Sony TC-D5 PRO II tape speed way too fast.

Hi Folks, I have an interesting problem with a Sony recorder. I just bought a Sony TC-D5 PRO II on eBay and discovered it runs at double the speed for a cassette.
The potentiometer near the CX069 Servo chip doesn't make any difference when turned. But the resistance does vary on the ohm-meter.
Why would it be going at double the speed?
I noticed that the voltage on pin 6 of the CX069 chip should be 2.2V but its 5v. Does that mean the chip is blown or could it be something else? Highlighted is pin 6 of the chip. Also highlighted is the tape speed potentiometer.
The chip must be working to a certain extent if the tape is actually running (but at too fast a speed).
Any help is appreciated.

 

Hi @MICHAEL MURRAY .
I can't provide direct help, but I think over in the Walkman section there are members discussing the TC-D5(M).
Perhaps they can help.
Emiel

 

@MICHAEL MURRAY The symptom you are describing is typical of a servo IC failure. The other thing to be checked is the FG amplifier (on the left of the picture, partly visible).
Check what you get on pin 3, prefferably with a scope. You should have a signal with frequency of 860Hz or so. New old stock replacement ICs can be found on ebay, so it's not a really big problem if it's burnt.

NOTE: A sawtooth waveform should be present at pin1 if servo IC is working correctly.

EDIT: The 860Hz frequency mentioned will be on a good working device, which plays at the correct speed. In your case, the frequency will be higher, but if FG coil and FG amp are good you should get a signal, that's the point.

 

Thanks for the help guys. Much appreciated.

 

Hi Valentin. I am getting a sine wave signal of 1.8 Khz and every so often it hops to 2.2 Khz.
Does this mean its the Servo control IC needing replacement?

 

Yes, given the voltage at pin 6 is 5V instead of 2.2V. The fact that you are getting a sinewave at pin 3 does indicate the FG coil and FG amplifier are indeed working correctly.

 

Thanks Valentin. Do you know of any reputable dealers selling the Servo IC online?

 

I would go for the ones in US. There seems to be about 3 sellers on ebay from US and only one sells per piece. I don't want to recommend one specifically, cause I don't remember if I bought from them before or not.
But things like 100% (or close to it) positive feedback, other similar items for sale are all postive aspects.
Another aspect that you should search for (I'm talking in general of replacements ICs of this kind) is price: it needs to be about 10-15USD. Anything lower than that potentially points out to a counterfeit IC.

 

Thanks Valentin. I will take all those suggestions on board.

 

Did you ever solve this? I’m chasing this exact same issue of it playing too fast.