Ok guys my skyraider increases in volume and then dies off when it is switched off. I know this is not right but what could it be . Maybe a capacitor ?. its just teething problems and the old girl has not been completed yet but soon will be. Oh and there is a slight squealing noise when the tone is adjusted but not continous.

increases in volume and then dies off when it is switched off

I've heard of similar symptoms being associated with bad IF caps.

AH HAAA well its going back to be checked. Its been basically brought back from the dead anyway.

The volume going up as you switch off is not unusual, I have had sets that have been doing that for decades.

Tone is another matter. No circuit ..... no idea where it is connected. Might be ticklish?

Marc

Yes and very hard to get a circuit diagram for this one.

I just find that annoying; Could not get one for an EMMCO Troubadour, nor one for an STC 59 Chassis both of which were to some degree hacked.

So I reverse engineered them from the chassis, drew a circuit & then sorted out the mess. Both have gone back to their owners working. It is just part of the game, that every so often you really have to put a lot of effort into getting some sets right, especially when some Monkey has been in there and added more faults, or destroyed something.

Marc

This has only just happened . I just think a new component may not have been real good

Just because its new does not guarantee good. I have had an electrolytic fail on the first power up & others fail within months. I have a Kriesler that is coming back, showing signs of a B+ one going after 7 years. Its a daily driver so will have done a lot of hours.

Normally one burn tests the set for around 3 hours, when they can keep an eye on, or an ear listening to it. After 3 hours the probability of a fail drops dramatically.

Marc

It might be a faulty volume control/ power switch. Maybe the ground connection on the volume control isn't making good contact with the circular carbon path the wiper wipes on inside the control. When you turn the volume all the way down to make the power switch turn off, the wiper may be pressing on the ground connection enough differently to break the ground connection. And it that happens, the audio level goes up, until the radio's B+ collapses. You might try squeezing the ground lug where it attaches to the carbon trace with needlenose pliers, if you can get access to it. Or a dab of conductive paint or epoxy on it where the break is (wait for it to dry before making the wiper go near it). Or just live with it, knowing that it won't burn anything out.

Does it have the switch on the volume control?
I would have guessed similar to Wa2ise, some bias being thrown out by one entire rail changing potential before the other.

One point of total significance: Once supply is interrupted, you have still got heater emission, but with falling B+ the only power is that being drained from the filters and with the falling voltage comes instability, due to the valves operating outside their design parameters.

Marc

The switch is on the volume control