Old School Test Equipment Resurrection - Warnings?

[FairfaxStu]

{Disclaimer} I would have posted this in a different forum but the intention is to eventually repair 2 RF Punch 150 HD's that I have laying around.

Back in my college days (early '90s), I was insanely into car audio and this included repairing amps and head units. At the time, I purchased some test equipment at auctions including a HP 200AB Audio Oscillator (tube based), HP 1200A Oscilloscope (also tube based, I think??), and a lab grade 12V 25A rack mount PS (linear).

Since these have been weathering the climate here in Virginia since 1995 in the garage, I am wondering what precautions/service steps I need to take before powering them up. They are now inside the house (after 15 years). Aside from some dust, they still appear fine externally. I figure I should give them several hours to acclimate to the temp inside my house which is about 40 degrees F higher than outside.

Beyond this, any suggestions or past experiences would be greatly appreciated.

[Perry Babin]

It's generally recommended that you bring the voltage up slowly. This allows any caps that have deteriorated to 'reform'.

If the humidity is high in the house and there is a chance of condensation forming on the interior parts of the equipment, you may want to wait 24 hours. The combination of dust and condensation can form conductive paths.

[FairfaxStu]

Thanks, Perry. I will definitely wait 24 hours or longer as my house is quite humid. As far as bringing up the voltage slowly, I don't have a variac at present. I assume that is what you are referring to as it is test equipment (120 VAC input). If it is, can you recommend one? Otherwise, would a bulb tester setup work?

[Perry Babin]

Yes, a variac.

A 120v lamp in series would also help protect the equipment. If you have them, start with low wattage. 40w >> 100w would probably be good enough.

[FairfaxStu]

After sleeping on it, I have decided that investing in a Variac would be a good idea. While I don't have much $ invested in my test equipment, replacing any one piece would likely be more than the cost of a variac. Can somebody recommend a particular model and vendor?

-Stu

[807tubenut]

Whom ever has the best warranty?

[FairfaxStu]

Originally Posted by 807tubenut

Whom ever has the best warranty?

Thanks but [IMO] given the simplicity of a variac there is/should be little chance of something happening to it, right? Of course, that assumes it is used within the load range it is rated for.

-Stu

[Perry Babin]

sencore pr57

Ebay is where you'll find the best prices.

[FairfaxStu]

Thanks again, Perry. I found this on CL:
General Radio Type W10MT3A 10 Amp Metered VARIAC, Great for Guitar Amp

Given my love of old [couldn't break it if you had to] equipment, it seems like a perfect fit. Actually, I am going to take a look at it in 45 mins or so and will likely pick it up. So yell quickly if I am making a huge mistake

-Stu

[Perry Babin]

I know nothing about that piece. I've had a pr57 for ~20 years and it's never failed to work properly. That's why I recommended it.