[Ron Ramirez]

Okay,

I really feel stupid at this point...

I set things up to make the measurements. Just prior to hooking up the scope, I decided to make a reference measurement of the voltage with my DMM.

It read 46.2 volts.

At that point, something told me to check fuse F2. I turned the receiver off and unplugged it, then measured the resistance in ohms across the F2 fuseholder.

Wait a minute. I wasn't getting zero ohms as I expected!

I removed the cap of the fuseholder. No wonder...there was no fuse inside! With no F2, voltage was going through resistor R38 (330 ohms) instead, dropping the "DD" voltage.

I then had to do a search to find a 4A 3AG fuse. Finally finding one in a Fisher 500-T that I have not touched yet, I popped it into the 440-T and hooked the speakers back up.

I turned it on and measured "DD" voltage with the volume at zero - 49.2 volts.

I turned it up to 1/4. The 400 cycle signal sounded clear. Voltage remained steady at 49.2 volts.

I turned it up to the halfway point. Between 1/4 and 1/2, the voltage began to drop and distortion was evident at the halfway mark. Still, a great improvement over how it was previously.

Volume turned halfway up is louder than I would want to play it anyway.

I then turned everything off, removed the 10.7 mc signal from the IF strip, and turned the receiver back on and tuned in some signals.

The sound is much, much better now. Up to near 1/2 full volume, it sounds fine. At 1/2 volume I can hear distortion, but not like it was before. Again, too loud for normal listening anyway.

Mike and Mike, this receiver has all new electrolytics but the bridge rectifier is still original. Should it be replaced? What else would cause the voltage to sag at 1/2 full volume?

I think once this is addressed and I get the multiplex decoder fixed, this thing will finally be good to go. I think I will also need to replace R38 as it has dropped in value somewhat.