A310 with ARM 3-Upgrade is looking for a harddisk

[Wobblestone]

Hi,
this is not a repair thread
But it is maybe a little stupid question:
I've just purchased a great lot of Acorn computers: Two Micros with two disk drives and an A310. This works great and contains 4 MB or RAM, an upgrade to ARM 3 (one of these beautiful ICs with the gold plate on top ), but not a harddisk.

The OS is Risc OS 2.00 from 5.Oct 1988)

I would like to add a harddisk to that great machine, but I have not much knowledge of the early Archimedes, especially with such an early version (is it early?) of RiscOS.

Could somebody recommend me a way to put a harddisk into that computer? I would prefer SCSI since I have some BlueSCSIs here and I'm familiar with SCSI (at least on Macs and Amigas and PCs). Also there is still an unused Castle 32/16 bit SCSI II card in my cupboard which I could use.
I also have a card which could be a ZIDEFS card. It has "Acorn IDE Podule V1d" written on it. I never could manage to make it work on my RiscPCs

Thank you for you advice in advance!

[IanJeffray]

ARM 3 (one of these beautiful ICs with the gold plate on top )

Those ones are pretty rare. Very nice. Usually clocked at 36MHz - faster than even the fastest (33MHz) A5000, as standard.

I would like to add a harddisk to that great machine, but I have not much knowledge of the early Archimedes, especially with such an early version (is it early?) of RiscOS.

Are you SURE you want to keep RISC OS 2 in there? You won't find much working software. You really want RISC OS 3.1 - but in order to put that in an A310 you need a ROM carrier board fitting as well (the sockets on the motherboard appear to be the correct size for RISC OS 3.1 ROMs, but they're not wired up 'correctly' for that).

Could somebody recommend me a way to put a harddisk into that computer? I would prefer SCSI since I have some BlueSCSIs here and I'm familiar with SCSI (at least on Macs and Amigas and PCs). Also there is still an unused Castle 32/16 bit SCSI II card in my cupboard which I could use.

Does the A310 have a backplane fitted? (It wasn't standard, but if yours is 4MB/ARM3 it's already well upgraded so probably has one). You might try sticking that SCSI card in the A310. If it shows up under *podules you'll be ok, but it might be RiscPC-only. There are a frankly ridiculous number of SCSI cards available for RISC OS and not that much use for any of them these days. Again, though, you may find some are RISC OS 3+ only.

I also have a card which could be a ZIDEFS card. It has "Acorn IDE Podule V1d" written on it. I never could manage to make it work on my RiscPCs

As far as I'm aware, ZIDEFS is again only for RISC OS 3 and above. But we can surely help get that working in your RiscPC. Does it show up in *podules ? If so:
*configure ZIDEFSDISCS 1
*configure ZIDEFSDRIVES 1
then reboot, and you should see a drive icon.

[IanS]

ZIDEFS is RISC OS >=3 only.

There is a version of the original ICS software for 16-bit cards that will work with RISC OS 2. viewtopic.php?p=235731#p235731

It should be popssible to reprogram the flash chip to allow it to run on RISC OS 2.

[Wobblestone]

Are you SURE you want to keep RISC OS 2 in there?

No. I rather would have the newest OS which is available. But where do I get these carrier boards from? By the way - they look great in that purple colour
Which OS version would this be? 3.5? I can burn EPROMS, but is it possible to burn these ROMs by myself, even If I had the carrier?

There are a frankly ridiculous number of SCSI cards available for RISC OS and not that much use for any of them these days.

I love SCSI With BlueSCSI there is a perfect way to resurrect many Amigas, Macs - and also these cards.
Or... at least on Amigas and Macs SCSI is a blessing. I might not know enough of how it works on RiscOS.

My A310 came with a backplane with 4 slots. 3 are already populated, but I can remove the MIDI-podule as well as a podule with "Armadillo Systems Ltd. A440a Issue 5" (no clue what this even is). But I'll keep the ROM-podule (although I also have no idea what to do with this yet)

ZIDEFS is RISC OS >=3 only.

My ZIDEFS did not work at all. It hangs at boot. Maybe this explains why. But maybe not - this particular podule did not work on my RiscPC as well.

