Compukit UK101 - upgrading

Talk about non-Acorn classic computers/hardware/software here (including retro consoles)
Post Reply
User avatar
flaxcottage
Posts: 3779
Joined: Thu Dec 13, 2012 8:46 pm
Location: Derbyshire
Contact:

Compukit UK101 - upgrading

Post by flaxcottage » Wed Mar 09, 2016 5:27 pm

I've been toying with the idea of upgrading my UK101 for almost two years now and this week I finally got round to it. :D

The requirement was that all upgrading would not detract from the basic machine and would be entirely reversible. The machine I bought had already been upgraded by the previous owner;
  • a 300/600 baud switchable cassette save mod,
    the 48 chars by 32 lines VDU upgrade
    an up-rated PSU
These upgrades would remain.

Another problem I had was the machine ran very hot. The PSU for the basic UK101 was really at its limit even with just a basic board. My intent was to reduce the current needs of the computer by using modern components.

My first upgrade then was to replace the 8K on-board user RAM with a 32K CMOS static RAM. One of these chips would use only a fraction of the power of the original chips and give a massive increase in memory. The upgrade I made is a plug-in carrier board and needs no other connections.
IMAG0114.jpg
IMAG0116.jpg
The second photo is the screen just after booting and shows proof of concept. The pdf gives a circuit and further photos.

Now I have 32K, saving to tape is excruciatingly slow! :( My next upgrade will be to add a 6522 or similar to interface to a Raspberry Pi running RISCOS pico. The Pi will act as a backing storage device controlled by the UK101 through the 6522-GPIO link.

Watch this space - eventually! :lol:
Attachments
32K upgrade UK101.pdf
(1.54 MiB) Downloaded 101 times
- John

Image

User avatar
richardtoohey
Posts: 3720
Joined: Thu Dec 29, 2011 5:13 am
Location: Tauranga, New Zealand
Contact:

Re: Compukit UK101 - upgrading

Post by richardtoohey » Sun Mar 13, 2016 2:56 am

Never had one of these BITD - before my time - but ... =D> :D

GuitarPhil
Posts: 27
Joined: Sat Jan 16, 2016 7:52 pm
Contact:

Re: Compukit UK101 - upgrading

Post by GuitarPhil » Sun Mar 13, 2016 8:59 pm

Excellent!.

My first computer was a UK101 - and I still have it :lol:

Phil.

User avatar
flaxcottage
Posts: 3779
Joined: Thu Dec 13, 2012 8:46 pm
Location: Derbyshire
Contact:

Re: Compukit UK101 - upgrading

Post by flaxcottage » Sun Mar 13, 2016 9:42 pm

Mine too!

I built it from the bag of bits they called a 'kit' in 1979. Took me all day and it worked first time. I also built all the Practical Electronics interfacing boards.

Sadly it died in 1982, though I did rescue most of the chips. Now it is a nostalgia-fest and great to program in a primitive BASIC.
- John

Image

User avatar
IanB
Posts: 412
Joined: Sun Sep 04, 2011 7:28 pm
Location: South Wales
Contact:

Re: Compukit UK101 - upgrading

Post by IanB » Tue Mar 22, 2016 1:28 am

flaxcottage wrote:I've been toying with the idea of upgrading my UK101
How about trying my "no snow" mod which got published in PC world:
viewtopic.php?f=45&t=6108&p=78582#p78584

It eliminates the on screen noise whenever the video memory is accessed without affecting processing speed.

User avatar
flaxcottage
Posts: 3779
Joined: Thu Dec 13, 2012 8:46 pm
Location: Derbyshire
Contact:

Re: Compukit UK101 - upgrading

Post by flaxcottage » Tue Mar 22, 2016 8:10 am

Yes indeed. I have the article put by for a future mod.

