Re: G08 woes...

My advice would be to unplug the yoke and use a voltmeter to check the
voltages going to the yoke (this is explained in the G08 FAQ). It will at
least save you a $4 part per test. Since the X and Y circuit are very
close, you can mostly test the readings of the same transistors between
circuits, but at this point if you don't see any failures visually it will
be the tedious job of testing each component in the circuit.

On Wed, Dec 26, 2012 at 1:08 AM, Jonathan Koolpe <jkoolpe@hotmail.com>wrote:

>
>
>
> Hey all!
>
> I've got a G08 that was working great for many years, and survived several
> trips to the CA Extreme show through the years that I have owned it (it's
> in a Star Trek upright). Been working on it off and on since the failure
> back around Halloween...
>
> I've been posting on KLOV, but thought I'd also post here.
>
> My initial symptom was horizontal collapse with the picture all of the way
> off to the right of the screen. But after a new cap kit, check of the MPSU
> transistors (Q601-604 and Q701-704) out of circuit and then replaced on the
> deflection board as they tested OK, reflowing of several solder joints,
> detection of a bad solder trace between pin 1 on the HV main connection and
> an adjacent resistor (fixed with a jumper), and replacement of the 2n6259
> with new ones, replacement of cracked resistor on one of the paddle boards
> (in the 700 circuit), I now get smoke when I fire it up and it I've blown 2
> more of the 6259s (the same one each time in the Q700 circuit).
>
> When I fired it a second time, at first I got a) no smoke (yea!), but b)
> full horizontal collapse (with the graphics squished into a vertical line
> in the center of the screen).
>
> So I again looked at the deflection board, and wouldn't you know it...the
> wire soldered to the collector pin of Q704 had caused the entire collector
> leg of this transistor to break off! The wire was just hanging there (that
> goes to pin 2 of the corresponding paddle board)!
>
> OK I thought...all I should have to do is get this wire re-attached and
> maybe I'll be good. So I resoldered this wire directly to the collector
> itself on Q704 and reinstalled it. Then when I fired it all up....
>
> SMOKE again! And the 4 Amp fuse at Q700 even blew and I took out the same
> 6259 transistor) Another $4 part...but I still have more at least. The
> resistor teepee was super hot, too.
>
> I'm not sure where to go now except that it sure does seem that there has
> to be something unhappy in the Q700 part of the deflection board. I'm going
> over it right now, but thought I'd post on this Christmas Day to see if
> anyone out there has advice.
>
> BTW, I managed to secure some NOS IC600 chips so if it turns out that this
> chip is my problem, I even have those at the ready now.
>
> Any help for a long-time collector but relative newbie to the vector list
> with moderate monitor repair experience? :)
>
> I sure hope to have this machine back up and running by the next CAX as a
> lot of folks play it each year! Plenty of time until July, right? ;)
>
> Thanks,
>
> Jonathan
> ------------------------------
>

---------------------------------------------------------------------------
** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org
** Please direct other questions, comments, or problems to chris@westnet.com
Received on Wed Dec 26 11:36:12 2012