Redgate gets a Zeddy
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- Posts: 170
- Joined: Tue Sep 05, 2023 11:56 am
Redgate gets a Zeddy
I appear to have agreed to buy a ZX81, untested, but looks OK. 1A PCB. I'll make an adaptor lead for my Speccy PSU and give it a test when I get hold of it.
Let the fun begin, how soon before 3D Monster Maze is loaded I wonder
Let the fun begin, how soon before 3D Monster Maze is loaded I wonder
Re: Redgate gets a Zeddy
You'll need a 16k RAM pack for that.
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Re: Redgate gets a Zeddy
Plan is to do an internal 16K conversion
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- Posts: 170
- Joined: Tue Sep 05, 2023 11:56 am
Re: Redgate gets a Zeddy
Yep, that's the one
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- Joined: Sat Nov 26, 2016 2:42 am
Re: Redgate gets a Zeddy
A socket and a RAM chip, about £5:
http://blog.tynemouthsoftware.co.uk/201 ... n.html?m=1
Edit - see this post though!
https://www.sinclairzxworld.com/viewtop ... 353#p51353
http://blog.tynemouthsoftware.co.uk/201 ... n.html?m=1
Edit - see this post though!
https://www.sinclairzxworld.com/viewtop ... 353#p51353
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: 5120
- Joined: Mon Sep 26, 2011 10:56 am
- Location: Looking forward to summer in Somerset, UK...
Re: Redgate gets a Zeddy
Nah, all those are easy peasy lemon squeezy solutions. If you are a real Sinclair fan, you want the hardcore modification such as this one
Mark
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer 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 later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer 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 later in the year.
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- Posts: 170
- Joined: Tue Sep 05, 2023 11:56 am
Re: Redgate gets a Zeddy
Well it’s in hand, a bit tatty and has extra holes in the bottom case as it’s been screwed to a wall in the past
It came with an issue 4 Speccy that had the same treatment. Got the pair for 40 quid.
Ordered a 3.5mm jack and 2.1mm socket to make a power supply adaptor. Let’s see if it powers up next week sometime.
It came with an issue 4 Speccy that had the same treatment. Got the pair for 40 quid.
Ordered a 3.5mm jack and 2.1mm socket to make a power supply adaptor. Let’s see if it powers up next week sometime.
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- Posts: 170
- Joined: Tue Sep 05, 2023 11:56 am
Re: Redgate gets a Zeddy
So, let’s see where we are with the ZX81.
power lead adaptor made, tested positive tip, 11.87v
Connected to two different modern tvs there is what looks like an inverted screen, black background not white, but there is a visible white K cursor and some of the keys respond.
Opening it up there’s no noticeable damage, unlike the Speccy that came with it that has holes drilled in the pcb! Clearly the pcb tails are goosed, but the top face of the keyboard is dented, scratched etc so would be getting a new one anyway.
Here’s a couple of pics including some mods underneath? Are these factory?
So, the odd display, is that a function of using a modern tv, or is there something more sinister going on?
power lead adaptor made, tested positive tip, 11.87v
Connected to two different modern tvs there is what looks like an inverted screen, black background not white, but there is a visible white K cursor and some of the keys respond.
Opening it up there’s no noticeable damage, unlike the Speccy that came with it that has holes drilled in the pcb! Clearly the pcb tails are goosed, but the top face of the keyboard is dented, scratched etc so would be getting a new one anyway.
Here’s a couple of pics including some mods underneath? Are these factory?
So, the odd display, is that a function of using a modern tv, or is there something more sinister going on?
- 1024MAK
- Posts: 5120
- Joined: Mon Sep 26, 2011 10:56 am
- Location: Looking forward to summer in Somerset, UK...
Re: Redgate gets a Zeddy
The components on the underside near the jack sockets are normally fitted on the component side. And yes, that’s work that was done in the factory.
I have no idea why you have an inverted display. Using a modern TV should not make any difference. The video signal is generated in the ULA.
Normally you either need some extra circuitry to invert the screen (or use a ULA replacement module or a modified ZX80 or a clone that has this feature).
Mark
I have no idea why you have an inverted display. Using a modern TV should not make any difference. The video signal is generated in the ULA.
Normally you either need some extra circuitry to invert the screen (or use a ULA replacement module or a modified ZX80 or a clone that has this feature).
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer 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 later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer 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 later in the year.