[Boatanchors] Modified AR-88

[Joe Connor]

I'm working on a heavily modified AR-88 that I bought a few years ago. I am trying to understand what some of these mods were designed to do and where they came from.

Some are basic, for example, the 5Y3 was replaced with diodes and a new output transformer was added so an 8-ohm speaker could be used. 

Some are weird. The audio output was changed from a 6K6 to a 6V6. Along the right edge of the set (in front of the power transformer), a 6SN7 and a 6K6 were added. I'm sure I'll find more as I probe further. The workmanship is so good that it would be easy to confuse the mods with factory work. This leads me to assume that the former owner knew what he was doing. 

The set is gorgeous and works well with two weird problem: with AF Gain wide open, it sounds great. If I back the AF Gain to a half-way position, the set motorboats. Thus, I am leaving the audio gain fully open and am using the RF gain as my volume control. The second odd-ball problem is that the radio has far more gain with the Selectivity Switch in the No. 2 position. It should have more gain in the No. 1 position. It motorboats with Selectivity set to the No. 3 or No. 4 positions. 

Any insights and help would be appreciated. 

                                Joe Connor