Whats this symptom?

[bluesguitar]

After about 30 minutes of playing my amp starts cutting out with a lot of static sounds. I have new rectifier and power tubes. No indications of redplating. Recently cleaned all connections. Been reading everything I can. A bad capacitor is usually a hum. This is static and cutting out. Definitely worse with increase in volume and bass. Anyone had similar symptoms, and found the trouble?

[Super_Reverb]

I corrected a similar problem with a newer Marshall amp with an effects loop: one of the jacks was bad and would intermittently cause the amp to cut out because the unused effects loop was opening up. I verified it by running a patch cord from effects loop out to effects loop in.

rob

[Reeltarded]

Sounds like a cold joint that gets worse with expansion. Volume and bass just means it's shaking it more, right?

Could be anything. Get a chopstick and (oh, bamboo or wood.. no plastic) and poke around on the board when it it making the noises til you make the noises.

[Milkmansound]

are you using the new Rohs complaint Switchcraft jacks?

[cbass]

Sounds like a cold joint that gets worse with expansion. Volume and bass just means it's shaking it more, right?

Could be anything. Get a chopstick and (oh, bamboo or wood.. no plastic) and poke around on the board when it it making the noises til you make the noises.

Old tooth brush.Preferably One thats ground down to a sharp point on a cement floor.

[martin manning]

What amp?

[bluesguitar]

What amp?

'72 Deluxe Reverb

[Reeltarded]

Ok, get a pencil..

The board. Tap the board all around when the amp is cold. (with the shank you made on the jailhouse floor from post 6 from cbass) Be methodical and try to narrow down the exact place if you find a problem.

Did you find anything? If not..

Tube sockets.. hangy upsidedown amps cook parts above the tubes. Do you see anything brown? Tap it with the jailhouse shank..

Did you find anything?

This list gets long and could even be the board itself..

[ampdoc1]

Get one of those "duster" spray cans used to clean computer keyboards.
Turn it upside down (you'll be spraying the propellant, which is very cold) and try spraying each component with a small blast.
This will help find loose connections and/or failing components,

I recommend this a lot because it works about 90% of the time on intermittent noise problems.

[Firestorm]

Also check the integrity of the grounds along the bottom of the brass plate. I've seen some where the leads actually pulled out of the solder as the boards warped over time.

[boots]

+1 on the shank and freeze spray.

But be careful with that freeze spray around the hot glass tubes!!!

[Structo]

No offense to Miles but a pencil is a poor choice for probing an amp.

The lead is conductive and bad things can happen if it does come in contact with high voltage.

Use a wooden dowel, chop stick, toothbrush shank, etc.

Non conducting materials.

[Reeltarded]

Not to probe with! To make a list a mile long..

[M Fowler]

Pencil do not use lead and I don't ever have.

[Reeltarded]

No wonder that last amp you built had a 47000uF bass cap.

Periods in math too.