Welcome to Solid State Guitar Amp Forum | DIY Guitar Amplifiers. Please login or sign up.

October 15, 2025, 05:54:40 PM

Login with username, password and session length

Recent Posts

 

Realistic MPA-200 volume pot replacement

Started by saturated, October 13, 2025, 12:29:27 PM

Previous topic - Next topic

saturated

Ok guys time to get to work  xP

First order of business attempt to reach this little guy

Oops need some background info: customer (me) claims left channel spins 360.  Amp has been tested seems to pass DBT and passes sound from guitar 🎸 (not the plan just testing)

So I figured the best way was to disconnect the front face plate.  That did not leave me much room because the wires are tightly bundled and I do NOT want to open that Pandora's box unless I have to.  So I laid it upside down and access was better.

You cannot view this attachment.

Then I saw I could unscrew the potentiometer bracket so I went at it with a sideways screwdriver but that was tedious I remembered a little ratchet set I bought a while back  :tu:

You cannot view this attachment.

This has been educational because I learned there is a song by Eric Johnson called "zap"

You cannot view this attachment.

And no I won't be attempting that  :lmao:

Now my volume pot is almost liberated

You cannot view this attachment.

I need to find a suitable replacement it's A250K

Also would you clip it off or desolder  :loco
I ask stupid questions
and make stupid mistakes

criticism, critique, derision, flaming, verbal abuse welcome

g1

From you pics in the other thread it looks like it's an Alpha brand A50K (log) pot.
First before you even disconnect it I would pop the back cover off it and check if maybe it has just come apart.  If the plastic piece with the wiper and stop has popped off the shaft you may be able to just press it on again.
Otherwise, if you have to replace it, Alpha pots are easy to come by, but you will want to match up the shaft so the know will fit right.

g1


saturated

Yes sir thanks

I might be up the creek trying to find a pot with the splined split  long shaft.  I think I looked at every one on eBay and Mouser last night  :grr

None are even close to this length I need to measure it

You cannot view this attachment.

I know

I still need to attempt the repair

I guess I'm getting a taste of what the big boys have to deal with when doing this professionally  :'(

"Hey man I fixed your amp.  If you need to adjust the left channel volume just use a little flat head screwdriver 🪛"

 :dbtu:

But I'm really excited about this amp  :dbtu:
I ask stupid questions
and make stupid mistakes

criticism, critique, derision, flaming, verbal abuse welcome