EH Scott Radio Enthusiasts

The Fine Things are Always Hand Made

Looking for advice on how to start restoration on my aw23 electronics

Comment by Kent King on March 5, 2020 at 7:53pm

Well, at a minimum, you'll need to completely re-cap the power supply, especially the electrolytic caps. Really, I would strongly recommend re-capping the tuner as well, you'll have much better results. Obviously test all the tubes and check the fuses (there are two). If either is blown, it could indicate other issues in the power supply. 

I start by removing all the tube shields and tubes, and even the coil covers. This makes all the paper/wax caps accessible and easily replaced. It is also a good time to clean the chassis and all the covers. Watch the rubber covered wire which connects the large tuning capacitor and the RF switch in the center coil can. I usually replace these wires too if they are brittle. After cleaning, replacing the caps, testing all tubes, I am ready to do power tests.

Kent

Comment by MICHAEL DOWNING on March 8, 2020 at 5:39pm

Kent: I'm starting on the power supply, both fuses were bad, some of the tubes tested bad,and two f the 2a3 power tubes were a different type. Can you guide me on replacing the 3 electrolytic condenser's for the power supply. The outside of the tube's have the numbers 20107 k628.

Thanks Mike

Comment by Kent King on March 9, 2020 at 8:06am

Mike -

All of the filters are 30 MFD at 450 VDC. A couple of the are grounded to the chassis ground but there is also a negative bias and the can also be the "ground" for a filter. Look closely at the schematic for this difference. You'll note that one of the existing "cans" is isolated from the chassis - that will be the cap that is grounded to the bias. The bias is required for the 2A3 tubes to operate and also can be what pops the small 3/4 amp fuse. 

You'll want to get some actual 2A3 tubes as replacements. The numbers you gave don't help much, you can try testing the tubes in a tube tester as a 2A3 to see how they fare. 

Kent

Comment by Kent King on March 9, 2020 at 8:08am

Mike -

If this is your first (or you are fairly new to) radio restoration, the Scott will be quite challenging. There are several folks in that area that may be able to help, and I am only about 3 hours south if you need assistance. Go slowly and you will have a set that gives amazing performance. 

Kent

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