A310 restoration

Arc/RPCs, peripherals, RISCOS operating system & ARM kit eg GP2x, BeagleBoard
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simonm
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A310 restoration

Post by simonm » Mon Apr 22, 2019 12:26 pm

I've been tinkering on and off with a couple of cheap A310's I bought with the idea of advancing my hardware skills using a couple of "guinea pig" machines that aren't ones I'm too worried about mashing up. That said, my aim is to restore them (ideally both) to a working condition again, but i have the feeling I might be able to get one good working machine using parts from the two. We'll see!

I've posted in a couple of other threads on here about them, but thought it might be useful to kind of blog my progress in a dedicated thread 1) for my own reference, plus 2) in case it might be useful for any other hardware amateurs.

One machine I paid £10 for (base unit only). The other I paid £83 for - boxed with keyboard. The £10 one was from Gumtree - he wanted £20 but it went up in smoke when the guy demo'd it to me! The other was a cheeky ebay buy.

I've dismantled them both and the prognosis is generally:
The £10 one.
Is a bit dirty inside but seems generally in good shape - no battery damage. It's got a MEMC upgrade and has a two floppy front panel. RISC OS2 I'm guessing. UPDATE: it is RISC OS 3.10 and 4Mb RAM.

The £83 one.
Is battery gunked and looks like its had a hard life. It's got an ARM3 (36Mhz!) upgrade, and a harddrive with an IdeA interface podule. RISC OS3. Also a computer concepts colour card and a wildvision video capture card. Plus a 4 podule IFEL expansion. RAM board looks to be 4Mb.

Some forum links that have been handy for me so far:
Help with an A310 - resetting etc.
Repairing a dead A310 PSU - I added some posts about the PSU in the £10 one.
Arm3 Upgrade - I was thinking about swapping the CPUs over
A310 buzzing/dead PSU - fixing C37 on the 12V line if the tantalum cap has shorted
Fixing an arc mouse - the mouse I got has intermittent horizontal axis movement, possibly weak/depleted IR LED. Although see here for other opinions on this.
32 bit fault finding index - some excellent tips from forum members here

Other handy links:
Acorn BBC Archimedes A310 with RISC OS 2 - Retrokit Info about an A310 RISC OS 2 machine restoration
Acorn BBC Archimedes A310 with RISC OS 3 - Retrokit Info about an A310 RISC OS 3 machine restoration
Acorn Archimedes A300 Series - Chris' Acorns info pages
Retrokit ARM3 36Mhz IFEL upgrade info - turned out the ARM3 upgrade was the rare 36Mhz version
Retrokit link to Acorn Power Up Self Test (POST) sequence - useful reference, also another reference for POST codes with extra info in it.
Acorn Service Manuals - Chris' Acorns useful repo of manuals
Reference doc for a SIMtec 4mb A310 memory upgrade.

So the process so far was:
Dismantle machine
Clean the cases etc.
Clean out the dust bunnies from the case
Remove the motherboard, give it a brush to remove surface dirt/dust, then wash with white vinegar (if corroded) then water then IPA and dry well
Recap the PSUs - replacing the two RIFA capacitors - C1 (10nF X2) and C2 (100nF X2) and then C9 (470uF 25V)
Recap C37 - tantalum 100uF 16V
Reassemble mobo
Test the system powers up (hold down delete when powering up to ensure CMOS is reset)

Still todo:
Retrobrite the various plastic parts
Clean the floppy drives
Install a flash harddrive
Put all the best parts into one machine to create a beast.

:D
Last edited by simonm on Mon Apr 29, 2019 12:57 am, edited 17 times in total.

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Re: A310 restoration

Post by RobC » Mon Apr 22, 2019 6:27 pm

Well done - they are lovely machines and work really well with extra RAM, ARM3 and HD :D

If you need to respray the metal case, Rustoleum Hard Hat Oyster White is the right colour and works well.

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simonm
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Re: A310 restoration

Post by simonm » Thu Apr 25, 2019 11:45 pm

So I stripped down the £10 one first. It was pretty dirty inside.
2018-07-20 15.18.33.jpg
2018-07-20 15.19.36.jpg
2018-09-02 14.32.07.jpg
2018-09-02 14.36.02.jpg
2018-09-22 22.46.48.jpg
2018-09-22 22.57.02.jpg
2018-09-22 22.57.47.jpg
2018-09-22 23.06.58.jpg

Has a standard two podule expansion, 1 podule is a Computer Concepts ROM/RAM podule. Varta poisoned.
2018-09-02 14.21.09.jpg
The other one is a Computerware hard disk podule, which had a harddrive attached.
Last edited by simonm on Fri Apr 26, 2019 12:02 am, edited 1 time in total.

