25th Apr 2021, 6:55 pm
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#1747
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Octode
Join Date: May 2012
Location: Perth, Scotland
Posts: 1,803
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Re: Non-working Commodore PET 3016
The POKE didn't help - PRINT PEEK(59458) returned 30.
Colin.
Quote:
Originally Posted by ScottishColin
Measurements taken on UC5/14.
Colin.
Quote:
Originally Posted by ortek_service
Quote:
Originally Posted by SiriusHardware
#1727
Plug a datasette into cassette port 2 and look again at the voltage on cassette port 2 pin C-3. I suspect that variable high voltage you are seeing there will vanish when there is a load connected to pin C-3.
You may also find that the voltage on pin D-4 (CASS READ) will be different when you do have a datasette plugged in / don't have a datasette plugged in.
With a datasette plugged into port 2, what voltage / logic level do you see on UC5 pin 14...
-When cassette port 2 is idle (not doing anything)?
-When cassette port 2 is trying to load something?
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Quote:
Originally Posted by ScottishColin
re 1727 - 2.4V in both instances.
For the record, when I try to LOAD a program from port 2, there is no power to the datasette - play, rewind or FF do not work.
Colin.
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Where did you measure this 2.4V?
- Was it on cassette port 2 pin C-3 or UC5 (6522) pin 14? (or one both?)
If UC5 (6522) pin 14 is always high, then that means the cassette port 2 interface's power-regulator supply will always be being disabled. So, unless something is shorting externally, then that could indicate a fault on the 6522's pin itself
- But best to check the correct software commands are being used to control this / could try POKE-ing it's PB4 low
I think POKE 59456,0 should do this, but might there may be a clash with what the Kernal is trying to do, as the 6522 PortB lines are used as both outputs & inputs, some for internal use.
And have to ensure the data-direction has been set correctly by the Kernal etc. first. So maybe try PRINT PEEK(59458) and see what that returns, if the POKE doesn't make any difference. |
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