OLD tube radio - variac?

[Gearhead]

A friend of mine has an old Tram D201A as well as a couple other old tube radios, that are in mint condition, but have'nt been plugged in for at least 15-20 years. I heard that to get them up and running again, we need to start them up slow through a "variac" to prevent damaging the caps. My friend was able to get a variac from his boss, but I want to know what the CORRECT way to do this is. Do we just plug the radio into the variac, turn it on, and start turning up the voltage slowly, or do it in steps? Neither one of us any experience with a variac and very little with tube radios, especially ones that have been sitting for so many years, and we hate to ruin such a nice radio.

 

[station 716]

variac

I wish I had asked this before I fired my old National up; it would not be on ebay right now....wish I could help you, but you'll get an answer

 

[Captain Kilowatt]

The best way is as you thought.Plug the radio into the variac and bring up the voltage slowly.Most of the time bringing it to full voltage over a minute or two will be fine.If it was something like an amp with a couple thousand volts I would bring it up slooooowly over 5-10 minutes and monitor the voltage while doing so. I hear some guys taking hours to do it but that is totally not necessary.The only time I would take a long time to do it is if the gear was really old and had not been powered up for many,many years. I powered my DX-60 transmitter up over a minute or two after it had been off for over 10-12 years and all was fine.The big problem is if the equipment has old paper type capacitors that can dry out.They make a really loud bang when hit with full voltage at the flip of a switch. :shock: They also tend to make a mess inside the radio. The big ones have been refered to as a tar and feather grenade. Anyone that has had one go off knows what I mean.