UK101

Introduce yourself and reminisce
DenisM
Posts: 12
Joined: Mon Aug 19, 2013 7:44 pm
Location: Cork, Ireland
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UK101

Post by DenisM »

Hi All,

I'm retired now for a few years.
I've rediscovered in my garage my UK101 built in 1980 and would like to restore it.
It's a bit dusty and fragile. It boots , but will crash when typing. The pcb is a little
loose in the case.

Some of the mem chips are dud....I've got it to boot with 6K :)

D/C/M/W - Oh How i remember the thrill of the first switch on.

When I had it built (in 1980) and working, at about 4 am on morning, I woke my wife to come see
a graphic flying about on screen, responding to left/right/up/down !
She was less than enthusiastic at the time, but has been very understanding :)

I've removed all capacitors - and will replace them.
I''ve cleaned up the board with spirits to get the dust/crud off.
I've replaced two keyswitches ( i've had a set of spares stored since way back )

I did at one time have the RS232 port working to a modem (all of 300 baud)
The excitement of logging on to a bulletin board in London was too much :)

I did also have a mem card giving 40K - It was originally an Elektor 16K project.
And I did get it to operate a DOS system - with two 5" floppy drives.
The drives are long gone.....the controller may still be in a box in my garage.
(You accumulate so much junk in a lifetime )

I experimented with different Monitor ROMs - having multi rom at one time (Cegmon/Wemon).
Sound cards - the Ay-89???
PIA chips to control the world :)

But of course - life took over - and the PC became the centre of the universe for a while.

But now, for fun, after 33 years, i'm restoring it to it's simple profile as a single board system.
(Hope i can remember it all ! )

I had the i/o ports wired directly to the PCB - soldered.
I know that the OSI challenger used molex connector - much tidier.
In my time they were not readily available :(

Is it possible to now get those plug/socket component ?

Who has a source ?

Denis
(Cork , Ireland)
dave
Site Admin
Posts: 710
Joined: Tue Sep 09, 2008 5:24 am

Re: UK101

Post by dave »

Welcome, Denis!

Thanks for sharing your experience with us. I'd love to see your machine fully working again! If you are able, include some pictures.

The Molex connectors are:

12-pin right-angle (horizontal) edge connector (sockets): Molex 09-52-3121
12-pin vertical molex connector (sockets): Molex 09-52-3123
12-pin header (pins): Molex 26-60-2120

They should be easily sourced.

Intermittent lock-ups are the most frustrating kind of bug to hunt down. Possible culprits include a flaky connection of the CPU, ROM, RAM, or addressing chip in the scoket due to oxidation; flaky/cracked PCB trace; marginal timing on a ROM or RAM, among other candidates. Try reseating the chips to see if that makes a difference. Also, see if moving or flexing the PCB induces any failures. If not, it may help to run a memory test program; it will help to get your RS232 port working so you can download test routines, etc.

Keep us posted!

Dave
MK14HAK
Posts: 356
Joined: Wed Mar 16, 2011 1:49 am
Location: New Zealand

Re: UK101

Post by MK14HAK »

Hi Denis,

It looks like a few of us are going down the restoration track of these old boards at the moment. I worked for COMP SHOP in London who distributed the UK101. I fixed many of these boards for customers who had assembled them and pre assembled boards also.
I remember suppliers like Maplin , Watford Electronics , Cricklewood Electronics Farnell etc. I Googled a few suppliers in Ireland and I dont think youll have any trouble finding those molex connectors.
If you get stuck fixing it Im happy to help where I can, to be sure...
Cheers Mike
600RevB:16K,2MHz,64x32,470,CEGMON
SuperKit:502,540B,542B,CEGMON, 8" and 5" FDDs
Cards:PE IO,6522 D-A-D, AY3-8910,ProgramGraphics,Color,UK101
WIP:HexDOS,FDD Emulator
DenisM
Posts: 12
Joined: Mon Aug 19, 2013 7:44 pm
Location: Cork, Ireland
Contact:

Re: UK101

Post by DenisM »

Hi Mike, Dave,

I bought my kit at a computer fair in London in either 1980 or 1979 (most likely 80).
I think it was a CompShop stand :).

So far I've just been cleaning the pcb - removing remnants of previous experiment etc.
I've removed all the decoupling cap - they were for the most part falling off . The legs seem to have
become brittle with age.

The case was plastic - and has suffered a little....

