ZX80 3K Ram Pack memory
Re: ZX80 3K Ram Pack memory
The blank PCB is a "Replica"-PCB based on the original one.
Mathias
ZX-Team member and classic computer collector
ZX-Team member and classic computer collector
- 1024MAK
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Re: ZX80 3K Ram Pack memory
If you want to compare the board to a schematic, I have found these two different versions:
This version is by Phill (Prime) on this forum, (link to post).
This version I found in a link from a post by Markus on forum.tlienhard.com (link to forum page) link to zip file.
Neither shows any connection between edge-connector contact 23B and 0V/GND.
Mark
This version is by Phill (Prime) on this forum, (link to post).
This version I found in a link from a post by Markus on forum.tlienhard.com (link to forum page) link to zip file.
Neither shows any connection between edge-connector contact 23B and 0V/GND.
Mark
ZX81 Variations
ZX81 Chip Pin-outs
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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.
Re: ZX80 3K Ram Pack memory
Charlie, you beat me to it by 2 minutes!
TS 1000 bought in 1982 and brought back to life by Sir Ian
Re: ZX80 3K Ram Pack memory
The ZX80 3K memory pack reproduction has just been posted on the SMR site. Thanks to everyone here for your generous help and advice!
TS 1000 bought in 1982 and brought back to life by Sir Ian
Re: ZX80 3K Ram Pack memory
Hi Mike, I had to search a while. Would you be so kind to also list it in the ZX80 section?
And it extends the internal ram by up to 3 k giving a total of 2 to 4 k of RAM.
Kind regards Paul
In theory, there is no difference between theory and practice. But, in practice, there is.
Re: ZX80 3K Ram Pack memory
Will do, Paul, and thanks for the 4K reminder. The SMR listing has been updated.Hi Mike, I had to search a while. Would you be so kind to also list it in the ZX80 section?
And it extends the internal ram by up to 3 k giving a total of 2 to 4 k of RAM.
Thanks,
Mike
TS 1000 bought in 1982 and brought back to life by Sir Ian
- 1024MAK
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- Joined: Mon Sep 26, 2011 10:56 am
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Re: ZX80 3K Ram Pack memory
1024MAK wrote: ↑Tue Apr 17, 2018 12:32 amHmm. I have a TS1000 around he somewhere. I can't remember if it works, I think it has been modified to run at 50Hz. I also have a 3k RAM pack around somewhere. I'm working late turn shifts through to Thursday, then I'm away Friday and Saturday. So it will be a while before I can dig them out. If the TS1000 works, I'll post any findings here.
Well, about time for an update...1024MAK wrote: ↑Tue Apr 17, 2018 12:32 amI was expecting the circuitry in the 3k RAM pack to treat the existing 2k RAM chip in the TS1000 the same as it treats the 1k RAM chip in the ZX80 and ZX81. The end result being a total of 4k bytes of useable RAM (it's the decoding circuit that decides the memory map, not just the RAM chips themselves).
My TS1000 has indeed been modified to work at 50Hz video. The keyboard membrane tails are shot. But never mind, I'm using a Memotech keyboard . Also, as the modulator is a VHF type, I'm using one of PokeMons ZX8 CCB modules to get a nice clear composite video output I also tracked down my 3K byte RAM pack. Now, I should mention that this is a recreation and not an original. However, this reproduction did faithfully include the track connecting the 0V/GND to the edge-connector pin 23B.
With this track intact, the TS1000 does not work properly. Instead I get a rolling pattern of white dotted lines on a black background.
With the offending track cut, the 3K byte RAM pack works fine, as you can see from the photo below:
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.
Re: ZX80 3K Ram Pack memory
Thanks for getting back to me Mark. Unless I just don't know what to look for ( a distinct possibility) there does not appear to be anything going to 23B on the Brenner design I am using. Take a look below and see if that is correct.
TS 1000 bought in 1982 and brought back to life by Sir Ian