My (other) A3000 project.

[Charlie]

Warning, foreign p0rn alert!

Those with long memories may remember my hacking a reasonably high-spec PC into an A3000...
...here's the 'retro way'.

A3000, complete with moody lighting.


1 - 'Bird of prey' monitor stand.
2 - SCSI slot-loader, more later...
3 - My favourite joystick.
4 - A3000, just in case you were still thinking this was an Amiga project
5 - Mouse - duh! No Acorn mouse, computer not usable!


The rear end, fnar-fnar.


1 - Undressed network card.
2 - 9-15 pin VGA adapter, thanks Maplin.
3 - Rude not to have a HDD in a retro box.
4 - Joystick plugged in to the serial port..?
5 - Island Princess.


Top off, more fnar-fnar.


1 - PSU, all 22 burning watts of it!
2 - IDE interface with CF adapter plugged into it. Thanks Zetr0.
3 - Floppy drive, duh!
4 - 4mb RAM expansion.
5 - SCSI card.


IDE interface close-up.


Notice the butchered 40-pin port? Well, my mother-in-law is still teaching me to solder...

Remember that serial port masquerading as a joystick interface?
Easy! Pull the serial chips from the mobo, replace with a joystick interface bodge & Bob's
your significant other. It's under the IDE card - pictures on request.


Toy SCSI interface.


Who remember's Flopticals..? Plugged in to the Econet port(s).

Sadly no power left to drive that SCSI slot-loader. I'm going to have to upgrade the PSU
if I'm going to plug anything else into this computer...
...an internal mod to keep things looking nice, I think - ideas..?


Battery 'n Chips.


The new battery (and holder) was my first bit of soldering. Acorn soldered the old button to the
mobo, so the battery clip is hand-crafted by yours-truly.

A3000's came with OS2.0 roms. OS3.1 makes a nice upgrade, especially when you have an ARM3...


ARM3 & FPA10 Upgrade board.


A little explanation required:
The A3000 came with a 8mhz ARM2 surface-mounted to the mobo. Very roughly four times
as fast as an unexpanded Amiga A1200. A common upgrade for big-box ARM2 machines was to
fit an ARM3 card into the processor socket as a 25mhz one is about 5 times faster than the
8mhz ARM2...
...The tricky bit is the A3000s ARM2 will need replacing with a socket. Not a trivial operation
so done much less commonly. Also as the board has to fit under the keyboard and most
versions were too tall to fit - mine does!
Then, there's the matter of the FPA10 FPU - these are like rocking-horse poo & upgrade cards
that can take one are very uncommon anyway. FPA10s were very bad overclockers so were
never rated past 25mhz which was the bottom end for the ARM3...
Notice the 66.66mhz crystal? Yes, I've overclocked my ARM3 to 33mhz and so the FPA10 too:
Totally stable! I've not seen another FPA10 that can do this!

Sorry, showing-off now.


W.E. VIDC enhancer.


A VIDC enhancer? More explanation needed...
To a lesser extent older Acorns have the same problem interfacing with modern monitors
that classic Amigas have. But the full ARM chipset is rather less closely bound together
than, say the AGA chipset.
The advantage here is that if you want to attach an Amiga to a modern monitor you'll
most-likely have to invest in a scan-doubler / flicker-fixer of some description...
...Not so for the Acorn. All the parts of the chipset can be clocked independently so if
a chip doesn't go fast enough 'all' you need to do is plumb a faster crystal in to that chip!
Now the graphics chip (VIDC) in these Acorns was clocked @ 24mhz but will overclock to
50mhz+ More than enough to produce 1024x768x256, flicker-free!
(all parts of the mobo ran at multiples of 8mhz, hence the 24mhz VIDC)

The little board in the photo is a bunch of extra crystals under software control for
this very purpose! It plugs into the mobo's genlock header with a 'few' flying leads to
various other spots - needless to say I've long since dispenced with those unreliable
probe-clip thingamies & soldered the wires in.


To do?
-Need to upgrade the PSU before it will be worth putting that slot-loader in.
-Looking for an A3000 8mb RAM + MEMc upgrade. PLEASE, Please, please...
-A high-density floppy upgrade would be nice as it would save me the pain of hacking it
myself.
-Some yet-faster crystals!

-Maybe someday look into butchering an ARM 600/710 in to my A3000.

[Zetr0]

WOW..

my friend, I am completely lost for words.... any word i try and use fails to describe how Awesome this computer really is, even Awesome is unworthy!!!!

a great level of precision and detail has gone into this build and I am both impressed and humbled by it my friend.

