[sdiy] Arp Odyssey sliders cleaning/ restoration

[jeff brown]

This was covered several years ago on this list by Kevin Lightner. Rather 
than being a weenie and telling you to search the archive for it, I'll 
insert it here ;^P

---------------------------- Quote from May 24, 2004 (I 
think) -------------------------------

Hi Bob,

Hope this doesn't come off sounding too self-absorbed, but it's not
easy to note what *I* do without using the *I* word often.... ;-)



I do wash boards, though I've a few precautions and practices well down.
For me, I use high pressure softened water and usually a good grease
cutting detergent.
I prefer SimpleGreen for this as it's biodegradeable and easily available.
Also De-SolvIt is great, but is oily and it itself must be removed
with simplegreen as well.
I don't allow things to soak too long, but 3-5 minutes immersion is
usually needed to dislodge old grease.
After a rinse, the boards are blown using compressed air and placed
in a forced air dryer.
A hair dryer (not too hot) will substitute fine. Allow them to sit
overnight before powering up.

Boards are often washed when originally made and soldering, both by
hand or machine, exposes a board to higher temperatures than any
water you'll handle, even boiling. The main thing is that water is
not left to dry and leave mineral deposits or react with metals to
oxidize (rust, aluminum oxide, lead oxide, etc). The only components
that have ever acted up, and rarely at that, are the larger foil
wound caps found in CV memory circuits such as key memory and sample
and holds. I replace them if so, but out of about 30-50 Odys that
have received this treatment, only 2 needed components replaced.
Those odds are well within my confidence range considering the
positive results otherwise.

One plus about this technique is that it removes coatings on the pcb
that can degrade audio and CV's.
It's quite common to have things more stable and of better fidelity
after a total cleaning.
Sample and hold circuits can droop simply from body oils on a board.
Imagine what 28 years of atmospheric junk can do when accumulated.

After washing, most sliders feel much better, but keep in mind that
immediately afterwards they are still wet inside and will still feel
lubricated. After drying, they will need new lube. I use GC
Electronics Luberex and apply it through a hypodermic syringe. It
helps to remove and disasemble one slider so as to give you an idea
what points require lube the most. Lube on the resistive element
generally won't hurt it or affect its operation, so you don't have to
be ultra careful. I will also use a drop or two of TriFlow Teflon
lube if they need to be a bit less frictional. It's all on a "as
needed" basis, so I'm hesitant to provide any blanket rules or offer
this as the bible of slider repairs. This is what has worked for me
and is proven over time.

The sliders are not terribly easy to remove nor to replace the shafts.
You must remove the entire slider in order to swap the shafts also.
I really don't know how to detail what's involved if you've never
done the operation before.
Like teaching guitar via email: I could take apart 20 sliders in the
time it took to write this email, but it took years of doing and with
many failures that taught valuable lessons. I would recommend some
smooth jawed flat pliers and whatever you feel comfortable with for
desoldering. If I didn't use power desolderers, my next choice would
be solderwick. The little bulb or piston solder suckers just don't
cut it for me. More pain than they're worth.

When I use or offer sliders for sale, they are made up of selected
parts from several sliders.
Often the tops are hand polished to get them smooth again and remove
scratches.
The inside wiper plate and contacts are polished using swabs and chrome
polish.
They're solvent cleaned and relubed, then assembled, checked for
proper tension and then bench tested using an audio generator and
scope. Lots of work for sure. The payoff for me (besides the money)
is getting an Arp to feel almost brand new. Many people have no idea
how nice they can usually turn out.
They've never played a new one.

Also, I very much recommend on any gear, a very close inspection
under bright light.
Solder connections, especially on larger pins and connections, or
leads of items that are subject to physical force are the most common
places. Pins that carry high current or experience higher
temperatures are subject to premature cracking as well.
I do this operation to *every* board of *every* unit that comes in
here. No exceptions.
It's that important. The pcb is the most important component and
makes the most connections.
So many repairs I and other techs do everyday is nothing more than
resoldering cracked pcb connections.
On some units, I won't even power them up until this is done. For
example, the display board of the Roland S-50 is sooo often filled
with cracked connections, it's assumed that's needed everytime. After
a while, one gets savvy where to look and what to touch up. My secret
weapon to not seeing any rework ;-)

Hope this helps!

-- 
Regards,
Kevin Lightner

http://www.synthfool.com