Obtaining Marshall TSL100 board question

[wyomingrocks]

I have a TSL100 with the origional board, I have thougth of upgrading the board one of these days. I guess I should before they stop producing them. How do you go about getting a new board, do you write Marshall or do you have to send it into an authorized service center? Also does anyone know approximately how much they cost? Thanks for any feedback.

[Enzo]

Is there something wrong with the board you have?

The main board part number is TL10600200 and it lists for $210.00. You should be able to order it through any Marshall dealer or marshallparts.com

Installing it is up to you, or hire someone.

[wyomingrocks]

thank you

Thanks for your response Enzo. I repaired my board a year or so ago and I don't play this amp much anymore, but I don't want any future issues that may be avoided with a new board. I have noticed more and more people saying this board starts having thermal issues. And a common response is to replace the board. I just started thinking maybe I should replace it while it Marshall still manufactures it. It was working fine the last time I fired it up, so no issues at the moment. I would have no issues installing it myself so I guess I would just have to replace the board. Anyway I have rambled enough and as always appreciate your response. Thanks again

[J M Fahey]

Hi wyoming.
Is that a Marshal-suggested mod?
I worry that your new board willbe the same as the old one, only newer, not addressing the bottom of the problem.
What are those thermal problems, specifically?
Maybe you should try to address them directly, such as separating overheating power resistors from the board or installing somewhere a small fan, not to cool some specific point but to increase air flow inside the chassis and refresh everything in a general way.
That will be good for the board, electrolytics and other parts.

[wyomingrocks]

board replacement

Thanks for your response J M Fahey. I am not sure if it is a Marshall suggested mod or not. I went to this web site. The Marshall TSL122 JCM2000 Repair/Mods Page Which got me thinking, it is a site about how a tech goes through all kinds of replacements and such trying to isolate and fix the problem. About 1/2 to 2/3 of the way down the page some other techs chime in and say they replace the board and it is a Marshall suggested fix. I am just an owner of the TLS so I am not sure if that information is correct or not. From what I get out of the discussion is that some boards were stuffed with the wrong resistor at the factory leading to the thermal problems associated with bias drift. I am not sure if that over heating leads to bigger problems down the road or not. So to stay on the safe side I thought I would pose my question here. The web page is an interesting read on his approach to solve his particular thermal problem.

Anyway, I guess since mine is probably 8 years old and I haven't had any issues yet maybe I am safe. Unless the majority here says they replace the board whenever they come into your shop, I guess I will keep on doing what I have done, nothing for now. Thanks for your response and ideas how to tackle this problem if it ever develops.

[bajaman]

I have had problems with two of these - it only seems to be a problem with boards numbered issue #5 and lower though. My replacement boards were issue #10 - both were better quality fibreglass AND had the correct grid stoppers (5k6) fitted. It appears to be a combination of things with the early issue boards - wrong resistors, dry solder joints between the top and bottom layers especially on the output tube sockets and leakage through the poor quality board material used ( definitely not mil. spec. board material).
Once these early issue crappy boards are replaced, ALL the problems magically dissapear
bajaman

[wyomingrocks]

Thanks

Wonderful information bajaman , thank you for your response.

[Alex R]

The newer boards that don't leak HT are a darker green and you can see a kind of woven material under the surface. Glassfibre I guess. The older ones are a paler green and a very uniform colour with no weave visible. Sometimes they are ok but once you start to have overheating problems with them I would say it is new board time.

Marshall don't officially admit the problem but they do keep the boards at a fairly reasonable price, and the new board does solve the problem. Fitting a new one is ticklish. It is possible to go one connection at a time if you juggle the two boards right. Unplug everything on the old one and you will lose track of where everything plugs in on the new one unless you label leads and sockets with extreme prejudice. It is an awkward job. I am ok with it but I would not be delighted to be handed an amp with the old board removed and all the leads unplugged!

[trem]

I had to replace one of these for a friend of mine. It had become impossible to bias his amp. I guess the board becomes "conductive", and perhaps there are other issues as well. I emailed Marshall several times, they were absolutely no help.....other than to suggest I purchase a new board. How nice of them. "There is no problem with our gear, but if you install a new board the problems that do not exist will go away."The best new Marshall is called Metro, Germino, Ceriatone, Reinhardt.......
Anyway, that is the only one I have ever done. It took me several hours, don't know what a tech would charge. A decent tech would probably just refuse to do a job like this. Honestly, if it were my amp, I would be tempted to strip it of usable parts and just landfill the rest of it. Use the new board money toward a better quality amp.......it's shameful really.
Good Luck

[Alex R]

The problem doesn't emerge till the boards are a good few years old, and is only solvable by a full replacement of most of the innards of the amp, a job which takes me more like two hours than one, and I have done quite a few now. I have a certain amount of sympathy with a company that doesn't go quite so far as recalling all their amps with the original board, but which at least maintains a supply of the new one.

