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It looks like it was exposed to water for a long time, are the cards still functional?

Someone said that FreeVMS "only covers 10% of OpenVMS". What is missing, Userland? Drivers? something else?

I would say that it is more complicated than a mechanical switch: * You have to debounce the mechanical switches. * You have to make sure you are in Minimum mode (MN/MX pin is wired high) otherwise it's a different logic that applies: RQ/GT0 and RQ/GT1 are bidirectional. * After requesting Hold...

Another question, you said "It definitely won't work doing by de-powering one CPU, because what happens is when a pin is pulled high on the non powered CPU from the powered one, current is sourced by the input protect diodes into the non powered chip die. " Won't the same phenomenon happen when...

@Hugo Holden, I am a noob in electronics and you are a giant, here is my question: The output Pin of CMOS CPU is not really symmetric, Vdd is connected to a P-MOS and Gnd to a N-MOS transistor. Is this the reason why removing Vdd would have different effects than removing Gnd? What about leakage...

Hi again, I clumsily managed to create a draft Kicad eschematics version of what I am thinking about a Kim-1 65816 based on @eduardocasino beautiful work. There are no 6530/6532 only VIAs. There is only 3 ERC errors in it, but I am sure it's full of mistakes. Anyway just to show I still work on...

That would be an extreme form of tri-state! But switching from one CPU to the other would be extremely complicated, at the end it would be much simpler to buffer all input and output pins of both CPUs with a logic circuit that you have to invent (and the software that goes with it). A much...

I may be wrong but I guess fjkraan schematics are here: https://electrickery.nl/comp/pdp11_23plus/clock-wakeup_1.0.pdf

Many thanks, I asked my correspondent, but as on my VS there is a capacitor at the same place I would assume they have a VS 3100 model 38 VS42A

Someone who damaged a capacitor near the power connector on the mainboard of their VaxStation 3100, asked me for a photo. Unfortunately, my photos do not reveal any text. I wonder if someone knows where to find the main board schematics for the 3100? I have included a photo of the damaged...

There was a plugin made for KiCad and used for a Kim-1 replica by Eduardo Casino, that replicates the "old" look. Here is a copy if his readme of the Kim-1 replica, it has a lot of information: # KIM-1 Replica ## Introduction Welcome to the MOS KIM-1 reproduction project repository, where you...

Here is what Google's Gemini (the successor to Bard) says: "Unfortunately, pinpointing the exact Harris mini computer model used in the 1980s with the information provided is quite challenging. Harris offered a wide range of mini computers during that era, each with varying capabilities and...

Sorry if this post is unrelated. I had a power problem on my VaxStation. On close visual examination indeed some caps had bulged and leaked but there was also a tiny diode that was burned and a tiny transistor with a suspicious color. The problem for me was that these components were not really...

I am selling this DECVaxstation: DEC VAXSTATION 3100-38 VS42A-CC KA42-A 24MB RAM RZ24 204MB SCSI HDD 8 PLANE GFX graphics I have too many projects, so I wanted a DEC computer that would work. I bought this VaxStation in November 2022 on e-b-a-y, and the seller told me that it was refurbished...

@dcminter , you could perhaps remove a few cards and/or connectors one by one and see if the station message changes?

I don't know what it is worth but I asked Bard, the large language model from Google. Here is what it told: The error messages on the boot screen indicate that there are problems with all of the SCSI devices on the system. Each "? n 010A 010A.1901" message corresponds to a different SCSI...

I don't know if it's relevant but there is a thesis in archive.org, to simulate the 6502 microprocessor using BASIC-PLUS on the PDP-11/34. Unfortunately, each page is provided as a jpeg picture. https://archive.org/details/TheSimulationOf6502Microprocessor/page/n73/mode/2up

Thanks @Joerg Hoppe, I will think about it.

Thanks @pbirkel@gmail.com, I know that (thanks to that forum, there is also @Hunta's solution as well as Diane's solution), but it's not a question of cost or anything else, it's just that some weird mental process makes me not use these solutions.

Please ignore if this is a stupid question: I have a 7264 board, a Qbus 4K memory board, and a DLV11 board. I have a QBUS backplane and an ATX PSU. What blocks me is the need for managing BRPLY, BHALT, BDCOK, and BEVENT despite the help provided here. I don't know what stops me from building a...