Militarised ZX81

Any discussions related to the creation of new hardware or software for the ZX80 or ZX81
sirmorris
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Re: Militarised ZX81

Post by sirmorris »

Some nice suggestions there - thanks!
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1024MAK
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Re: Militarised ZX81

Post by 1024MAK »

Paul wrote:Wow, the ULA has a date code 8119, so on the bottom side there will the printing 2c158?
Did this Zeddy have any mods? Which version is the ROM? The very early or was is it replaced since then?

If this is beeing used on stage, I would advise to have the ULA conserved and replaced against a AndyRea type to prevent overheating troubles.
12:23 ARRG I just saw this Zeddy comes from the small period where the old ULA was soldered in :evil: before Sinclair was aware there were problems with the ULA :(
I haven't seen this often on issue one boards.
I have a Issue one board with a ULA with a date code of 8111.
See attached pictures...

Alas, the ULA does not produce the 3.25MHz clock for the Z80 so it does not run :( (no output from the ULA pin to the buffer transistor).
And all the chips are soldered (yes ALL of them) :evil: .
I do have another ULA that just has a date code on top, and which works. I will have to go and find it now... :roll:

Mark
Attachments
Early ZX81 #1 (ULA 8111).JPG
Early ZX81 #1 (ULA 8111).JPG (50.77 KiB) Viewed 3770 times
Early ZX81 #2.JPG
Early ZX81 #2.JPG (109.99 KiB) Viewed 3770 times
Early ZX81 #3.JPG
Early ZX81 #3.JPG (127.59 KiB) Viewed 3770 times
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp

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PokeMon
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Re: Militarised ZX81

Post by PokeMon »

sirmorris wrote:This machine is being prepared for the rigours of live performance. When complete it's heading to Poland to hopefully take a place on stage with Yerzmyey and the AY Riders.

Image
I think I missed this thread.
Found something familiar in the modulator case.
Good job, Charlie. :mrgreen:
Spirantho
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Joined: Fri Oct 16, 2009 5:36 pm

Re: Militarised ZX81

Post by Spirantho »

Apologies for resurrecting this moderately old thread...

I'm fitting a ZX-ULA2 at the moment for a customer, and I'm keeping the ULA in part exchange. Bizarrely, the ULA is like the ones talked about earlier - it has 8111 written on top, and 2C158E 04 written underneath.

As far as I know this ULA works perfectly but I've not tested it thoroughly yet.

Do we know what this mystical 2C158E is all about? Are there differences to the 2C184E? This is the first I've seen but of course these date-coded chips with the code on the bottom tend to be soldered down directly to the board. Interestingly, although it doesn't appear to be kit built (the chips would be socketed), some of the pins were not inserted correctly, and were bent either inward or outward. There was no sign of it being desoldered before, and the connection was still good, but the solder pads on the bottom of the dodgy pins were flat because the pins were bent away from the hole.

Anybody any ideas about this ULA?
Ian Gledhill
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Moggy
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Re: Militarised ZX81

Post by Moggy »

Hi Spirantho.

the ULA is discussed on this thread... viewtopic.php?f=7&t=451&p=3706&hilit=2C158E#p3706

The 2C158E's that I have behave no differently than the 2C184E's that followed it so I don't think there would be any difference, at least none that anyone has been able to explain.

Moggy.
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yerzmyey
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Re: Militarised ZX81

Post by yerzmyey »

Spirantho wrote:Apologies for resurrecting this moderately old thread...
Hehe, no problem, actually it's too late anyway, too short before the concert. :)
IN NIHILUM REVERTERIS - a big text-adventure game for ZX81: http://tiny.pl/g2m6m
"MONOCHROME" issue 5 - (Spring 2014) free paper/PDF magazine about ZX81: http://tiny.pl/q2m44
ZX81 COMPETITIONS 2007/2009: http://zx81.republika.pl/
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