424 MKII slow counter problem

[Mcnutty]

Anyone have experience with normal playback sound combined with the counter getting slower and slower after each rewind. I have normal operation for about 1/2 hour, then this issue starts happening.
It gets to the point where the info from the counter is so wonky that the machine stops it's self.

 

[SkywaveTDR]

Some counters are driven by belts and they are very thin belts. Next the reel tables can be be losing the lubrication and if that happens the deck losing take up will then go into stop mode.
Some counter have magnetic wheels on them that operate a hall effect or reed switch on the older decks to give square waves to a motion detection circuit. When the counter that also has a bearing it is at the worm gear gets sticky that also might have to be oiled- I do it all the time with Reel decks- take the counter out clean number face and oil the bearing. I think the counter issue you may have is a slipping belt. They are also very small as in 2.5" or something like that as well as .039" thick or maybe a .029". These can fail but I have not seen a lot of them from that age of device. What I did not mention above is that the counter belt is driven by the take up- right side reel table so it goes from a pulley on that to the counter pulley. IF the motion sensing is from the counter the belt if broken or removed will shut the machine off in 2 seconds or less. If the counter is only a mechanical counter and motion sensor is by IR reflector under reel then taking the belt off will have no other effect but the counter will not work. They had about 4 different type of motion sense systems. The IR reflector types do have decaying photo transistors in then under a reel table.

 

[Mcnutty]

Very curious all that. Thanks for the info download!
Much appreciated.