Recent content by cmao

I have a 68010 based Heurikon HK68/M10-5 Multibus CPU board. Does anyone know where to find the Heurikon UNIX . This board came with MC68451 and MC68450. I have installed a RTC so this board is ready for UNIX.

Do you know what is the purpose of s2 switch ? Thank you in advance.

Thank you ! I will re-make PCB with JLCPCB

I have tried both KiCad and Eagle but none of them can open the *.sch file. I don't have OrCAD to try so I am not able to see the *.sch file. How was the original *.sch file created ?

Hi, I want to build diagnostic pcb for 11/83. Can you share the schematics in pdf ? I have no way to open your *.sch. Thank you in advance.

I asked AI. Below is the answer from OpenAI... " ## Bing Yes, QBus requires bus terminator. The backplane in the BA23 chassis (H9278A) has four onboard socketed resistor packs for termination, so a separate terminator board is not required. " I have made a simple terminator. As soon as I have...

I think it doesn't make sense to add terminators to both AB and CD. I would think the terminator should be added to CD instead of AB.

I will make a simple small PCB populated with 180ohms and 390ohm resistors as shown in the pdf file. I plan to place the PCB on the back side of the backplane with the help of the wire wrap pins. It seems no termination is required for C and D slots ??? Can I add terminators to both AB and CD.

Yep. I am sure no resistors including single-line resistors on my backplane. so...the termination is required. correct ?

I suspect that my 9-slot backplane needs termination to be inserted in slot #9. There are no resistors or sockets for resistors on my backplane. Can someone confirm that the termination is an important configuration ? If the termination is required, where to find schematics to manually add...

I will try to modify the memory with bootstrap code shown on p.20 and execute 2000G to see what happens.

Do you have a list of cmd's so I can look up the meaning in case I have other commands in future testing?

Don, I have little progress in booting M8189. I record both outputs from RX emulator and M8189. What could be the issue ?

jack, private/direct email sent. I am so lucky to have valuable comments from PDP-11 experts and experienced PDP-11 users who quickly bring me to PDP-11 world. All my hardware components were obtained form the eBay with the cheapest prices. The learning path for me is very long but successful...

What is the QBUS continuity card ? what happens if I don't have it installed ?