Recent content by leegleason

I hope you're not disappointed with its capabilities. It can draw what DEC callls "waveform graphics". Basically, for each X position it can draw two pixels above it, along with some added capabilty to "fill" beneath a wave, draw axes and add text. Basically intended to allow you to draw graphs...

Thanks!

That sounds interesting. How do you request a PRO to boot from the network?

Thanks!

You can disable the memory on the MXV11, or remove the memory card and use the MXV memory. Another MXV advantage - it provides two DL11 ports, so one is the console and the other can be used with a TU58 emulator. I have a two card RT11 system in a BA11-VA, with an 11/02 processor and an MXV11...

This looks great. I've been wanting to do something like this - I have two BA23s under my desk and the fans are pretty loud. Do you have the airflow specs of the old fans and these?

Lessee...if you switch an MXV11 for the DLV11, you get a console port and sockets for boot ROMs, as well as some memory. As far as a bootstrap goes, how about this one? https://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/bootstraps/mscp_rt11.txt It would be long to toggle in...

Isn't the resistor in the Frain design serving to limit the current through the transisistor, as well as serving as a pullup? Maybe that's why it's there.

It's a pretty regular looking fuse that it holds. 1.25" long.

I had dozens of RA92's back in the day. They were pretty reliable, but occasionally we'd have one fail to spin up after a shutdown. DEC FS would replace the HDA and we'd be good. One time, though, a relatively important disk failed, and there were no RA92 spares in the city. It would take 24...

I need a new fuse holder for a VT220. It's the kind with an inline carrier that holds the fuse and screws into the fuse holder body. Anyone know of a source for this sort of holder? Or the real name of this type so I can search for one?

No experience with this specifically, but with problems of this type. If you can operate it with the cover off, try blowing on parts of it with a hot air gun (not set too high) and see if you can cause the problem to occur by heat - then note what you were pointing at at the time.

OK, got the new chips (bought 5 of 'em, in case finding the right one to change turned out to be a game of desoldering whack-a-mole). I'm waiting for the bypass cap to come from Mouser, so I figured, I'd give it a try without a cap in that spot. Got the right bad chip on the first try. Worked...

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There's a ROM, but it doesn't contain any code - it was almost all 1's. I'm hoping I can find a way to load software in it and tell it to go. Writing standalone MicroVAX code is pretty trivial, so I'm sure I could get it to do something interesting...if I can just find a way to load it and tell...