Teething troubles with 'new-to-me' Elk

[jugganaut]

I recently purchased a new (to me) Electron with Slogger MRB installed and came with a Plus 1 and AP3 (but no drive). I also bought an ElkSD cartridge. It was advertised as untested, but the price was good enough to take a punt on. The seller confirmed it beeped and the yellow light came on at power up. He had recently got it out of the attic after being stored for some years (believe it was his late FIL's machine).

When I first booted the machine up a few days ago using the SCART cable that came with the machine on my modern-ish flatscreen TV, I could make out the Acorn Electron, BASIC > text, but it was skewed and flickering. The cable was a homemade RGB to SCART which looked OK but old, so first things first I thought I would check was the cable so I bought a brand new RGB to SCART and tried that and got the same result (or slightly worse in fact). I subsequently tried the UHF alongside a couple of different TVs to no effect.

I tried it again today and, would you believe it, it booted up fine! I typed some instructions (some of the keys are a bit sticky) and all seemed well, except flicking the MRB switch/rebooting made no difference - it only booted up in 'normal' mode. Also, on a couple of occasions, it would 'crash' exhibiting the similar symptoms as before (mostly blank screen with some white specks).

I opened the cover and had a loof for anything obviously loose, pressing and wiggling various things. Following that, I did manage to get it to recognise the different MRB modes, although with the Plus 1 connected, sometimes different switch positions would not notice the peripherals (ElkSD+1 &/or AP3) in the cartridge slots.

Given the intermittent nature of the faults, it seems clear something is loose or badly connected. Can anyone advise me what things to check first? I thought removing/re-seating the MRB might help but it didn't lift easily - should it just pull out (I was wary of exerting too much force on a 30+ yr old PCB)?

With the sticky keys, I thought I would start with some contact cleaner squirted in the key switches first and see what that does. The ribbon cable looks OK and I can't see any obvious external damage to any of the keys.

Any help/advice you can give would be gratefully received.

Tim

[rmbrowngr]

A picture of the screen output would help and knowing which motherboard issue (e.g. a picture of the inside of the Elk).

Try a minimum setup first e.g. only the Elk. If this works one by one add the additional hardware to see what happens.

[jugganaut]

Thanks for the reply. Here are photos of inside the machine plus an example of what the screen looks like when it crashes. Before it crashes, the display looks normal.

[rmbrowngr]

I would guess it’s either the ULA or memory. Take a look at this topic viewtopic.php?f=3&t=19887 for the ULA.

[jugganaut]

Thanks. I'll have a go at cleaning/reseating the ULA later today. I tried some switch cleaner on the sticky keys and managed to get a few back but 9, Left Arrow, Right Arrow, P, Up Arrow, D, Left Shift and Full Stop are all completely not working. Is it possible to remove individual switches to better clean them.

Incidentally, whilst I was working on the keys, it did it's usually crash once but when I hit Ctrl Break, I got a very weird screen

The only way to reset from here was to unplug.

Also I have ascertained that it seems to consistently stop recognising the Plus 1 when changing between Normal and Turbo/64k operation, i.e. if you flick the switch then Ctrl Break, it doesn't see the +1. However if you unplug it sees it again. Switching between Turbo/64k is fine, it's just between either of those and Normal, if that makes sense?

[daveejhitchins]

Thanks. I'll have a go at cleaning/reseating the ULA later today. I tried some switch cleaner on the sticky keys and managed to get a few back but 9, Left Arrow, Right Arrow, P, Up Arrow, D, Left Shift and Full Stop are all completely not working. Is it possible to remove individual switches to better clean them.

Incidentally, whilst I was working on the keys, it did it's usually crash once but when I hit Ctrl Break, I got a very weird screen

The only way to reset from here was to unplug.

Also I have ascertained that it seems to consistently stop recognising the Plus 1 when changing between Normal and Turbo/64k operation, i.e. if you flick the switch then Ctrl Break, it doesn't see the +1. However if you unplug it sees it again. Switching between Turbo/64k is fine, it's just between either of those and Normal, if that makes sense?

Tim . . . I think you need to do a little maintenance, as follows:

First - the ULA: Just follow the instructions in the link you've been given.

Next - Remove the Electron PCB and clean the rear edge connector with a soft rubber and finish off with IPA.

