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wm6929
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« on: November 17, 2015, 09:38:59 pm » |
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I purchased a Ms. Pacman the other day, in non-working order. As far as I can tell, it has never been worked on before. It has never had solder work on any of the boards, filter board removed, or a cap kit done to the monitor.
One of the things I decided to do was to do a tube swap. The original monitor has the worst screen burn I have ever seen and i found a good TV to swap it with.
The Donor TV tube has the correct pins and neck size. The tube number is A48ACE26X. I removed everything off the donor and placed the K4900 ground strap, degauss coil, and yoke on it. I re-used the rings from the donor.
When I hook up the chassis, to adjust the yoke, all I get is a horizontal line. I swapped in another K4900 chassis (recently recapped) and got the same problem.
Checked the solder on the board and its okay. Checked the yoke plug, it looks okay, and I ohm'ed it on the voltmeter, I have 3.3 and 40 ohms.
What else should I look for?
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iankellogg
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« Reply #1 on: November 19, 2015, 11:31:40 am » |
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the only thing I can think of right now would be to try to do the ohm reading on the yoke while its plugged into the PCB. measure from the solder side.
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wm6929
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« Reply #2 on: November 19, 2015, 03:36:19 pm » |
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Truth be told. I never ohm'ed out the donor's yoke before I pulled it apart.
Last night I did. I got 2.8 and 54 ohms. Kinda wondering if I can put the donor back together and drop the chassis in and use it.
The original K4900 yoke is 3.3 and 40 ohms. Is the donor close enough?
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iankellogg
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« Reply #3 on: November 19, 2015, 03:38:57 pm » |
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you might have some size issues but it should be close enough.
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wm6929
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« Reply #4 on: November 19, 2015, 09:29:26 pm » |
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Ok
Since the yokes were somewhat similar I used the donor's yoke and the k4900 together.
Same issue, horizontal line.
put the plug back on the K4900 yoke, swapped to ANOTHER donor tube. Placed yoke, rings, chassis on donor #2.
Horizontal line.
So, now what? There has to be an explanation.
Where do I get a new plug?
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wm6929
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« Reply #5 on: November 20, 2015, 01:05:06 pm » |
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I cant seem to find the right plug for the yoke. I have tried a couple of variations of word combos, but cant seem to find the plug.
Does any body know what the plug is on a K4900 monitor? Molex, radio shack, etc? I will try and find it on Mouser.
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