Well done

[alexh]

Interesting stuff... my Archie had green keys so I think it was an A3020?

[Paul_s]

Next week Charlie expands a ZX80 with SSD drive and implants a Quad-Xeon processor

[cosmicfrog]

as usual charlie thats NICE very very NICE love the post keep it up dude

[Charlie]

Thanks for the kind words chaps

@Zetr0: Praise indeed! Notice the CF adapter? It's the one you gave me.

@Alexh: Close - green keys most likely = an A3010 - probably the most appropriate machine for retro-gaming under RiscOS...
...The A3020 is a little easier to upgrade but no joystick port(s).
...The A3000 (above) starts as the lowest-spec version but has the most potential - typical Acorn, that.

@Paul_s: Hmmm, tempting...
...but Memotech pretty much beat me to that years ago. Well, almost. The amount of stuff they made to plug into the ZX81 is amazing - or crazy.

@cosmicfrog:
Thank you!


An example of every cloud has a silver lining:
I bought two crystals from Amigakit - A 66.667mhz & a 60mhz. The faster one intended for my Blizzard '060, the slower for the ARM3 board...
...even then I half expected the FPA10 to baulk @ 30mhz.

So the slower crystal into my Acorn - pleasant surprise: The FPA10 will do 30mhz - these REALLY weren't overclockable chips.
Faster crystal into Blizzard - bzzzt! No chance!

Hmmm, 60mhz crystal into Blizzard - all good if a bit disappointing.
But what now? Do I have to go back to running the ARM3 + FPA10 @ the rated frequency..?
Being the butcher I am, into the Acron with the 66.667mhz crystal knowing a lot of 25mhz ARM3's wont go to 33mhz & having never heard of any FPA10 going that fast...
...RESULT! It works!!!
Quick check: No, the chips aren't even slightly warm... torture both chips for a bit to make sure...
...still rock-steady & so cool to the touch - adding heatsinks seemed like a wast of time.

Now what about my poorly overclocking '060? Well, with a good heatsink it's pretty warm @ 60mhz (not hot). It is an 'early' 060 so do I go buy an E41J..?
No... Swapping '060s is way beyond my soldering skills & as I want to keep my SCSI working can't justify sending it off to those nice people in France...

[Zetr0]

Originally Posted by Charlie

....
@Zetr0: Praise indeed! Notice the CF adapter? It's the one you gave me.....

Indeed praise where its most certainly deserved, its obvious to any retr0-computer enthusiast the sheer diligence that has gone into this build, and that's just in scoring the components!

Hell that effort alone has my admiration!

Aha! glad that CF adapter got there in the end, sorry for the delay on that took me an age to post that off... btw did that 512MB 2.5" hdd work for you or did the postal service finally see to its demise?

anyway my friend, its a great build and one I hope your proud of as it really is good stuff to say the very least!!

[TheCorfiot]

Hey Charlie

Well done my friend, Well Modded. Wish I still had my A3000 they are so accessible & easier to tinker with than the A3010.

TC

[Charlie]

Yes, the HDD survived the trip - thank you...
...the 40pin IDE port you sent me sadly had a rather different fate: By the time I finished f*cking it up in an effort to solder it to the above IDE card it was junk - I'm very lucky the IDE card still works...
...mind you that's where a mother-in-law comes in handy - I'll soon be soldering like a pro', maybe.

[Charlie]

Thanks TC.

Yes, the A3000 is the one to get if you're modding - I've been very lucky sourcing some very rare parts & finding a chap from IFEL who did the mobo for me, so allowing the ARM3 to attach...
...more to come, if I can find the parts:

I NEED an A3000 8mb upgrade!
I want an A3000 HD floppy upgrade, though I could hack that - I guess.
I'd love an HCCS A3000 'ultimate upgrade' card. The great thing about these (apart from the added expansion options) is they come with their own PSU which would help my 'power issues'.

[alexh]

I think my A3010(?) had an ARM3 in it. Definitely had a HD floppy drive.

[Charlie]

Oooo, more rocking-horse poo! Drool!

As you probably know (but for the sake of general babbling) the A3010, A3020, A4000 came with the ARM250 - a whole chipset in one chip jobbie...
...the great thing about the ARM250 is the bus speed as well as the ARM2 core was 12mhz rather than the A3000s 8mhz...
...a faster system all round - bus bottlenecks less apparent than the A3000.

