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Success Stories If you have successfully repaired or restored a piece of equipment, why not write up what you did and post details here. Particularly if it was interesting, unusual or challenging. PLEASE DO NOT POST REQUESTS FOR HELP HERE!

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Old 4th Feb 2018, 10:39 pm   #1
OldTechFan96
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Default 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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Old 5th Feb 2018, 2:18 pm   #2
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Default Re: TEAC CX-270 Crackly Left Channel Repair

Thanks for posting the outcome (one for my memory bank)
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Old 5th Feb 2018, 3:32 pm   #3
OldTechFan96
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Default Re: TEAC CX-270 Crackly Left Channel Repair

I forgot to mention that the original belt turned into goo. From what was left I was able to work out what size replacement belt was needed.

The replacement I ordered was 88mm in diameter, flat section.
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