WildBill777 Posted May 6, 2022 Share Posted May 6, 2022 I recently picked up an Atari 800. Upon testing further, it seems to be working fine except for the joystick port 1. When a plug in a known good joystick, the ship in Atari Blast or any other game will move to the far right and not move. What should I look at checking first to fix this? POKEY chip? It generates sound just fine, but this chip also reads the joystick ports, correct? Quote Link to comment Share on other sites More sharing options...
WildBill777 Posted May 7, 2022 Author Share Posted May 7, 2022 Maybe the PIA chip. Is the PIA from the 1200XL compatible with the 800? The PIA in the 1200XL is CO14795-12, the 800 is just CO14795. Quote Link to comment Share on other sites More sharing options...
Panther Posted May 7, 2022 Share Posted May 7, 2022 It's compatible with a number of different PIA chips, including from various Atari systems (any C01495) or even the W65C21N, at least for the most part (not in a 576NUC+ if you want to be able to program the PIC while the PIA is plugged in). Quote Link to comment Share on other sites More sharing options...
WildBill777 Posted May 11, 2022 Author Share Posted May 11, 2022 On 5/6/2022 at 11:10 PM, Panther said: It's compatible with a number of different PIA chips, including from various Atari systems (any C01495) or even the W65C21N, at least for the most part (not in a 576NUC+ if you want to be able to program the PIC while the PIA is plugged in). It's weird, because I pulled the 800 PIA and plugged it into the 1200xl and it wouldn't boot at ALL. I put the original 1200xl PIA back in and the 1200xl booted fine. Quote Link to comment Share on other sites More sharing options...
Panther Posted May 11, 2022 Share Posted May 11, 2022 They are the same chip, so that is certainly peculiar. The numbers after C014795 simply have to do with where they were manufactured. Quote Link to comment Share on other sites More sharing options...
Rybags Posted May 12, 2022 Share Posted May 12, 2022 (edited) Later machines use PIA bits for memory banking so if it's problematic can stop the computer working totally. 800 would likely work without the PIA even present though be unable to use just about any external peripheral except paddle knobs. Edited May 12, 2022 by Rybags Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted May 12, 2022 Share Posted May 12, 2022 (edited) It is possible to have a partially functioning PIA... A side dead, B side fine, vice versa and other aberrations.... also note that not all PIA's are created equal... I had made mention of this previously and some members did a study on them right on down to how bit banging peripherals on the I/O ports (joystick ports) was more or less effective. That being said I'd still check the passive, support components, and the pokey. The I/O ports (joystick ports) touch a number of paths... no harm in checking the connections and connectors either. Edited May 12, 2022 by _The Doctor__ Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted May 12, 2022 Share Posted May 12, 2022 Quote Link to comment Share on other sites More sharing options...
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