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Re: A310 restoration

Post by simonm » Thu Apr 25, 2019 11:54 pm

Since this is the one that popped with magic smoke I tackled the PSU recap. Bought a kit from Mark @ RetroClinic and some of the 470uF caps from ebay.
My initial forays to open up the PSU started out here: viewtopic.php?f=16&t=9112&start=30#p214763
2018-11-27 20.20.12.jpg
Yep definitely exploded RIFA
2018-11-27 20.20.21.jpg
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2018-11-27 23.59.53.jpg
2018-11-28 00.00.18.jpg
2019-04-22 00.26.51.jpg
All new X2 caps & C9
2019-04-22 15.24.46.jpg
Reassembled and base unit cleaned out

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Re: A310 restoration

Post by simonm » Thu Apr 25, 2019 11:57 pm

Next up, I cleaned the PCB over the bank holiday with IPA and a brush. Came up nice!
2019-04-22 13.52.01.jpg
From this...
2019-04-22 13.52.12.jpg
2019-04-22 13.52.29.jpg
2019-04-22 15.15.13.jpg
To this! :)
Last edited by simonm on Thu Apr 25, 2019 11:58 pm, edited 1 time in total.

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Re: A310 restoration

Post by simonm » Fri Apr 26, 2019 12:00 am

Amazing what rubbish you find! These were folded up and stashed under the motherboard???!! #-o
2019-04-22 14.10.44.jpg
2018-09-02 18.24.38.jpg

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simonm
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Re: A310 restoration

Post by simonm » Fri Apr 26, 2019 12:07 am

I re-installed the mother board and PSU tonight, and thought I'd try giving it a powerup whirl, to see if I might hear a soothing bootup beep...
2019-04-26 01.03.23.jpg
Sadly.... nothing. I heard two small "tink" "tink" sounds from PSU in short succession at first, since then just a quiet repetitive but high pitch "pip pip" 2hz buzz. No fan activity. No beeps. Measured the voltage on the +5V black/red pins, and got 140mV. :(
Last edited by simonm on Fri Apr 26, 2019 12:14 am, edited 1 time in total.

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Re: A310 restoration

Post by SteveBagley » Fri Apr 26, 2019 2:30 am

Try powering it up with the 12V (yellow) wire to the motherboard disconnected — doing that revived one of my A310s. There was a short on the motherboard (from a tantalum, I think) which stopped the PSU providing any power to the MB.

The 12V line is only used to drive the fan header on the A310 iirc so I left it disconnected in mine,

Steve
Last edited by SteveBagley on Fri Apr 26, 2019 2:34 am, edited 1 time in total.

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Re: A310 restoration

Post by simonm » Fri Apr 26, 2019 2:37 am

Wow - thanks Steve. That made a difference - getting 5V on the red/black lines now, and a speaker pulse. Holding down delete on boot gives me a beep! I have hope again! :D
I also tested the disconnected yellow line and there's 12V there too now, plus the molex is also delivering 12V + 5V.
Last edited by simonm on Fri Apr 26, 2019 2:46 am, edited 1 time in total.

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DutchAcorn
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Re: A310 restoration

Post by DutchAcorn » Fri Apr 26, 2019 3:41 am

This is one of the most common faults for the A310. See here for more information: https://www.retro-kit.co.uk/page.cfm/co ... ouplingcap

If the other A310 does boot it is probaly still a good idea to replace this tantalum cap (C37).
Paul

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Re: A310 restoration

Post by Kazzie » Fri Apr 26, 2019 4:16 am

Nice work so far. :)

I see a ROM carrier board in your pictures: this would have been used to install the larger RISC OS 3 ROMs, so it seems it's already been upgraded in that respect.
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Re: A310 restoration

Post by IanS » Fri Apr 26, 2019 7:40 am

simonm wrote:
Fri Apr 26, 2019 12:00 am
Amazing what rubbish you find! These were folded up and stashed under the motherboard???!! #-o
Is it missing the middle plastic support pin?, if so, those are probably doing you a big favour, stopping the pcb from shorting on the bottom of the case.

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Re: A310 restoration

Post by fordp » Fri Apr 26, 2019 7:54 am

Maybe an admin can move this over to the 32bit hardware space so more people can find this.

Well done on getting more Acorns back working!
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Re: A310 restoration

Post by Kazzie » Fri Apr 26, 2019 8:00 am

fordp wrote:
Fri Apr 26, 2019 7:54 am
Maybe an admin can move this over to the 32bit hardware space so more people can find this.

Well done on getting more Acorns back working!
Did you click the ! (report post) button to bring it to their attention? If not, I just did so for you. :)
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Re: A310 restoration

Post by 1024MAK » Fri Apr 26, 2019 8:14 am

Thread moved.

