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Retrochallenge 2011 Summer Challenge

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We are a couple of weeks from the Summer Challenge!

About Retrochallenge


In a nutshell, the RetroChallenge is a loosely disorganised gathering of RetroComputing enthusiasts who collectively do stuff with old computers for a month.


The event is very much open to interpretation... individuals set there own challenges, which can range from programming to multimedia work; hardware restoration to exploring legacy networking... or just plain dicking around. It really doesn't matter what you do, just so long as you do it.


While the RetroChallenge has its competitive side, it's not really a contest... it's more like global thermonuclear war -- everyone can play, but nobody really wins.


Come on... give it a go!

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Dude! Which PET?


I actually picked up three of them for free about a month ago... and ironically managed to give away the most easily fixed one, which was a chiclet-keyboard 2001-8. (But oddly, it has a PET Dynamic motherboard in it. I don't know if that's stock/correct for a really late 2001 or if it was repaired with a later board.) I still have a 9-inch screen 4032 and a CBM 8032, and both need a lot of TLC. I've been concentrating on the 4032 mostly because its monitor works. (TTL scares me less than CRT problems.)


The poor 4032's a wreck. So far I've fixed two broken traces which were preventing both system RAM and VRAM from being written to. (There's still some screen corruption that I hope is just a bad 2114.) At this point it will crash to a ML monitor screen with no keyboard activity, which is a vast improvement from where it was, but I'm worried there's a long way to go. (Best guess at the moment is there's something wrong with the 60hz interrupt.) In the process of working on this I've actually taught myself enough 6502 assembly language to write a primitive diagnostic EPROM that fits in place of the F000 Kernal. It's pretty crude, all it does is flip-flop between doing a really elementary test of the first 1000 bytes of RAM and displaying the full character set on the screen in an endless loop with a two-second-ish delay between cycles, but in my defense it's really hard to do useful work when you're restricting yourself to *only* running from CPU registers. (You get three 8 bit ones, if you can't trust RAM for a stack at all you can't do any subroutine calls, and it's also a *huge* pain to not be able to use the zero page. I guess that's what makes it fun.) It did work to provide enough useful bus activity for the logic analyzer to find some problems, at least.


But... yeah, loads of fun, considering I'm almost a complete newbie in dealing with electronics outside of Radio Shack discovery kits.


I also picked up three PET disk drives. (A 2040 upgraded to a DOS 2.0 4040, an 8050, and an MSD SD 1. Two out of three pass diagnostics, the 2040 claims it has a bad ROM.) I hope someday to actually have a machine to use them on. :^b

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Hmm..what to do this summer for RC?


I didn't get enough takers for the Battle Chess tournament (although if anyone wants to play me via modem sometime I'd be up for it; simply send me a PM and we can arrange for a chess match) so I'm thinking of a Plan B. I'm tutoring with a 150 again this year, but used that as last year's project so I can't re-use it.


I may just do some restoration work on my rinky-dink Classic. I've had it for almost six years now and it needs a little love. The floppy drive only reads 1.4MB disks; it won't recognize any 400K or 800K disk. (And no, it's not some modified USB drive, it's the original Sony). It currently has a donor logic board; the original needs re-capped. The case is the color of dijon mustard. Furthermore, it has a Revision A logic board, which amazingly still works. I'm thinking "Extreme Mac Makeover: Scott's Classic Edition" is going to be my project, but I haven't committed to it just yet. I'll keep thinking of other possibilities over the weekend although I'd like to get that Classic cleaned up soon.

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The good thing about retrochallenge is that it tends to gently encourage you to go from 'I must do x/y' to 'I'm doing x/y'.

I spent years saying 'I must write some VAX/Macro code' to 'I've written some VAX/Macro code' which I'm sure wouldn't have happened had it not been for retrochallenge. Honestly, looking back at that challenge I'm still seriously impressed that I wrote assembly code to produce fractals! http://www.wickensonline.co.uk/rc2009sc/miller-time.html




It's a month of retro-sillyness, and by the end you'll probably want to get back to the real world, but it sure does focus the mind. Peer-pressure is a good thing sometimes!


Get those entries in to me at msw@hecnet.eu !!!


Regards, Mark.

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I actually got my PET to the BASIC prompt this weekend, so I might be done before the challenge starts. ;^)


(Still plenty of repair work to go, though. I'm starting to suspect someone tried practicing their origami skills on the system board.)


I suppose the fact that I've neglected to blog about it sort of hamstrings the repair as an entry anyway.

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a tips for what to do with the PET watch this: http://pouet.net/prod.php?which=56410


Heh. Unfortunately that demo only runs on 12" "CRTC" PETs. ;^) (Mine's a nine-inch, which lacks a programmable video circuit. No hardware special effects are possible beyond flicking between character sets.)


I just got it to recognize all 32k of RAM today. If I can nail a small video corruption issue and get a storage device working I'll be frighteningly close to have fixed the silly thing.

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