Some way to go :)

Denis
nama
Posts: 357
Joined: Wed Mar 30, 2011 9:44 am
Location: New Zealand
Contact:

Re: UK101

Post by nama »

Would love to see pictures as your restoration progresses.

Phil

2P (1mhz 32k) - 502 + 8k + CEGMON + garbage collector fix BASIC, D&N MEM-CM9 + 24k, 540 (mono) [SOLD]
4PMF (2mhz 24k) - 505, 540, 527, D13 + 5.25" + Gotek
Superboard RevD - CEGMON + 610 board 24k + D13
Spares - 3 x 527, 1 x 505, Backplane
DenisM
Posts: 12
Joined: Mon Aug 19, 2013 7:44 pm
Location: Cork, Ireland
Contact:

Re: UK101

Post by DenisM »

Hi All,

I've ordered the Molex parts from Mouser UK .

In the meantime , for your amusement , I've put some images on my home page. :(

http://www.iol.ie/~themahony/ - very much a work in progress ......... forgive the raggedness ........

You may even see me bullfighting in my younger days. :)


DenisM
DenisM
Posts: 12
Joined: Mon Aug 19, 2013 7:44 pm
Location: Cork, Ireland
Contact:

Re: UK101

Post by DenisM »

Tonight I powered it up as a test, after all the cleaning out of cobwebs and dead bugs.
Did it work ? Not on your life !
A screen of garbage - not even tuning in correctly. I'm using an old TV which auto-tunes.
Will not lock on to ch36 .....

I checked all the clocks - all ok
Ah! Memories of past problems arise ......
It's' the memory chips , isn't it !

Sure enough, I swap out the first pair of 2114s , for the last pair, discard the first pair, and up it comes.
Rock steady image, but rolling ! Damn ! It could be the telly is at fault.
Most investigation :)
But it does give the D/C/W/M, and responds as expected.

Of course only 6K of Ram working now.

I've got some more mem chips to try...looking good :).

Of course I got the connector strips from Mouser.
I ordered both horizontal and vertical - just in case...

When I fitted the connectors, it seemed like they were a tight fit.
They were never part of the UK101 kit.
Then when I assembled it to test - I remembered why I didn't fit the connector strips
way back 30 or so years ago. The strip interferes with the modulator output. so you cannot
plug in a normal connector to the modulator.
I soldered a flying connector to the modulator just as a temp fix. Works fine, but I must do something more elegant. :)

Tomorrow.................
DenisM
Posts: 12
Joined: Mon Aug 19, 2013 7:44 pm
Location: Cork, Ireland
Contact:

Re: UK101

Post by DenisM »

I've repaired the case and it now provides a stable platform for the pcb again. Failed RAM was stopping boot up - now fixed.

I removed the 12 point connector (J3) again and mounted it under the pcb. That way it allows access to the modulator.
Boots up npw - just a quick test - many ram chips failed - pins corroded and broke off when being removed/cleaned.
6 K working. picture is steady clean - but it rolls - vertical sync problem to be investigated.


D.
dave
Site Admin
Posts: 710
Joined: Tue Sep 09, 2008 5:24 am

Re: UK101

Post by dave »

Awesome. Sounds like fun. I'd love to see pics if you have a chance.

Dave
DenisM
Posts: 12
Joined: Mon Aug 19, 2013 7:44 pm
Location: Cork, Ireland
Contact:

Re: UK101

Post by DenisM »

Hi Dave,

Still struggling with Ram chips. I only had 6K in and it was reliable. I got some new old 2114s from USA (via ebay).
When Itry to get more than 6K installed , it hangs on the mem test.
Sounded like an address decode problem ? Some more tests/experimentation needed.
With 8K installed now it gives 0E-04 Bytes Free ! and will allow me to list a two liner basic program.
But hangs on run.
Must remove Bas chips again and clean legs and reseat.

I tried it with two portable TV - one rolls slowly all the time - but a very readable image, another will not sync an image at all.
A small TV (5") will give me a stable pic but it's a little too large for the screen - can't see the top left character.
I've a feeling I can tweak that into view by edjusting a resistor/cap.

Tried it with a TV capture card in my PC - no way would it capture the image - rolling & tearing.
I guess it just will not display welll on any modern TV.

I did once have it driving a video monitor without any extra circuitry. I know you can use of a single transistor emitter follower in old Sinclair
zx80/zx81. Wonder if it would help ?

The idea may be to give up on TV , get RS232 working and use it as a terminal.....

So I'm not out of the woods yet :)

Regards

DenisM
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