Recent content by MattisLind

Never understood Intel date codes.

@anasana sent me a hint that I could connect the RX50 to a standard PC and after som fiddling I was able to use disk 2 as a PC disk. Imagedisk thought the speed was 293 RPM so a bit too low. Perhaps the diags are very sensitive so they give you an error with just around 2% error in speed? I...

Since the floppy refused to work. Consistently gave 330 error code, I simply removed the floppy and floppy controller and it actually booted into P/OS! So the RX50 sure is in need for refurbishment. I had fixed one missing pressure pad. Cleaned the head and lubricated the head screw. But I was...

With an unstuck spindle I get error code 330 which means "Drive speed not in limit". The motor is probably bogged down by spindle bearings that need lubrication. That tiny bit of oil I managed to put on the motor bearings wasn't sufficient. Unfortunately.

I double checked the ROM. All the strings are on the disk. None of them are in the ROM. I did write three floppies and tried with those. When I tried them it came to me that I didn't hear the floppy disk spin. So I dismantled the RX50 and sure enough it wasn't spinning. With some force I...

As I said. It does load from the hard disk since the text message on screen is in the hard disk image I already have dumped. One clearly see tha printout on screen coming one after each other after some hard disk activity. So I think the controllers are working fine. Besides, neither hard disk...

The keyboard itself is known good. One can see that the cursor reacts when pressing certain keys. It sorts of stop blinking in the slow pace and makes a very quick blink. Almost steady for some time. It also reacts differently depending of what key I press. Some makes it beep, pressing F1 lights...

I am now trying to revive my old Pro 350 which I had since high school years (gymnasium in Sweden). I wrote my final year paper on this machine in the late eighties. It has been sitting in storage since then but I removed the battery 10 years ago. Unfortunately it seems like te damage already...

Never found any schematics. I would urge you to check capacitors very carefully since I had plenty of them leaking in mine. Many of them showed low values when checking them with a capacitance meter. Unfotunately I had to do a full recap which is extremely timeconsuming given the huge amount of...

I wonder if it is possible to set up a 68k cross GCC and build the kernel with the stuff in the image? At least it could be a way forward. The Omnibyte board seems to be quite different. Uses 68xx peripherals instead of 68k peripherals. I have an idea of how to build an interposer to check...

I think that the -9V is used for the ethernet tranceiver. They are usually isolated from the rest so that is why you only get good readings between those specific pins.

It is still development, for sure it is not a finished product. It does work fine to test regular logic boards. It was when it came to flip-flops I found it had problems when the load module was active. Without activating the load module it worked fine to check the logic behavior of flip-flops...

The power supply is generating the logical signal but that doesn’t imply that it is sourcing any current. The source of the logical signal and the source of the current that develops the signal is two different things. In the case of an OC bus the current source is the terminating resistors and...

It was entirely designed by Anders. He shall have all the credit. I have been with him in this project throwing ideas and testing. One interesting feature is that it can verify that the output transistor can sink the correct amount of current. It also check how much load the inputs have. It is...

The BRS-tester by Anders Sandahl works with negative logic. https://github.com/anders-bzn/brs-tester