Hi George,
I received the replacement Gavazzi PSU today and that was indeed the issue. The replacement's Vout measures at 24VDC whereas the bad PSU measured at 9V. So I don't know how/why the other one went bad, nor do I have any clue as to how things were (partially) working with a 9VDC output. But with the new one in place, everything works as it should.
I called the one (and only) company that rebuilds these machines and they told me the manufacturer never had a standard by which they built them. Earlier machines used a proprietary board, later versions used Mitsubishi PLCs. The guy said he had never seen a machine with a MicroLogix PLC, so this could have been a custom requirement or another company rebuilt this machine at some point. If I wanted to have my machine rebuilt, they would strip out and throw away all the electronics, use their own serviceable parts, and charge me $10k (plus freight both ways). Perhaps if someone is looking for a very cheap PLC to mess around with, they may be able to obtain one from this company: afmeng.com
Anyway, I won't be touching anymore of this machine for now, but I will be purchasing a spare MicroLogix 1000 (probably off eBay) and making a backup just in case something happens. Thanks to everyone for all the assistance.
I received the replacement Gavazzi PSU today and that was indeed the issue. The replacement's Vout measures at 24VDC whereas the bad PSU measured at 9V. So I don't know how/why the other one went bad, nor do I have any clue as to how things were (partially) working with a 9VDC output. But with the new one in place, everything works as it should.
I called the one (and only) company that rebuilds these machines and they told me the manufacturer never had a standard by which they built them. Earlier machines used a proprietary board, later versions used Mitsubishi PLCs. The guy said he had never seen a machine with a MicroLogix PLC, so this could have been a custom requirement or another company rebuilt this machine at some point. If I wanted to have my machine rebuilt, they would strip out and throw away all the electronics, use their own serviceable parts, and charge me $10k (plus freight both ways). Perhaps if someone is looking for a very cheap PLC to mess around with, they may be able to obtain one from this company: afmeng.com
Anyway, I won't be touching anymore of this machine for now, but I will be purchasing a spare MicroLogix 1000 (probably off eBay) and making a backup just in case something happens. Thanks to everyone for all the assistance.