A310 with ARM 3-Upgrade is looking for a harddisk

[DutchAcorn]

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

Not sure tbh, I’m not aware of games that require RO3 to run but I guess some of the newer games can have issues.

In terms of games compatibity you may want to look for a utility that disables the cache on the ARM3 processor. Many games are written to run on ARM2 and run too fast on an ARM3.

[Wobblestone]

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

Especially this one has already been replaced. Indeed it was dead, but that kept the whole machine from working since the PSU just shut off. Maybe that was one reason why I got that machine for a reasonable price

In terms of games compatibity you may want to look for a utility that disables the cache on the ARM3 processor. Many games are written to run on ARM2 and run too fast on an ARM3.

Well... I think I should just give it a try

[Wobblestone]

I again checked the documentation of the carrier board. It mentions that it is also possible to put the original ROMs (0296-04x-02) on it. After changing some jumper settings on the board that worked fine. At least I can now remove the rom carrier itself from the list of suspects.
Then I tried to replace the ROMs by EPROMs or EEPROMs. Of course I have no clue what type of EPROM/EEPROM I needed to use on my TL866-II to read the original ROMs.
In this thread
viewtopic.php?t=23326&sid=f83758712f902 ... c99091a7c2
I found a picture with 27C4001 and another one with 28SF040. With that I tried to read the ROMs and burn them into 28SF040. But that did not work at all - the system did not boot.

The question is now: How can I read the original ROMs and how can I copy them to EPROMs/EEPROMs? Which type of ICs do I need?

[IanS]

27C4001 shouldwork as is.
28SF040 (or 39SF040) will need some creative use of links and wires as A18 is in a different place. For some carrier boards this can be hard as there isn't a jumper for pin 1. Which carrier do you have, got any pictures?

You c\n grab RISC OS 3.11 from here - https://4corn.co.uk/archimedes.php

Whilst that zip has 4 "ROM" files in it, they can't be directly written to replacement chips.

Each "ROM" file is a coloured area, but you need to write the data from the columns 0-3 into the 4 chips. Concatenate the files into one big file, then load the data from evey fourth byte with offsets 0-3 into each cip (most programmer software has facilities to do this). e.g.

rom-read.PNG (13.88 KiB) Viewed 501 times

When the machine does boot into RO3, does it flash any error codes. The POST does a rom checksum, so if your chips were bad you'd probably know.

[Wobblestone]

27C4001 shouldwork as is

I'll check if I have some of those.
Instead of downloading the file from your link - would it be possible to just read the ROMs and burn it into the 27C4001?

When the machine does boot into RO3, does it flash any error codes

Where should it do that?
When it boots, everything works - I can use the keyboard, the mouse, I can do everything.
But after some seconds, maybe even after a minute it either freezes instantly - or the screen starts to roll and becomes unusable. Then it freezes.
Reset does nothing afterwards.
When I do a quick powercycle (Switch off and on again just after some seconds), it does not boot anymore.
If I wait at least a minute or so - it usually boots again to the desktop. But in this case it is stable for just a few seconds.
The longer it is switched off, the longer it is stable.

[IanS]

Instead of downloading the file from your link - would it be possible to just read the ROMs and burn it into the 27C4001?

If you have any doubt over your existing chips, why would you want to copy them?

Where should it do that?

Erro codes are flashed on the floppy drive disc access light, along with a solid red screen. https://www.retro-kit.co.uk/user/custom ... ote225.pdf
See here to help decode the flashing if you see any - https://www.retro-kit.co.uk/page.cfm/co ... index.html

[Wobblestone]

First of all - and since I forgot this until now - a big THANK YOU for trying to help me

If you have any doubt over your existing chips, why would you want to copy them?

The thing is - "something" seems to work for at least seconds or even minutes - before it causes the system to hang. It might be a temperature related problem, although I did not feel any component or IC to get warm. Therefor I think that reading the ROMs using my TL 866 might work.
And if it does not work and the copy is instantly faulty, it should not boot at all.
But I might be wrong
Also I try to minimize the sources of additional issues. I've never done what you described above to get the files for the EPROMs. This means so much could go wrong and I even would not get to the actual problem, but I would be stuck before, just by trying to create the files for the ROMs.

Error codes are flashed on the floppy drive disc access light, along with a solid red screen

I did not know that at all. Cool! Let me try that....

