Repair/modify/upgrade on hot chassis GE solid state AM radio

[wa2ise]

Originally Posted by centralradio

What was the big deal for them not putting a power transformer in the set.Copper was not that expensive then.

I'm glad you got it working better.

Thanks. I suppose the high voltage transistor was cheaper than the transformer. The clock is an analog mechanical Telechron movement, the same as used in their tube sets. And partly company tradition? When electronic digital clocks came out, those needed a power transformer, and then it was a short jump to install a radio circuit just like the kind used in battery operated portables.

Oh, on further review, I decided I should check the old carbon comp resistors to see if any drifted out of spec. Which may have caused the problem I "solved" with a better diode. I did find a few, like a 1.2K that went to 1.45K, a 18K that went to 22K, and a 1.5K that went to 2.2K. As these are around the detector circuit, I replaced them with new resistors that are the same as the drifted values, idea being that the new resistors won't continue to drift. Now that I modified the detector diode, new resistors of the old values may make it not work as well. If you know that you are doing this, it will be fine to do. Trouble comes in if you change something that accidentally compensates for other unfound defective parts.

Also replaced two small electrolytic caps in the front end with surface mount ceramics (lower ESR, less internal inductance, thus better RF bypassing)