Marshall JCM 2000

They may well be chinese pattern copies of ALP`s switches, replace them with genuine ALPS parts and they will be fine

Ron

here. 2

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Actually 3.5 mm pin spacing, yellow stem "angle logo", found 4 ALPS marked ones, blue stem replacements and some slightly larger diameter knobs. Required slightly opening out the "gold" fascia holes but not the underlying panel and unfortunately red in colour. Permanent black felt marker over them , cooked in with hot air and repeated again sorted out that aesthetic problem.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

The ALPS 'blue' range are pretty universal on many major brands of pro quality mixing desks tec, and are very reliable.

Ron

You may find that the yellow stem switches have solder tags on the metal cover, giving a mounting arrangement that the blue Alps switches do not have, being all plastic. IME though, the yellow switches are way inferior.

The blue Alps ones are indeed universal and are found in many pretty decent recording and live consoles, where they give a pretty decent lifespan. They do not tend to break, unlike the yellow ones, but just wear out. I would go with Ron's advice and replace with the blue.

Gareth.

Another solution I tried, padding out the gap with cut 5mm LED clips or cut down 8mm clips and they would work with the original knobs but the fascia would need opening up a bit also.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Actually, after re-reading your post more carefully, you are right about the problem.

I changed one of those yellow switches on a Marshall TSL100 about 4 o'clock this afternoon. There is indeed far too much play in the knob / chassis hole arrangement, so maybe this is more the problem rather than the switches themselves being inferior.

I would still replace them with the blue ones, even though the one I replaced this afternoon was a Marshall stock yellow one. (Only because I didn't have a blue one and the guy needs the amp tomorrow, but ..... what to do?)

I think you will find the blue ones negate the need for faffing too much with the oversize hole problem.

Gareth.

here.

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The easy fudge would be peripheral cut a 5mm LED clip or 8mm with a section removed fitted in the gap , but enlarging the fascia hole a bit, and gluing-in the clips internally. The other problem is the black knobs seem to be pushed on the shafts, hot, rather than gummy glued on , so do not come off easily. I could only remove one with (too much) hot air heating. Those black knobs, there is an axial seem that is somehow disguised, becoming apparent on heating, so will try finding the seem on another and knifing axially at that point to remove

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

here.

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the way to remove the knobs is to squash slightly in a flat jawed vice, diagonally relative to the square stems. To break the melt between black and yellow. Always leaves a crack or undisguised seam, cannot decide which

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on