But the Castle shows up when I type "podules". I now try to attach a BlueSCSI to it with a small 100MB partition.

[IanS]

I also have a card which could be a ZIDEFS card. It has "Acorn IDE Podule V1d" written on it. I never could manage to make it work on my RiscPCs

Sounds like one of mine, but I can't find record of ever selling one to you, where did it come from, do you have a picture you can post?

They should work fine in a Risc PC, I think they appear in *podules in RISC OS 2, but just don't work as a filing system. So it may be broken.

[IanJeffray]

Which OS version would this be? 3.5? I can burn EPROMS, but is it possible to burn these ROMs by myself, even If I had the carrier?

Not 3.5, but, 3.1, as I mentioned Yes, you can create EPROMs yourself. And make yourself a carrier - Mattmos kindly opensourced his design, as per the thread I linked. I may have spare PCBs in hand if you need one.

"Armadillo Systems Ltd. A440 :b :a Issue 5" (no clue what this even is). But I'll keep the ROM-podule (although I also have no idea what to do with this yet)

The Armadillo card is a nice sound sampler card - works with !Armadeus. The ROM podule is nigh useless really.

[Wobblestone]

Sounds like one of mine, but I can't find record of ever selling one to you, where did it come from

I bought it from eBay some years ago as I did not know that you are the creator and selling them. Do you still have some?

I may have spare PCBs in hand if you need one.

I would be very interested to buy one from you.

[Wobblestone]

Now I tried it with the SCSI podule and an attached BlueSCSI with 100MB.
"*podules" reports the podule as expected.
But I cannot access the SCSI drives.
I guess I need some SCSI utilities or drivers.
But the problem is, that the floppy is not working. The green light goes on, but it always reports "Drive empty". I first need to fix this as right now I guess the floppy drive is the only way to get software on that thing.

[IanJeffray]

I guess I need some SCSI utilities or drivers.

Here : https://chrisacorns.computinghistory.or ... chive=orig

[Wobblestone]

In the meantime I found the reason for the "Drive Empty" error: As I noticed that also the fan did not spin, it became quickly obious: The decoupling capacitor between 12V and GND has shorted the 12V rail which was completely flat (close to 0V).
And no 12V, no disk drive.

Finally I don't need to open the PSU; I hate to do that.

But I don't have tantalums with 100µF/>20V on hand. Would it be possible to also use normal electrolytes with 100µF as well? I have plenty of them, also with even higher voltage ratings.

By the way - the mainboard looks as new. I love it

[IanJeffray]

The decoupling capacitor between 12V and GND has shorted the 12V rail which was completely flat (close to 0V).
And no 12V, no disk drive.

Hmm. I didn't think the A310 floppy used 12V - just the fan. You don't need that capacitor - just leave it off.

[TimoHartong]

In the meantime I found the reason for the "Drive Empty" error: As I noticed that also the fan did not spin, it became quickly obious: The decoupling capacitor between 12V and GND has shorted the 12V rail which was completely flat (close to 0V).
And no 12V, no disk drive.

Finally I don't need to open the PSU; I hate to do that.

But I don't have tantalums with 100µF/>20V on hand. Would it be possible to also use normal electrolytes with 100µF as well? I have plenty of them, also with even higher voltage ratings.

By the way - the mainboard looks as new. I love it

Yes those tantalums pop. For the 12 Volts a normal electrolytes with 100µF will do as well. I don't fully agree with Ian Acorn did put it there with a reason. And believe manufacturers will leave out components if they don't really need them.

[TimoHartong]

By the way - the mainboard looks as new. I love it

Could you perhaps a photo ?.

[IanJeffray]

I don't fully agree with Ian Acorn did put it there with a reason. And believe manufacturers will leave out components if they don't really need them.

Oh we put LOTS of components on boards that "aren't really needed". Particularly capacitors and chokes, to pass EMC. My guess is that this tant was just there to limit choppyness of the fan motor getting back to the PSU/etc.

