TEAC CX-270 Crackly Left Channel Repair
At the end of last year I bought a TEAC CX-270 cassette deck from about 1980-1981.
After a good clean, including the tape transport and heads (which are in perfect condition), I powered the deck up and started to play Michael Jackson's 'Thriller'. After about 10 minutes of playback the left channel started to intermittently pop and crackle.
I duff transistor I thought, but where?
I suspected one of the two transistors near the output jacks (Q104). These are 2SC945 transistors. Instead of randomly changing components I thought that I should wait until I bought an oscilloscope. Into the 'to do' pile it went.
After coming to grips with my Hameg HM203 oscilloscope in early January I thought that It was time to sort the TEAC deck.
I waited until the crackling started before I started probing the suspect transistor. When probing the transistor I could see the crackles on the oscilloscope's display. The audio waveform was fine before the transistor and distorted after it. Since I was sure that Q104 was defective I ordered a packet of 2SC945 transistors.
Once the transistor was replaced the deck worked perfectly and I have had no trouble with it. Sorted!
The only problem is that I don't have many cassettes!
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