part repair advice for volume on an answering machine

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I have a microtape answering machine with a bad volume control. It's one of the ATT ones with a slider that is soldered to the board in the unit.

http://cgi.ebay.com/ws/eBayISAPI.dll?VISuperSize&item=380146063447

Taking the cover off and bypassing the the shell switch attached to the actual
control does some good.

But can I simply desolder this strange looking slider with a standard rotary
volume/potentiameter control?

I have not taken the board out, so I don't know how many leads have to be tinkered with.

Apologies if this appears off topic. I have not known how to frame the question to get a response from appliance repair sites. I regularly post in full range speaker forum.
 
Just another Moderator
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Assuming it is mono, I would think that it would only have three connections to the board. I assume what you are proposing is to use a standard rotary pot with leads going to the relevant holes where the slider was originally (and somehow mounting that rotary pot to the device. Provided you get a rotary pot with the same resistance and taper it should behave the same provided that running leads from the pot to the board doesn't pick up stray RF and cause noise problems.

I take it the problem is with finding a replacement.

Tony.
 
Just another Moderator
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yes a multimeter with ohms setting will give you the info. You need to take two measurements (if the existing pot isn't labeled). One is the total resistance of the pot and will tell you what value it is (eg it might be 10K between two points of 20K or 50K) this value will not vary when you slide the pot.

The other measurement to work out if it is linear or audio taper is to take measurements from the wiper at various positions. One lead on one side and the other on the wiper lead (which one is which you can work out from the first test :) If it is a linear taper then the value will go up in a linear fashion when you slide the pot. If it is an audio taper the value will go up in a logarithmic fashion.

But I'm starting to wonder if it is the pot that is the problem, or whether it is a switch intergrated with the pot?? I may not have properly understood the original question.

if you can find an equivalent slide pot (as Glowbug has suggested) that would be best. Farnell also has slide pots...

Tony.
 
Ok, I may be biting off more than I can chew. I do not have a DMM and only occasionally chat with an experienced electrician for digital.

As to troubleshooting this device, I removed the cover of the device which got rid of the slide switch shell (or cap depending how you think of it.) This frees up the switch and at least allows me to use the answering machine. Running it open is no big deal for all of that. I have thought better about doing this twiddling until the unit goes-- but then I'd need a replacement for sure.
 
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