Hello all,
I'm rejuvenating a Zenith portable solid state stereophonic phonograph player. It has no model number or chassis identification, and I haven't been able to find an owners manual with a schematic. I have experience troubleshooting electrical devices. The left amplifier channel works fine so I'm comparing 'like/similar connections' on both R and L channels for voltages, signals, and resistances using an older HP oscilloscope and multimeters. The 4 pots on the bottom of the chassis are for Balance, Volume, Treble and Bass control. It is tedious and time consuming and I'm hoping to acquire a 'typical ' 1960's solid state' stereo schematic that might help reduce the time needed to find the cause of the problem.
There are two low power 3 lead transistors ( round cans) above the 2nd and 3rd volume and treble control pots about 1/3 of the way up from the chassis bottom. Both these transistors have the audio signal from the phonograph on two leads. No capacitor leakage or burned resistors apparent ....so far. .. indicating that the problem is in the power transistor circuit powering the speakers. The pix's show the right speakers, chassis in the main section of the box, and the underside of the chassis. This pix immediately below shows a similar Zenith with only 3 controls but my guess is that it has the same amplifier as the one I'm working on.
Thanks for any help
I'm rejuvenating a Zenith portable solid state stereophonic phonograph player. It has no model number or chassis identification, and I haven't been able to find an owners manual with a schematic. I have experience troubleshooting electrical devices. The left amplifier channel works fine so I'm comparing 'like/similar connections' on both R and L channels for voltages, signals, and resistances using an older HP oscilloscope and multimeters. The 4 pots on the bottom of the chassis are for Balance, Volume, Treble and Bass control. It is tedious and time consuming and I'm hoping to acquire a 'typical ' 1960's solid state' stereo schematic that might help reduce the time needed to find the cause of the problem.
There are two low power 3 lead transistors ( round cans) above the 2nd and 3rd volume and treble control pots about 1/3 of the way up from the chassis bottom. Both these transistors have the audio signal from the phonograph on two leads. No capacitor leakage or burned resistors apparent ....so far. .. indicating that the problem is in the power transistor circuit powering the speakers. The pix's show the right speakers, chassis in the main section of the box, and the underside of the chassis. This pix immediately below shows a similar Zenith with only 3 controls but my guess is that it has the same amplifier as the one I'm working on.
Thanks for any help
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