The bad thing is you couldn't upgrade it - no ARM'350' was ever made...
...but because of manufacturing problems early A3010s & A3020s had a 'mezzanine' board containing the full ARM2 chipset as separate chips plugged-into the ARM250 socket...
...which meant you 'could' remove the ARM2 from the 'mezzanine' board & replace with an ARM3!!!

Such a A3010 / A3020 would be considered the 'ultimate' wedge-shaped Acorn...
...I'm now most jealous of you!

Hmmm, it will likely remain technically beyond me forever but adding an ARM600 / 710 to a 'classic' Acorn should be doable & would be another 'great leap' in speed for such a machine...
...I think OS3.1 would just about cope with few updated modules soft-loaded on boot-up...
...a StrongARM's not going to be doable.

[alexh]

While I dont own it anymore (like I said I gave all my Acorn stuff away in 1999, Atom, Electron, Beeb, Archie & RISCPC) I have found some photo's of it and it did have an ARM3 in it

You can see two boards double deckered in the middle.

As I remember, RISCOS 3.50(?) dropped support for the older VIDC hardware so even if you could fit a faster CPU you'd be stuck with RISCOS 3.11

I also remember it came with these funky stickers on it (which almost certainly got removed).

I could have sworn my A30x0 had an internal IDE port for a 2.5" drive but looking back at the photos it didnt (or it wasnt in use).

[Charlie]

Ahhh, the recipient's a lucky chap!

Yes, no 3.5 for older VIDC hardware as you say. My hope (likely never to be tested) is that the ARM600 / 710 instruction set is sufficiently like the ARM3 that 3.1 will run...
...possibly with the aid of a few 3.5 modules soft-loaded.
StrongARM won't work on less than 3.7 so that's a non-starter even for 'dreaming'.

[alexh]

I found a source of 4Meg A3020's for £8 each plus postage... might have to get one

[Charlie]

[AlfaRomeo]

Great work here Charlie, congratulations.

[alexh]

The first two images seem broken...

[Charlie]

Bloody ImageShag...
...is it working now?

Thanks AlfaRomeo

[alexh]

You're welcome Coke

Unfortunately they are still broken. Perhaps they are too big for ImageShack?

[Charlie]

Hmmm, on a computer @ work & the images are fine.

Could this be your browser?
or
Is this a subtle 'There are such things as thumbnails, you know' hint?

[tonyyeb]

Pictures have worked fine everytime I've checked this thread.

[alexh]

Clear your browser cache and then try

[tonyyeb]

Originally Posted by alexh

Clear your browser cache and then try

My browser clears its cache after every close and it still works. Looked at the thread in IE and Chrome for the first time and the pictures still show.

[Charlie]

I've tried several browsers on several computers (some which have never browsed the EAB), tried clearing caches too & have had no problems...
...well the odd reload was occ needed - ImageShack can be a bit 'dodgy'.

Here's the funny thing:
I don't think alexh has ever been mistaken about anything, um, ever! (d*mn him!) I'm confused now.

[alexh]

They still do not load here.. I guess it must be my ISP using a transparent proxie cache or sommat?

I tried IE7, Chrome and Firefox all with same results.

The last five images work fine, it's just the first two images:

The one below "A3000, complete with moody lighting."

http://img391.imageshack.us/img391/9261/dsc03538fs3.jpg

and the one below "The rear end, fnar-fnar."

http://img391.imageshack.us/img391/1529/dsc03539qq9.jpg

Neither ever load for me from Imageshack, even in a new browser window, I just get "Error 320 (net::ERR_INVALID_RESPONSE): Unknown error."

Stoopid fekkin VirginMedia ISP!

[Jope]

Heh, did Watford Electronics do anything else than addons to Acorn computers? :-)

What happened to Watford after Acorn dropped out of the computer business and focused on the ARM?

[tonyyeb]

Originally Posted by alexh

Stoopid fekkin VirginMedia ISP!

Change your ISP then try

[Zetr0]

@Jope

I believe a few years ago, Watford got bought up by SavaStore and can still be accessed online... prices are a little erratic for an online store though.

[alexh]

Originally Posted by tonyyeb

Change your ISP then try

They must have been listening because today they all work

[mfletcher]

Sorry to necro this thread everyone.

Finally got around to fetching my A3000 / A3020 out of the closet to see if they work. I have a toshiba PAL LCD TV that I brought over from the uk a while back.

