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Hi all,

I am now a proud owner of an OSI Superboard II

First a little about me, I am an Electronics Engineer who loves electronics as a hobby too. During the day I volunteer at a tourist railway doing things from electronics design (doing a new automatic gearbox controller) to auto electrical and it.
I live in Perth Western Australia, just outside the Swan Valley
My My Superboard nearly works. It can get to the W/C/D/M ? Screen, caps lock is on if I scope the data bus I can see changes when I hold a key down and release it. After a random time 0 -30 seconds I loose most of the address bus. It looks like it is hitting a small loop. I will connect a logic analyser and do a trace from power up. I re seated all the socketed chips, sprayed all sockets with deoxit, swapped cpu. I have read all the roms but can not find a list of checksums to see if mine are still good.

Any ideas great fully appreciated

Regards,

Kat.

Welcome to the forum, and congratulations on picking up the Superboard 2!

A lot has to be working for you to see what you are seeing: All the video circuitry, the 6502, most address decoding needs to work. If you are seeing activity when you press keys, that means the keyboard circuit likely works as well. I don't have a dissasembly at hand, but unless the ROM code is designed to run without any page 0 references, you should have at least a couple of good RAM chips covering page 0.

Have you checked the shiftlock key itself to make sure it's actually making contact? A bad shiftlock key would be my first guess.

And, happy new year!

dave wrote: ↑Mon Jan 01, 2024 4:37 pm
Have you checked the shiftlock key itself to make sure it's actually making contact? A bad shiftlock key would be my first guess.

And, happy new year!

Hi Dave,

Happy New Year back (and to everyone else on the forum)

Yes I can see a difference in the data bus when I toggle the shiftlock (On pin 2 of U4 I get a negative pulse 84uS long every 522uS, this then changes the displayed waveform on Pin 3 U4)

I will make up a 40pin dip cable to pin header and use that to plug in my logic analyzer (It is just a Digilent digital discovery but it works and tolerates +5V signals)

I will post my results later

Regards,

Kat.

OK, so seems like shift lock is working.

I am sure this is obvious, but there are a few choices from the D/C/W/M? prompt. Do all of these choices do the same thing?

If you don't have a disk, I would expect the "D" option to lock up.

The "M" option should bring you into the monitor. You would expect to see a 4-digit hex address and 2-digit hex data feild at the top of the screen. Because of the overscan on the superboard II, it is not unheard of for the monitor address and data to be off the scree, depending on the overscan severity. Some sets can be adjusted to reduce the vertical height.

The "W" option will generally hang if you haven't already done a BASIC cold start.

The "C" option should bring you in to BASIC if you have good BASIC ROMs. If you can see the "D/C/W/M" prompt, then you'd definitely be seeing the BASIC startup prompts, since these scroll up from the same line as D/C/W/M on the superboard II.

A stuck key would also prevent normal operation. Using the same method that use used to check shiftlock, you could confirm that with shiflock released, you don't see any pulses on the inputs to U4 and U5.

Let us know what you find out.

dave wrote: ↑Tue Jan 02, 2024 4:55 pm OK, so seems like shift lock is working.

I am sure this is obvious, but there are a few choices from the D/C/W/M? prompt. Do all of these choices do the same thing?

Yes Dave, They all seem to do nothing.

dave wrote: ↑Tue Jan 02, 2024 4:55 pm If you don't have a disk, I would expect the "D" option to lock up.

No Disk drive YET I am thinking of designing one with an SD or Compact Flash Card in the future

dave wrote: ↑Tue Jan 02, 2024 4:55 pm The "M" option should bring you into the monitor. You would expect to see a 4-digit hex address and 2-digit hex data feild at the top of the screen. Because of the overscan on the superboard II, it is not unheard of for the monitor address and data to be off the scree, depending on the overscan severity. Some sets can be adjusted to reduce the vertical height.

The "W" option will generally hang if you haven't already done a BASIC cold start.

The "C" option should bring you in to BASIC if you have good BASIC ROMs. If you can see the "D/C/W/M" prompt, then you'd definitely be seeing the BASIC startup prompts, since these scroll up from the same line as D/C/W/M on the superboard II.

I think I got into Monitor ONCE

dave wrote: ↑Tue Jan 02, 2024 4:55 pm A stuck key would also prevent normal operation. Using the same method that use used to check shiftlock, you could confirm that with shiflock released, you don't see any pulses on the inputs to U4 and U5.

Let us know what you find out.

OK If I probe Pins 3, 11, 6, 8 on U4 and U5 using the active low RKB Signal as the trigger, I can see the keys correctly displayed on the data bus

Thanks for the help Dave

Regards,

Kat.

Hi All,

Todays activities

I burnt a copy of a SYN 600 rom to a 2716 eprom, changed W6 and W7, removed the bridge between pins 20 and 21, tied pin 21 to VCC.

I now get /H/D/M? up the top of the screen, still no response to keystrokes (Caps lock on and M key pressed results in nothing) although on one cold boot it did boot into the monitor screen but no keyboard function instead of filling the screen with characters waiting for break key

Regards,

Kat.

Hi Kat,

That's great progress and I had a similar issue when I first powered up my reproduction Superboard II PCB.

It turned out the copy of SYN600 which I found on this site, in the ROMS area was incorrect, I have been meaning to point that out since I discovered that.

I downloaded another copy via the links section on this page http://osi.marks-lab.com/software/roms.html which solved the problem.

There were different variations of the monitor ROM and some were to suit hardware using a serial rather than polled keyboard so I'm pretty sure the file I used in the first instance was some other variation of SYNMON and not the correct SYN600 hence the no keyboard response..

Hope that helps, regards John.

P.S great work finding an original Superboard in the first place!

Just got mine running as well and new to forum and new to OSI.
The guys in here helped me out a ton and bxdanny made a SYN6000 ROM image for me that supports the 48 column mod I have on this board. Thread here-> viewtopic.php?f=3&t=861&start=10

I have a lot to learn still. Next thing I plan on tackling is trying out serial i/o and see if I can save / load from cassette interface. Not sure if that is working yet. Also plan on looking at / repairing the original PSU.