07/02/2026
Summer update. I'm currently working on 2 units. One is the 1969 Morse I had working for several months. It quit working. The other is one that is "new" to me, a Motorola SK24 three channel from 1959.
The amplifier in the Morse might be shot. The circuit board is in bad shape due to heat from the transistors and the fact I already did a bunch of work on it. I could not troubleshoot it due to problems that kept going away and then coming back. I tried building my own amplifier from the schematic and that was also unsuccessful. I am looking into whether I can put a more modern amplifier in it that would allow me to keep all the current k***s, because the part of the circuit with all the k***s still works! It's just the main amplifier that's not working. It's turning into another project.
The 1959 Motorola was totally dead when I got it. I did the normal service on the amplifier (replaced all suspect capacitors and 2 vacuum tubes that tested bad) and after that it would power on but it was only intermittently working. I found a loose power wire in a connector that was causing power to cut in and out. I replaced that connector entirely. So power is good now but the right channel is seemingly dead and the left one is intermittently working. The center channel (which is the massive bass woofer) is the only one working consistently. There were 2 times when I had all 3 channels working for a few minutes, and it sounded nice. I'm also adding an external on/off switch, as well as an A/B switch. Adding these parts will allow me to add an aux input. This would allow me to hook up a Bluetooth receiver or any other device to it.