At the moment I am experimenting with connecting a Raspberry Pi as a fileserver for the UK101. Communication is fast enough using a 6522 on the 6502 side and a Ciseco Slice of PI/O on the GPIO ports. I have managed to SAVE and LOAD programs, recognise and report errors and CATalogue the SD card as proof of concept. :D
- John

Image

User avatar
tinplatepete
Posts: 30
Joined: Tue Oct 06, 2015 9:50 pm
Contact:

Re: Compukit UK101 - upgrading

Post by tinplatepete » Fri May 13, 2016 4:33 pm

Hi John
I am very interested in this project, looking forward to see how you get on.
I did Ian’s brilliant “No Snow” screen mod back in the day and It worked well, I will be doing the same mod to my current UK101.
Pete
Pete

User avatar
IanB
Posts: 412
Joined: Sun Sep 04, 2011 7:28 pm
Location: South Wales
Contact:

Re: Compukit UK101 - upgrading

Post by IanB » Sun May 22, 2016 8:29 pm

tinplatepete wrote:Hi John
I am very interested in this project, looking forward to see how you get on.
I did Ian’s brilliant “No Snow” screen mod back in the day and It worked well, I will be doing the same mod to my current UK101.
Pete
WOW!

That's the first ever feedback I've had that the instructions worked!
My UK101 had so many different mods that I was concerned I'd missed an important step out!

It's about 35 years too late to do anything about it if there was a problem but thanks a lot!

I'm surprised that it wasn't designed like that to start with as it used one less chip after the mod! (the blanking monostable).

User avatar
tinplatepete
Posts: 30
Joined: Tue Oct 06, 2015 9:50 pm
Contact:

Re: Compukit UK101 - upgrading

Post by tinplatepete » Mon May 23, 2016 10:51 am

I did this modification to more than one UK101, back in the day I knew a few people with UK101s and they all wanted to get rid of the black lines, so this modification was done on their UK101s to, all of them worked with no problems.

I still have the copy of the PCW magazine it was published in.

Many thanks for coming up with the modification back in the 80s and shearing it with others.

Pete
Pete

User avatar
IanB
Posts: 412
Joined: Sun Sep 04, 2011 7:28 pm
Location: South Wales
Contact:

Re: Compukit UK101 - upgrading

Post by IanB » Mon May 23, 2016 3:10 pm

tinplatepete wrote:I did this modification to more than one UK101, back in the day I knew a few people with UK101s and they all wanted to get rid of the black lines, so this modification was done on their UK101s to, all of them worked with no problems.
Pete
Good to know that it worked for multiple machines.
I got the idea after looking at the circuit diagram for the Microtan 65 which was published in Computing Today earlier that year.
Reviews of the Microtan praised it's no-snow screen access so I compared the screen circuitry of the Microtan with the UK101 and found they were already very similar but that switching of the RAM between CPU and video was synchronised on the Microtan so I decided to try and get the same synchronisation on the UK101. It took a lot of experimentation with different clock signals before I finally hit on the right combination of frequencies and phases to get the necessary synchronisation working.
I don't think the mod would have worked on the original Superboard II without further changes because it's screen was half the horizontal resolution of the UK101's and so it accessed the video RAM at 500Khz. The UK101 video system accessed the video RAM at 1Mhz, the same speed as the CPU, so it was possible to synchronise them so that one accessed when the cpu clock was high and the other when it was low. (The BBC micro uses the same technique)

I wish I'd come up with the mod a year or so earlier as by the time it was published the UK101 was in it's dying days and within six months I had my first BBC micro so the UK101 was consigned to the Attic for ~30 years.
tinplatepete wrote: I still have the copy of the PCW magazine it was published in.
Pete
Unsurprisingly, I still have my copy and I also kept this:
pcw-tjw.jpg
£10 (about £35 today) was quite a lot for me back then as I was still at school but I remember I had a problem cashing the cheque as I was a bit too young to have any need for a bank account.

