I may,later, feel like an idiot for asking this..
I bought a tube type receiver that was in its original shipping box..
It had never been opened.. Brand new, still in the box..
I opened it.. Now I want to plug it in.. Should I assume the caps are bad??
Variac it?? Just plug it in??

Stan

If you plug it in you'll probably pop the filter caps.

I'd put it on a variac, turn it up to 40 volts or so, let it sit there for half an hour, then turn it up another 10% every 15 minutes. Around 60% it should start to perk or hum. If the hum is real bad, turn it off and replace the filter caps.

Maybe half the old radios will power up pretty well, a quarter will hum some, the last quarter will hum really bad.

The coupling caps will likely need replacing, the one to the audio output tube grid is the most critical one.

If the radio uses paper capacitors they will need to be replaced. Electrolytic capacitors should be replaced as well.

It might be worth a lot more back in the box. What make and model is it?

Carl

Might be worth more, but would do no good to the OP if he wants to use the radio.

What is it? How old is it?

Regency AR-136.. Mid 60s I believe.. Aircraft band.. I bought it in part, for the thrill of opening it.. Although I must admit, part of me didn't want to open it.. And I fly,.. so I wanted to use it..
Seems a shame but I will probably go ahead and replace the caps.. Maybe keep the strain off the other components..
Opinions please..

Stan

In that case do whatever you want to it, it wont have much collector value for at least another 50 years and will be good practice.

Carl

If it's like the other Regency Monitoradios of the 60's, it will have disc ceramic caps and no paper.

I have seen them where the can type electrolytic fails in units that have had a lot of use. But sitting unused for 50 years isn't good for electrolytics either.

I would be tempted to try it on the variac, with a wattmeter, and see if the unit works properly after bringing it up slowly over several hours. If wattage is good, I would then feel the electrolytic can and see if it is getting warm or hot. Since these radios are crowded there will be some heat absorbed from nearby tubes but if the can is reasonably cool to the touch then it may be OK. If it's quite warm or hot, then it isn't. Or you could replace just the electrolytics and you should be good to go.

(plug it in)
got a GFCI outlet ?
that may be safer for your radio

Plug it in, already. Ain't gonna' do nothin' but work.

Ok,.. I took a break from my Hallicrafters nightmare and worked on this new one..
I replaced the E-caps.. I opted to leave the old caps in place, clip the hot leads and put the new ones beside them.. Powered it up,.. it lit up GREAT!! I let it warm up and,...... It hummed..
Very light hum,.. almost not enough to hear.. Nothing else.. Fearing I had done something wrong, I opened it back up and looked again.. The caps I used were not an exact match, but were very close.. and the voltages over what I needed..(was all the locals had) Then I noticed the metal can on top of the chassis.. A multi-can, in a very tight place..Not coming out..
So,.. Can I clip the leads to the can and put the new caps under the chassis without causing problems??

Stan

Yes you can simply cut the wires to the can capacitor and then install terminal strips near to mount the new capacitors on then connect them up.

What if they held a competition at hamfests for the stuff that does not sell and does not want to go back home.... you would buy a ticket for a chance to bet on what it will do when they plug it in and throw the switch.

Greg

then if you're right you will get to take that piece of equipment home