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Old 3rd Feb 2023, 1:09 am   #46
PETERg0rsq
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Join Date: Jun 2009
Location: St Helens, Lancashire, UK.
Posts: 641
Default Re: Help needed with - Racal Dana 9081

Quote:
Originally Posted by 3pinplug View Post

Here's what the display is showing:-
5-32MHz - displays 0.000
32-64Mhz - displays 67.688
64-128Mhz - displays 135.376
128-256MHz displays 270.754
256-520Mhz - displays 541.358
If the output is pegging over to maximum, one possible cause is the logic board . This would also likely explain lack of Spinwheel and switch function.

Band edges are detected by the PROM, and send out a signal, that is converted into pulses either step up or step down if the band edge has been crossed, steering it back into the band. If this is the case, then the signal generator is basically working, but the UP/Down detection is not working, so always running in the wrong direction, to the band edge!.

Check to see if you have any pulses on the pins 15 and 17 on logic board. If you do, see if they are up or down pulses. Check the UP/Down output corresponds with the directions on pin 13. Temporary reverse the wires to these pins to test the up/down output switches correctly.

Also check for pulses on pin 18 of logic board to see if the pulse generator is driving the counters/dividers when it should not.
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