User avatar
Seldon2k
Posts: 111
Joined: Sun Dec 08, 2013 3:19 am
Location: Redditch, UK
Contact:

Re: Compukit UK101 - upgrading

Post by Seldon2k » Wed Jul 06, 2016 9:43 pm

Hi John,

I remember suggesting something like this about 2.5 years ago!
Actually it was for a proposed hardware clone of the UK101. viewtopic.php?f=45&t=6108&start=60
"Another comment is about the HOT and GREEDY 2114 Static RAM, if the board is entered into a CAD package the RAM used could
be upgraded. I suggest a 6116 for a 2kB Video RAM replacement and a single 6264 for the 8kB main RAM to stay as original as possible.
Or for those who like big programs the extra space could be used to add a 62256 with decoder for a total of 40kB of cool SRAM 8)
"

As there is a lot of space on that Veroboard you could add the 6264 on the high side of the 62256 really maxing out the UK101.
This is the amount of RAM that people with the Audio Computers board ended up with (8kB+32kB=40kB).
It did however clash with the Hi-Res Graphics Board as that started at 8000H, so you could fit a switch to disable the top 8kB if you ever make
or acquire this board. Also the 'PRINT FRE(9)' command in MS Basic gets confused above 32kB.

If you choose 33539 as the memory size on boot PRINT FRE(9) returns 32767, anything above this returns a negative value.
I vaguely recall seeing this addressed somewhere but can't pin it down, it may have been fixed in a Basic upgrade, or it could
have been mentioned as a problem on one of the many other 8 Bit Micro's to have this MS Basic.

Also if you replace the Video Ram sockets with turned pin ones you could make a similar mod to use a 6116 giving you the 2kB required for 32 lines. This would result in a further reduction in the 101's power requirements.

I think we had an exchange on the current drawn by the 101 and how hot everything was quite a while ago, I wonder if you can tell me if
my recollection of over 2A drawn through the Fuse was accurate and I wonder if you have the new readings for the modified 101?

Terry, (Seldon2k)

User avatar
tinplatepete
Posts: 30
Joined: Tue Oct 06, 2015 9:50 pm
Contact:

Re: Compukit UK101 - upgrading

Post by tinplatepete » Mon Apr 30, 2018 4:26 pm

Another common upgrade to a UK101 was to add a Sound board, various types were produced by different manufacturers with different addresses, my first Sound board was made by Chromasonic and poorly addressed at 61680, 61681and conflicted with the ACIA, I then bought one produced by Premier Publications called Sound/VIA with an address that did not conflict with the ACIA also this was fully compatible with Basic X.
I have made a prototype reproduction of the Chromasonic Sound board and have included a picture but what I would like to reproduce would be the one by Premier Publications but have little info on it, if anyone has one of these please can you post some pictures of it.
Attachments
20180430_142145.jpg
Prototype copy of Chromasonic Sound board.
Last edited by tinplatepete on Fri Feb 08, 2019 4:16 pm, edited 1 time in total.
Pete

User avatar
tinplatepete
Posts: 30
Joined: Tue Oct 06, 2015 9:50 pm
Contact:

Re: Compukit UK101 - upgrading

Post by tinplatepete » Thu May 23, 2019 6:12 pm

Well, I wanted to make a Sound Board for my UK101 but with no info about the Sound VIA board by Premier anywhere apart from the old photo I have, so I decided to build one from scratch based on this board.
The board layout is similar to the one by Premier Publications but instead of a soldered on data cable that are not easy to install and had a habit of the cables snapping I decide to use a 40 pin IC socket and use a 40 pin to 40 pin IC header cable to connect the board to J1 on the UK101, also instead of the power and speaker cables being soldered to the board these are now on a 4 pin plug.
The board is fully compatible with Premier`s BASIC X and all the Sound Commands including the RESET command work, both of the VIA`s also have a software reset via a POKE command, I have yet to test the Parallel Printer Commands but there is no reason these shouldn’t work.
Just as on the original Premier Sound VIA Board the I/O ports are on the right hand side of the board including the one for the I/O on the AY-3-8910 Sound Chip.
Attachments
20190523_151620.jpg
Compukit UK101 Sound VIA Board
Pete

