A310 restoration

discuss the archimedes & risc pc, peripherals and risc os/risc os on pi
Kazzie
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Re: A310 restoration

Post by Kazzie » Sat May 04, 2019 7:34 am

/me joins in the happy dance =D>

Of course, now that you have two working machines, you'll need a pair of econet modules for them... :)
BBC Model B 32K issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM, ZIDEFS with 512MB CF card
RiscPC 600 under repair
Acorn System 1 home-made replica

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simonm
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Re: A310 restoration

Post by simonm » Sat May 04, 2019 1:33 pm

daveejhitchins wrote:
Tue Apr 30, 2019 7:50 am
The mod procedure, for the firmware update is here. I can do this for you, if required (?)

Dave H :D
Sounds very interesting Dave, I'll be coming onto that shortly when I'll be wanting to choose the best components out of the two machine!
danielj wrote:
Tue Apr 30, 2019 7:13 am
Time to buy the desoldering gun, Simon :)
Haha - yes. Here we go... :lol:

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simonm
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Re: A310 restoration

Post by simonm » Sat May 04, 2019 1:38 pm

Ok, well with the fault identified I guess my next step is to replace those IC's - what would you folks suggest?

Getting to the underneath of the board for soldering is going to be impossible without removing the whole thing, and I'm feared of breaking something else in the process of doing that.

Should I cut the chips out and suck out the solder as best I can? Should I put an IC socket in first or solder the new chips in directly? Or is there a better way?

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paulv
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Re: A310 restoration

Post by paulv » Sat May 04, 2019 1:55 pm

Without removing the board it is tricky indeed. There's not a great deal of room to work.

This is how I'd approach it.

1. snip the legs of the old chips as near to the body of the chip as possible so there's plenty of leg to get hold of.
2. heat up and remove each leg using an iron and some tweezers or needle nose pliers to pull each leg.
3. Use soldamop to remove all of the solder left behind, the capillary action of soldamop will be better than a sucker in this instance
4. if there's not enough room to comfortably work between the motherboard and the daughterboard and you don't want to remove the board, solder in new chips from the top side using a lot of flux to help the solder flow through the holes.
5. if there is enough room to work, put some sockets in and then put the chips in.

Before you decide to do 4 or 5. Make sure that the board will fit under the steel bridge with a socket and chip which will be proud of the board quite a bit more than the chips are now.

Paul
Last edited by paulv on Sat May 04, 2019 1:57 pm, edited 3 times in total.

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simonm
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Re: A310 restoration

Post by simonm » Sat May 04, 2019 3:39 pm

Thanks for the tips Paul. I've narrowed the fault down to IC7, IC11 is fine.
This might be crazy talk, and probably not the cleanest solution, but could I cut the old IC out leaving the legs, and then solder the new IC legs onto the old legs?
There's no room to manoeuvre under the board at all.

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danielj
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Re: A310 restoration

Post by danielj » Sat May 04, 2019 3:56 pm

Take the board out. Just be gentle. You're fairly unlikely to break anything else. Do the job properly :) Snipping it out is the way forward though!

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paulv
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Re: A310 restoration

Post by paulv » Sat May 04, 2019 4:02 pm

danielj wrote:
Sat May 04, 2019 3:56 pm
Take the board out. Just be gentle. You're fairly unlikely to break anything else. Do the job properly :) Snipping it out is the way forward though!
Given the daughter board is soldered onto the motherboard what you're suggesting is not an insignificant task. If Simon is feeling brave then fair enough but given the amount of de-soldering required and the tone of the thread at the moment, I'd guess that he's not feeling that brave :)

Given the options, if I weren't feeling brave, I'd look to snip and solder to the legs left behind or for a slightly neater job, snip, desolder and clean with Soldamop and then solder the new chip in from the top using a lot of flux to try to flow some solder through the holes.

Paul

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danielj
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Re: A310 restoration

Post by danielj » Sat May 04, 2019 4:21 pm

Ahhh, sorry, missed the daughter board bit! Lazy reading... :oops:

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DutchAcorn
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Re: A310 restoration

Post by DutchAcorn » Sat May 04, 2019 5:09 pm

Wow, that’s a stroke of calculated luck!

Apart from the obvious “it is the right thing to do” is there any other compelling reason not to leave IC7 piggy backed (soldered on)?

