Crackling (again!) on 112 RD 100 combo

Hi. I have a silver badge 112 RD 100 watt combo amp.
Several years ago I had a complete re-cap job and tubes replaced, etc. Since then, the amp had seen relatively light-medium usage.
About 2 months ago, the amp started experiencing some crackling sound which went away if I shut the amp off momentarily and sometimes if I played a really loud chord.
The crackling and loss of volume got worse where I couldn't fix it by the previously mentioned methods anymore.
I replaced the tubes with some spare (used) tubes I had lying around and the problem went away. I then ordered new tubes (same kind as had been in there originally) and, when they arrived, I put in these brand new tubes.
Now, 2 months later, the SAME problem is back again! It's not the guitar cable, etc.
Can anyone point me in the right direction in terms of troubleshooting?
Thanks.
LouLoomis

Fisrt thing that I'd try, since you said it sat is to clean and re=tension the tube sockets. Crackling is cause by the dirt and corrosion(sometimes) from the tubes not seating and making good contact. Then I'd get it to crackling with thte chassis out and start tapping things with the plastic or wooden probe(not a pencil). Barring that, I'd start measuring the resistance of the resistors in on and around the tube sockets with a DMM and wiggling them at the same time. One of the carbon caompa could have taken a dump. Mike.

I had a similar problem with my HD 130 combo that started with crackling and popping noises and developed into redplating valves and with mike and some of the other guys advice and prevous posts/topics posted by other users managed to fix it with a cap job and new tubes.. since you got the caps done recently maybe one of the tricks i did when installing the new tubes might help you out,i got this off the guy in eurotubes where he sprayed the pins of an old output valve with some electricial switch cleaner and worked it in and out of the tube sockets..i used one called Servisol and i also sprayed the RCA connecters for the reverb tank and it started working as well......!!!

Hello all
Lou... i don't know if you got to the bottom of your problem..i had a similar experience recently on a gig...i did what you did and whacked up the master volume a played a loud chord which seemed to cure it ...as a precaution i turned off the reverb and it hasn't happened since so possibly it's reverb linked inside the amp somewhere...i use the reverb unit in my rack lately and so far so good.....

Hi. Sorry to have not followed up on this in a while. Basically, I did this:
1. using old (unwanted) tubes, I put radio shack electrical cleaner on the tube pins and worked them in and out of the sockets.
2. put in a set of brand new tubes.
The problem seemed to have gone away, then came back a few months later, and now seems to be gone again.
It's possible it's the tension springs in the sockets, no? I haven't had these re-tensioned since my cap job several years ago...
This is where I am now. Still curious about the problem so any feedback would be welcome. Thanks again.
LouLoomis

The problem is back yet again. But, this time I touched the "Standby-hi-low power" switch and it went away. Then, it came back and I put the switch on Standby for a few seconds and flipped it back to Low Power and the crackling went away.
If this means that it's the switch, I'd be surprised because I had both toggle switches replaced when I had the amp re-capped several years ago.
Any thoughts?
Thanks.
LouLoomis

What was the outcome on this? It seems like my RD-100 is doing the same thing, sometimes the crackling will start w/out instigation. If I power off the amp, remove the tubes, replace same tubes, and power on the crackling goes away.
Also, my reverb doesn't work. When I turn it up all I get is a loud annoying hum. Sometimes turning up the reverb will initiate the crackling.
Thanks for any insight. Also, I am going to try some contact spray on my tubes and work that around as recommended.

If I had to guess at this point without seeing it, I'd say clean and re-tension tube sockets and look for any cracks on the resistors over the bottom of the tube sockets and also the solder joints ON the sockets themselves. Maybe re-flow them all and be done with it. Reverb-unplug the tank and see if the hum goes away first Mike.