Marshall JMP-1 part #

[Randall]

I need the rotary Data Controller part # for Marshall JMP-1 rack preamp. Having a heck of a time finding how to contact Marshall Support directly.

[nosaj]

I need the rotary Data Controller part # for Marshall JMP-1 rack preamp. Having a heck of a time finding how to contact Marshall Support directly.

I bet tayda electronics has it or one similar. But you'll have to do the heavy lifting. At their prices though you might could get several different ones.

nosaj

[Enzo]

If you plan to order rfom Parts is Parts or someone similar, why not just call them and ask about the part. Chances are it has come up in the past, and there is only one encoder type in them, they can identify by description and tell you availability.

But when I encounter encoders, my first stop is Mouser.

Is yours 12mm, 14mm, 16mm, other? Three legs? Other legs? vertical/horizontal mount? That is a start.

They also come in forms absolute or relative (I think those are the two terms). Absolute means if you turn the knob to 1:00 o'clock, it means a certain thing, like a selector switch. You might find those on a panel behind a knob to select effects. The other kind is relative, the kind you spin for higher and lower. The knob doesn't point to anything in particular, you just spin it until you reach some point on a display.

The relative spinning type are more flexible in replacements. The absolute ones need to agree on type and code.

They come in various numbers of steps in a full circle, ie how many degrees is each step. Absolutes care, relatives don't, mostly.

I don't have my dicuments handy, but pictures look like a common data knob, so relative type.

[Randall]

I think this one is a relative type. I don't have the unit, customer wants to get a back up because the one he has now took a hit and punched out the back of the encoder. I was able to put it back together and melt the four corner posts with a soldering iron and make new "rivets" to hold it together. He is worried it could happen again, so he wants one on hand. It is in a working rack, so I don't have easy access to it.

One thing I think I do know is that it's a long shaft, and is on a 3 wire connector. They are available from a guy called VooDoo AMps, but he wants $49.95 plus shipping. Sorry, but no way. If I could get a part # it would be a simple matter of asking the Marshall dealer down the street to get me the exact part. Plus, I do his amp repairs, so it would be good.

I just need the Marshall part #. It shouldn't be this difficult.

[nosaj]

I think this one is a relative type. I don't have the unit, customer wants to get a back up because the one he has now took a hit and punched out the back of the encoder. I was able to put it back together and melt the four corner posts with a soldering iron and make new "rivets" to hold it together. He is worried it could happen again, so he wants one on hand. It is in a working rack, so I don't have easy access to it.

One thing I think I do know is that it's a long shaft, and is on a 3 wire connector. They are available from a guy called VooDoo AMps, but he wants $49.95 plus shipping. Sorry, but no way. If I could get a part # it would be a simple matter of asking the Marshall dealer down the street to get me the exact part. Plus, I do his amp repairs, so it would be good.

I just need the Marshall part #. It shouldn't be this difficult.

Here is a very intersting thread regarding the encoder. Please do read and post an opinion

nosaj
jmp-1 rack mount preamp control knob issue | MarshallForum.com
Contact Marshall service for the correct part #, order it from a Marshall dealer.
Kevin (Kdog) Drury
Marshall USA Service
1000 Corporate Grove Dr.
Buffalo Grove, IL 60089
800-877-6863

[Enzo]

From the thread nosaj linked, does this look like your part?

http://ca.mouser.com/ProductDetail/B...KATjUY%252bQ==

[Mick Bailey]

If you don't have any luck I can call the factory on Monday. The only reference I have is 'RE1'.

[Enzo]

Yep, "rotary encoder 1".

[Mick Bailey]

It wouldn't surprise me if this was the actual part reference for ordering. Just looked back at some of my factory invoices and their numbering is often very simple. E.g; Output transformer for 9100......

OP2.

Simple

[Randall]

"From the thread nosaj linked, does this look like your part?"

Enzo, no that's not the one.

[g1]

The mouser part Enzo linked uses a generic picture with a different (than marshall) shaft shown. The actual part number he gave is for a flatted shaft 1&1/8 inch long as used in the marshall unit. See attached data sheet.
Marshall part # M-POTM-00005
Mouser part # 652-ECW1J-C36-CC24L
(Data Encoder for Marshall JMP-1 Preamp? | MarshallForum.com)
There was another post on marshall forum where someone said the mouser shaft was different, but I don't think he ordered the correct shaft type. In any case, comparing the old one to the data sheet will confirm.

[Randall]

Thanks fellas, that's just the info I needed. Unfortunately, I'd have to get the customer to take it out of his working rack so I could disassemble it enough to get a better look and measure, etc. And I really don't want to do that. Depending on how much Marshall wants for the exact replacement, I may get one of each and then post my definitive investigative report here to end the question once and for all!

Also, btw the Marshall encoder is wired to a little harness and connector, so there's that.

[Enzo]

OK< I guess instead of relative, they are called incremental.

OK, then does this look more like it:
http://www.mouser.com/ds/2/54/EC12R-777795.pdf

Just your recollection might help.

I have replaced many of those in various products, and so far they have all been common encoders. I suspect the three wire harness and connector find a tiny bit of pc board with the encoder itself on it?

[Randall]

No it doesn't look at all like that one. I looks like this one:
Marshall® DATA-Control of the Marshall JMP-1 Pream - Marshall style

This is odd, because the same part # is visible right on the encoder, but the data sheet shows a different one. Another puzzling thing is the letter J in the part # designates an anti-rotation lug, when the original has none, it is continuous. But the adjustment to the part # yields no matches.

[nosaj]

No it doesn't look at all like that one. I looks like this one:
Marshall® DATA-Control of the Marshall JMP-1 Pream - Marshall style

This is odd, because the same part # is visible right on the encoder, but the data sheet shows a different one. Another puzzling thing is the letter J in the part # designates an anti-rotation lug, when the original has none, it is continuous. But the adjustment to the part # yields no matches.

I'd suggest getting a pic of the actual component. How many different revisions of that preamp are there were there any production changes? And if your anything like me. The longer I go from seeing something the hazier my memory get.
Not downing you just adding some hopefully helpful thoughts.
nosaj