ALPS motor/servo function selector switch

Nigel,

I've worked on many of these. The switches don't come apart easily, and often get damaged just removing them from the board, which you would have to do to take one apart. My experience is that they don't hold up for more than a few months if you spray them out. You can put some contact cleaner or lubricant on the new switch if you like, and that may help it last longer than the original one.

Arcam still has them in stock, part number A1207. E-mail them at snipped-for-privacy@arcam.co.uk.

Regards, Tim Schwartz Bristol Electronics

knob.

just

But any specific hidden hazards beyond taking any switch or pot apart ? As its an otherwise unpopulated area of board I intend hot-air gunning it off. Also intend taking apart to renovate, presumably cleaning off CuS corrosion going by other parts in the amp, rather than happy-squirting and original part replacement would be a back-stop.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Nigel,

Nope, as I recall you can unbend the front tabs and remove the front metal casting with the motor drive. The individual wafers can be unclipped. Just mind the positions of everything, as it is possible to to get a section 180 degrees out of phase with the others. I'd clean out the old goo with alcohol on a cotton swab, use a synthetic oil and reassemble. I've done it once or twice, and it is a 2 hour job, making the new switch seem cheap. Occasionally, some of the pins on the switch will break off as you remove the switch from the board, and then you need a scrap switch to make one good one, if the pin is used.

The board is double sided with plated through holes, so be careful when removing it not to pull out the plate through holes.

Regards, Tim Schwartz Bristol Electronics

anything?

would

may

it

corrosion

original

I would not fancy desoldering that one by conventional means. No broken pins or lifted tracks/pads. Desoldered the motor and straightened the bent over pins while melting solder before hot-airing apart the whole switch mechanism. All conductors covered in black corrossion, but does all come apart quite safely, after labelling. I will note the contact connections in a specific position for anyone coming a cropper with another one of these.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

anything?

would

may

it

corrosion

original

That was the easy part, no one said anything about replacing it back onto the board.

What has round pin sockets of .156 inch spacing , 2 row , staggered ? If it was symmetric you could line it up on the other side of the board.

So either engineer a gauge plate with 41 holes , .156 in spacing in 7 rows staggered . or drill 2 holes in the pcb to allow rotational symmetry and lining up on the reverse side of the board. or put pins in all the pcb holes and caste a gauge plate in epoxy or something

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

Lined up the pins visually in both senses, opened out the topside holes with a dart point and at the third time of offering up / viewing on reverse side/ adjusting, got it replaced

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

bloody thing I tested the switches and also that bending the wipers had not produced trouble with extra back torque and driving round via the motor. Now its all soldered in, the safety clutch operates in one position, too much back torque. I had tested before fixing the metal casing back into place around the switch sections and there must be some sort of additional strain/misalignment. Anyway it will desolder easier this time.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on