Next - While you have the Electron PCB out - Carefully remove the MRB board and spray the 40 pin socket with contact cleaner - then replace the MRB. If you have a multimeter or continuity tester (?) test the three position switch.

Next - The keys - They don't seem to be tied together (you can find the Electron Service Manual online via Google) so the usual cure is tapping each of the 'bad' keys, with vigor, 100 times! If that doesn't work let us know and I'll describe the way to clean individual switches - They're relatively easy to remove one at a time.

Dave H.

[davidb]

I've never used a Master RAM Board but, according to the user guide available from the 8-Bit Software site, you'll need to press Ctrl-Break after switching between modes. Maybe that will make the Plus 1 visible again.

[jugganaut]

Tim . . . I think you need to do a little maintenance, as follows...

Thanks Dave. I've completed all the above and, fingers crossed, so far I seem to have achieved some stability (i.e. it hasn't crashed again...yet!)

Unfortunately the non-functioning keys are preventing me from doing much more than typing on the screen right now (one of the keys that doesn't work is the D so I can't type any of the MMFS commands required to load any software!) so I can't really put it's through it's paces until I resolve the keyboard issues. I've tried tapping the bad keys as described and that hasn't helped any of the ones previously listed (9, Left Arrow, Right Arrow, P, Up Arrow, D, Left Shift and Full Stop), although it did improve the performance of some of the other keys that were a bit off/on. Looking at the back of the keyboard PCB, there are some small spots of corrosion (pic below) - could this be affecting things at all ?

I've never used a Master RAM Board but, according to the user guide available from the 8-Bit Software site, you'll need to press Ctrl-Break after switching between modes. Maybe that will make the Plus 1 visible again?

Thanks, I was using Ctrl Break and this doesn't work - although unplugging the power does work. TBH it's a minor inconvenience for now so I might just leave it. Although I was looking at the Slogger MRB installation instructions I found online and they mentioned a mod to the Plus 1 which doesn't appear to have been done on mine. Could this have anything to do with it do you think?

[daveejhitchins]

Unfortunately the non-functioning keys are preventing me from doing much more than typing on the screen right now (one of the keys that doesn't work is the D so I can't type any of the MMFS commands required to load any software!) so I can't really put it's through it's paces until I resolve the keyboard issues. I've tried tapping the bad keys as described and that hasn't helped any of the ones previously listed (9, Left Arrow, Right Arrow, P, Up Arrow, D, Left Shift and Full Stop), although it did improve the performance of some of the other keys that were a bit off/on. Looking at the back of the keyboard PCB, there are some small spots of corrosion (pic below) - could this be affecting things at all ?
The corrosion you're pointing out just looks like Flux. Someone may have already tried to 'fix' the keys and just not bothered to clean-up. Don't worry too much about it.

Fixing keys: Remove the key caps from the offending keys and wick the solder off around the pin. It's a single sided PCB so it's easy - then follow: this, this and this.

When you've removed the pin cleen off the 'black' with whatever you have to hand. I use Silver-Dip but have used Brasso in the past. No scratching! While you have the pin out spray some switch cleaner in there.

I've never used a Master RAM Board but, according to the user guide available from the 8-Bit Software site, you'll need to press Ctrl-Break after switching between modes. Maybe that will make the Plus 1 visible again?[/quote]

Thanks, I was using Ctrl Break and this doesn't work - although unplugging the power does work. TBH it's a minor inconvenience for now so I might just leave it. Although I was looking at the Slogger MRB installation instructions I found online and they mentioned a mod to the Plus 1 which doesn't appear to have been done on mine. Could this have anything to do with it do you think?

That mod. won't stop the MRB from working - I've not fitted it to any Plus 1 and I'm still not sure what it's for. Note to self - you need to investigate this further

Dave H.

[Marvin]

Also I have ascertained that it seems to consistently stop recognising the Plus 1 when changing between Normal and Turbo/64k operation, i.e. if you flick the switch then Ctrl Break, it doesn't see the +1. However if you unplug it sees it again. Switching between Turbo/64k is fine, it's just between either of those and Normal, if that makes sense?

The solution to that problem is listed here please read from there to the end.

As for a temporary work abound for your faulty "D" key, why not use the FN key plus any letter that had a function key word with a D in it and then use the cursor keys & copy the D on the screen into the command you're trying to type.

