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Volume Pot Troubles
Posted: Fri May 27, 2005 7:12 pm
by Ricky Lee
1962 Bluesbreaker RI:
The volume pot on # 1 when cranking to full volume, the volume drops. If I back off just a fraction the volume comes back. I've replaced the pot twice already with same problem on all. Ant ideas how to correct greatlly appreciated.
Posted: Fri May 27, 2005 7:16 pm
by Billy Batz
I have a suggestion. Its not the pot.
Try a quick tube swap.
Posted: Fri May 27, 2005 7:32 pm
by Ricky Lee
Power or preamp they're all brand new?
Posted: Fri May 27, 2005 7:36 pm
by Billy Batz
Preamp. you could try power if you have a set
couldnt hurt
re: I have the same problem
Posted: Mon Jul 25, 2005 1:30 pm
by TubeGuy.
Did you get this fixed? I am having the same problem , vol #1 cuts out at 8 and 10, but is fine everywhere else. I need some direction on diagnoses. I have refreshed all solder points so I don't think it is a bad solder joint, but I could be wrong....
Any suggestions?
Posted: Mon Jul 25, 2005 1:53 pm
by Ricky Lee
Do you have some pics of the board?
What kind of amp?
Does this happen on channel 2 as well?
1. Check for DC voltage at the pot terminals - should be none with exception to the presence pot, if there is this is a good sign of leaking coupler cap/s.
2. Switch-out both power and preamp tubes, typically bad preamp tube, but can be power as well. Even if they are new they can be bad!
3. If that doesn't help try a different pot.
I accidentally fixed mine when I replaced the heater wires. I've since sold the amp and the new owner says everything works great!
re:
Posted: Mon Jul 25, 2005 10:12 pm
by TubeGuy.
Do you have some pics of the board?
What kind of amp?
Does this happen on channel 2 as well?
1. Check for DC voltage at the pot terminals - should be none with exception to the presence pot, if there is this is a good sign of leaking coupler cap/s.
2. Switch-out both power and preamp tubes, typically bad preamp tube, but can be power as well. Even if they are new they can be bad!
3. If that doesn't help try a different pot.
I accidentally fixed mine when I replaced the heater wires. I've since sold the amp and the new owner says everything works great!
It is a 1987x with PTP board and rich mod....I tried switching out tubes, to no avail. There is no voltage at the pot terminals, so that's ok...I think it must be the darn rich mod, which I am going to remove. I have George's PPIMV kit, and the shielded wire is so tiny, I am thinking there has got to be a short in there somewhere, so I'll pull it out, get it working and then rewire it....
Thanks
Posted: Mon Jul 25, 2005 10:39 pm
by Ricky Lee
Could be the problem. I heard a guy the other day had to do the same thing, but I don't remember what kind of problem he was having, but when he removed the Rich mod the problem went away. It's probably something simple.