Maestro Stage Phaser: Where to find replacement potentiometer?

[louloomis]

Hi Everyone,

I am trying to repair a Maestro Stage Phaser (the big one).

The left potentiometer has broken. I tried to repair the broken potentiometer, but it turns out the damage was more severe and I couldn't get it working. In the process, I damaged the wiper, etc. So, now I need to replace it.

Here is what the part is called in the manual:

"925-040079-001 Potentiometer, Reverse Audio, 1 Megohm"

The unique thing about this potentiometer is that the outer lugs are spread out so they, along with the center lug, can be soldered into the effect's PCB inside the unit. This mounting method ensures that the shaft of the potentiometer aligns with the exterior roller wheel once the unit's side panels are reinstalled.

I'm attaching a photo, taken from the back of the broken potentiometer, which shows the lugs attaching to the PCB. Any ideas would be greatly appreciated about sourcing this replacement part.

Thanks.

LL

[Leo_Gnardo]

Reverse taper pots are rare enough as it is, but you can find 3 Meg versions meant for Fender amps at a couple of places. Antique (tubesandmore.com) is one of them. You'll have to solder in short jumpers from the circuit board to the pot electrodes. If you can't find a source of 1M reverse, try the 3M. I guess the worst that could happen is you might get an extended range of phaser rate, which might not be such a bad thing.

[louloomis]

Thanks. Very good suggestion.

I've seen the reverse 1 Megohm pot online for sale but it's the right lugs that was my issue all along. But, maybe you're onto the solution there: maybe I should just assume I will have to attach the pot to the side panel only and just solder in jumpers to connect the new pot to the old lugs. Hmmm...very good suggestion there!

LL

[Mick Bailey]

A 1M linear pot may be close enough to get it working OK. A CTS pot may have sufficient lug length to straighten them out and bend them into the correct alignment with two pairs of needle-nose pliers. If this looks viable, be sure not to apply pressure to the wafer crimp connection.

[louloomis]

A 1M linear pot may be close enough to get it working OK. A CTS pot may have sufficient lug length to straighten them out and bend them into the correct alignment with two pairs of needle-nose pliers. If this looks viable, be sure not to apply pressure to the wafer crimp connection.

Thanks very much for the advice. I may need to do just that after all:

I realized after posting my previous comment that the space inside that part of the effect unit is very limiting so I may not have much flexibility to do anything but try to bend the lugs of a replacement pot and align the shaft with the side panel opening. I was thinking maybe I could just wire a pot to small pieces of the old lugs (if I could remove most of the upper part of the lugs) and then mount the pot as-is onto the side panel and leave extra length on the wires to be able to remove the side panel.

Still thinking about this repair and how best to do it. I don't want to damage the PCB of the pedal no matter what...

LL

[52 Bill]

I can't really tell from your photo, but it looks like a CTS pot. Is the wafer and resistance element okay?

The wiper and shaft components can be swapped with one from an unbroken pot if you have one.

[louloomis]

I can't really tell from your photo, but it looks like a CTS pot. Is the wafer and resistance element okay?

The wiper and shaft components can be swapped with one from an unbroken pot if you have one.

Unfortunately, the wafer was cracked completely in half (I know that's not entirely obvious from the photo because I reglued it before that photo was taken). So, I tried to repair it but could not. It also turned out the resistance element was damaged as was the wiper.

Thanks anyway.

LL

[Mark Hammer]

If by "left one", you mean the control labelled "Balls". then a linear-taper should be fine. Dialing in preferred settings might be a little trickier than before, but use of a linear taper won't affect whether it works or not.

[Janus Alfador]

Hi Everyone,

I am trying to repair a Maestro Stage Phaser (the big one).

The left potentiometer has broken. I tried to repair the broken potentiometer, but it turns out the damage was more severe and I couldn't get it working. In the process, I damaged the wiper, etc. So, now I need to replace it.

Here is what the part is called in the manual:

"925-040079-001 Potentiometer, Reverse Audio, 1 Megohm"

The unique thing about this potentiometer is that the outer lugs are spread out so they, along with the center lug, can be soldered into the effect's PCB inside the unit. This mounting method ensures that the shaft of the potentiometer aligns with the exterior roller wheel once the unit's side panels are reinstalled.

I'm attaching a photo, taken from the back of the broken potentiometer, which shows the lugs attaching to the PCB. Any ideas would be greatly appreciated about sourcing this replacement part.

Thanks.

Hi. This Alpha pot is a 1Meg reverse audio pot with the same style and sized shaft:

https://www.mouser.ca/ProductDetail/...CJNGaAj%2Fnw==

The part number is: RV16AF-20-15S1-C1M-LA


That should work as a replacement. The base of the pot might be smaller than a full-sized pot, but if the terminals don't fit into the circuit board holes, the pot's terminals could be connected to the circuit board holes with soldered wires.

[louloomis]

Hi. This Alpha pot is a 1Meg reverse audio pot with the same style and sized shaft:

https://www.mouser.ca/ProductDetail/...CJNGaAj%2Fnw==

The part number is: RV16AF-20-15S1-C1M-LA


That should work as a replacement. The base of the pot might be smaller than a full-sized pot, but if the terminals don't fit into the circuit board holes, the pot's terminals could be connected to the circuit board holes with soldered wires.

Update: I just measured the pot shaft length and it is approx 2 cm (if not slightly more). Since this possible replacement pot (above) has a 1.5 cm shaft length, I don't think it will work due to the location of the set screw which holds the left side rotary control in place.

I will see what else turns up at mouser and will see if I can find the same type of unit but with a longer pot shaft.

Thank you.