Mark 1 Reissue question

[Tom K]

Gentlemen. When I first got my mark 1 reissue combo this board was very helpful. Thank you. I now have another question. Lately when I've been turning the amp on it's been acting strange. Wierd noises and volume loss and gain. After a while it apparently goes away. I'm fooling with the knobs in the meantime. Is this common with tube amps? Is it a warm up issue? The amp is about 2 years old and haven't played it for about 6 months. Just mentioning that in case that may be part of my issue.

 

[Blue Gilbo]

Hi Tom K,

I seem to remember having sort of the same problem with my MK 1 reissue a few years after I bought it (2002). I removed all of the old tubes and installed all new ones. Problem solved.

Not the most economical way of solving the problem I guess but it worked.

 

[Pablomago]

My MK I RI was giving me problems recently. Weird noises and loss of power, distortion when you play hard, things like that. I replaced the first two preamp tubes and it's now quiet and sounding sweet. Tubes are somewhat cheap and easy to replace. Start with the preamp tubes.

 

[acorkos]

before replacing tubes, consider the pots as a possible problem....

sometimes amps that are sitting unused for awhile get dust/dirt inside the control pots, which can lead to static and intermittent operation. pulling the chassis and spraying contact cleaner into the pots and twisting can solve that problem, or at least rules out the pots as a problem and lets you move onto other area of troubleshooting. sometimes even without contact cleaner, sweeping the pots several times across their full range left-to-right works some of the crud out of the signal path and gets the amp sounding right again.

 

[phyrexia]

Make sure your effects loop jacks aren't dirty. Try using a patch cable to go from the send to the return.

 

[Blue Gilbo]

Good one phyexia, the effects loop can also be a trouble spot especially if it's not being used (like me).

I remember reading an article about the switching jacks in the effects loop. Because of the construction of the jacks if the loop is not used corrosion could form on the contact points and cause some problems.

A yearly shot of contact cleaner works for me.

When I change tubes I also shoot some contact cleaner in the tube sockets. Before inserting the tube I'll spray some cleaner on the pins and scrub lightly with a small brush to remove any corrosion. This helps to eliminate possible future problems.