[gray_wolf]

On 25/12/2019 11:44 am, Fred McKenzie wrote:
In article ,
mcp6453 wrote:

One thing I do for fun is refurbish Dorrough Discriminate Audio
Processors. It's been a thing for me for years. Over that time, however,
I'm understandably seeing an increase in the number of VU meters that
are sticky. The one of the bench now has two meters that need to be
replaced or repaired. Replacements (Modutec) are not available, and
repairs are tough.

As an experiment, I connected my function generator to one of the sticky
meters are started hitting it with 2 Hz. As the movement seems to free
up, I increase the swing such that it eventually reaches full scale high
and low. The first meter I did this too seems to be working normally.
The second one is undergoing treatment at the moment.

Based on a previous recommendation here a long time ago, I got some
super fancy oil for the movements. At that time, I tried oiling a couple
of movements. It didn't help either one. Either I got the oil in the
wrong place, or oil wouldn't solve the problem.

My question is, if this conditioning process frees up the movement, how
likely is the movement likely to function before it starts freezing
again? Alternatively, does anyone repair meters any more?

MCP-

Meters I have come across, had dry "jeweled" movements. Something like
needle points riding in depressions or holes in jewels of some kind.

Your sticky movements may be due to use of lubricants that dried. You
might try using a solvent to unstick them.

Fred


My dad repaired watches when I was a kid. A lot of them started working after
he flushed them out with naphtha. Seems they get gummed up after a while.