How do I get this chipmunk living in my recorder, out of it?

I have a Sony cassette recorder roughly 30+ years of age that plays tapes beautifully.


However, whenever I record anything from voice to music, it sounds weird like Alvin the chip monk. I have already checked the tape speed with a special cassette speed gauge thing, and its dead on. I鈥檝e worked on many cassette recorders over the years in a small repair shop, and never came across this weird problem before now.


I don鈥檛 want to junk this machine, because it was a gift from a long dead friend.





There must be a super brain out there somewhere that can help me with this problem





Please help me.............................How do I get this chipmunk living in my recorder, out of it?
Have you tried cleaning the capstan roller assembly unit with alcohol(91%) to remove all of the film residue from the tapes? You have to clean this roller until your cotton swab or cotton cloth is no longer Black from this residue. Try that first. I will assume that you also cleaned all the tape guide pins. Also, if any belts are still intact in their size and elasticity. Don't want them slipping. You might also clean the inside of the pulley wheels where these belts go in with a cotton swab and alcohol (91%). You've probably already have done this, considering working in a repair shop. Just checking.How do I get this chipmunk living in my recorder, out of it?
my goodness chip monks you say? it sounds like you're literally pulling your hair out on this one. however, i believe i have the answer for you.





obviously since the tape speed is constant with no deflection, we must assume that it is an electrical problem other than a mechanical one. after considering all the possibilities i would say that the biased oscillator is running quite a bit off frequency. It鈥檚 probably running higher than normal. if you open the unit up you will see a fairly good-size circuit board with 2 small transistors sharing the same heat sink. There鈥檚 a third way down on the other end its on a smaller heat sink too, the record biased oscillator (40 to 150 kHz to the audio signal) is located right off that transistor. There should also be a black in color coil with an adjustable slug in it. If you don't have a frequency counter then you'll have to do this the old-fashioned way ';by trial and error';





to lower the frequency try turning that slug clockwise about one turn to start off with. Now record something and see if the playback is somewhat different now. if you notice a difference, turn the slug clockwise one turn once again and continue on until the audio quality is satisfactory. now if adjusting the slug makes no difference whatsoever then my next best guest would be that the transistor may be weak and damaged, it's quite possible that the device has failed due to its age. There are also capacitors that can dry up and cause a frequency shift too. Therefore, pick the most obvious electrolytic and substituted it with one of the same value. you鈥檒l find a couple of them very close to that coil surrounded by a few fairly large resistors too.





Note: It's quite rare for titanium condensers to change value.


However, there is one that鈥檚 directly connected to the oscillator coil then to ground. this one controls the total frequency range. If you feel uncomfortable about replacing the transistor just remove this capacitor and increase its value.(.0047) to (.0060) or (,0085 this will dramatically change its overall maximum range giving you the ability to slide the frequency even further + or -





working as a technician for 35 plus years this information should fix your small problem.





Peace my friend

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