Search found 42 matches

by jpagen
Sun May 31, 2020 9:57 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Spent a few hours this weekend stripping down the keyboard and giving everything a good clean. ..no change. I then noticed there was a slight curve in the keyboard metal back plate ..between the LEDs which were not working...too much of a coincidence! I temporarily placed some tissue between the mem...
by jpagen
Tue May 26, 2020 10:20 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Excellent - glad to hear you've successfully restored your A3000 back to it's original early 90's greatness :) Cheers steve3000! It is actually better than early 90s. I only had 2MB back then. Now I have a massive 4MB! :D . Got an external CMOS battery fitted now and bypassed the sound filters. Als...
by jpagen
Mon May 25, 2020 10:36 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Looks like D16-D19 are being read incorrectly, That corresponds to IC24. Check the connections to all the pins and trace the data pins back to the ARM via R50,R115,R116,R117. I finally replaced IC24 and issue resolved. No more corrupt display when booting with the on board RAM. :D You'd have to dis...
by jpagen
Sat May 16, 2020 5:51 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Not sure what to suggest, if the test roms show a video display, then aiui risc os 2 should display something. I don't think swapping from test roms to risc os 2 should need any link changes. How confident are you in the risc os roms being all good? Can you post pictures of the roms fitted and the ...
by jpagen
Fri May 15, 2020 10:39 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

I'd focus on this. Without that connection, none of the keyboard is likely to work correctly. Thanks IanS-you were right! I restored the Pin 12 to IC2 connection this evening, rechecked all the traces from IC4, ignoring the different LK<x> and the machine accepts keyboard input with the RAM Test Ro...
by jpagen
Thu May 14, 2020 10:43 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Hi All Managed to get a bit of time after work today to check my connections from IC4 and IC5 According to the circuit diagram http://chrisacorns.computinghistory.org.uk/docs/Acorn/Manuals/Acorn_A3000TRM_drawings.zip , most of the connections on IC4 and IC5 appear OK. However there seems to be some ...
by jpagen
Wed May 13, 2020 10:34 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Hi All Seem to have gone back a step! Got some new SN74LS145N today and inserted in to the sockets.Tried the RAM TEST ROMs which boot but there is no response from the keyboard. Swapped in the RISCOS 3.11 ROMs and changed the ROM jumpers but they refuse to boot with no POST boot flashes or messages....
by jpagen
Sun May 10, 2020 9:30 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Great modifications those Thanks Steve3000-the first thread is yours and the 2nd one was Zarchos =D> Any evidence of the machine crashing during normal operation? E.g. if you leave a demo or game running? Or fill the memory with lots of desktop apps running? I had one crash but that may or may not ...
by jpagen
Thu May 07, 2020 10:42 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Hi All Continuing with my A3000 project. Performed the sound mod https://stardot.org.uk/forums/viewtopic.php?t=13630 and fitted a Burr-Brown OPA4134PA https://stardot.org.uk/forums/viewtopic.php?f=16&t=11287 I made a recording from the headphone socket pre and post mod and It sounds significantly cl...
by jpagen
Sun Apr 12, 2020 9:45 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

This may be what you need: https://uk.farnell.com/schurter/4850-29 ... /dp/152392 Thanks Kazzie Looking at the technical document, that appears to be the right layout. However I managed to disassemble the original mouse socket and reassemble. The short is resolved and I have a fully functioning mou...
by jpagen
Sat Apr 11, 2020 5:08 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

I did remove the mouse socket to clean off the corrosion so I will remove and check again. OK so I removed the mouse socket and the short between IC2 pin 26 and pin 40 is resolved. Checking the removed mouse socket and the short between pin 5 and 6 is within the mouse socket itself. :o I will try a...
by jpagen
Sat Apr 11, 2020 3:13 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Firstly, I'd suggest checking if there's continuity between the two with your mouse unplugged (in case you haven't already done so). If the short is still present, R576 is a 10k pull-up resistor between Xd and 5V, there may be a short bypassing that resistor. On the mouse socket, pin 6 (adjacent To...
by jpagen
Sat Apr 11, 2020 9:20 am
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Working from the A3000 datasheet, pin 2 on IC2 (8051AH) is part of Port 1, which is wired to the keyboard interface socket SK6. It shouldn't be connected to pin 26 and the mouse as well. Thanks Kazzie Just to clarify, it is pin 40 and pin 26 which appear to be connected on IC2, not pin 2 and pin 26...
by jpagen
Fri Apr 10, 2020 9:50 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Thanks sP1d3r for the responses. I have been investigating further and tried another mouse to rule out problems with my mouse and get the same problem. ie no movement in the x axis. Actually I get a slight flicker in the x axis so clearly something is being read but no actual movement. Mouse buttons...
by jpagen
Tue Mar 31, 2020 9:30 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

