Suggestions for testing a never installed, 20-year boxed amp.

I think the advice being given about contacting Pass Labs before powering up is sound. Not being familiar with Pass equipment, is there any current limiting circuitry in them? I have a Mark Levinson ML335 that's been boxed for 25 years or so. When I asked a similar question here about powering it up, it was recommended I send it to a shop to have the capacitors checked first. I found a shop in Austin (Pyramid) that I'll be sending it to BEFORE I put it in my system.

Incidentally, I had occasion to visit my daughter in Austin recently so took the opportunity to visit the shop. I was very pleasantly surprised at the facility and evident expertise available. 

Good luck waking up your amp and as always...

Happy listening.

Pyramid does good work. And they are a Harman authorized servicer.

I used a Variac and 2, 8ohm 10watt resistors on the output with volt meters across them.  Short the inputs.  Take the covers off.  As I easy up the variac, I watch the meters, sniff around and look for smoke.  Now I would use an infrared thermometer.  Before I used to use my trusty finger.  Hoping B+ doesn't get me.

I had a laughed watching Vice Grip Garage.  When he connects a battery to a car he's resurrecting, he sniffs around and looks for smoke.

OK - I took your advice and contacted Pass Labs. Someone actually answered the phone and referred me to Kent who was very helpful. His concern was with the capacitors as some of you mentioned. Kent recommended a "current limited power up" using a 120vac current limited power supply. I asked if a light-bulb limiting circuit would be Ok and he said to cook the amp for a day with a 60w bulb then move up to a higher wattage bulb for another day. Of course, he cautioned me about safety concerns. No connections to inputs or outputs are necessary. 

Kent offered to do this for me if I wanted to ship it to them for a nominal fee. He said he could also re-cap the amp if it becomes necessary. He also offered to send me instructions to make the speaker connectors banana plug ready. 

@philliprcook just curious, what speakers are you using that meets your spouse’s approval?