Powering up with a VARIAC

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Hello Chaps,

My name is Orazio and this is my first post.

I have several Revox Pr99s that have been stored for over a decade. All decks power up and I don't see any functional issues but since they have not been used for years all electrolytic capacitors should be replaced but it would be a lot of work.

I have been thinking to power them up using a VARIAC in order not to blow up electrolytic capacitors that inevitably will need replacement.

My question is, what kind of VARIAC should I use and how many amps? I do not want to spend a fortune in an expensive VARIAC just for playing with these tape decks.

Please advise.

Kind regards,

Orazio
 
Powering up with a variac is excellent for reforming the aluminum oxide barrier in old capacitors. It does nothing to replace the protentially cracked oxygen damaged rubber seals of the electrolytic capacitors. Reforming prevents sudden initial failures, does nothing for the "it worked fine for two weeks" syndrome. Heat of use can evaporate water out of old electrolytic caps and cause them to change value, and eventually short. The exception are any of the extremely rare epoxy sealed electrolytic capacitors.
 
I have a Variac.

I don't use it to test for the safety of starting up a mains powered project.

I use a mains bulb tester to check for safe start up.

I use the Variac to investigate the variable input voltage effect on a "working project".
 
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