UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Non-working Commodore PET 3016

Mark1960 · 28th Feb 2021, 5:17 pm

For UD9 it might be worth trying to measure DA2 and DA3 again, just in case of a bad scope probe connection. I wouldn’t expect to see no activity on those data pins.

DA0 could possibly try adding 4.7k pull up to 5v. That might show if its a weak output instead of something pulling it down. Try measuring DA0 from the other proms first.

28th Feb 2021, 5:17 pm	#710
Mark1960 Octode Join Date: Mar 2020 Location: Kitchener, Ontario, Canada Posts: 1,298	Re: Non-working Commodore PET 3016 For UD9 it might be worth trying to measure DA2 and DA3 again, just in case of a bad scope probe connection. I wouldn’t expect to see no activity on those data pins. DA0 could possibly try adding 4.7k pull up to 5v. That might show if its a weak output instead of something pulling it down. Try measuring DA0 from the other proms first.