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7A24, 7A26,7000 sera Vert plug-ins pots, Var switch?

 

Hello Kon,

I would clean/lubricate the pots only with DeOxit F5 fader lube:



Don't use the Caig D5 contact cleaner product for pots as it can damage some pots over time. I wrecked a Dynaco PAT 4(or5) Volume control by using D5 on it and I have never found a replacement pot.

The D5 contact cleaner is for mechanical contacts and switches only.

Let us know how you make out.

P.S. No affiliation?with Sweetwater other than they are great people to deal with and probably have the best price on Caig products anywhere.

Sam
W3OHM


Sam Reaves
ARS W3OHM
Owner / Moderator of:
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Electronics and Mechanical Hardware Design Engineering Manager
Staff Scientist Andritz Rolls Global Research Center (RETIRED)



On Thu, Feb 16, 2023 at 9:57 AM Froggie the Gremlin <jonpaul@...> wrote:
Hello all, working on four 7A24, similar question 7A26...

The variable knob controls an elegant multipurpose mechanical

Push push toggles VAR/CAL, red variable OUT, CAL IN
To,CAL the plug-ins channels to the 7000 MF, a small screwdriver can depress the center knob ( blackjack, slotted) and latch the CAL trim after rotation. This? allows a second control pot to CAL the channel.

Releasing the knob fixes the CAL pot and? returns the channel to CAL.

There are two gaged concentric Bourns MOD pots and the CAL detent mechanism.

Finally on the PCB,? a switch to select CAL/VAR, according to the knob push push control in CAL, black, out, VAR, red.

In restoring these marvelous 1980s..1990s plug-ins, performed MOD pot cleaning proceedure, screws loosened for contact cleaner.?

issue's

1/ VAR/CAL pots still scratchy after lots of spraying thru the slightly loosened MOD pot case.

2/ the PCB VAR/CAL knob toggle is still scratchy after contact cleaner in to the PCB slide switch

3/ on one channel of one unit, the knob cannot toggle to the OUT VAR red position.?

Anyone seen these issues? Suggestions appreciated!

Can post a photo album if needed.

Bon journ¨¦e

Kon
 

Sam many thanks, never used the Craig or Sweetwater cleaners, have old Miller Stephensen and GC , also use 99% ISO ALC.

Never had any issues .

Problems here are deeper .... access to the MOD pot for the cleaning fluid and failed CAL/VAR PCB switch mechanical latch. and scratch contacts.

Kind Regards,

Jon

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