Anyone ever clean the pots on a Yamaha em-150II?

[dharmabum]

hello, I don't know if this is the correct room for this but just picked up a sweet yamaha em-150II mixer and wanted to know if anyone has cleaned the pots on one of these or that can steer me towards some online tutorials, if there are any. I do have the owners/service manuals but nothing shows how to get the knobs off or the procedure to get to the pots, etc.. I couldn't find anything online either. The main thing is getting the knobs off. I know, noob questions but just don't want to break anything.

[g1]

If I recall correctly, this is a very service friendly mixer. You will not need to remove any knobs etc. The mixer flips up on a hinge and the channel strips are on individual boards. From there you just need to get a shot of cleaner into each pot and turn it a few times.
Suggest deoxit F5.
Please post or link the service manual.

[dharmabum]

YAMAHA EM-150II SM Service Manual free download, schematics, eeprom, repair info for electronics

for some reason, it won't upload the PDF

[g1]

That's ok, the link works.
It looks like I was mistaken about not having to remove the boards, I don't think they are individual vertical mount as I had hoped.
Maybe once you have it open you can post some gut shot pictures.
On page 16 of the pdf, there's a screw shown #19. There will be a few of them along the front and sides of the bottom.
Once they are removed, the whole mixer will lift at the front and be held by the hinges along the back.

[Enzo]

Over the last 40 years I am sure I have serviced some of those. There are two kinds of mixer: those you can get to the pots from the inside as they sit, and those where you have to pull the boards.

ALWAYS make a color chart for the kknobs so you can get them back on in the right pattern. Knobs pull straight up and off the shafts. Then a nut comes off each pot bushing. You free up whatever is holding the board in place until you can remove it from the panel. The spray cleaner into the controls and spin them back and forth. Reassemble.

[oc disorder]

[Enzo]

There you go, exactly that. Set the mixer up on end like in the photo and spray on each pot so it drools down into the opening and thus inside. Exercise the pot to rub it around.

[g1]

From the looks of the picture, the master section board will have to be removed to clean it's pots. The master section sliders should be able to be done from the outside of the mixer.

Edit: That pic OC Disorder posted is EM150, not EM150II.
The service manual shows one board for all the channel strips, so it will probably have to be removed also.
I don't think the II has accessible pots like the original 150.

[Enzo]

Oh...sorry.

[dharmabum]

thx everyone for your input. Honestly, I know my limitations and I don't have the expertise to be pulling boards etc.. The unit works fine but it does need a good cleaning. anyone know of reputable techs in the phoenix area?

[g1]

Try sending a PM to DrGonz78 , he's in Phoenix.

[dharmabum]

thx, will do.

[vintagekiki]

WD40 and similar sprays are used only for quick cleaning usually when the amplifier or guitar sales.
Spray after a relatively short time (one month) evaporates and potentiometer again rustles, cramps, interrupted.

The only correct way though the thesis is that the potentiometer is opened, and with a neutral degreaser (isopropyl alcohol) carefully degreased and clean the graphite layer.
Metal sliding part carefully degreased and cleaned of oxide with pencil with fiberglass
After cleaning disassembled potentiometer reassemble

useful links

http://www.geofex.com/article_folders/potsecrets/potscret.htm

http://www.keithrobertmurray.com/articles/potentiometer-cleaning-showdown.html

https://www.youtube.com/watch?v=I96fkD36MKY

https://www.youtube.com/watch?v=Z4h6wvTqIUo

[DrGonz78]

Not saying I use this method but it can be a short cut for someone who does not want to take the whole thing apart. However, you might try this method and get mixed results. Just throwing it out there for what it's worth. I bought a roll of sprinkler tubing from Home Depot a few years ago and made my own version. This would make sense in a case where the was only one or two pots and you just did not want to spend 30 minutes taking it apart.

Pot Cleaning Cap | stewmac.com

[dharmabum]

Do I need to use a pre-amp to hook up condensers? I see no button for phantom power so I assume I would. Manual doesn't say anything about this.