I wondered if you'd seen the 'Very Dead A3000' post re: L7->8051 connection Thanks! No hadn't see that. Here is the link if anyone else is looking https://stardot.org.uk/forums/viewtopic.php?t=18126 I have continuity between L7 and the 8051 though and my mouse y axis is fine. Does anyone know where...
by jpagen
Sun Mar 29, 2020 9:58 am
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Kazzie wrote:
Sat Mar 28, 2020 8:27 pm
Is that the same chip as used in the A4x0/1 series for on-board RAM expansion?
Thanks Kazzie. Checked the service Manual http://chrisacorns.computinghistory.org ... R140SM.pdf
They seem to have the same part number (0704.118)
by jpagen
Sat Mar 28, 2020 7:08 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Congratulations! It's a good feeling when that desktop appears! Thanks! Yes it was a great relief! Looks like D16-D19 are being read incorrectly, That corresponds to IC24. Check the connections to all the pins and trace the data pins back to the ARM via R50,R115,R116,R117 I traced the pins from IC2...
by jpagen
Thu Mar 26, 2020 10:03 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Have you tried reseating the ARM3 board (to help remove any oxidation between the socket pins and riser board) I took a look at the ARM3 board today. On removal I could see some slight green corrosion in a few pins which came off easily with a little white vinegar , rinsing with water and finally a...
by jpagen
Wed Mar 25, 2020 10:30 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Thanks Steve3000! yes using the original Riscos3.11 ROMs. I have never removed the ARM3 board. I have gently pressed down on it to see it was loose but it feels secure. I could see if I can remove it and re-inserting if the connections are oxidised Unfortunately I don't have the ARM2. I will also tr...
by jpagen
Wed Mar 25, 2020 9:25 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Thanks IanS and Steve3000 for your help. I will check the traces when I get a bit more time...probably the weekend. I did try my 4MB ram card and it is looking more hopeful now. The screen corruption has gone The test roms aborted after about 10 mins or so though. I bought the 4MB board on line rece...
by jpagen
Tue Mar 24, 2020 10:19 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Hi All Just tried the RAM Test ROMS-here is a screenshot- a3000 test roms.jpg As you can see-there is finally visible text along with a pattern displayed in columns. I was able to use the keyboard to choose option 2 (Cyclic Memory test). This is the first time I have at least been able to confirm th...
by jpagen
Wed Mar 04, 2020 10:08 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Just to check, did you switch the ROM links back over to the RISC OS 2 settings? I would have hoped to see at least "RISC OS 1024K" on startup before a crash of some sort...? Thanks for checking Steve3000! I changed the links for RISCOS 2 based on notes I made when I upgraded to RISCOS3- Link posit...
by jpagen
Mon Mar 02, 2020 11:00 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

So the only way that your motherboard has been modified for the ARM3 processor is that a PLCC socket has been soldered to the pads for the cpu pins? I have had the machine since new The following upgrades have been performed:- -Serial port rom installed shortly after purchase -Installation of the A...
by jpagen
Sun Mar 01, 2020 9:30 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

I don't think that the RO3 roms are the right ones, I think they might be for a different computer. Thanks for taking a look. I believe the roms are OK. I installed the roms myself in the mid 90's and still have the instructions that came supplied referencing the A3000. I wonder if an Arm3 works wi...
by jpagen
Sun Mar 01, 2020 12:39 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Thanks everyone for the comments. I've watched a video of A3000 repair by 'Plan C' on Youtube that I thought was good, although getting a keyboard connector out without lifting traces would involve using a dremel with a mini grinding disc or similar to try to remove the plastic parts of the connecto...
by jpagen
Thu Feb 27, 2020 10:33 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

The new CMOS arrived today so I desoldered the old one, cleaned the area with white vinegar and IPA, checked continuity in the links before soldering in a socket and fitting the new CMOS. Still getting the &20101 POST flashing LEDs. :( To date, I have replaced the zero ohm resistors L6-L14, checked ...
by jpagen
Sat Feb 22, 2020 10:31 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

I've spent the best part of the day checking continuity around the battery area. As far as I can tell, looking at the circuit diagram there should be a connection from the resistor L7 up to pin 1 on the SK7 keyboard connector but that was broken. I was not expecting that to be the problem but bridge...
by jpagen
Tue Feb 18, 2020 10:56 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

After a busy weekend, I have finally got around to checking continuity, so far I have not found a problem. I am thinking I may need to desolder IC4 and IC5 and see what is happening underneath. Before I do that, I am wondering if I would be better to sort out my worn keyboard ribbon first. If the de...
by jpagen
Thu Feb 13, 2020 10:34 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

Thanks IanS. I tried inserting images before but they didn't display. I must have done something wrong. Here is an image after removing the resistors before cleaning with vinegar, water and IPA a3000_3.jpg I am still getting the &20101 error that I had before after cleaning and replacing the resisto...
by jpagen
Tue Feb 11, 2020 6:33 pm
Forum: 32-bit acorn hardware
Topic: A3000 power on test check error
Replies: 74
Views: 2841

Re: A3000 power on test check error

I have had another go at cleaning the affected area and it looks better. https://ibb.co/XF8BTJs The traces around L7, L8, L9 and L10 look like they may be intact. There is still some green corrosion but a lot better than it was. However I noticed that the L8 resister is actually broken so that may b...

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