[Boatanchors] HRO-50 Audio: Success

[Joe Connor]

Thank you everyone for your help. The audio problem is now mostly solved. I have enough audio to listen comfortably at about 6 on the audio gain scale. There were several factors that contributed to the problem:

1. Dirty socket contacts for the 6V6s;

2. A couple of leaky caps around V-10 (noise limiter);

3. A lot of resistors in the audio chain that were way out of spec (e.g., a 470K resistor that had drifted to more than 1 meg).

4. A coil set that needed alignment (i.e., the top of the band was weaker than the bottom)

Now, I will proceed with finishing the recapping job and replacing the out-of-spec resistors. I have to replace the speaker wiring because of rodent damage.  I'm still looking for coil sets if anyone has any they'd like to sell. This one should keep me busy until the beginning of hamfest season!

I bought this receiver at an estate sale that I knew had ham equipment for sale. When I arrived, I figured I would wind up buying something nice because I had to park about a quarter mile away. (Connor's First Law: the farther away from a sale you park, the more likely it is that you will find a very heavy bargain at the sale). The decedent must have been the kind of guy we would all have liked. He was seriously into electronics and had a lot of parts and test equipment, but he was also seriously into other things, like reloading ammo, classical music, fixing cars and building race cars. It looks like this guy's basement got clobbered during Hurricane Sandy because there was a lot of rust and water damage. During that storm, power was out for a week or two and, thus, a lot of sump pumps stopped working. 

Again, thank you for the help and guidance, and I'm sure I'll be back soon with more questions. 

Joe Connor