Re: identical G05-802 problem with 2 different deflection PCBs

I have an Omega Race but it's just a project at this time so probably
has more problems than this one :)

Apart from that, no. I did inspect the edge connectors for obvious
signs of damage but that's all I could do.

Colin

On 30 Nov 2009, at 04:49, Dan Todd wrote:

> Could it be a bad edge connector in the game itself and not making
> good
> connection with the PCB? I thought
> That a bad connection there could cause problems like blown
> transistors. Do
> you have any other B&W vector
> Games? It always helps me to narrow down the problem when I can swap
> things
> around to other working games.
>
> Dan
>
>
> -----Original Message-----
> From: owner-vectorlist@vectorlist.org
> [mailto:owner-vectorlist@vectorlist.org] On Behalf Of Colin O'Brien
> Sent: Sunday, November 29, 2009 6:19 PM
> To: vectorlist@vectorlist.org
> Subject: VECTOR: identical G05-802 problem with 2 different
> deflection PCBs
>
>
> Hello,
>
> I've been a lurker here for a while, quietly absorbing the insight but
> I've hit a problem that has me (and my limited knowledge) baffled.
>
> I have a working asteroids game board (2 actually), with which I can
> play fine on the scope (also when grabbing the signal from P100
> instead of the test points)
>
> When I initially got the machine, I had problems with the monitor
> (G05-802) having no horizontal deflection and the spot killer being
> active. After checking the PCB, I replaced a couple of transistors on
> the board a well as the Q708 & 709 chassis transistors.
>
> Upon powering up, I would lose the 2 chassis transistors in question
> and sometimes the F700 fuse. I practically inspected every single
> component on the board, but found no extra faults. I looked for
> shorts, tested voltages (95V at P500, 30-35 VAC coming in at P100 pins
> 7 & 10, 12kV for HV etc) but found nothing that looked suspicious to
> me.
>
> I recently got a new known working/tested deflection PCB as a
> comparison/reference point, hoping that would help me see what was
> wrong or, at the worst, serve as a working board. Well, no luck there,
> when I plugged it in the spot killer was on and I had no horizontal
> deflection. I guess I can deduce from this that my problem is outside
> the PCB itself?
>
> Powering it up a second time to take some readings, the spot killer
> was still on but I'd lost the picture, turning brightness/contrast up
> only produced a faint haze towards the top of the screen.
>
> Inspection of the PCB revealed R713 was burnt to a crisp as well as
> its neighbours Q705 and Q706 both being shorted. I checked the chassis
> transistors, they were fine, I looked for shorts in the sockets, plugs
> and cables leading to them but found nothing wrong either.
>
> I replaced the dead components but powering it up now blows F700 when
> I'm lucky or the chassis transistors. I'm weary of powering it up
> again as I don't feel like destroying components for the fun of it.
>
> I'm at a loss now, not sure where to look outside the PCB. Could the
> yoke be at fault? I'm in unknown territory here and would appreciate
> any pointers I can get.
>
> Thanks!
> Colin
>
>
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Received on Mon Nov 30 06:40:44 2009