View Single Post
Old 20th Dec 2022, 7:21 pm   #9
cmjones01
Nonode
 
Join Date: Oct 2008
Location: Warsaw, Poland and Cambridge, UK
Posts: 2,669
Default Re: Cassette deck head alignment - a surprise

Quote:
Originally Posted by ms660 View Post
Quote:
Originally Posted by theredhouseinn View Post
You cannot measure resistance of components in situ as there will be other components connected to the pre-sets which will give you a lower reading than the value of the individual pot.
Look at the pots concerned in the schematic:

https://archives.doctsf.com/document...5575&ref=75255
Indeed. I measured them out of circuit as well and they were just as bad. It was just much easier to take a photo while holding the meter prods on to the pots while they were soldered in to the circuit board! I'm not at all sure what the mechanism for a carbon track pot to fall in value is, but the 6 pots were all over the place. The 10k ones measured anything from 8k to 11.5k and the 20k ones were between 16 and 18k. Unfortunately the absolute value of the pots does affect the deck's calibration. If I was a perfectionist I'd replace them all, but I probably don't have any that would fit properly and it was easier to sneak a surface-mount resistor in series under the PCB...

Chris
__________________
What's going on in the workshop? http://martin-jones.com/
cmjones01 is offline