I have bought a MK 151 and assembled it. However the clock was running so fast. Adjust the trim capacitor (clock adjust) has no effect. Troubleshooting help? All solder joints were checked and appeared OK!
Please HELP…Thanks
Hi, was it “a little bit too fast” or “very very much too fast”?
Hi Dany,
Thank you for a reply…it seem like very very much too fast, from 0:00-23:59 approx. about 45 seconds! Please help…THANKS
Waw! That’s fast.
The only reason for running the clock so fast is that SW1 is pushed continously I think, so
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Did you check the push button SW1 and its connections via D8 and R9 towards pin 17 of the PIC for short circuits to other components or copper tracks?
You could do the test of removing (de-soldering of one end) R9. It the clock speed is ok now then SW1 is defective (short circuited). -
Also the value of R10 could be of importance (4K7 according to the circuit diagram).
Success!
Hi Dany,
After removing/replacing the push button SW1…the CLOCK now running great.
Thank you so much