[Wobblestone]

I just replaced the faulty cap with an electrolytic one (with 100V... yeaahhhh... Ok, I did not find other ones in my chaos).
Now the machine works perfectly fine. The disk drive reads, formats and write floppies without issues. Of course just 800kB (Format E).
In order to get the castle software (!setup and more) on this machine, I needed to format some old Amiga floppies there. Then I fired up my RiscPC. This can read MS-DOS floppies with 1.44MB - which I can write also on my modern mac with an USB floppy drive.
So I copied on my mac the ZIP-files on the MS-DOS floppy, inserted this in my RiscPC, unzipped it there and copied the content to the 800kB floppy, which previously was formatted in the A310.

Now I know that my SCSI card cannot be used on the A310 with RiscOS 2. It throws some error message.

And since I want that machine to have a harddisk, I already bought the ROM carrier with 4 original OS 3.11 ROMs from four-d-pi-shop (eBay). Lets see if it works then. I will even try the ZIDEFS again.

I would like to upload photos here. But I first need to find a web space from where I can upload it to here.

[IanS]

I would like to upload photos here. But I first need to find a web space from where I can upload it to here.

Just look a bit further down when posting, attach the files here.

attach.png (9.14 KiB) Viewed 1916 times

[Wobblestone]

Thank you very much!
Let me try it:
The first photo shows the mainboard of my A310. In the lower right corner, you can see the beautiful ARM 3.

The next photos show my ZIDEFS podule.

And the last two photos show something which was also in the machine: It was attached to the internal cable of the floppy disk drive. It unfortunately causes the floppy not to work properly. I could not find anything in the internet, maybe you know what this is.

[IanJeffray]

And the last two photos show something which was also in the machine: It was attached to the internal cable of the floppy disk drive. It unfortunately causes the floppy not to work properly. I could not find anything in the internet, maybe you know what this is.

It's an external floppy drive buffer board - so you can hook up a 5.25" drive, for example. I've several here, removed from machines - if you don't plan on using additional floppy drives, I'd say best to leave it out.
https://chrisacorns.computinghistory.or ... iscIF.html

[Wobblestone]

Hi!
Unfortunately I need to resurrect that old thread...
Finally I got the time and the parts to upgrade the ROM of my A310 to OS 3.11
This includes the carrier boards and the ROMs itself - which I got from CJE Micros.
After soldering the three wires to IC28, everything worked perfectly fine - after switching it on (while holding the DEL-key), it booted into the desktop and I could push F12 and.... it freezed
After that it did no longer work at all.

Then I replaced the carrier with the original ROMs - and the machine again worked perfectly fine, without getting crazy after some seconds.

Afterwards I put again the carrier in: Same situation - the first boot works fine. After some seconds sometimes the screen freaks out (it starts to roll or shows artefacts) and it freezes again. Switching the machine off, waiting 10 seconds, switching it on again has o effect: I first get a red screen, then a blue one and then a black one and the machine is dead again.

The reset-button on the keyboard does not have any effect after it freezes.

I used Deoxit on the sockets of the mainboard and on the sockets on the carrier -> no improvement.
I reseated the ROMs on the carrier and the carrier itself several times. And always with the same result: At the first power cycle it works for a couple of seconds, then I get the red screen, blue screen and black screen of death.

I don't know what to do now. That it boots at all seems to indicate, that the ROMs are fine, the carrier itself should also be fine and I soldered the 3 cables the correct way.

[a1exh]

As well as soldering the 3 wires to IC28 you have to change the LK12 jumpers. On older A310 motherboards like yours the jumpers are not present and you might need to cut a track (LA18). Check the instructions that came with the ROM carrier board.

[Wobblestone]

Thank you for your great advice!

The carrier came without instructions. I found something in the web, which seem to be matching the carrier board. It mentioned LK12, but did not describe what to do with it.

Indeed LK12 is/was not present on my mainboard. I had to cut two traces between LK12 1+2 and 3+4. Then I soldered a jumper block and added jumpers between 1+3 and 2+4 corresponding the schematics of the A310.

The system is now a little more stable, but it's still unusable, since it freezes mostly during boot or a couple of seconds after finishing boot.
But at least it now boots more often then before: Previously it almost never got beyond the black screen.

I also tried to change jumpers LK1 and LK2 on the carrier board. But then I did not even get the first red screen.

