BVH-2000 and "SYS ERR" message - help?

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BartConway
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BVH-2000 and "SYS ERR" message - help?

Post by BartConway »

Hello, all. As the subject says, I just took possession of a BVH-2000 which I was hoping against hope would be in operating condition. It was dusty as heck, and also clearly had taken at least one good whack, as I can see misshapen metal on the bottom and the whole bottom panel is missing a screw and partially detached. But I have two issues I need help with:

1) After cleaning it thoroughly and cleaning the heads, my one recorded tape was showing no signal until I connected to the Monitor Out. Once I got a signal, the top and bottom were tearing, and the color was flickery and unstable. Couldn't seem to get a better picture. It was only then that I realized from poking around on this forum that it is supposed to have internal TBC cards in slots 5-9... is that correct? It does not. They are empty.

2) When I went to get ready to hook up external TBC – after leaving it off overnight – the machine is now effectively dead. All I get is a screamingly loud siren, and the "SYS ERR" message. Manual says it relates to the CPU.

So: is there a user-serviceable fix or reset? Do I likely have a boat anchor?
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PID_Stop
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Re: BVH-2000 and "SYS ERR" message - help?

Post by PID_Stop »

Sorry for the delayed reply -- things have been hopping at work.

Yes, the missing cards are for a BKH series plug-in time base corrector. If the machine doesn't have them, it must have been using an external BVT-2000 time base corrector. I have not had success using other TBCs -- for one thing, the dynamic tracking system wants to interact with the TBC in fairly specialized ways.

The "SYS ERR" message issue is interesting. There are actually four Z80 CPUs in the machine:
  • The SY-79 card's CPU largely handles communication with the outside world: remote connectors, control panel, etc.,
  • The SY-80 card's CPU controls general internal functionality,
  • The SV-43 card's two CPUs handle all of the real-time servo functions.
The fact that you're seeing a message on the control panel indicates that the SY-79 is working at least enough to boot up and interact with the control panel. Offhand, the most likely issue is that it isn't communicating with the SY-80 board somehow. I would suggest pulling both cards, making certain there's no debris floating around, and pressing all socketed chips gently to make sure they're fully seated. Given the age of the machines, the most obvious possibility is that one or more capacitors have failed on these boards.

Another thing that can provoke the alarm buzzer: if the toggle switch on the front of the SV-43 board ("TAPE RUN") is accidentally knocked into the lower "STOP" position, it will sing the song of its people until you press the STOP button on the control panel. The switch wants to be in the upper "NORM" position unless you're doing fairly arcane diagnostics.

Jeff
BartConway
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Re: BVH-2000 and "SYS ERR" message - help?

Post by BartConway »

Jeff, thanks so much for the reply... and alas, I wish it had been as easy as following your instructions. Nope! The switch on the SV-43 was in its desired position, and I didn't detect any chips loose. I pressed upon everything. Only thing I've not done and still might do is pull each card, spray some Deoxit around the terminals, and clean everything up real good.

I took a $25 chance on eBay and bought a spare SV-43 card, just to see what happens, so maybe in a few days when that shows up, I'll get a nice surprise (I doubt it somehow).

Is there anything I can glean from the LED readouts on the cards, by the way?
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