I finally build up the courage to start my build, having acquired all of the parts, watched way too many videos, and read / reread all of the available guides.
My build is using:
- Uncle Bernie's parts kit, and his ACI gen2.
- Newton PCB
- Newton keyboard
- P-lab jukebox
- Misc parts from digikey.com, anchor electronics, eBay, etc.
- Super high quality copies of the original manuals (incredible! )
- Eventually some kind of case and or display mounting. TBD
A huge thanks to this forum and all of the enthusiasts here and above who made this possible.
I'm going slow because the build (for me) is a ton of fun. I build as many retro kits as I can get my hands on since I'm an old heathkit fan.
I'll post my progress as I go, just a few components soldered down now. I test everything as I go, which usually improves my success rate.
You have very cool kit, good luck building it!
Good luck with your build!
Keep us posted! :-)
Claudio - P-LAB
I made a couple of stupid mistakes soldering, despite being super careful.
Thankfully I have a vacuum desoldering tool. It made quick work of the repairs without damage to the board. I am no expert, and having good tools feels like cheating!
Next step, check out the power rails and do some cleaning.
Power supply built (at least temporarily), power cable built, and all rails are good!
All built... sort of... I skipped a step or two in hopes I'd get lucky. In fact, a whole lot is working great and I'm super pleased. It boots, runs the ram test in prom, keyboard works (and looks great).
Unfortunately, I get bit errors and the video is all twitchy (no surprise I'm sure). I tried two panel TVs, and one doesn't work at all. Sadly I don't have a crt. So, I probably need to build Uncle Bernie's video fix.
In the meantime I will debug the ram errors, but first I'll do the reliability mods (as I should have in the first place!). P-labs sd card storage has a ram bank replacement capability which I can play with. I also have a retro chip tester. So, lots of things for me to do and try.
Uncle Bernie's reliability mods fully installed. My dram errors didn't go away until I installed the 390 ohm pull-ups on the dram address lines. Unfortunately my video is still not displaying properly on my lcd panel, but I mostly expected that. I have parts on order to implement Uncle Bernie's video fix, so making good progress!
Added Uncle Bernie's video fix and I now have a usable and stable picture. I'm playing with some of the component values to see what gives me the best picture on my two monitors.
Before finishing up the video fix, I thought I should get the clock frequency more on target. Once I replaced c4 (10 nF) with 12 pF, my dot clock is much closer (see my post on the crystal thread).
I then finished installing Uncle Bernie's video fixes, and am very pleased with the results (see the other thread). This was some tricky/challenging soldering for me!
While I was at it, I checked the pulse widths out of the 74123, and they look fine. I was a little mislead by the 480ns pulse as I initially was looking at the negative cycle. Looking at the schematic, it seems the positive pulse is used? Fortunately, it is within 5%. It is odd how the duty cycle is nearly 50%.
Next up is probably an extended burn in / stability test / cleaning.
After running the memory tests for a while, I got impatient and wanted to play. I plugged in P-lab's microSD storage card and started to mess around. I know I need to build my ACI, but I couldn't wait. The storage card made it super easy to load all kinds of programs. Of course I had to run the apple demo ascii art to show it off!