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! :-)
Best,
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!
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Next step, check out the power rails and do some cleaning.
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Power supply built (at least temporarily), power cable built, and all rails are good!
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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.
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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!
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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.
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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!
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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%.
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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!
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