Marshall TSL 100 Issue

[mikeboone]

I have a friends amp that is acting strangely.

At first it sounded OK, but would cut out with the volume above 4. It has since dropped dramatically. The output is almost nil.

- I have changed the tubes
- I have checked the bias according to info I read in threads regarding TSL 100 Bias. Set to 90mV per side. Bias voltage is -40VDC
- I have tried plugging into the effects loop to see if it is past the preamp. Sound is low there also.
- I have celaned and checked the speaker jacks.
- I have cleaned and checked the tube sockets for contact and cracked solder joints.

The volatge on the power tubes is:

1 - .090 I am assuming there is a 1 ohm R for bais measurment
2 - 3.3AC
3 - 471
4 - 457
5 - -40
6 - NC
7 -
8 - .090

Anyone have any experience with these amps?

Thanks,
Mike

Are there any common

[Amp Kat]

Try patching a cord from the send to return jack and see if the volume comes back. wiggle the preamp tubes very gently while playing and see if it comes back. Check all of the fuses mainly the HV fuses I thionk they are 500ma's.

[mikeboone]

Thanks Kat...

I tried the send/retrun patch on both effects loops and all combinations there unto pertaining to no avail my friend.

I checked all those fuses, they're OK. The voltages on the tubes seem relatively normal and I say that based on records I have where I worked on a JCM800 (2205) a while back.

This amp has way too many handles and the schematic doesn't have many clues on it pertaining to the behavior of particular circuits the way Fender does.

I think I am going to get out of the amp repair biz. There is only one other guy in Houma that repairs amps and its just way too busy. I dont have time to finish my builds or repair my own broken stuff!!!

In the interest of getting my buddy's back up and working I dropped it off McCann Elect. in Metairie today. They are the local Marshall factory repair shop.

[Amp Kat]

I know what you mean about the busy part and in Baton Rouge I was swamped and didn't have time to play or record and that's why I got out plus our shop closed down so that was the nail in the coffin. MCCanns is good but they are very high. It will cost you 3/4 of the amp value before you get it back. Let me know what it was and next time contact me as I know someone local who could handle that for you for way less.

[mikeboone]

Thanks again...

As fate would have it, McCann called and said they ran the serial number through Marshall and the amp is still under warranty. So my guy only has to pay for parts. It has been in McCanns before with a bad reverb tank a month after he bought it.

At this point he had better hope its something expensive like the OT and not a few out-of-tolerence components!!! I'd hate to see him get hit for 2 hours of labor and $2 of free parts.

It was a frustrating amp to work on and my wifey is killing me with spring time honey-do's.

[WholeToneMusic]

I just started working on amps in my sleep to save time.

[ahamay79]

I think I may start doing that too.