Lexicon PCM42 delay time

[psych60s]

Hello everyone

I got a PCM42 with the extra memory board. Maximum delay times should be 2400ms in normal mode and 4800ms in 6kHz mode, both with the manual knob set to "x1.5".
If I set the knob to "x0.5" I read correct values which are 800 and 1600. In fact I get 888 and 1700ms respectively. But I can't go higher than  4132ms instead of 4800. I have removed two ICs on the extra memory board (both at the same time and one by one) but still can reach the 4132ms delay time at max.

Any idea about what could be wrong?

Thanks 

 

[psych60s]

I have to add : I've just tried to remove one of the six stock DRAMs, and I get the same values! Seems a bit strange to me but I may miss something?...

 

[psych60s]

Okay I've found what was wrong

 

[Rob Flinn]

& the problem was ??

 

[psych60s]

There are 3 trim pots inside which allow you to adjust frequencies the clock oscillator is generating. You could adjust the lowest and the highest frequencies that could be generated.
Mine had a lower maximum frequency than it should have