Given the work (and risk) of replacement it sounds to me as a fair consideration?
Paul

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simonm
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Re: A310 restoration

Post by simonm » Sat May 04, 2019 7:22 pm

DutchAcorn wrote:
Sat May 04, 2019 5:09 pm
Wow, that’s a stroke of calculated luck!

Apart from the obvious “it is the right thing to do” is there any other compelling reason not to leave IC7 piggy backed (soldered on)?

Given the work (and risk) of replacement it sounds to me as a fair consideration?
I agree, I feel pretty lucky it wasn't something more sinister at fault.

I think if the machine hadn't worked with this chip replaced, I'd feel a bit more gung-ho about desoldering more stuff, but since it does, Paul's right - I'm reluctant to add risk of damaging it in the pursuit of an ideal repair as I'm no expert at soldering so I'm happier to take the path of least resistance if it results in a defunct machine becoming useful again.

Right now, I'm inclined to think the "easiest" solution is to solder the chip on in piggy back configuration. Although I do feel that snipping out the old IC and leg-to-leg soldering would feel like a more effective resolution. Any future reviewer of this machine would I'm sure be sympathetic to that repair approach given the complexity of desoldering the RAM board!

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simonm
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Re: A310 restoration

Post by simonm » Sun May 12, 2019 6:43 pm

DutchAcorn wrote:
Sat May 04, 2019 5:09 pm
Wow, that’s a stroke of calculated luck!

Apart from the obvious “it is the right thing to do” is there any other compelling reason not to leave IC7 piggy backed (soldered on)?

Given the work (and risk) of replacement it sounds to me as a fair consideration?
Kinda wishing I had done that now. I snipped out IC7 leaving the legs soldered into the board, then slotted in a replacement chip and soldered leg-to-leg. Powerup no longer works - red screen of doom and RAM failure error code is back. :(
Last edited by simonm on Sun May 12, 2019 6:48 pm, edited 1 time in total.

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simonm
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Re: A310 restoration

Post by simonm » Mon May 13, 2019 2:12 am

So I've decided to leave the faulty machine alone just now, and concentrate on harvesting the best bits to build a beast using the good motherboard.
I've also transplanted the ARM3 CPU board into this mb

Nicking the best bits then, I now have at least one good working, nicely retrobrited, salvaged & restored A310, specs:

A310, 4Mb RAM, 36Mhz ARM3, RISC OS 3.10, MEMC1a
IFEL 4 podule expansion.
computer concepts Colour card, with wild vision video capture card.
Backplane floppy connector - seems like a good way to plug an external gotek in.
IdeA card, with 300Mb hard drive (& was fully loaded with previous owners software)
I'll probably looking into attaching a secondary IDE/CF card also for backup.

I've kept the single floppy drive front panel (rather than the dual floppy front panel from the other one), which although it has a novelty, it didn't seem like a useful thing to keep.

I also picked up a spare A310 series keyboard, so I've swapped the keyboard PCB and kept the nice casing.

Lastly I managed to get an original A310 mouse on ebay the other day, so I'm pretty happy with that.


So the "left overs" machine is:
A310,RISC OS 3.10, 4Mb, ARM2, MEMC1a
Standard podule bay
Two floppy front panel w/ two floppy drives
Computerworks ST-506 hard disk podule.
It has a hard drive, which seems to be pretty ancient - an ST506 Rodime. I suspect around 10Mb, and I tried powering it up, but it no joy accessing it.

Faults:
It has a RAM fault to be fixed. And the keyboard tracks need sorting.

Will come back to the broken one soon, but I'll also post some pics of the working one once it's all back together.

Thanks for all the help folks.

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simonm
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Re: A310 restoration

Post by simonm » Sun Jul 28, 2019 3:18 am

Finally came back to this and sorted it out - on closer inspection one of the legs on the new chip wasn't connected properly, so I fixed that and it's all good now. Thanks again everyone.

---

In other news, I've acquired a third A310 (yes, I may need counselling :lol: ), which unfortunately is even deader than the previous ones, so I'm looking for sage wisdom again!

It's a standard ARM2, with what looks like an IFEL 2Mb upgrade and RISC OS 3.

The previous owner reported the last time they powered it up, the PSU popped with magic smoke, and C37 sure look fried on the PCB. Apart from that the board looked clean, dusty but no battery gunk and no other signs of fried components.
2019-07-25 23.31.49.jpg

I've replaced the 3 tantalums, but powering it up (with a known working PSU) the power LED lights and a brief flash of the keyboard lights, but no other signs of life - no video signal or any floppy lights.

I've checked all the chips are seated, and I also swapped MEMC, VIDC, ARM and IOC with known working chips, but to no avail.

Seems like it's not booting at all, so some type of short perhaps? Any pointers on where to go next would be much appreciated. TIA!

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Re: A310 restoration

Post by steve3000 » Sun Jul 28, 2019 12:43 pm

simonm wrote:
Sun Jul 28, 2019 3:18 am
In other news, I've acquired a third A310
No harm in that, the A310 is a great machine :)
simonm wrote:
Sun Jul 28, 2019 3:18 am
Seems like it's not booting at all, so some type of short perhaps? Any pointers on where to go next would be much appreciated. TIA!
When powered just with 5v line (forget the 12v for the moment), can you measure a good 5v signal at all the right places on the PCB? (pick an easy to access IC +ve leg at each corner)

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Re: A310 restoration

Post by SteveBagley » Sun Jul 28, 2019 11:48 pm

Given…
simonm wrote:
Sun Jul 28, 2019 3:18 am
It's a standard ARM2, with what looks like an IFEL 2Mb upgrade and RISC OS 3.
And the symptoms…
I've replaced the 3 tantalums, but powering it up (with a known working PSU) the power LED lights and a brief flash of the keyboard lights, but no other signs of life - no video signal or any floppy lights.
I wonder if there’s an issue with the ROM carrier board, might be worth checking one of the address jumper wires hasn’t come loose?

Steve

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simonm
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Re: A310 restoration

Post by simonm » Sat Sep 26, 2020 9:36 pm

Since this came up again recently on Facebook I thought I'd bookend the outcome.
I salvaged two of the A310's - one is the "beast" made from all the best bits, A310 ARM3 36Mhz 4Mb, and now with a gotek. The other is a A310 with ARM2, 4Mb.
Fortunately the previous owner of one of the machines had already enlarged the floppy drive and fitted a high density fdc podule, so I didn't have to do any butchering to fit a gotek instead. The podule is handy as it exposes a floppy interface on the back of the machine too, so can always plug in a real floppy if needed.
Theres a 512Mb IDE compact flash adapter fitted too, and I've had no problems using it with the IdeA interface.
Again, thanks all on here for their help.
2020-09-25 18.43.49.jpg
With gotek fitted
2020-09-25 18.43.37.jpg
Rear view
2020-09-25 18.43.31.jpg
Top view
2020-09-25 15.02.10.jpg
17 MIPS!
Last edited by simonm on Sat Sep 26, 2020 9:39 pm, edited 1 time in total.

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danielj
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Re: A310 restoration

Post by danielj » Sat Sep 26, 2020 9:38 pm

That is one sexy A310. Great work :)

d.

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IanJeffray
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Re: A310 restoration

Post by IanJeffray » Sat Sep 26, 2020 10:53 pm

Lovely - but that gotek makes me weep. SO ugly.

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simonm
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Re: A310 restoration

Post by simonm » Sat Sep 26, 2020 11:04 pm

IanJeffray wrote:
Sat Sep 26, 2020 10:53 pm
Lovely - but that gotek makes me weep. SO ugly.
I had the same misgivings. As I mentioned above the slot was already carved out by someone else, bit it means a real floppy can always be restored if desired.
However, now I've used a Gotek on an Arc its a revelation frankly. It makes the machine a whole lot more usable in this modern age - just copy some ADF files to your USB stick and you have them instantly available on your Arc. So I think the usability/aesthetic tradeoff is ok.

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Re: A310 restoration

Post by IanJeffray » Sat Sep 26, 2020 11:42 pm

simonm wrote:
Sat Sep 26, 2020 11:04 pm
However, now I've used a Gotek on an Arc its a revelation frankly. It makes the machine a whole lot more usable in this modern age
Ah. Hm. What you really want is a network card. I've always had NICs in [almost] all my machines and consider it a basic requirement really - even RISC OS 3.1 is very Internet-friendly and usable.

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Re: A310 restoration

Post by IanJeffray » Wed Oct 07, 2020 6:17 pm

I am slightly unwittingly taking on the task of trying further to breathe life in to this A310 :roll:

Doing the usual check of "ARM counts addresses under reset" test, several of the high-order addresses look like this right at the ARM. I'm loathe to believe ARM or MEMC has died, more likely the 74HC537 (IC35) that sits next in line - opinions?
image.png

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IanJeffray
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Re: A310 restoration

Post by IanJeffray » Wed Oct 07, 2020 8:58 pm

Pulled MEMC - still same multi-level logic showing with no MEMC present. Pulled ARM, noted that some donkey had obviously hit the socket with a soldering iron (likely when installing the 2MB RAM board) .... carefully fixed that up using a scalpel, straightened two wonky pins on ARM itself ... and we have a POST! :) "Long RAM test failure" she says. Ok.

No video output either, but the keyboard LEDs respond as expected and there's the usual A310 video inteference noise on the speaker. So that's some good progress :)

No video output and lack of any beep suggests something gubbed around VIDC that's not detectable by the POST perhaps. We continue...

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IanS
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Re: A310 restoration

Post by IanS » Wed Oct 07, 2020 9:16 pm

Does it have the jumpers on the genlock connector? (Does that get detected by POST, does it depend on OS? RO2 or RO3?)

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Re: A310 restoration

Post by IanJeffray » Wed Oct 07, 2020 9:27 pm

IanS wrote:
Wed Oct 07, 2020 9:16 pm
Does it have the jumpers on the genlock connector? (Does that get detected by POST, does it depend on OS? RO2 or RO3?)
Yep, 1-2 and 3-4. And yes, it completely fails to POST if 1-2 is missing. 3-4 missing simply makes the video "iunreliable" :)

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Re: A310 restoration

Post by IanJeffray » Wed Oct 07, 2020 10:02 pm

It always helps to plug the correct monitor cable in. #-o Ooops. :)

Now I've got "Address exception at &%0" showing on screen which is fun. Very likely related to the RAM test fail.
Dunno about the lack of beep - less fussed about that right now.

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Re: A310 restoration

Post by IanJeffray » Wed Oct 07, 2020 11:00 pm

So this machine has a "-10QC" MEMC1A, which means it's slightly special (10MHz not 8MHz stock). I'm guessing maybe this machine originally had ARM3 in it (re the above historical goings on). Question is what PAL it has - how to tell. It's a PAL16LA8CN and doesn't have identical signals on opposite pins. Perhaps I should pull the PAL and drop some links in instead to be sure?

I tried swapping MEMC out for a standard 8MHz MEMC1A but no difference in operation (other than obviously 8MHz rather than 10MHz operation).

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IanS
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Re: A310 restoration

Post by IanS » Wed Oct 07, 2020 11:06 pm

IanJeffray wrote:
Wed Oct 07, 2020 11:00 pm
Perhaps I should pull the PAL and drop some links in instead to be sure?
With a MEMC1a. I would.

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Re: A310 restoration

Post by IanJeffray » Wed Oct 07, 2020 11:25 pm

IanS wrote:
Wed Oct 07, 2020 11:06 pm
IanJeffray wrote:
Wed Oct 07, 2020 11:00 pm
Perhaps I should pull the PAL and drop some links in instead to be sure?
With a MEMC1a. I would.
It made no difference. Damn.

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Re: A310 restoration

Post by IanJeffray » Thu Oct 08, 2020 12:05 am

It looks like the 2MB board was installed by a blind donkey with a pickaxe. Now I look closely on the understide of the board, the board's ripped round almost all the pads of all four RAMs that get pulled and replaced by sockets. There's chunks of bare fibreglass all over the place. Tracks running next to these pads have clearly all been prised off the board and have been run-over with solder to repair them. Horrible. I've re-repaired quite a slew of these now, but with no change to operation. I'm vaguely minded to remove the 2MB board and restore to stock configuration.
IMG_1662.JPG

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IanJeffray
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Re: A310 restoration

Post by IanJeffray » Thu Oct 08, 2020 2:21 am

Progress. We can call that progress, right?
IMG_1667.JPG
I can i"RmReInit" some modules - BASIC works. It seems to be falling over at MessageTrans though - RMReInit that and it gives the same error that's borking the boot.

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