Quote:
Originally Posted by 3pinplug
Disconnecting pin 15 removed pulses from pin 18.
|
Good, as expected.
Quote:
At rest ie not moving spinwheel I positioned trace in centre of screen on oscilloscope, moving spinwheel anticlockwise - no movement! trace stayed in same position as at rest.
Turning spinwheel clockwise trace jumps upwards on screen.
|
What pin/testpoint? Pin 18 or pin 13? Volts/div
?
Quote:
I tested the spin wheel with Pin 15 still disconnected as you didn't say to reconnect it for the second test, hope that was correct?
|
Correct
For all future tests disconnect pins 15, 17, 13, and pin 18.
Measure pin 13. Does state change between 0V and 12V when you flick "UP/DOWN" switch one way, then the other?
Same for clockwise, and anti-clockwise rotation of spin wheel?
Now measure pin 18. Are there any pulses showing when not operating controls? Should be non.
You should see pulses when operating spin wheel and up/Down switch.
In my manual there is table 2 in section 4.37. set the channel size to 5kHz and band to highest frequency band (band 5). Flick the up/down switch. Do you see a single pulse (pin 18)? It will be narrow, at about 1.6uS wide. Try the other settings in the table, but i is not important at the moment. Without a storage scope it is difficult to count them! If you have an analogue scope trigger on them to see them.
While on the board check you have 37.5kHz on pin 10.
If it passes all these tests then the Logic board is working fine.