StJimmy

My TSL122 blew it's mains fuse the other day and on the advice of my local shop I replaced the power tubes. After about 60mins of playing the fuse went again.

Is it worth me replacing the preamp valves before I admit defeat and take it in to get repaired??

Also (and this may sound like a stupid question) but the spec for the amp says there are 4 preamp values, however when I peer into the back I can only see three, the third space is taken up by a aluminium tube type thing approx 2inches or so long. Is this right or am I missing something here??

Cheers y'all

Lee

Marshall Amps

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apw

Sounds like you have the drifting bias problem that this model suffers from, You need to take it to a Marshall dealer and get the main board changed, the part is only available from Marshall. When the amp warms up the main PCB acts like a NTC thermistor (YES The PCB Board) this causes the output tubes to draw more and more current until they destroy themselves. The only fix for this is to change the board and another set of OP tubes.


The aluminium tube has a tube (Valve) inside it, the aluminium is to screen the tube inside.

I repair about 2-3 TSL122 per month, When I see one of these with a blown HT fuse I replace the PCB with one of the new type as a matter of course, I've been bitten by TSL122’s too many times. I work for a Marshall Dealer in Kent in the UK.

If Your in the UK PM me as I may be able to help.

StJimmy

Hi

Cheers for the reply - I'm up in Notts so I've sent the thing back to Marshall for their care and attention.
I gotta say the more I read about the TSL122 the more I wanna get shot of it. Seems a lot of people have problems with this model.

As for the valve in a tube - is it still part of the pre-amp and is it a different type to the other 3 pre-amp valves??

apw

The 3 preamp and the phase splitter are all ECC83's and the outputs are EL34's

Once the board is changed there normally OK

Benjamine1979

Hi StJimmy,

I also have a similar issue on my DSL100 - Can you let me know how much Marshall finally charge you to fix it and send it back to you?

Ta

Ben

StJimmy

Well they called me yesterday and I stumped up the princely sum of £66 (give or take) and that was for the repair and the carriage.

They picked it up last Weds and I should be getting back this Weds

apw - If one of the pre amps tubes is a phase splitter - how does that differ from the valve and what does it do?

Benjamine1979

£66 - if they replace the main board then that is one heck of a bargain. I have just ordered the board and two plastic covers and that came back at £76. Marshall said if I was to send it away it would be approx £160. Don't you just love random prices!

StJimmy

Well hopefully there'll be some kind of paperwork with it.
I know they replaced some type of board, but I was only half listening when she rang.
I'll give you a run down of parts etc tomorrow.

StJimmy

Well I'e unpacked and tested the amp and *crossed fingers* all seems OK. Unfortunatly there is no paperwork with it so theres no description of the work carried out.

I vaguely recall the telephone conv I had with Marshall and I think they said they replaced the "Tranformer Board".

stookiebhoy

This exact same thing happened to me a few weeks back, and it's the 2nd time this has happened this year. They had to replace the output transformer on mine also as it was fried. I have a TSL 602 which I've been using for 9 years and I haven't had 1 problem with it, yet the 122 which is only 18 months old has had 2 sets of new tubes, a new board, new transformer, and squillions of fuses. I love this amp when it works, it just doesn't work often enough. Also, on its' return from Marshall the emulated line out does not work for whatever reason, except in mute mode, so am not a happy bunny right now.