[a1exh]

Do you have a MEMC1a chip fitted? I *believe* they are compulsory for ARM3 upgrades? Check the PAL which comes with it?

I'm not an expert in these matters but when you have an ARM3 installed does it increase the speed of the ROM bus?

I think the A310 had 8MHz ROM/RAM bus but I believe newer Archimedes had 12MHz RAM/ROM bus?

If this has been done to your A310 could it be that the ((E)EP)ROM chips fitted are too slow?

This is pure speculation, perhaps this is not possible and A310 with ARM3 has 8MHz ROM still.

[Wobblestone]

Hmmmmmmmmmmmm......
The ROMs, which I have installed right now, seem to be "old" ROMs - neither EPROMS nor EEPROMS. They are all labelled "0296-04x-02" (While "x" is 1 - 4). There is nothing else printed on these ICs.
What I could do is copy the ROMs to some 28SF040 which I have lying around.

I already had a look to some of the signals on the ROMs: They look great. Nice rectangular waveform.

But I doubt that the ROMs are too slow: If the bus speed is increased compared to a stock A310, why does it then work stable with the original 2.00 ROMs?

[a1exh]

They are probably MASK ROMs? (i.e. real ROMs)

Looking on the forum I don't believe that the A310 is a candidate for increasing the ROM/RAM bus speed. It was just an idea.

[Wobblestone]

I don't believe that the A310 is a candidate for increasing the ROM/RAM bus speed. It was just an idea.

That's a pity Since I ran out of ideas, I would need every hint, which could help me fixing that thing.
OS 3.11 is necessary for adding a ZIDEFS-card to the A310. I do not want to just use diskettes for it.

[DutchAcorn]

...OS 3.11 is necessary for adding a ZIDEFS-card to the A310. I do not want to just use diskettes for it.

If all you want to achieve is getting a hard disc working on your A310, and you have a way to burn an eprom, you could downgrade the IDE interface using the ROM I posted here: viewtopic.php?p=206429#p206429. That works under RISCOS2.

BTW, BITD I never upgraded to RISCOS3, I was fine using RISCOS2 with the various module updates for all the software I used (but to be fair, I did not use it after 1996).

[IanS]

As well as soldering the 3 wires to IC28 you have to change the LK12 jumpers. On older A310 motherboards like yours the jumpers are not present and you might need to cut a track (LA18). Check the instructions that came with the ROM carrier board.

LK12 on the motrherboard does nothing once a carrier board is fitted. Because LK12 was not always fitted, or even existed as pcb pads on some versions of the PCB, every carrier board reproduces LK12 on-board (or makes it unneeded), that is why LA18 is one of the wires needed to be added.
A lot of carrier boards obscured LK12, another reason to reproduce it on the carrier.

[a1exh]

Ok. I thought it depended on the carrier board? Which is why I said look at the original instructions.

I *think* the original Acorn ALA32 ROM carrier board had instructions to modify LK12?

http://chrisacorns.computinghistory.org ... ctions.pdf

Thanks for letting us know. I am looking to get a ROM carrier board for my A310. I'll look to get one that has LK12 onboard.

[Wobblestone]

If all you want to achieve is getting a hard disc working on your A310, and you have a way to burn an eprom, you could downgrade the IDE interface using the ROM

I'll try that. But one question: How much software (still) runs with OS 2? Especially games

LK12 on the motherboard does nothing once a carrier board is fitted

I now tried to just remove both jumpers completely from LK12. It made no difference. The system boots sometimes, but hangs sometime later.

I *think* the original Acorn ALA32 ROM carrier board had instructions to modify LK12?

My carrier looks different. It only has three jumper blocks: LK1, LK2 and JP7. All should be set correctly. If I change one of the jumpers, the system does not start at all (which I've mentioned above already).

I've made one observation, but it could be just conincidence: The longer I power off the computer, the longer it runs stable after I switch it on again. As I started it today the first time, it worked stable for several minutes even!
After I switched it off for a minute, it booted, but died after pushing F12 and entering "configu..." or so.

Very strange and way too difficult for me to fix.

[a1exh]

There have been several notes about removing (or replacing) the tantalum capacitors in particular C37. Might be worth a go if it has failed?