[a1exh]

As RISCOS 3 is "bigger" than RISCOS 2 is it logical to assume it will potentially be using more ROM address lines?

If one of these upper address lines was faulty, in a way that was temperature dependant e.g. the ARM3 plug in CPU board then it would work with RISCOS 2 but not RISCOS3? So perhaps the ROMs are ok? And it's the ARM3 plug in board?

This might be a completely wrong suggestion because the ROM might not appear in the memory map at the top of the address and so these address lines may have already been tested by accesses to other HW?

But if you're completely stuck could you replace the ARM3 board with the ARM2 from the other A310 to test the ROMs?

I would be careful as the plastic on these sockets is now very brittle.

[UPDATE : I don't think the CPU accesses the ROM directly but via the MEMC?]

[Wobblestone]

But if you're completely stuck could you replace the ARM3 board with the ARM2 from the other A310 to test the ROMs?

I just have this A310
The other machine which I have is an A420. They look so similar; I always get confused.
By the ways, now I dared to remove the ARM3 board in order to "deoxit" the sockets. This did not help at all. But at least I discovered that the MEMC contains this text: "VL2304-QC ANNA ACORN ...".
Anna... isn't this the first - original - MEMC? Maybe this is not compatible with OS 3.11?
EDIT: The second machine is an A420, not an A410 ....

[SKS1]

As RISCOS 3 is "bigger" than RISCOS 2 is it logical to assume it will potentially be using more ROM address lines?

Much bigger - it's in 4 Mbit devices not 1 Mbit. So, yes.

[UPDATE : I don't think the CPU accesses the ROM directly but via the MEMC?]

MEMC generates the ROM chip select; ROM address lines should be from latched address bus. No data line goes anywhere near MEMC.

[SKS1]

But if you're completely stuck could you replace the ARM3 board with the ARM2 from the other A310 to test the ROMs?

I just have this A310
The other machine which I have is an A420. They look so similar; I always get confused.
By the ways, now I dared to remove the ARM3 board in order to "deoxit" the sockets. This did not help at all. But at least I discovered that the MEMC contains this text: "VL2304-QC ANNA ACORN ...".
Anna... isn't this the first - original - MEMC? Maybe this is not compatible with OS 3.11?
EDIT: The second machine is an A420, not an A410 ....

More that original MEMC is not compatible with ARM3 I believe. You need a MEMC1a and the accompanying PAL update, as in your A420/1. Someone has possbily bunged an ARM3 in the A310 to increase its value?

See viewtopic.php?t=8593, esp. the end bit.

[a1exh]

Good info. I imagine RISCOS 2 never turns the ARM3 cache on but RISCOS 3 does. I think that will be the cause.

CJE still sell the MEMC1a upgrade kit

Yet another thing I have to buy for my A310.

[Wobblestone]

More that original MEMC is not compatible with ARM3 I believe. You need a MEMC1a and the accompanying PAL update, as in your A420/1. Someone has possbily bunged an ARM3 in the A310 to increase its value?

That could be. The seller used this machine frequently back in the 90s. But maybe he has replaced the MEMC1a by the MEMC before selling it. I just don't know.
One thing still is strange and has not been explained yet: Why does this machine work fine under OS 2 - with ARM3 and Anna?
On eBay I see offers for MEMC1a - some (cheaper) with 10MHz and some (more expensive) with 12MHz.
Which one would you recommend to buy?

[SKS1]

More that original MEMC is not compatible with ARM3 I believe. You need a MEMC1a and the accompanying PAL update, as in your A420/1. Someone has possbily bunged an ARM3 in the A310 to increase its value?

That could be. The seller used this machine frequently back in the 90s. But maybe he has replaced the MEMC1a by the MEMC before selling it. I just don't know.
One thing still is strange and has not been explained yet: Why does this machine work fine under OS 2 - with ARM3 and Anna?
On eBay I see offers for MEMC1a - some (cheaper) with 10MHz and some (more expensive) with 12MHz.
Which one would you recommend to buy?

Perhaps the ARM3 cache hasn't been turned on at any point when you have been using RISC OS 2?

Buy a full kit! The MEMC1a is useless without the accomanying PAL.

BITD I didn't buy an ARM3 upgrade for my A440. Just waited for the A540!

[a1exh]

On eBay I see offers for MEMC1a - some (cheaper) with 10MHz and some (more expensive) with 12MHz.
Which one would you recommend to buy?