User avatar
IanB
Posts: 412
Joined: Sun Sep 04, 2011 7:28 pm
Location: South Wales
Contact:

Re: Compukit UK101 - upgrading

Post by IanB » Thu May 23, 2019 8:04 pm

tinplatepete wrote:
Thu May 23, 2019 6:12 pm
Well, I wanted to make a Sound Board for my UK101 but with no info about the Sound VIA board by Premier anywhere apart from the old photo I have, so I decided to build one from scratch based on this board.
Very nice, I recall there was also a colour card available for the UK101, anyone have any details on that?

I managed to connect my UK101 to one of hoglet's beeb to HDMI interfaces with excellent results so a colour UK101 would look amazing:

uk101-video.jpg
See here for further details:
viewtopic.php?f=3&t=14430&start=420#p220071

I put a beeb style RGB connector on the back of my UK101 with TTL level sync and TTL mono video fed to the RGB pins so I can plug the converter into either computer and I just have to change the profile.

However I think I'm going to have to do major surgery to it sometime as it is very unstable. If left for more than a few days or even just hours the chips need reseating or the board flexing to get it operational.

This isn't surprising looking at the state of it :lol:

uk101-top.jpg
uk101-bottom.jpg

I don't even remember what some of those mods are for #-o

I suppose the ultimate restoration would be to strip it back to the bare PCB like some on here have done and rebuild it back to original spec, using plugin pcbs to replicate the mods but that would lose the charm of the original hackery.

User avatar
flaxcottage
Posts: 3779
Joined: Thu Dec 13, 2012 8:46 pm
Location: Derbyshire
Contact:

Re: Compukit UK101 - upgrading

Post by flaxcottage » Thu May 23, 2019 8:37 pm

Blimey! That is a lot of modifications. You must have had fun building that lot. :lol:
- John

Image

User avatar
flaxcottage
Posts: 3779
Joined: Thu Dec 13, 2012 8:46 pm
Location: Derbyshire
Contact:

Re: Compukit UK101 - upgrading

Post by flaxcottage » Thu May 23, 2019 8:38 pm

That sound/via board looks a beauty. Congrats. =D>
- John

Image

User avatar
IanB
Posts: 412
Joined: Sun Sep 04, 2011 7:28 pm
Location: South Wales
Contact:

Re: Compukit UK101 - upgrading

Post by IanB » Fri May 24, 2019 4:44 pm

flaxcottage wrote:
Thu May 23, 2019 8:37 pm
You must have had fun building that lot. :lol:
I did indeed.

The mods I can remember were:
Noise free display
switchable 16 and 32 line display (Which also switched to 16 and 32 line versions of the 2K monitor ROM)
switchable WEMON monitor ROM
switchable BASIC ROMs
EXMON in EPROM
6821 PIA board (veroboard on the right) which I used to control a home made EPROM programmer and it also controlled a "VOXBOX" speech synthesizer
Creed 7B teleprinter interface (vertical veroboard on the left) with built in EPROM based driver so I could print listings

Unfortunately the teleprinter was junked back in the late 80s and I wish I'd kept it as it was fascinating to watch.
It only cost about £35 from a surplus dealer back in 1980 but it looks like it would be a lot more expensive to replace these days :(
It was this exact model:
https://www.ebay.co.uk/itm/WW2-Creed-7B ... 2629161776

User avatar
tinplatepete
Posts: 30
Joined: Tue Oct 06, 2015 9:50 pm
Contact:

Re: Compukit UK101 - upgrading

Post by tinplatepete » Sun Dec 01, 2019 10:59 am

Hi All.
I know this is a long shot but has anyone got one of these Floppy Drive cards for a UK101 made by Premier Microsystems back in the 80s, this is the only picture I can find on the net of this card? The hope is to get some high res pictures to recreate one. Also, any info instructions etc would be useful.
Pete
Attachments
Premier FDD card 2.jpg
Pete

Post Reply