On Tue, Aug 11, 2026 at 8:26 PM Jon Elson via cctalk <[email protected]> wrote: > On 8/10/26 12:27, Ethan Dicks via cctalk wrote: > > On Sun, Aug 2, 2026 at 8:44 PM Jon Elson via cctalk > > <[email protected]> wrote: > >> The ground was the problem. For some CRAZY reason, pin 5 of > >> the 9-pin serial connector of the KA630-AA and cabinet kit > >> has a 1K Ohm resistance to system ground. > > I don't doubt that you had a problem with ground, but on a MicroVAX > > console port, Pin 5 is not ground. Ground is Pin 7. > > > > 5: Data Terminal Ready (DTR) > > 7: Signal Ground > > > Thanks, Ethan for the reminder! Fixing the cable makes > things work a bit better...
Excellent. > ...but I still have the ?24 UNXINT > error. I also get some garble when I first start it up. I > doubt the uVAX is doing and auto-baud, as it has the rotary > switch, so maybe the USB-serial adapter is trying to > outsmart the settings given to minicom. Not sure about your baud barf. Yes, the uVAX won't be sending at any other speed than the one it's set to. > But, I can't seem > to get around the UNXINT error. It may be a bad KS630 board. I looked over the KA630 manual and it lists 24 UNXINT but doesn't go into specific situations, just an unexpected interrupt. Ultimately, it's an interrupt coming from some source that's not expected (as the language of the error text would suggest). That can be a defective CPU board, can be a defective peripheral, a misconfigured peripheral, or in some very rare cases a backplane or extender card problem that affects bus lines. If you don't have a spare CPU (or a second system box), I'd list out what devices are on the bus and see if you can pare any down. Not all Qbus devices have the vector set by DIP switch, so for those, it's all soft configuration. If you have devices that have a Vector DIP switch, check the settings and honestly, check the switches themselves. I have seen DIP switches fail with age (especially if there's graphite in there because someone used a pencil in the past). Back in the day, we'd also run the "CRD" (Customer Runnable Diagnostic) which isn't as extensive as old MAINDECs or XXDP but should hit the high points with the CSR and vectors and a few local hardware tests. We used to boot our CRD off of TK50 which is its own perilous journey these days. If you can reduce the machine to CPU, RAM, and your boot device, that would simplify testing. -ethan
