Powering up with a VARIAC

[355F1]

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

 

[adason]

any variac for few hundred watts should do
like this one...
Technipower W5MT3 Variac Autotransformer/Transformer - eBay (item 290438294245 end time May-28-10 12:59:28 PDT)

 

[adason]

or this one...up to 5A...with meters, so you can see how much its taking
Technipower W5MT3A Variac (Vout: 0-140V/0-5A) - eBay (item 390199276972 end time May-28-10 16:21:09 PDT)

 

[mickeymoose]

Cheap: Use a bunch of 110V incandesced lightbulbs in parallel with each other, but in series with the DUT. Screw them in one at the time to bring up your voltage. E

 

[rulonvences]

Why a variac friend, do you checked if the transformer is damaged?
If you're shure that using variac just chec in the rear specs how many power in watts is required for the right functioning and just by the Ohm law: I=W/V

 

[indianajo]

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.

 

[AndrewT]

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".