Re: Star Wars 25 inch Amplifone issue

I know it sounds like a monitor/CRT issue, as I have similar symptoms - I occasionally lose all colors except for red, then objects show up fuzzy and with retrace lines. I would blame the monitor if I didn't have a working game boardset that proves the monitor is OK. Try game self-test or another vector source.

-Douglas

On Sep 11, 2013, at 7:28 PM, Ken Sumrall <k_lists@scrapheap.net> wrote:

> I have a Sencore CR-70 rejuvenator I got on eBay a few months back, but I've not yet used it. I've not even read the manual. :-) Does it also test? If so, I'll dig it out and try it.
>
> Couldn't I also just check for a short with an ohm meter on the tube pins (with the machine powered off and the socket disconnected, obviously).
>
> You don't think it could be a short in the green drive circuitry on the deflectinon board? We've not yet pulled it to check the transistors, nor have we put a scope on the signal while the game is running.
>
> Thanks for the suggestions. We'll looking into a possible CRT issue. If it is a CRT issue, that will suck, as the 25" CRT is hard to find, and expensive.
>
> ___
> Ken
>
> On 09/11/2013 04:18 PM, Rodger Boots wrote:
>> Heater-cathode short in CRT green gun? Don't suppose you have a CRT tester?
>>
>> On Sep 11, 2013 6:10 PM, "Ken Sumrall" <k_lists@scrapheap.net
>> <mailto:k_lists@scrapheap.net>> wrote:
>>
>> The monitor on our Star Wars sit down machine at work is having issues. It
>> started with an intermittent issue where the screen would suddenly turn
>> green, and it was very bright and all the retrace lines were showing, and
>> all the lines were out of focus. Smacking the cabinet would sometimes bring
>> back a good picture. Then we also lost vertical deflection, so we opened it
>> up to take a look.
>>
>> The deflection issue was easy to fix. We replaced a few transistors, and a
>> fuse, and it was working again. The other issue we're still struggling
>> with, in fact it's much worse, and is mostly in the bad state, with
>> occasional flickers of it working correctly.
>>
>> We initially thought it was a bad connection in the CRT socket, as it seemed
>> to change as I was poking the socket with a wooden stick. So I replaced the
>> CRT socket harness with a spare one I had. That didn't work. So poked some
>> more, and started to think there was a loose connection in the focus block.
>> But then poking further didn't do anything.
>>
>> So, we started to suspect that something is just randomly working for short
>> moments, and whatever I was poking when that happened made me think that was
>> the issue.
>>
>> We are now wondering if maybe the green drive transistor is shorted on?
>> That would explain everything looking green, and the retrace lines, and
>> the brightness. Would that also explain the poor focus?
>>
>> Any other suggestions?
>>
>> Thanks!
>>
>> ___
>> Ken
>> ------------------------------__------------------------------__---------------
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Received on Wed Sep 11 20:00:12 2013