & dirty with this thing before the battle's over.

        First thing's first...what do you have your meter set on? It
looks to me like DC volts. +/- 10 VDC and jumping all over the place
seems normal to me, since that's an AC signal, and the OPAmps that
generate Xout and Yout are powered off +/- 15 VDC.

        There are 3 ways to troubleshoot an AVG problem:

        1) Break out the scope and do it the smart way. The monitor
manual even has the Xout and Yout waveforms for a crosshatch pattern, I
believe.
        2) Set your meter to VAC and look for places where the signal
stops (not very reliable)
        3) Shotgun the parts. Normally, back when I went this route, I
started with the least expensive, and easiest to find parts (the TL082
OpAmps.)

> Any suggestions? >
> Also, is there a mistake on the WG6100 X-Y Upgrade/Fix document for
> replacing R701 on the deflection board? It was originally a 1/4 watt and is
> recommended to be replace with a 5 watt! I can't imagine that this is
> really necessary or that the 1/4 watt would have worked in the first place.
> What gives?
>
        This doesn't sound right. I would NEVER replace a 1/4 W resistor
with a 5W resistor.

Joe
Received on Mon May 3 10:00:07 1999