Re: Battlezone and -5v

Kevin Moore wrote:
> The reason I ask, is I've got a BZ that most of the video output
> section was bad. All the way from the Dac upto the final output. I've
> replaced and socketed everything but the window blanking part of the
> circuit. But I'm having a problem with the Y bip being stable.
>
> When you turn it on, the Y bip will either be dead on, or way off. So
> it doesn't seem to be heat related. Sometimes it will be spot on, and
> then start to get a bit jumpy, to the point that the test screen is
> completely messed up, then it will just snap back in place, with maybe
> some slight jitter. I've replaced the Bip pots thinking it might just
> be a flaky pot. No help.
>
> Swapped both x and y chips does not follow. So I'm thinking there
> might be something flaky with the data shifter, but as of yet my
> attempts to catch a bad signal with my scope have proved futile.
>
> Kevin
>

Interesting - I'd be looking for a noisy resistor at this point.
Resistors can have intermittent connections inside where the lead joins
the body, rare, but it happens...

John :-#)#
>
> On Wed, Sep 1, 2010 at 11:20 AM, Rodger Boots <rlboots2@gmail.com
> <mailto:rlboots2@gmail.com>> wrote:
>
> So the XY outputs can swing negative.
>
>> On Sep 1, 2010 11:18 AM, "Kevin Moore" <talon.k@gmail.com
>> <mailto:talon.k@gmail.com>> wrote:
>>
>> Dumb question, what is the -5v for on BZ?
>>
>> Kevin
>>
>

-- 
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
                 www.flippers.com 
"Old pinballers never die, they just flip out"
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