Building an OSI 502B CPU Board

Jeff
Posts: 331
Joined: Fri Mar 07, 2014 4:44 am
Location: British Columbia, Canada

Re: Building an OSI 502B CPU Board

Post by Jeff » Thu Apr 04, 2019 6:07 pm

waltermixxx wrote:
Thu Apr 04, 2019 5:35 pm
perhaps I will even out the hole a bit and then3d print a plug or "filling".
That would be really cool.
Image

Jeff
Posts: 331
Joined: Fri Mar 07, 2014 4:44 am
Location: British Columbia, Canada

Re: Building an OSI 502B CPU Board

Post by Jeff » Wed Apr 17, 2019 12:27 am

I have added my 2716 mods and soldered in my 24 pin sockets. I decided to put the jumpers under the sockets, so that things are clean and "more permanent". There were no changes made to the bottom. I still need to add the jumper at W4, but I want to use wire wrap posts, so things can easily be reversed.
IMG_1295.jpeg
IMG_1295.jpeg (997.06 KiB) Viewed 1923 times
/Jeff
Image

waltermixxx
Posts: 118
Joined: Sun Feb 03, 2019 10:31 pm

Re: Building an OSI 502B CPU Board

Post by waltermixxx » Wed Apr 17, 2019 9:06 pm

Looks awesome. I willl be doing a digikey order to continue my board build. Looking forward to seeing your progress.


Cheers.
Turning into quite an OSI Junkie (HTFDTH?) Superboard II REV B-40K, 9600b, HC-05 Bluetooth, Superboard II Rev D, C4P rebuild- 502, 542c, 540B. :)

Jeff
Posts: 331
Joined: Fri Mar 07, 2014 4:44 am
Location: British Columbia, Canada

Re: Building an OSI 502B CPU Board

Post by Jeff » Thu Apr 18, 2019 1:22 am

Completed build (less IC chips)

Top:
IMG_1304.jpeg
IMG_1304.jpeg (1.32 MiB) Viewed 1898 times
Bottom:
IMG_1305.jpeg
IMG_1305.jpeg (1.26 MiB) Viewed 1898 times
/Jeff
Image

waltermixxx
Posts: 118
Joined: Sun Feb 03, 2019 10:31 pm

Re: Building an OSI 502B CPU Board

Post by waltermixxx » Thu Apr 18, 2019 8:07 pm

Damn that looks sharp.
what is the mod you did by the serial interface?

:)
Turning into quite an OSI Junkie (HTFDTH?) Superboard II REV B-40K, 9600b, HC-05 Bluetooth, Superboard II Rev D, C4P rebuild- 502, 542c, 540B. :)

Jeff
Posts: 331
Joined: Fri Mar 07, 2014 4:44 am
Location: British Columbia, Canada

Re: Building an OSI 502B CPU Board

Post by Jeff » Thu Apr 18, 2019 10:22 pm

Thanks!

The mod brings TTL level RxData, TxData, +5V and GND to 4 adjacent pins to connect to a USB or WiFi module.

/Jeff
Image

waltermixxx
Posts: 118
Joined: Sun Feb 03, 2019 10:31 pm

Re: Building an OSI 502B CPU Board

Post by waltermixxx » Sat Apr 20, 2019 1:11 pm

Cool, looks like I will be doing the same on mine.

After Steve an I work on the colour interface for the 600 Rev D (mostly Steve), I will continue to work on my 502B and 540B boards.

Looking forward to more progress reports on yours. :0)
Turning into quite an OSI Junkie (HTFDTH?) Superboard II REV B-40K, 9600b, HC-05 Bluetooth, Superboard II Rev D, C4P rebuild- 502, 542c, 540B. :)

Jeff
Posts: 331
Joined: Fri Mar 07, 2014 4:44 am
Location: British Columbia, Canada

Re: Building an OSI 502B CPU Board

Post by Jeff » Fri Aug 23, 2019 12:11 am

Finally all the IC's arrived and I had some time to tinker. Now I have to test it.
502.jpg
502.jpg (1.18 MiB) Viewed 940 times
/Jeff
Image

Jeff
Posts: 331
Joined: Fri Mar 07, 2014 4:44 am
Location: British Columbia, Canada

Re: Building an OSI 502B CPU Board

Post by Jeff » Mon Aug 26, 2019 1:43 am

If U11 is left unpopulated, the board will need a jumper installed at W1 so it can use the clock signal originating on the 540 video board.
/Jeff
W1 Jumper.png
W1 Jumper.png (112.52 KiB) Viewed 912 times
Image

Jeff
Posts: 331
Joined: Fri Mar 07, 2014 4:44 am
Location: British Columbia, Canada

Re: Building an OSI 502B CPU Board

Post by Jeff » Wed Aug 28, 2019 12:44 am

While working through getting my 502 board to work, I discovered that there is a missing trace at U16, pin 14 on the Reproduction board.

See picture.
Missing Trace on 502 board.jpg
Missing Trace on 502 board.jpg (495.21 KiB) Viewed 886 times
/Jeff
Image

Post Reply