Puzzling Power Supply Voltages on Crate PA-B8360

[TwinBeech]

Thanks for the reply. They were hot but I only turned on long enough to get a voltage reading then back off. I will change the IC I found and see if that changes the amp ops. The rails are at their proper voltage now.
Cheers

[Enzo]

The amp has 61v rails, he is measuring 71v I presume. 61 not to be confused with the 16.

So those resistors get hot? What is the actual rating stamped on those "1/4A fuses" in the fuse holders? I am having difficulty imagining how 1/4A fuses won;t blow while getting 10 watt resistors scorching hot.

[TwinBeech]

Buss agc 250V 250mA. If no load the supply rails are at +-71V. Normal ops they are at 61 V.

[Enzo]

Aside: Twin Beech as in Sky King? (And his niece Penny?)


Sorry, all these years I remembered it as a Twin Beech, but apparently it was always a Cessna.

[TwinBeech]

As I remember, The first airplane was a Cessna T50 Twin Engine Bobcat. Then he went to a Cessna 310. Twin Beeches are one of my favorite planes. I operated 2 of them, both high cabin E-18 S. One was a pax and the last was a freighter. I sold it about 2002 but enjoyed all the time in them.

[TwinBeech]

Well thanks to the help on this forum, I have an audio signal going through the amp now. The pots are scratchy and sometimes intermittent.They look like sealed units so it may be hard to lubricate them. I can fiddle with them and get a lot of static so I think it is also causing the limiter to turn on occasionally. AT first I could not control the volume but after a few minutes they started to work. Still digging.

[Enzo]

I don't recall them being sealed types, aren't they the little square ones with plastic shafts?

[TwinBeech]

That's what they are. I just don't see the little holes in them to apply some contact cleaner. I hope that will stop some of the noise.

[Enzo]

Sometimes there is lot area near the leads, sometimes you can drip some cleaner down around the shaft.