To be honest, I don't know.
On the printer, what happened to the lights on the printer? The key question is whether all eight lights were still red, or only the five for the IJM carts? If eight lights are still red, then I think it's time to talk to your repairman about that cable connection.
If the lights for the three OEM carts didn't turn red it means that those three are recognised, so I'd be asking the repairman if he upgraded the firmware for the printer. As I said earlier, upgraded printer firmware is a known cause of the R1430 no longer accepting third party carts, and I've never heard of anyone solving this. I.e. AFAIK you can't downgrade, or at least I've never heard of it being done. But the 1430 is the only printer that I can recall hearing of where this happened.
If only five lights turned red then I guess you could try the same test with a few from your spare set of IJM carts, but I'm still sceptical whether than will make a difference.
You said that you're desperate to finish a print job. If it recognises OEM carts but not either set of IJM carts, then I think your only solution is to do that print job with OEM.