Hi RickyRay,
Thanks for the reply.
I totally agree, I tried and finally mange to get the motor schematic (attached)
Bit of naive here but couldnt understand that if I want to test the IC with multi-meter which pin should remain constant while other are checked against it.
and what output values to be accepted as apt.
Kindly, see if you could help.
Regards
Thanks for the reply.
I totally agree, I tried and finally mange to get the motor schematic (attached)
Bit of naive here but couldnt understand that if I want to test the IC with multi-meter which pin should remain constant while other are checked against it.
and what output values to be accepted as apt.
Kindly, see if you could help.
Regards
I would start with testing the +12 volt and -12 volt power lines both when it is cold and when it gets hot and starts spinning fast. I would also check for +5 volts and -12 volts at the chip. looks like it has voltages displayed on the chip pins.
Do you have an oscilloscope? It gives you what the waveforms should be, start with the frequency generator, then see if the chip converts into a square wave.
Do you have an oscilloscope? It gives you what the waveforms should be, start with the frequency generator, then see if the chip converts into a square wave.
First things first Many many thanks to you RickRay for suggestion 
Well I did cleaned VR1 and VR2 including the pitch control pot but one thing, I used WD40 general one which worked for me always but somehow you mentioned it (thanks a lot for that) and I thought of getting 'WD40 Fast Drying Contact Cleaner' and tried that....and bingo! it worked I have my TT on for around 24 hrs now and no crazy speeds 🙂 🙂
Well I did cleaned VR1 and VR2 including the pitch control pot but one thing, I used WD40 general one which worked for me always but somehow you mentioned it (thanks a lot for that) and I thought of getting 'WD40 Fast Drying Contact Cleaner' and tried that....and bingo! it worked I have my TT on for around 24 hrs now and no crazy speeds 🙂 🙂
Note to all people who have a can of WD40 around - it should never be used with anything electronic.
It can eat away and be harmful to the carbon tracks of control pots.
DeOxit, CRC contact cleaner, are more recommeded.
It can eat away and be harmful to the carbon tracks of control pots.
DeOxit, CRC contact cleaner, are more recommeded.
Glad to hear that worked for you, wish it had worked for me. My issue is an unobtanium Chip bad.
Working on bypassing the chip and just running it at 33 1/3 speed with a different board to take it's place.
Thanks wiseoldtech,
I would keep that in mind
I wish you best of luck.RickRay said: