Repair volume control on Musical Fidelity M3si

[Multicore]

My Musical Fidelity M3Si has recently developed what I think is a dodgy volume pot. Iiuc, it has an old-fashioned pot (rotary variable resistor) that's motor driven for the remote control.

I have a can of DeoxIT D5. Is it safe to squirt that in the pot? or should I get DeoxIT F5 the one that's designed for faders?

- https://hosatech.com/products/accessories/cleaners-conditioners/caig-cleaners-conditioners/d5/
- https://hosatech.com/products/accessories/cleaners-conditioners/caig-cleaners-conditioners/f5/

 

[RayDunzl]

DeoxIT D5 versus DeoxIT Fader cleaner - CAIG

QuestionsProduct CategoryA. General QuestionDeoxIT D5 versus DeoxIT Fader cleaner All questions Answered questions Unanswered questions Product/Industry Product Category- A. General Question- B. DeoxIT® General/Multiple- C. DeoxIT® D Series- D. DeoxIT® Gold- E. DeoxIT® Shield- F. DeoxIT® Fader-...

caig.com

 

[Multicore]

wow! super sleuthing @RayDunzl

 

[Doodski]

I think DeoxIt has two kinds of fader cleaner/lub. One is a for the plastic element and the other is for the carbon element.

 

[Vini darko]

Good luck finding a port to spray the cleaner into.

 

[amirm]

If you can't find a way to spray into it, turn the unit off. Then quickly and strongly turn the volume control all the way to min and max. Repeat this at least a dozen times. Then power on and see if it is improved. If it is still not perfect, repeat the cycle again. Even if you squirt cleaner into it, you need to go through this procedure to get it cleaned.

 

[Doodski]

@Vini darko this pic seems to show some access for cleaning the volume pot.

 

[Vini darko]

The pot looks like the sealed type to me. I'm also not sure its being used in the traditional manner with audio signal. It may be being used to produce a reference for that chip it goes to......maybe , prehaps

 

[Multicore]

I took this photo. The volume pot is that tiny thing dwarfed by everything else, especially that gigantic knob. The pot had two holes, one or two mm diameter, on each side of the cylinder part of its case. I squirted DeoxIT D5 in both of them, one at a time.

I tested it by listening to the Pre Out via my audio interface. It sounded perfectly clean. Do you think that is sufficient or must I find speaker cable and speakers to test it with? (I don't want to dismantle the living room again.)

"No user-serviceable parts inside" it says on the rear of the amp. Oh really? There are two fuses in fuse holders easily replaceable.

 

[Doodski]

I took this photo. The volume pot is that tiny thing dwarfed by everything else, especially that gigantic knob. The pot had two holes, one or two mm diameter, on each side of the cylinder part of its case. I squirted DeoxIT D5 in both of them, one at a time.

I tested it by listening to the Pre Out via my audio interface. It sounded perfectly clean. Do you think that is sufficient or must I find speaker cable and speakers to test it with? (I don't want to dismantle the living room again.)

View attachment 223145

"No user-serviceable parts inside" it says on the rear of the amp. Oh really? There are two fuses in fuse holders easily replaceable.

I test the speaker outputs too. There is no headphone output so can't use that for checking the operation.

 

[Sal1950]

wow! super sleuthing @RayDunzl

That's what he gets paid for.

 

[Multicore]

I test the speaker outputs too. There is no headphone output so can't use that for checking the operation.

I ordered speaker cables. I can report back after they get here, should be Wed.

 

[Vini darko]

I took this photo. The volume pot is that tiny thing dwarfed by everything else, especially that gigantic knob. The pot had two holes, one or two mm diameter, on each side of the cylinder part of its case. I squirted DeoxIT D5 in both of them, one at a time.

I tested it by listening to the Pre Out via my audio interface. It sounded perfectly clean. Do you think that is sufficient or must I find speaker cable and speakers to test it with? (I don't want to dismantle the living room again.)

View attachment 223145

"No user-serviceable parts inside" it says on the rear of the amp. Oh really? There are two fuses in fuse holders easily replaceable.

Sweet I was wrong , glad it was a pot with service ports. The sealed ones are a massive pita to clean.

 

[RayDunzl]

"No user-serviceable parts inside" it says on the rear of the amp. Oh really? There are two fuses in fuse holders easily replaceable.

Well, it doesn't say "No user-replaceable parts inside".

 

[Multicore]

Sweet I was wrong , glad it was a pot with service ports. The sealed ones are a massive pita to clean.

I guess the designer's dilemma is to permit service or choose a part that might last many more years before needing service.

We ventilate our home as much as possible. (We like having windows open.) But the rate of dust accumulation is often surprising. Electronics and musical instruments are the biggest worries with the dust.

This amp, like most I've used, (and the @Buckeye Amps unit that will replace it) have cases that are open to dust. I guess the alternatives are to put the heat sinks outside the case and seal the box or to use fans and filters like in some server-grade computers.

Now that I think of it, for a while I had a Quad 405. That probably had a sealed case.

 

[Multicore]

Well, it doesn't say "No user-replaceable parts inside".

FTR, see image.

Btw, does anyone know where I can get a replacement transparent cap for that speaker binding post/banana socket? Looks like the ones on the @Buckeye Amps unit but bigger.

 

[RayDunzl]

FTR, see image.

This?

I'm always amazed at the apparent complexity of internet links when they are presented to me like this...

That should be enough detail to identify and locate a single atom anywhere in the observable universe by my crude estimation.

Too bad it didn't find and present the intended information.

Well, it does say "no" at the end.

 

[Multicore]

This?

View attachment 223301

I'm always amazed at the apparent complexity of internet links when they are presented to me like this...

That should be enough detail to identify and locate a single atom anywhere in the observable universe by my crude estimation.

Too bad it didn't find and present the intended information.

Well, it does say "no" at the end.

I'm sorry, I must have pasted the wrong thing. I edited my post. Does it display the image now?

The complexity of the URL has to do with the crypto used to authenticate web clients, iiuc.

 

[RayDunzl]

Ask Musical Fidelity what part they used and locate a pair... I'd think it unlikely they make their own.

If no good, try to find some that look the same and hope for the best.

Similar example:

https://www.amazon.com/Amplifier-Terminal-Transparent-Connectors-Small-Short/dp/B077ZQ98SH

Or replace all four if you're industrious.

 

[Multicore]

Speaker outputs passed the test too. Apart from that transparent plastic binding post cap, this unit is ready for its new home. Who wants it?