A3000 - connected to LCD TV via scart. Boots but grey screen. If I connect it via monochrome out I get a bad picture, but looks like the system is up. Dont know how to reset it to work with LCD TV

A3020 - connected to LCD TV via PC monitor cable. Boots and gets to desktop. I can use it just fine! I have to reset the cmos though if I leave it off for a day or so - how do I replace the battery? (Couldnt find one). Also had a CF card attached to it with some progs - try starting Elite, but the LCD TV cant display output. Anyway how to resolve this?

Thanks,

Mark

[prowler]

Originally Posted by mfletcher

Sorry to necro this thread everyone.

Finally got around to fetching my A3000 / A3020 out of the closet to see if they work. I have a toshiba PAL LCD TV that I brought over from the uk a while back.

A3000 - connected to LCD TV via scart. Boots but grey screen. If I connect it via monochrome out I get a bad picture, but looks like the system is up. Dont know how to reset it to work with LCD TV

Thanks,

Mark

Hi Mark,

I may have a little insight into this problem:

I have my A3000 running fine with an AKF12 as monitor.

However, a while ago I tried to solve the problem of why I hadn't been able to get it working with either a CRT or LCD TV as monitor.

The RGB to SCART video lead I have for it works fine with the Acorn monitor, but just gives a grey screen on the TVs. The AKF12 is an RGB monitor with SCART input, but the lead has no connections to the 'AV Mode' (Function Switching) or 'Blanking' SCART pins 8 and 16, respectively.

I have an Amiga RGB to SCART lead that works with my Amigas on the AKF12 monitor as well as the CRT and LCD TVs. The 'AV Mode' and 'Blanking' pins are connected via signal diodes to +12V D.C. at the Amiga end, so I made an adapter to connect the A3000 to the TVs through the Amiga RGB to SCART lead, connecting the 'AV Mode' and 'Blanking' via the same diodes to the only voltage source available from the A3000's video socket ('Pulled High' - measured 4.5V D.C. on my multimeter), but this still didn't fix the problem!

With this setup, I got a very faint display, possibly in inverse video and not synchronised properly. "Better than nothing", I thought, and it least it showed that the signals were there, but I wasn't sure that 4.5V was sufficient to switch the TV to RGB mode properly.

If I booted the A3000 with the Delete key held down and then selected F12 to get the command prompt up, entered STATUS and then pressed the Shift key to finish listing the options, I could see them displayed with very little contrast in white on a very dark purple background (hence 'inverse video'), so it was there, but not quite!

It's difficult to see how the Archimedes can supply more than 4.5V D.C. at the video socket when the PSU generates only 5V D.C. (it has no +12V D.C. rail, unlike the Amiga), and yet it's supposed to work with 50Hz PAL TVs! I just can't see how that's possible.

I did some experiments, using dry cell batteries to boost the voltage to +12V at the 'AV Mode' and 'Blanking' pins of the SCART plug to see if that would cure the problem.

I was right about the voltage on the switching function pins of the SCART plug. At zero volts the TV is locked in 4:3 AV mode (no display from the A3000), at 5.97V D.C or above the set switches to 16:9 AV mode (still no display), then at 10.22V D.C or above the set switches to 4:3 RGB mode and the display finally comes up! (Due to hysteresis, the 16:9 AV mode resumes only when the voltage drops to 9.08V D.C and 4:3 AV mode is restored at 4.18V D.C.) I wasn't sure if it's possible to increase the voltage beyond +12V D.C. to see if a 16:9 RGB mode comes up, so I didn't try it.

That just leaves the problem of how to get it to work permanently.

[mfletcher]

Hey Prowler -

I gave it another go tonight - tried the usual steps of holding R or T at startup to reset the CMOS, or * to drop into supervisor mode. No luck.

However, I did note that for the LCD TV I was using, I was having a similar problem with a ZX Spectrum +3 that I brought back from the UK - except it was a flashing screen.

Turns out it was the LCD TV that was the root cause. Going into TV settings, it wasn't enough to just select SCART as the input. Theres another menu where you can tell the SCART to use RGB, composite, Auto detect etc etc. Flicked through all the modes to RGB and voila! I had a perfectly good picture.

So now I have a working ZX Spectrum +3 and A3000 in the US!

Next step is to open up the A3000 and see what goodies are in it. So far I see 2MB ram, RISC OS 3 rome on boot. At the back I have a SCSI podule and what looks likes an interface for a second floppy drive.... will post pics soon.