[Alex R]

A decent tech would probably just refuse to do a job like this.

- that makes me an indecent tech.

[trem]

The problem doesn't emerge till the boards are a good few years old, and is only solvable by a full replacement of most of the innards of the amp, a job which takes me more like two hours than one, and I have done quite a few now. I have a certain amount of sympathy with a company that doesn't go quite so far as recalling all their amps with the original board, but which at least maintains a supply of the new one.

Sympathy?
It's like buying a car and the transmission fails after 2 years, but the car manufacture makes you pay for a new tranny.
Regards my comment about "decent" techs.....in no way was that meant to be an insult. I can imagine a tech who is busy might just pass on a job like this. An amp tech I am not.

[Alex R]

- it was just a gag about the indecent tech.

I think the difference with a car manufacturer is that amps - even Marshall amps - arte made in such relatively small numbers that the R&D and testing are necessarily a bit limited, and if something goes wrong in a wholesale way there simply won't be the resources in the entire company to put it right via a recall, say. I'm thinking of the sort of problem that appears to be emerging with the hissy switching ICs in certain amps built by a well-known company bearing the name of an ex-Fender designer. If there's a fix for that one I'm not hearing anything from them about it. I wouldn't expect a public statement admitting a faulty design, because amp firms are small and can't afford that, so I find Marshall's approach, viewed realistically, as kind of ok, that's all I'm saying.

Anything with both a PCB and some tubes in it is likely to require more product development to be entirely reliable than any amp manufacturer can afford (or to result in amps costing more than most customers would pay). Most of us know that simple eyelet/turret/ptp designs produce quite expensive but reliable amps, and a niche market still buys them, but PCB amps supply the complex switching circuits that the market demands at a much cheaper price, so they're not going away even though there might be reliability issues.

Have you had a look inside the Epiphone Blues Custom 30? Decent quality PCB, wide spaced tracks, simple circuit, tone not sacrificed to wattage... I think that's the right way to build a reliable PCB amp.

[bajaman]

some good comments since my last post - yes it is possible to build a decent PCB based tube amp - Soldano has been building the best Marshall amps for some years now.
Marshall used shitty PCB material for the early issue DSL and TSL amps - they also used double sided boards and mounted the output tubes on the board - a recipe for disaster - they should supply replacement boards a whole lot cheaper than they do AND they should own up to a very serious design fault with these amps.
I can replace a complete board in less than an hour
This is what happens when you let computer savvy kids loose with CAD
I tried to order replacement boards direct from Marshall Service in UK - they completely ignored my emails - not even a courtesy reply. I had to contact the local service agent and have them order the boards for me - 3 months later (and after their mark up) one of the boards arrived.
I have NEVER had to replace boards in earlier Marshall products - maybe because skilled engineers designed them NOT kids with fancy CAD programs on their computers.
How the hell did they manage to produce DSL amps with 220k grid stopper resistors???? instead of the correct value 5k6 as in all the other Marshall amps!!!!!!
Obviously the computer CAD whizkid that designed them got confused by the 220k bias feed resistors and the production team (robot insertion machine) simply placed the incorrect parts in the board as specified on the schematic - LOL.
The reissue replacement boards have the CORRECT 5k6 resistors inserted.
If you have a DSL with problems - check the grid stoppers - if you have 220k fitted then remove the board and send it back to Marshall because it is not gonna last more than 10 years (if you are lucky - lol).
bajaman

[catstrat]

comment

Shoot. I work on p.c. board amps all the time and i consider it just part of doing business. The problem i find with TSLs is almost always a bias problem and i've seen that sometimes with even with the new boards installed. But i think what happens is some people grab a screwdriver and take the back screen off and start monkeying around with the bias pots and pretty soon they've screwed the whole thing up. There is a guy on the internet, and it may have been on this forum, who modified his TSL by mounting a single bias control pot on the board instead of the 2 pots the amp normally has. According to him it cured his problems but i don't know if it will work on the early boards or not. Another just cut his bias voltage tracings on the board and wired his bias circuit. There is also a very small ceramic disc cap that is located under the end output tube socket that sometimes fries. This leads to hum problems. A friend of mine just removed it completely with no ill effects but i just replace it. I think it's there to help with oscillations. Good luck. Terry