"Different" ZX81's
Re: "Different" ZX81's
Thanks Moggy, that's good to know. I hadn't heard about the "back porch" issue until I started reading through these forums again. Not a day goes by on here without learning something new. I also still don't know enough about the different ULAs in circulation to know which ones have the issue and which ones don't (same goes for the bug issue in the ROM - how to find out that info?).
But alas, sadly, I only have an old B&W analog CRT television to use with all my ZXs. So it can only mean that my original Zeddy is just plain broke.
Best,
-mark
But alas, sadly, I only have an old B&W analog CRT television to use with all my ZXs. So it can only mean that my original Zeddy is just plain broke.
Best,
-mark
3 ZX80s (1 UK issue 2, 1 US issue 2 & 1 US issue 1), 5 ZX81s, 1 TS1000, 2 Memotech 16k RAM,
2 ZX81 16k RAM, 2 TS 16k RAM, 1 ZX81 unbuilt kit, 1 TS2040 printer, 2+ ZX8-CCB and counting
2 ZX81 16k RAM, 2 TS 16k RAM, 1 ZX81 unbuilt kit, 1 TS2040 printer, 2+ ZX8-CCB and counting
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- Posts: 2220
- Joined: Sat Nov 26, 2016 2:42 am
Re: "Different" ZX81's
Addictive? Nope! It's only two months later and I have 7! Oh wait...
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
- 1024MAK
- Posts: 5302
- Joined: Mon Sep 26, 2011 10:56 am
- Location: Looking forward to summer in Somerset, UK...
Re: "Different" ZX81's
Need to buy some more to catch up with me
<Although I appear to have more Zeddy PCBs than cases >
Mark
<Although I appear to have more Zeddy PCBs than cases >
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer being good this year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer being good this year.
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- Posts: 2220
- Joined: Sat Nov 26, 2016 2:42 am
Re: "Different" ZX81's
In my defence I have not been doing this long! But fully intend not to go crazy with this...
I have a 1:1 ratio of PCBs to cases and in fact 6 of them are even boxed! Although 2 of the boxes are far from brilliant...
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
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- Posts: 2220
- Joined: Sat Nov 26, 2016 2:42 am
Re: "Different" ZX81's
The last of my recent eBay madness arrived today (finally...) and is a very nice condition issue one, as below:-
Check out the screen output! A bit dark but very well defined and solid as a rock! I wonder if this one would be usable with RF if a later ULA was put in?
Lardo
Check out the screen output! A bit dark but very well defined and solid as a rock! I wonder if this one would be usable with RF if a later ULA was put in?
Lardo
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
Re: "Different" ZX81's
Niiiice.
Another clean example and four different chip manufacturers, so full house!
Judging by the picture Lardo I don't see why the later ULA wouldn't work seeing as the only thing lacking at the moment is brightness.
Now step away from ebay and give the rest of us a chance.
Another clean example and four different chip manufacturers, so full house!
Judging by the picture Lardo I don't see why the later ULA wouldn't work seeing as the only thing lacking at the moment is brightness.
Now step away from ebay and give the rest of us a chance.
Re: "Different" ZX81's
Nice Zeddy that one, Lardo - bet it's a 01 batch on the bottom of the 2C184E so one of the first of these types of ULA. A chap from NZ sent me a pic of a 8127 2C158E ULA, also on a cream PCB, helps define the transistion from 2C158E to 2C183E nicely.
ZX80, ZX81 - 2C158C Bugged Rom iss.1, 2C158C "kludge fix" iss1, 2C184E iss1, 2C210E iss3, US NTSC iss1 "straight traces", US NTSC iss3 TS1000
Re: "Different" ZX81's
Lots of ZX Spectrum ULA's with similar markings, Ferranti had a fab plant over there. Generally considered to be a bit less robust than the UK made ULA's which tended to carry the Ferranti logo. Basically - it's OK
ZX80, ZX81 - 2C158C Bugged Rom iss.1, 2C158C "kludge fix" iss1, 2C184E iss1, 2C210E iss3, US NTSC iss1 "straight traces", US NTSC iss3 TS1000
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- Posts: 2220
- Joined: Sat Nov 26, 2016 2:42 am
Re: "Different" ZX81's
Well I bought another one... I saw the soft spongy feet and thought it looks interesting. It's a kludge fix (I assume) issue one! Nice. It works as far as I have tested it - most keys and it produces a dark output which is just about legible.
The underside has what can best be described as 'frosting'. The board is a bit hazy except near the edge connector and solder points. It looks deliberate rather than age related?
Lardo
The underside has what can best be described as 'frosting'. The board is a bit hazy except near the edge connector and solder points. It looks deliberate rather than age related?
Lardo
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
Re: "Different" ZX81's
Wooo - nice!! The kludge fix ones are really nice to have in a collection. It amazes me that they could fix a software bug in the ROM by plonking hardware on the CPU - amazingly clever (at least from my point of view!)
ZX80, ZX81 - 2C158C Bugged Rom iss.1, 2C158C "kludge fix" iss1, 2C184E iss1, 2C210E iss3, US NTSC iss1 "straight traces", US NTSC iss3 TS1000