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Old 23rd Apr 2021, 4:23 pm   #1742
ortek_service
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Default Re: Non-working Commodore PET 3016

Quote:
Originally Posted by ScottishColin View Post
UA7 and UA8 replaced and the test program now runs through without error - thanks all.

Cassette port 2 next.

Colin.
Good to hear that replacing these has now sorted that.

Luckily there's really only 3 transistors & a zener-diode (all quite low-cost), in each of the cassette ports interface.
- So assuming the check SiriusHardware mentioned earlier shows that Port 2 is being controlled-correctly by the UC5 (6522), then it should be just a case of following through this switched transistor regulator circuit by measuring a few voltages with it enabled and disabled.
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