[Boatanchors] AR-88 Update

[Carole White-Connor]

About a month ago, I posted for some help on an AR-88 I had just bought. Thanks to all who
responded. Your suggestions were very helpful. I'm wrapping up the restoration of this set and it
has turned into a real keeper.

This set is different from the AR-88 schematics that I have seen because it has a 6V6 push-pull
audio. That became a problem because what was under the chassis did not always match the
schematics I had.

When I started, my first problem was the dial. The tuning knob would turn somewhat and the
variable cap turned somewhat but the dial was frozen. I soaked the gears with WD-40 but it didn't
help. I dropped the front panel and the dial worked perfectly. It turns out there was friction
between the dial and the front panel. I couldn't see what was warped or bent so I took the
coward's way out. I placed a nylon washer between the retaining brackets and the front panel. The
miniscule bit of clearance solved the problem. The set now tunes as smoothly as an SP-600.

This set had been heavily modified. The rectifier tube and socket were gone. In their place, a
prior owner had installed a circuit board with diodes and dropping resistors. The work was very
professional. Also, the prior owner had installed a very large output transformer with 8-ohm
output impedance. This output transformer was so large that it covered half of the hole where the
rectifier socket had been. Again, the work was very professional.

The non-professional modification was three oil-filled caps hanging precariously under the
chassis. I checked the voltages on these caps at start-up and during operation. All were under 400
V so I placed the hanging oil-filled caps with modern 10 mfd/450V units. There was also a
four-section capacitor can on top of the chassis. It looked to be of 1950s vintage. I replaced the
four caps with modern electrolytics. One of these can sections was open. When I replaced it, it
cleared up an annoying distortion problem.

With new electrolytics in place, the radio played like a dream. I imagine the new output
transformer was a high-priced replacement. I can't believe a stock AR-88 would sound this good.
(I'm using an inexpensive Radio Shack stereo speaker).

This set had been worked on several times in the past. The workmanship ranged from pretty good to
crappy. The caps in the set ranged from bath-tub caps, to black beauties, to ceramic discs. The
ceramic discs measured good so I left them in place. I replaced the black beauties as a matter of
course. Not surprisingly, all leaked. Several sections of the bath-tub caps were leaky so I
replaced them all. Surprisingly, only two or three resistors had drifted up in value. I replaced
those.

The end result is a tremendously sensitive receiver with a killer audio. Selectivity could be
better but I'm learning to make due with the variable selectivity settings. This set does not have
a cabinet. However, it plays so well and looks so good that I'm thinking of buying a $150 Hammond
cabinet from Fair Radio.

I thought you all  might enjoy this story.

Joe Connor