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#31
01-20-2016, 09:16 PM
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A 5U4 pulls an extra amp on the filament supply.
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#32
01-21-2016, 12:35 AM
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Quote:
I've used a 5U4 in place of a 5V4 Damper temporarily, it worked fine but I was advised not to leave it in permanently.
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#33
01-21-2016, 04:02 AM
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I'd sooner use 5Z4 (preferably) or 5Y3 as a temporary sub if I had to.
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#34
01-22-2016, 04:20 PM
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I briefly tried a 5U4, and that didn't help. Pin's 2 and 8 should have 300V and both have about 255. Pin 8 has a fuse (which is good) that goes to the horiz lin coil. I put the HV probe on the cap of the 6BG6. No HV, but when the probe touches the cap, I can hear it cackle in the speaker.
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#35
02-05-2016, 10:13 PM
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After a break, I have gotten back on this and found a mistake I made. An 8200 ohm resistor was going to pin 5 instead of pin 6 of the 6SN7 horiz osc tube. Correcting that now gives me a partial raster as shown.
Any ideas on why only 1/2 of my screen is lit, and where to start troubleshooting?
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#36
02-14-2016, 04:10 PM
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I've gone as far as I can. I think the horiz is running off frequency. I can see what looks like a blurred overlapping image on the screen. I checked the horiz hold control, and it's fine. The horiz lin control measures good. I even replaced the 56pf cap on the yoke for the horiz. I posted most of the schematic, but the hoirz and HV section can be found on PG 2 of this thread at post 10 that starts as "I've completely lost the raster." It wouldn't let me repost the same pic again.
If someone recognizes the problem or has any ideas of that's wrong, please advise me as I'm about to give up on it. Thanks Doug Also, this set has 3 trimmer caps. Horiz lock, horiz drive, and horiz freq. Lock and drive have to be screwed in almost completely or I lose what raster I have. Freq seems to make no difference.
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#37
02-14-2016, 04:23 PM
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Get rid of those two candohm resistors underneath, no matter how they test. I just went through hell with a somewhat similar issue.
__________________
"Restoring a tube TV is like going to war. A color one is like a land war in Asia."
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#38
02-14-2016, 04:30 PM
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Judging by that picture it appears to be scanning top to bottom, not side to side.
Is it possible the yoke has been turned 90°? If that's the case then the vertical is short, not the horizontal, though that may be off frequency.
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#39
02-14-2016, 05:47 PM
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Eric, the yoke is not off. I was getting a good pic, then lost the horiz sync, then it shrunk. I did take the yoke off to replace the 56pf in the yoke windings, but I put the yoke back on correctly.
On the Candohms, what's in there are still the originals. I did have a replacement for the 350 ohm, and I just installed it. Still no change. I can see an image on the screen, but it is very blurry. I'll have to get a replacement for the other candohm. Doug
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#40
02-16-2016, 08:03 PM
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While I hunt a suitable replacement for the other candohm, I'm wondering if the yoke could be bad and causing this problem. During the whole time I have been working on the set, the raster never filled the screen completely to the left. It always lacked about 1/2 inch then got wider as I lost the horizontal sync finally giving me what I have now: just 1/2 of the screen lit on the right side.
The Sams does not give the ohms for the yoke however. Crosley# AB-144901. crosses to a Stancor DY-1. Thanks Doug
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