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Marshall mg50fx master voulme pot

Started by vr4, January 23, 2012, 10:47:51 PM

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vr4

Hello I have a friends amp here. His master volume potentiometer is shot. Some dude sprayed something in there to clean it and no it just spins freely.

I can solder, and I know what I'm doing but the thing is I can't find a replacement pot! I believe it's a 11mm B10K vertical pot, but I can't find that value anywhere. All 9 pots are labeled B10K.

Any help?? Who to call??

Thanks!!

J M Fahey

Google Mouser or Digikey and browse their online catalogs.
B10K is a *very* common value, but the 11 mm size limits that search a lot.
Measure case and shaft diameter too, so knobs fit.

armstrom

#2
You want a 10K linear taper pot. Is it PCB mount or does it have free wiring between it and the board? The fact that all the pots are 10K linear taper seems to indicate that this is a digital amp and the 10K pots are just providing signals to aux ADC inputs on the board that are used to control the DSP circuitry. Take a look through the list of pots smallbear offers. Find one that looks like what you need to replace. Once you select the style you can change the value using a combo box on the product page. Remember, you want 10K linear.

http://www.smallbearelec.com/Categories.bok?category=Potentiometers+and+Trimpots
(the pots you want to compare against are on the first three pages of results)

Good luck!
-Matt

mensur

Quote from: vr4 on January 23, 2012, 10:47:51 PM
Hello I have a friends amp here. His master volume potentiometer is shot. Some dude sprayed something in there to clean it and no it just spins freely.

I can solder, and I know what I'm doing but the thing is I can't find a replacement pot! I believe it's a 11mm B10K vertical pot, but I can't find that value anywhere. All 9 pots are labeled B10K.

Any help?? Who to call??

Thanks!!
Can you take hi res pics of the amp inside, and upolad it here?

vr4

Hey guys thanks for all the input! It looks just like the one 9mm one on the 3rd page armstrom. Awesome link!! They do have the directional half circle knob though.

It's just a 3 pin pot and the 2 side posts in the middle are the ground/mount. 5 solder points total.

Here are some pics! Video is uploading as we speak in 1080p. I will upload that tomorrow and I will check back in to answer everything after I get some sleep.  Thanks guys!! will + rep

joecool85

vr4, might want to resize those pics - they're HUGE.
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

vr4


armstrom

That looks very similar to a panasonic EVU series pot:
http://search.digikey.com/us/en/products/EVU-F2MFL3B14/P3G7103-ND/243621

But I think the shaft on the panasonic pots is slightly longer. Since it's plastic you could probably just trim it to length.

Might be worth a shot.
-Matt

vr4

#8
Damn you are good armstrom!!!! Just bought two of those. Will give them a shot!! thank you!

Do you have rep or anything on this forum?

J M Fahey

A good practical picture size is 640x480 / 800x600 / 1024x768 or at most 1280x¿¿?? (don´t remember) but not more, because it either gets resized to screen size (so you lose any theoretical advantage plus wasting bandwidth) or it´s so huge that you get lost into it.

mensur

#10
I can't tell, is the middle left board digital preamp or analog with smd or both?

armstrom

Hopefully they fit :) They are not identical to the pictures you sent, but they look close. Did you take a look at the datasheet for the Panasonic pots and compare the physical dimensions to the part you need to replace?
-Matt

joecool85

Quote from: vr4 on January 25, 2012, 04:40:24 PM
Damn you are good armstrom!!!! Just bought two of those. Will give them a shot!! thank you!

Do you have rep or anything on this forum?

Under the user's name there is a spot that says "useless" or "informative", click "informative" and it will raise their "chip points" which are basically "rep".
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com