I think the 10MHz kit should be fine. I read that some Archimedes can use the 12MHz version and overclock the memory? I don't think that is possible with the A310 motherboard design?

[IanS]

If you get a chance before it locks up, see if you can disable the cache.

Code: Select all

*cache off

Then configure it to not turn it on.

Code: Select all

*configure cache off

See if it's any more stable like that.
The PAL for the MEMC1a is effectively just a few wire links. easy enough to make a replcement.

On;y RISC OS 2.01 (as supplied with the A540) turned on the cache.

[Wobblestone]

"Cache off" made the machine much, much more stable. But if I turn it off and do not wait enough time, it still doesn't boot. Same when I reset it.
For now I don't have enough time for further tests. But it's enough to be quite sure, that the original MEMC causes these issues.
I'll order a replacement one - and since I spend always way too much for such old scrap (my wife talking about my hobby ), I'll order the more expensive one with 12MHz
Well, my dear wife, you have your clothes and shoes and I have my old hardware

[DutchAcorn]

Alternatively, I’d be happy to send you an ARM2 which would bring the A310 to the original speed, and you can sell the ARM3 for silly money so that your wife can buy some more shoes.

[Wobblestone]

My wife should definitely not see your post; this could trigger some new ideas in her brain

[Wobblestone]

Finally I received the "new" MEMC (+PAL) for my A310. After inserting it, everything worked fine. The system finally even recognized my ZIDEFS card and booted from it.

BUT...
... the system is still unstable. Sometimes it just freezes, after some seconds, after some minutes - it's different.
But the most annoying problem is, that it does not boot, after it stopped - or after I shut it down and switched it off.
When I wait minutes - or better hours - it boots just fine.

I also tried the CONFIGURE CACHE OFF trick, which worked well with the old MEMC.
But still the same: It just does not boot.

I used a contact cleaner on the sockets for the MEMC and CPU, where the daughterboard for the Arm3/MEMC/Memory is inserted. But no improvement.

Since it always works after switching it off for a longer time, I suspected something to overheat. But in that machine nothing at all get's warm or even hot.

Now it's time for me to give up. I have no idea what else I could try.

[a1exh]

Do you have another PSU to try?

I have read that they can have age related issues and there are several threads about recapping the internals.

Are there any memory test programs you can use to see if all memory locations can be written and read back? I don't know how RAM is allocated in RISCOS but a flakey RAM chip could result in it working after booting but fail later as more RAM is allocated?

[Wobblestone]

Thank you for your Answer!
I don't have another PSU for an A310. But that doesn't matter. I will use a modern SFX-PSU and wire it quick and dirty to the mainboard of the A310, just for sake of testing.
Well, I also suspected already the Memory. But we're talking about 32 ICs, all directly soldered on the PCB. I do not want to stress the PCB and desolder all ICs, just because I suspect something.
Do you know a good program, which does a thorough memory test?

[SteveBagley]

But the most annoying problem is, that it does not boot, after it stopped - or after I shut it down and switched it off.
When I wait minutes - or better hours - it boots just fine.

What about a DELETE power on to reset the CMOS when this happens? Does the cause it to boot?

Steve

[Wobblestone]

What about a DELETE power on to reset the CMOS when this happens? Does the cause it to boot?

Unfortunately not.

[IanS]

Do you know a good program, which does a thorough memory test?

The memory tester here is a useful test - viewtopic.php?p=333818#p333818

[Wobblestone]

Hi Ian,
thank you very much . I will try it as soon as I have time and report the result here.

[Wobblestone]

That machine drives me cracy
I wanted to swap that memtest on it using a floppy disk. Usually I do it in that way:
On my mac I have an USB-floppy drive. It can only read/write 1.44MB floppies for PCs. So I download that program, write it on a 1.44MB floppy. Then I fire up one of my RiscPCs, unpack that file and copy it to a 800kB floppy, which the A310 can read.
So far, so good. But the floppy drive is broken now. It used to work fine, but not it just flickers once and I get "Drive empty". I hate old computer... really (ok, NOT really )

Ok, so I had to write it directly on the ZIDEFS card by inserting this in the RiscPC directly. This worked and I finally could run the memtest. This showed no memory error.
The machine ran perfectly stable. I really don't understand what's going on.

Last time I disassembled it, I used a lot of Deoxit on the sockets for the CPU and MemC. Maybe in the last weeks it removed some corrosion, which made the machine instable. I don't have a better explanation.