Marshall TSL 60

[lordnikon]

Definitive Amp Repair List:


- Volume is drastically too low, even when turned up to 11
sounds as if it is at around 2-3ish when mastervolume is
maxed.

- Tone is crackly and lacks proper Marshall fullness and
overtones.

- Has a tendency to blow fuses when left running for long
periods of time (an hour or more).

- One power tube burns brighter than the other, even when
tubes are replaced. (not a faulty tube problem)

- Presence knob seems to have know affect on tone when
adjusted as compared to a normal amp's range of
presence.

- Spring reverb tank seems to rattle more than usual while
moving and transporting the amp, may be normal however.
it does not affect the reverb of the amp (still sounds
crisp and airy)

- Foot pedal channel selector will sometimes reverse if
unplugged and replugged while amp is turned on. When the
pedal midi plug is wiggled in it's jack it sometimes
corrects this problem.

[Alex R]

Nice to know all this. Some of it sounds like the overheating issues some of these amps can suffer from. But do you have questions?

[lordnikon]

those are the questions. my friend doesn't have an account on here even though i told him to get one and these are the items for this head he can't figure out.

[Alex R]

Questions normally look different from that... but ok, I'll stop being a pedant - if he wants to work on the amp the first thing I'd do is to take out the power tubes and measure the bias voltage on pin 5 of each power tube. What are the voltages?

[rf7]

I don't think the channel selector pedal issue is a problem. Plugging it in and out while the amp is on is not a normal operational mode for most modern amps with relays in them. Old school Fenders---no relays, no problem, but your TSL60 will probably react as described by you.

[lordnikon]

Plate voltage of the tubes are 461, the idle current of V1 is 52.5 and V2 is 42. the tubes begin to glow blue only after a short period of time. and at full volume the amp sounds extremely low. ???????????

[captntasty]

tubes begin to glow blue only after a short period of time

that right there is probably telling you the tubes are bad or are being damaged quickly by the amp. Blue tubes = bad sound if any at all. Can't give you any diagnostic as to why.... just my .02

[Alex R]

Blue glow is caused by a little gas in the vacuum. Not necessarily a problem at all, plenty of amps do it happily.

Those current figures are ok, maybe a little high, but not themselves the cause of the problem (or the blue glow).

Next thing is, get hold of a preamp tube (12ax7/ecc83) and swap it in for each of those already there in turn.