Recent content by marmotking

I'm super impressed that you went through all this debugging. Personally, the capacitors on there are decades past their life span. I would consider them to ALL be bad and necessary to replace. I usually do that for any system before turning the power on. I mostly collect mini-computers though...

Do you still have the VAXconsole hard drive? I have an 8550 and haven't been able to find the VAXconsole software for it. Without an image of that drive, the machine cannot be booted and is a very large brick.

I'm using a 3.5" drive on a TRS-80 Model 4 as an external drive. I'm doing this with LS-DOS 6.3.1 and it works completely fine. I find posts all over the Interweb stating that you need to find a jumpered drive, so that you can disable the IBM PC disk change hack. This hack is suppose to make...

I've recently started restoration on a VAX 8550 in beautiful condition. This machine requires a PC-38N (I believed alternately labeled a "VAX Console") to boot. It appears a PC-38N is a PC-380 (Pro 380) with an RTI (real-time interface) board and special boot software required by the 8550...

I've recently attempted to fire up a PDP-11/23 that I acquired many years ago. I just never got around to firing it up and getting it working. But I'm at my wits end here after working with it all weekend. I'm now down to a pretty bare bones configuration: Slot 1 AB, M8186, Board Revision...

I've been searching for information about the DG Nova 3 bus. Does anyone know what bus this has and have any links to information about the electrical specifications of the bus? Does the bus architecture have a name that would be helpful? Thanks!

I have a working VAX 4000-200 and bought a spare CPU board for it. I plugged in the spare board and it seems to hang when starting the OS boot process. I've included the log below. I looked through the KA660 technical reference and couldn't find what might be hanging at this point in the boot...

Does anyone know if it is possible to convert a VAXserver 4000-200 to a VAX 4000-200 by simply replacing the EPROMs or is there a genuine difference in the CPU board? If not, what are the limitations of the VAXserver and how are they enforced in VMS?

Lately I've been trying to dump my VAX system ROMs in case the EPROMs or EEPROMs suffer bit rot. The KA53 (i.e. VAX 4000 105A) doesn't have EPROM chips on the motherboard, so I was attempting to use the boot console's "examine" command to grab the system ROM contents. This has worked before on...

When I boot my VAXstation 3100 M38 I get the following: KA42-B V1.3 F...E...D...C...B?.. etc. Note the B?, which indicates a memory error. Running TEST 50 shows the following: ?? MEM 000C.0200 00C00000 Which indicates 12MB memory, which matches what's in the system. However, the...

I have a PDP-11/23 which I thought maybe I could upgrade using an H9276-A backplane. Actually, I have lots of enclosures I could use. Could I use an KDJ11-BF with this backplane and make an 11/23 PLUS? Any help getting started in that direction would be very useful to me. Basically, I guess...

I have a very nice TU80 and TU81 that I'd like to get working again. The problem is, the heads on both look pretty worn. One looks like it's seen lots of hard use and the other looks like it was stored under water. Is there any chance that anyone here has spare heads for one or both of these...

I have a VAX 4000/200 which is entirely Q-BUS. I'd like to know if there's a Q-Bus video board that one can use on this machine, kind of like you'd do with a VAXstation.

Starting to work on my PDP-11/23. It's a pretty basic machine but in very clean shape.

I have a Computer Products NFS50-7608 power supply which is missing some components. I'm wondering if anyone has one of these (it's a 40W, -12V, 12V, 5V, I think). If so, I'd like to get some photos to help me fill out the missing components. Any help would be greatly appreciated!