Mark

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Re: A310 restoration

Post by simonm » Fri Apr 26, 2019 10:27 am

DutchAcorn wrote:
Fri Apr 26, 2019 3:41 am
This is one of the most common faults for the A310. See here for more information: https://www.retro-kit.co.uk/page.cfm/co ... ouplingcap

If the other A310 does boot it is probaly still a good idea to replace this tantalum cap (C37).
Aha, thank you!

Also, I realized this morning that this info was the original dead PSU thread too, I just didn't connect the dots! #-o
IanS wrote:
Fri Apr 26, 2019 7:40 am
simonm wrote:
Fri Apr 26, 2019 12:00 am
Amazing what rubbish you find! These were folded up and stashed under the motherboard???!! #-o
Is it missing the middle plastic support pin?, if so, those are probably doing you a big favour, stopping the pcb from shorting on the bottom of the case.
Ahhh that makes much more sense then because you are right - there were a few PCB risers missing which I've replaced. Much better reason than the previous owner being a farmer with a secret penchant for crop circles having to hide his documents in his pc.
Kazzie wrote:
Fri Apr 26, 2019 4:16 am
I see a ROM carrier board in your pictures: this would have been used to install the larger RISC OS 3 ROMs, so it seems it's already been upgraded in that respect.
Very interesting - I'd like the idea of being able to have either RISC OS 2 or RISC OS 3 by simply adding the podule. That being a possibility I'll try to clean it up and replace the battery to see if it still works. Lots of brown solder joints on the back of the PCB, so maybe its too corroded... we'll see.
Last edited by simonm on Fri Apr 26, 2019 10:28 am, edited 1 time in total.

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Re: A310 restoration

Post by Kazzie » Fri Apr 26, 2019 12:09 pm

simonm wrote:
Fri Apr 26, 2019 10:27 am
Very interesting - I'd like the idea of being able to have either RISC OS 2 or RISC OS 3 by simply adding the podule. That being a possibility I'll try to clean it up and replace the battery to see if it still works. Lots of brown solder joints on the back of the PCB, so maybe its too corroded... we'll see.
Rather than being a podule, it is (if I read corectly) a plug-in for the ROM sockets on the mainboard, which provides larger sockets for the larger RISC OS 3 ROMs, with flying leads soldered to the board for the extra address pins of the larger ROM.

The jumpers on the side of the board will enable or disable these extra pins, so that you could place the RISC OS 2 or RISC OS 3 ROMS on the board, as you chose.

There's a description and pictures of a similar type of board by IFEL online here, as well as a linked manual. I'm not sure the jumpers' layout will be identical, but it'll give you an idea of what the board does, and how it's meant to be fitted.

I think one of the three flying leads has come disconnected: the white wire looks loose at the mainboard end in your last overhead picture. Based on the earlier pictures and the IFEL example, it should be soldered to the pin between the yellow and green wires of IC28.

If you want to be able to switch between operating systems on a whim, the forthcoming ArcFlash in-system programmable ROM may be of interest to you.
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Re: A310 restoration

Post by simonm » Fri Apr 26, 2019 12:38 pm

Kazzie wrote:
Fri Apr 26, 2019 12:09 pm
Rather than being a podule, it is (if I read corectly) a plug-in for the ROM sockets on the mainboard, which provides larger sockets for the larger RISC OS 3 ROMs, with flying leads soldered to the board for the extra address pins of the larger ROM.
I think the picture might have been misleading - it's definitely a podule:
2019-04-26 13.30.30.jpg
It has 6 x Toshiba TC551001PL-10 1Mbit SRAM chips in it, so 768Kb of RAM on it as far as I can tell.
Kazzie wrote:
Fri Apr 26, 2019 12:09 pm
I think one of the three flying leads has come disconnected: the white wire looks loose at the mainboard end in your last overhead picture. Based on the earlier pictures and the IFEL example, it should be soldered to the pin between the yellow and green wires of IC28.
Well spotted - yes it came off when I unseated the ROM board to wash the PCB. In hindsight I should have disconnect the header pin connections first, but it was a fragile solder onto the chip pins. Now resoldered back on.
Kazzie wrote:
Fri Apr 26, 2019 12:09 pm
If you want to be able to switch between operating systems on a whim, the forthcoming ArcFlash in-system programmable ROM may be of interest to you.
This looks very cool. Ideal for these old machines that have had various types of OS over the years! Thanks for the tip.

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Re: A310 restoration

Post by Kazzie » Fri Apr 26, 2019 1:12 pm

I didn't look at the Podule as I was concentrating too much on your talk of RISC OS. Though it too is a ROM carrier. :roll:

While that board can take ROM (and RAM) chips, I believe they're for use as a ROM filing system, not as a replacement operating system.

