February 3rd, 2017, 06:02 AM
Just submitted the artwork to the PC board house! I'm ordering 25 bare boards. Looks like they'll be around $20 USD each + shipping.
February 6th, 2017, 07:48 AM
Ordered a bunch of 9x12" bubble mailers and "DO NOT BEND" stickers today -- expecting the boards in by the end of next week!
February 14th, 2017, 09:03 AM
Side-by-side with the original from which it was copied:
Boards are decent quality. Not out of this world, but you sort of have to go with cheap suppliers to keep boards this large at a reasonable price. I'll send out preorder emails tonight. Bare boards are $25 USD each + shipping. Shipping in the US is $5 USD, I will ship overseas but I'll need your mailing address to do so. If you didn't preorder and/or you don't get a preorder response email from me in the next hour, please use the contact form to get in touch with me and place your order:
Last edited by glitch; February 14th, 2017 at 09:23 AM.
February 17th, 2017, 06:35 AM
Looks like 8T95s for the parts kit are going to be easy -- one of my suppliers has 1800 of them in stock!
February 22nd, 2017, 10:18 AM
I put together a spreadsheet this morning while the test suite for $day_job is running. How's a $50 parts kit sound? That of course doesn't include a Z80 or IM-6100. It would include:
- All TTL ICs
- 8T26 and 8T95 bus drivers (I probably have enough 8T28s to sub if you use a positive data bus)
- 4x Motorola MC6821 PIAs
- Sockets for 8T26s, PIAs, and CPUs
- 2x NOS Mallory TAS-M tantalums for main power bus decoupling
- Handful of axial MLCC caps for bypass
- Misc. resistors, capacitors, diodes
- 8x NOS Molex KK-156 sockets for MOS and SYS bus connections
That's with US-made machine pin sockets, I can get them from China for significantly less, but it might knock $10 off the kit price. Add $5 if you need a Z80. I haven't gotten to the point of testing my handful of IM-6100s -- have to finish the 560Z build first
February 25th, 2017, 06:34 PM
I spent most of today hacking on the 560Z board. I got the 12-bit porthole going first, took a bit as the manual doesn't tell you that you need IC CC installed if you want to be able to write to the 4K exposed in the porthole. After that, I plugged in a Z80 and tried to get it running the test code in the manual. Turns out I had a dud Z80 With a good one installed the test code ran no-problem, as did a little hand written code to push data to the lamp register on the new memory board. I plugged in an IM-6100 and pretty much determined that at least the first one I tried is dead. I'll recheck the soldering on it later -- it's stuffed into a machine pin socket and soldered in, since half of the legs were rotted off by that corrosive black foam everyone loves so much.
Anyway, the second IM-6100 works! And the 560Z board works! And the 12-bit RAM board works! I made a (low-res, poorly focused) video with our old digital point-n-shoot:
The IM-6100 is running a little loop that increments the accumulator and stores it to the lamp register. Storing of course clears the accumulator, but I have the lamp register mapped over RAM, so I just read the value back out of it. My first foray into PDP-8 code, it's certainly different, but it's still just machine code. Very happy that this seems to be coming fully together! Now if only I could find more IM-6100s...I'll test the remaining 3 tomorrow.
February 26th, 2017, 03:48 PM
Had time to do a full writeup on building the 560Z: