32 bit Fault finding index

Arc/RPCs, peripherals, RISCOS operating system & ARM kit eg GP2x, BeagleBoard
User avatar
1024MAK
Posts: 6729
Joined: Mon Apr 18, 2011 4:46 pm
Location: Looking forward to summer in Somerset, UK...

32 bit Fault finding index

Postby 1024MAK » Fri May 13, 2016 10:07 am

So I thought it was about time that we had a Fault finding index for the 32 bit'ers like the 8 bit Fault finding index.

So quoting Martin B...
MartinB wrote:A frequent post topic on STH, and indeed all similar retro forums, is where someone has a hardware fault and is asking for advice on how to go about fixing it. In response there are usually plenty of helpful suggestions and/or pointers to ‘common fault’ articles such as those hosted by Sprow or Wouter.

EDIT :

In case this never goes anywhere, resources in the spirit of the approach can be found at....

For example :

http://wouter.bbcmicro.net/hardware/repair/index.html

http://www.sprow.co.uk/bbc/doctor.htm

and the zipped-up troubleshooting book mentioned in...

http://www.stardot.org.uk/forums/viewto ... 416#p43416


Thanks

Now, in the electrical goods industry (and motor vehicles, and…) there are engineers ‘bibles’, paper and electronic, which are essentially collections of actual fault fixing reports by engineers and technicians which briefly detail which action fixed a particular fault. For example, you might get a TV entry which says “Ferguson TX100 / Repeatedly trips to Standby / Replaced IC6”. These list entries tend to be short, to the point, and, importantly, don’t include actions which didn’t fix the fault, the latter phrase being the key to the success and usefulness of such an index.

As an example from our world, I’ll pick a test case I was involved in - not to blow my trumpet but because it actually demonstrates a downside of the ‘free advice’ problem! retro_junkie posted ‘Beeb not hearing tapes' and I suggested at least 6 possible causes, all valid, and I could have suggested more, but ultimately he replaced IC7 and this action fixed the fault. BeebInc also suggested some common solutions which might equally have fixed this particular snag. The valuable knowledge there then was that a failure of IC7 does really occur and that it’s a fault which can cause a loss of tape capability. The downside was that he had to wait for replies and he might have felt swamped with suggestions, some of which could be totally anecdotal and/or theoretical and would never apply in reality. That of course was just one example from probably hundreds buried in the forum, all with a similar story.

I have for a while been thinking that a similar index would be very useful for our community and it could be hosted on this very site. It needn’t be in any way complicated and would just be partitioned by machine, e.g. Beeb, Elk, Master, Arc etc., and would simply have three or four columns – Machine configuration summary, Fault Symptoms (as detailed as possible) and what action actually fixed the fault. The single most important feature of such an index is that it is free of theory, speculation and anecdotal evidence and ONLY itemises real and successful repairs.

It would of course take time to build up some useful weight but retrospective input from users is fine as long as the information is correct and is not discoloured by memory. The index would be available to all members and all incident reports would be included unless they were clearly impossible – e.g. "Standard Iss.7 BBC B / Powers up and beeps but black screen / Replaced clear plastic keystrip cover" would probably not make the index :wink:

Someone (some people) would act as a repository for reports and these would simply be technically vetted for plausibility and then added to the list. I’m only thinking of a simple three/four column text file, nothing fancy, which can be visually scanned when hunting for a solution to a problem. I doubt we’d get into thousands of entries so a database wouldn’t be necessary although end users could import it into a their preferred package as they saw fit.

So, anyone have any thoughts on this? Good idea? Bad idea?

Answers on an electronic postcard to this thread :)

Martin


So if you have fixed up an Arc, a RISC PC or anything related to 32 bit Acorn, please post the details here :wink:

If some interest is shown, we'll make the topic a sticky thread.

Mark
For a "Complete BBC Games Archive" visit www.bbcmicro.co.uk NOW!
BeebWiki‬ - for answers to many questions...

User avatar
DutchAcorn
Posts: 1618
Joined: Fri Mar 21, 2014 9:56 am
Location: Maarn, Netherlands

Re: 32 bit Fault finding index

Postby DutchAcorn » Fri May 13, 2016 10:51 am

Excellent! Can I suggest the post by Piemm fixing "RAM control line failure" on an Acorn A4 by replacing electrolytic capacitors?

http://stardot.org.uk/forums/viewtopic.php?f=16&t=8981

I suspect leaking capacitors may be the cause of death for many A4's (now and in the future), right after the leaking battery.
Paul

Zarchos
Posts: 2355
Joined: Sun May 19, 2013 8:19 am
Location: FRANCE

Re: 32 bit Fault finding index

Postby Zarchos » Fri May 13, 2016 11:28 am

I don't know what a sticky thread is, but may I suggest creating a category in the board index ?
In the 'hardware section' :
'Repairing ...'
The same could be great also for :
'Developments' for example Munchausen's IDE for the A3010 would be there, Dave's new IDE boards too ...
Additionally in the 'software category' :
'Developments', with subcategories apps, games, demos ...
Or WIP (work in progress) if you prefer, don't ask me to choose the more relevant English words. :mrgreen:

Compared to other boards, to me there are many entries missing in the index.
Other people opinions welcome, after all it's not sure I'm right, it's just my feeling.

User avatar
danielj
Posts: 5222
Joined: Thu Oct 02, 2008 4:51 pm
Location: Manchester

Re: 32 bit Fault finding index

Postby danielj » Fri May 13, 2016 11:43 am

That's a good suggestion, Zarchos - I'll flag it for discussion!

d.

User avatar
paulv
Posts: 3584
Joined: Tue Jan 25, 2011 6:37 pm
Location: Leicestershire
Contact:

Re: 32 bit Fault finding index

Postby paulv » Fri May 13, 2016 6:01 pm

Archimedes A300/A400 & A400/1 series not starting

Symptoms:

Machine appears dead with a possible audible ticking from the PSU....

Cause:

Typically a failure of the Tantalum capacitor C37 on the A300 schematic which is the +12V line decoupling cap.

For the Archimedes A400/1 series the equivalent to C37 is C53.

Test:

To test, simply remove the cap. and power up. If it works, then perform the fix.

Fix:

To fix, replace with an 25V rated equivalent. 16V as specified in the schematic is a little on the low side. To be on the safe side, replace all three Tantalum caps highlighted.

Image

Paul
Last edited by paulv on Fri May 13, 2016 6:25 pm, edited 5 times in total.

User avatar
paulv
Posts: 3584
Joined: Tue Jan 25, 2011 6:37 pm
Location: Leicestershire
Contact:

Re: 32 bit Fault finding index

Postby paulv » Fri May 13, 2016 6:04 pm

Faulty Audio on the A300 and A400 series where sound can be heard on headphones but not via the speaker.

Typically down to a couple of faulty transistors. Replace and test with BC548 functional equivalents.

Image

Paul

User avatar
paulv
Posts: 3584
Joined: Tue Jan 25, 2011 6:37 pm
Location: Leicestershire
Contact:

Re: 32 bit Fault finding index

Postby paulv » Fri May 13, 2016 6:10 pm

Replacing battery holders in the A300/A400 and A400/1 series machines...

Parts required... 2 off. BX0035 http://www.bulgin.com/products/battery-holders.html

Tools required:

Soldering Iron
Drill
Pop Rivet tool
Snips

Method:

1 Drill out the old pop rivets and remove the old battery holders
2. Mount the new holders in place and fix with new pop rivets
3. Remove all wiring from old battery holders and solder to the new ones.

Results:

Image

Paul
Last edited by paulv on Fri May 13, 2016 6:17 pm, edited 1 time in total.

User avatar
paulv
Posts: 3584
Joined: Tue Jan 25, 2011 6:37 pm
Location: Leicestershire
Contact:

Re: 32 bit Fault finding index

Postby paulv » Fri May 13, 2016 6:15 pm

A5000 faults due to RAM control line failures.

Reason for fault:

Leaky SMT cap damage like the Amiga's suffer from :(

What it looks like:

Image

Image

Repair:

1. cut out IC59 and then remove what remains of the legs or use a rework station to remove the IC.
2. continuity check the lines noting the available schematic has two lines mixed up...
3. repair any tracks with kynar
4. replace the capacitor with an SMT (or through hole if you haven't got an SMT rework station) capacitor
5. solder in a new 74AC138.
6. Re-assemble and test.

Paul
Last edited by paulv on Tue Aug 08, 2017 8:25 pm, edited 1 time in total.

User avatar
paulv
Posts: 3584
Joined: Tue Jan 25, 2011 6:37 pm
Location: Leicestershire
Contact:

Re: 32 bit Fault finding index

Postby paulv » Fri May 13, 2016 6:21 pm


User avatar
paulv
Posts: 3584
Joined: Tue Jan 25, 2011 6:37 pm
Location: Leicestershire
Contact:

Re: 32 bit Fault finding index

Postby paulv » Fri May 13, 2016 6:23 pm

RISC OS 3 POST documentation

Paul
Attachments
RISCOS-POST-AppNote225.pdf
(61.36 KiB) Downloaded 41 times

User avatar
1024MAK
Posts: 6729
Joined: Mon Apr 18, 2011 4:46 pm
Location: Looking forward to summer in Somerset, UK...

Re: 32 bit Fault finding index

Postby 1024MAK » Fri May 13, 2016 8:58 pm

Thank you Paul for all those detailed posts, excellent work and good examples for everyone =D> =D> =D>

Mark
For a "Complete BBC Games Archive" visit www.bbcmicro.co.uk NOW!
BeebWiki‬ - for answers to many questions...

munchausen
Posts: 168
Joined: Fri May 30, 2014 8:53 am

Re: 32 bit Fault finding index

Postby munchausen » Sat May 14, 2016 7:29 am

This is great idea, but if there were a dedicated sub forum it would be much easier to find specific issues. Otherwise wont we will end up scrolling through one enormous thread?

JonC
Posts: 616
Joined: Wed May 14, 2014 9:19 pm
Location: Wakefield

Re: 32 bit Fault finding index

Postby JonC » Sat May 14, 2016 3:35 pm

You could use the 'Search this topic' function and put some key words in. :P
Jon
Image

munchausen
Posts: 168
Joined: Fri May 30, 2014 8:53 am

Re: 32 bit Fault finding index

Postby munchausen » Sun May 15, 2016 6:45 pm

An index is better than a search IMO, but OK. And I applaud the effort anyway, this is a great initiative.

AndyMc1280
Posts: 582
Joined: Sat Aug 27, 2011 10:50 am

Re: 32 bit Fault finding index

Postby AndyMc1280 » Tue Aug 30, 2016 8:27 pm

Broken Floppy drive (or can I convert a PC drive to work with my Arc?)

http://www.chiark.greenend.org.uk/~theo ... -acorn.txt

Plus a whole load of other tasty resources from Theo Markettos

http://www.chiark.greenend.org.uk/~theo ... hdocs.html

Not my work, but I have had a floppy drive converted using the above instructions and it works fine on my A3010.

User avatar
paulv
Posts: 3584
Joined: Tue Jan 25, 2011 6:37 pm
Location: Leicestershire
Contact:

Re: 32 bit Fault finding index

Postby paulv » Tue Aug 08, 2017 8:25 pm

My refurbished A3000 died a couple of days ago.

After 6 hours up time, I went to reboot the machine and it failed to come back. Power cycling the machine left the BenQ 912 monitor flickering between a black screen and a no connection warning screen. The floppy drive light was flashing. It returned the POST error code of 10009 which translates to "Unreadable CMOS".

So, the machine got stripped down, the multi-meter was applied to buzz out the connections and everything was good. There was no sign of corrosion and the machine was cleaned up with an new Varta battery fitted about 3 years ago. I decided to whip out the CMOS chip and replace it with a brand spanking new chip from my current stock of these now "rare at sensible prices" through hole CMOS chips.

After putting the machine back together, I powered on holding the DEL key down to clear the CMOS, then power cycled with R and T until a picture appeared on screen. From there it was a simple case of setting the config back up correctly from my on disc backup and another reboot to get the machine up and running from the IDE CF flash card and the external network card working :D

So, even after the clean up of the original damage from the battery leak from years gone by, the alkali carried on working its evil magic on the CMOS chip until three years later, it went pop.

If you're reading this and have battery damaged A3000's, it might be worth switching out the CMOS chip whilst you're doing the battery replacement/cleanup regardless of how it works and/or looks for the future.

Paul

steve3000
Posts: 1702
Joined: Sun Nov 25, 2012 12:43 am

Re: 32 bit Fault finding index

Postby steve3000 » Tue Aug 08, 2017 10:11 pm

Great advice Paul, and coincidentally I have just had the very same fault from my A5000 - indeed I've just been interrogating your Web pages to decode the floppy POST message :)

Another job for the weekend...


Return to “hardware”

Who is online

Users browsing this forum: No registered users and 6 guests