#61
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Quote:
https://www.amazon.com/MIC-Silastic-...s%2C358&sr=8-4 not affiliated, jr |
#62
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Good thing I asked, then. I'm sure the codes in the service manual match specific products that are long out of production.
Part ordered. I needed to pick some of those up anyway. Fingers crossed this fixes my power supply issue.
__________________
To keep your tubes running smoothly, make sure to dust underneath the glass as well. |
#63
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X1 is replaced and I have life again. Out of circuit, it tested completely open.
Still having the height issue. I'll update once C2D comes in and I do the swap.
__________________
To keep your tubes running smoothly, make sure to dust underneath the glass as well. |
#64
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Okay,
C2D has been replaced. I'm not seeing any change. For good measure I also swapped in a new vertical output tube. Also nothing. I measured the ohms on R5. It peaks just around 2K, which I belive is what it's supposed to be. When I measure the voltage output coming off of R5, which is listed at 15V in the schematic, I'm seeing it maxing around 22-25V and brushing at 15V at the lowest. Any suggestions for what to check next?
__________________
To keep your tubes running smoothly, make sure to dust underneath the glass as well. |
#65
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Shouldn’t the cathode go to zero volts when the pot is at one end?
jr |
Audiokarma |
#66
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Let me double check. I know it looked like it dropped off right at the tail end.
I'll grab a video of the voltage and resistance readings today. Maybe you'll be able to interpret it better than I can. I'm wondering if my issue isn't in R5. I have no idea how likely that is, but could I have damaged that?
__________________
To keep your tubes running smoothly, make sure to dust underneath the glass as well. |
#67
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Portacolor sets are somewhat prone to tin whiskers in the pots...I had one which had the AGC pot dead shorted to ground via a tin whisker. The set had ZERO reception and it took some time troubleshooting the dead IF to trace it back to the AGC and then the pot...if a whisker developed on a pot connected to B+ or boost it could make the set really unhappy.
__________________
Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#68
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Here's a video where I took some measurements on R5. https://www.youtube.com/watch?v=aBqK...ature=youtu.be
Could this be tin whiskers? How would I go about correcting that?
__________________
To keep your tubes running smoothly, make sure to dust underneath the glass as well. |
#69
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That jumping near the end of the pot travel looks highly suspicious... have you tried cleaning the pot with deoxit?
jr |
#70
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Quote:
That being said, if I do need to replace this, does anyone know what replacement part I'd be looking for? Obviously I'll check Moyers with the part number first, but assuming they don't have a replacement.
__________________
To keep your tubes running smoothly, make sure to dust underneath the glass as well. |
Audiokarma |
#71
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My standard process for tin whisker infested pots is to remove, and dismantle the pot take a toothbrush then fine sandpaper to the metal parts clean everything with a good control cleaner and paper towels, reassemble the pot, check resistance and range with rotation between all terminals and also case metal, and if all is good reinstall.
__________________
Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#72
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Quote:
One thing I am sort of wondering about, and I can get pictures of this if you need it: I'm noticing that the pot doesn't have the standard three lugs. Instead, it has one that goes to C2D/the main PCB, and two that connect to ground. That matches the schematic just fine, but since this is unusual, is there anything I should be watching out for as I disassemble?
__________________
To keep your tubes running smoothly, make sure to dust underneath the glass as well. |
#73
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Quote:
__________________
Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#74
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Okay, well I really went at it with the deoxit on R5. Not seeing any change.
Are we sure this can't be a HV problem? Or maybe a voltage problem? My HV to the CRT is still measuring between 7 and 10 KV. It should be around 15 per the schematic.
__________________
To keep your tubes running smoothly, make sure to dust underneath the glass as well. |
#75
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I may have something here.
I'm noticing that my voltages are consistently 10 or so volts higher, except the HV which is several KV too low. I traced it back, and discovered that C103 has 0 volts when measured against ground. I've ordered a replacement. Could that be related to my issue?
__________________
To keep your tubes running smoothly, make sure to dust underneath the glass as well. |
Audiokarma |
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