There's a manual for that very board here. :)
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Re: A310 restoration

Post by simonm » Fri Apr 26, 2019 1:20 pm

Re-reading your post Kazzie, I can see you were referring to the board on the PCB now. Apologies entirely my misunderstanding,

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Re: A310 restoration

Post by simonm » Sat Apr 27, 2019 11:28 am

Had to buy a 9 pin to 15 pin VGA adapter, but Amazon delivered early this morning so I hooked it up to my Benq and.... It lives! [-o< :D
RISC OS 3.10 and 4Mb RAM.
2019-04-27 12.19.36.jpg
I've some tantalums in the post so I will fix that cap next week.
I've noticed that the PSU is quite "chatty" ie. it buzzes (not particularly loudly or distressingly) in tune with whatever is happening on the screen. Is that typical? Probably wont be as audible once the case is back on.

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Re: A310 restoration

Post by JonC » Sat Apr 27, 2019 12:35 pm

simonm wrote:
Sat Apr 27, 2019 11:28 am
Had to buy a 9 pin to 15 pin VGA adapter,
I'm probably going to need some of these soon, which did you order?
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Re: A310 restoration

Post by simonm » Sat Apr 27, 2019 12:49 pm

JonC wrote:
Sat Apr 27, 2019 12:35 pm
I'm probably going to need some of these soon, which did you order?
I got this one Jon: https://www.amazon.co.uk/gp/product/B00HJUDHV8/
There's cheaper ones on ebay, but I didn't want to wait! :D

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Re: A310 restoration

Post by JonC » Sat Apr 27, 2019 12:50 pm

simonm wrote:
Sat Apr 27, 2019 12:49 pm
JonC wrote:
Sat Apr 27, 2019 12:35 pm
I'm probably going to need some of these soon, which did you order?
I got this one Jon: https://www.amazon.co.uk/gp/product/B00HJUDHV8/
There's cheaper ones on ebay, but I didn't want to wait! :D
Cheers for that, at least I know they work!
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Re: A310 restoration

Post by simonm » Sat Apr 27, 2019 9:20 pm

Lucky me - the tantalums arrived in the post today, so I replaced C37, and now the 12V line is all fine. The fan now works (which is easily louder than the PSU chirping so I'm not going to fuss about that anymore) and I should probably replace C38 and C39, but maybe I'll do those another day.
2019-04-27 22.12.03.jpg

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Re: A310 restoration

Post by simonm » Sun Apr 28, 2019 12:03 pm

Ok so with the £10 machine up and running and mostly reassembled I thought I'd take a look at the other £83 one.

It's an A310 again, with an IFEL ARM3 upgrade, RISC OS 3 ROMs, and an IFEL 4 podule upgrade and various podules. Not sure how much RAM yet.
2019-04-22 01.08.46.jpg
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Last edited by simonm on Sun Apr 28, 2019 11:18 pm, edited 1 time in total.

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Re: A310 restoration

Post by simonm » Sun Apr 28, 2019 12:06 pm

It was badly battery gunked and rusty - not sure if the rust was because of the battery leak or because the machine had been damp at some point.
The battery case was beyond redemption so I've removed it and will fully replace that. Also the battery lead connecter PCB header had corroded so I've replaced that with a new header too.
2019-04-22 01.08.59.jpg
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Last edited by simonm on Sun Apr 28, 2019 12:23 pm, edited 2 times in total.

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Re: A310 restoration

Post by simonm » Sun Apr 28, 2019 12:08 pm

So I washed the board & metal with white vinegar, water & IPA. Looks better now, but not sure how much damage was done.
2019-04-22 18.29.42.jpg
2019-04-22 18.30.05.jpg
2019-04-22 18.30.10.jpg
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2019-04-28 00.32.13.jpg

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Re: A310 restoration

Post by simonm » Sun Apr 28, 2019 12:10 pm

Thought I recap the PSU next. This one looks like caps have already been changed, but I replaced them again anyway.
2019-04-27 23.25.45.jpg
2019-04-27 23.25.51.jpg
2019-04-27 23.52.30.jpg
2019-04-27 23.53.02.jpg
2019-04-27 23.53.45.jpg

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Re: A310 restoration

Post by simonm » Sun Apr 28, 2019 12:19 pm

Clearly this machine has had a few mods. The power led has been hacked to show the IDE HDD access light, and the power cables have been cut at some point then gaffer taped back together.

So I reassembled and tried a power up + delete. No joy on this one - same as last time, so I replaced C37.

Now, the power LED comes on, and keyboard lights flash momentarily then go off (and keys like the caps lock dont toggle the led). The speaker clicks twice and thats all it does. No beep.

I measured 13.5V on the 12V line and 5.6V on the 5V Line. I also checked all chips & boards were seated properly.

Clearly this one is gonna "teach me" :lol:

Since this is about my limits of experience for fault finding, any suggestions for what to try now are hugely appreciated! :D
Last edited by simonm on Sun Apr 28, 2019 12:22 pm, edited 1 time in total.

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