Along with the whistle, I hear a station at 1060 kHz clearly but quietly on the second radio. Tuning the good second radio (with digital tuner) to a mostly blank spot around 1010 kHz, I can hear a faint whistle when I tune the disassembled 56T1 to ~600 kHz on it's dial (given the lack of precision of the dial, the error is easily +/- 50 kHz). I do have some tantalum 25 uF electrolytics kicking around.īeitman-1956p67.jpg In my radio, C15 was 50 uF and that was clearly a factory-installed capacitor (vs 25 uF on the diagram).
#MOTOROLA ALL TRANSISTOR RADIO PDF#
I'm attaching a PDF of a better diagram that I found. If I have good connections, the radio is dead silent apart from the soft power-on click. So this suggests the audio output stage is working. If i disturb the cliplead connecting the speaker plate to circuit board ground, I can make the radio produce various tones and motorboating that can be varied with the volume pot.
Still dead silence apart from a slight click over the speaker when I turn the power on. To do this, I had to remove the speaker plate, which is soldered to the circuit board (thanks, Motorola). All had drifted 60%-100% and were giving high megohm resistance readings (very poor man's leakage tester), so I replaced them (10 uF for the 12 uF and 47 uF for the 50 uF). I did find three electrolytics: 2x 50 uF (the two large ones) and a 12 uF inside a black sleeve. I did not read the values, but suspect they are the 390 pF caps. Last edited by tym on Oct 4:30 am, edited 1 time in total. Hopefully I don't have any dead transistors (they are dual marked TI and Motorola, interestingly).Īpparently this was Motorola's first transistor model and the going rate is $80ish on the 'bay.įile comment: Motorola 56T1 with accessoriesĢ0201018_232319.jpg įile comment: Motorola 56T1 circuit boardĢ0201018_232343.jpg
I will also replace the electrolytics, which based on the schematic I found are 12 uF and 50 uF. So I will start by checking for any loose/broken connections in the battery connector wiring and power switch area. Case, instruction sheet, and earpiece (may not be original?) are all there. So while working on the Atwater Kent Model 20 that my dad and I found for $5 at a flea market, my mom handed me this Motorola 56T1 while I was visiting the folks this weekend.
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