Cleaning push switches on Tandberg TR2075?

[jpcoetzee]

I'm renovating a TR2075 and would like to use some switch cleaner on the Program Select switch contacts. The switches are all working fine and look clean but I still want to clean and protect them:



How can I clean the contacts? I don't want to desolder the switches from the Program Select board and then take them all apart. The switches are actually open at the back...



...so I'm thinking of thoroughly masking off to prevent the cleaner spraying everywhere, tilting the receiver so the fluid runs down and then giving a little squirt in the back of each switch.

Is there a better way to do this? Should I not bother?

Many thanks

[myhrrhleine]

Avoid cleaners with extra solvents or lubricants.

[Conrad Hoffman]

I would think a little blast of Caig DeOxit would take care of those just fine. I don't know if it's true with Caig because I haven't read the ingredients, but chlorinated solvents can be deadly to electrolytic capacitors if they get by the seal. I typically pack paper towels around anything I'm cleaning, so it doesn't get to other areas of the board.

[Elbert]

Ah! Another TR2075 owner!

As mentioned, use a "straight" that doesn't contain any additional lube or additives.

Best thing to do is to spray the contacts liberally, operate them to allow the contacts to clean them selves in the soak, then use compressed air to blow out excess cleaner and dissolved dirt and oxides.

If this doesn't help there Is a more serious problem which can't simply be sprayed away..

Good luck!

[jpcoetzee]

Slightly contradictory advice??? Caig DeoxIt DOES contain an extra lubricant. Anyway, I used Servisol Super 10 (http://tinyurl.com/5lgzy3 ) because I wanted to flush any bits out but leave some lubricant. It's very safe on plastics.

Without "masking" off, the spray spreads out very quickly, leaving a thin film all over the board. So I tightly packed cotton wool and rags around the switches, leaving only tiny holes to squirt into.

It worked very well. The switches got a decent blast but there was no trace of the stuff elsewhere.

The switches were working fine before, this is simply a maintenance job while I have the receiver apart. They still work fine...

[John Durbin]

Hi,

Saw this on Audiokarma & responded but thought I would here as well, for the benefit of the other members.

These Tandberg push-switches are easily disassembled for cleaning, the service manual has drawings & instructions for doing so. It's a bit fiddly but probably better than blasting with cleaner as you risk removing the lube the factory used. The little metal contacts can actually be removed and cleaned directly (or replaced) once the plunger is removed.

I also have a small assortment of original replacement plungers should you run into one that's too far gone to clean, although that is not common.

John
packrat014

[djk]

I wouldn't get too excited about cleaning the push-button input switches, unless they don't work.

IIRC, they only switch DC voltages, the signal does not go through them.

[destroyer X]

afraid of melt things, or dirty, or to attract dust, or to let oil into the boards......then push your buttons repeated times.... the mechanical work will remove dust and oxide.

Just put them to work many times...repeated movements...this use to be enougth.

Mechanical switches have surface contacts... watching that shinny contact area into the microscope you gonna see it is grainy, alike a sandpaper...it is able to clean one surface "scratching" against the other during operation.

Some switches are not used... so, they have dust and some oxide into the surface (even inoxidable metals have some small oxide over...impossible to avoid some surface oxide)...moving them you gonna clean them all.

Switches have spring inside...and the spring metal use to rust... a lot of oxide goes "eating" your spring that someday will broke.... so..... to allow them to last long time.... some kind of oil (WD40 or Singer sewing machine oil, or other used to weapons, may help.. despite there are hundreds that say "never use WD40"... i think...THEY have never used to allow them to say that only beeing inexperienced user about this marvell product...of course not good to eat, to frite potatoes or to intimate use)

I could see our forum has a new "automatic fashion unobtanium movement".... that says cleaning products are annoying.... another thing created and that has not too much sense (to me)... carefull with those things...there are stripped condensers too..... special cables...watch those things with carefull.

Now a days people are "against" chemical... well.. watter is a chemical product, also air can produce oxide, rust.... soap has a lot of chemical, including grease...so... can do nothing... have to put amplifier inside vacuum glass dome.... new fashion "Don't touch this!!!... big magic inside!"

Also people said we (mankind) have never landed on moon...and there are folks that believes that.

regards,

Carlos

[Mooly]

Just be careful what you use. Many so called "switch cleaners" by big companies have been responsible for attacking plastics over months and years. The ones that are "cold" and "crackly" to the fingers were the worst. I am speaking from experience, have seen countless plastic cabinets fall to bits through this (and switches self destruct as the plastic housing cracks and falls apart) sometimes months later. The plastic goes like the icing on a cake.
Never had a problem with WD40, and the best stuff of all used to be from RS called "moisture dispersal repellent" or something.