[jugganaut]

That's brilliant, thanks Dave. I'll be honest, my soldering skills to date extend to repairing/joining cables, and I've never 'de-soldered', but I'm willing to give it a go!

I noticed your location under your avatar - I had a good friend growing up who re-located from Wiltshire to Shildon in his teens. I used to visit him there and Newton Aycliffe was the stop before on the train, IIRC.

[jugganaut]

The solution to that problem is listed here please read from there to the end.

As for a temporary work abound for your faulty "D" key, why not use the FN key plus any letter that had a function key word with a D in it and then use the cursor keys & copy the D on the screen into the command you're trying to type.

Thanks I'll check that out. Sadly 3 of the faulty keys are arrow keys - only the down arrow works!

[walkerworks]

Although I was looking at the Slogger MRB installation instructions I found online and they mentioned a mod to the Plus 1 which doesn't appear to have been done on mine.

I remember that mod it came with the MRB I bought from Slogger. The capacitor came taped to the diagram but I've no idea what the value was and that Plus 1 was sold years ago so can't check - no help there . I did do the mod and had no trouble switching between modes.

My current MRB works ok as long as I switch it on in Normal mode, switching it on in turbo or shadow means I have to switch off again if I select normal. Maybe it would be worth trying the mod sometime..

[Marvin]

My current MRB works ok as long as I switch it on in Normal mode, switching it on in turbo or shadow means I have to switch off again if I select normal. Maybe it would be worth trying the mod sometime..

The mod doesn't fix the disappearing plus 1 when switching between Normal and the other 2 improved modes.

The routine is...
1) Start it in normal mode (plus 1 is okay at this point)
2) Switch to either Turbo or 64K, the machine will lock up at this point so a CTRL-BREAK is needed to unfreeze the machine.
3) The plus 1 will have disappeared now so enter *FX200,3 and CTRL-BREAK again (plus 1 should now reappear)
4) You can now jump back and forth between all 3 modes with only a CTRL-BREAK to reset the machine each time.

[daveejhitchins]

My current MRB works ok as long as I switch it on in Normal mode, switching it on in turbo or shadow means I have to switch off again if I select normal. Maybe it would be worth trying the mod sometime..

The mod doesn't fix the disappearing plus 1 when switching between Normal and the other 2 improved modes.

The routine is...
1) Start it in normal mode (plus 1 is okay at this point)
2) Switch to either Turbo or 64K, the machine will lock up at this point so a CTRL-BREAK is needed to unfreeze the machine.
3) The plus 1 will have disappeared now so enter *FX200,3 and CTRL-BREAK again (plus 1 should now reappear)
4) You can now jump back and forth between all 3 modes with only a CTRL-BREAK to reset the machine each time.

I've found, and recommend, that when switching between modes you carry out a power cycle. To make it easier fit an in-line switch in the low Voltage side of the Electron power lead. If you have data that you don't want to lose - save it first! There are enough storage options available these days!

Dave H.

[walkerworks]

My current MRB works ok as long as I switch it on in Normal mode, switching it on in turbo or shadow means I have to switch off again if I select normal. Maybe it would be worth trying the mod sometime..

The mod doesn't fix the disappearing plus 1 when switching between Normal and the other 2 improved modes.

The routine is...
1) Start it in normal mode (plus 1 is okay at this point)
2) Switch to either Turbo or 64K, the machine will lock up at this point so a CTRL-BREAK is needed to unfreeze the machine.
3) The plus 1 will have disappeared now so enter *FX200,3 and CTRL-BREAK again (plus 1 should now reappear)
4) You can now jump back and forth between all 3 modes with only a CTRL-BREAK to reset the machine each time.

I had a quick look at the mod and it does change fundamentally how the Plus 1 resets on power-on or on Breaks. The mod was issued by Slogger to fix a problem with the MRB/Plus 1 combination but for the life of me I wish I could remember the detail.

I just had a play with the MRB and I don't need to use Step 3, as long as I start in normal mode I can switch between any other with just a CTRL-BREAK. The Plus 1 never disappears.

I have decided not to take a scalpel to the Plus 1 to find out what the mod actually does so I'll be using an inline switch if power cycling is required.

[daveejhitchins]

I have decided not to take a scalpel to the Plus 1 to find out what the mod actually does so I'll be using an inline switch if power cycling is required.

I think it's time for me to look into this and see what happens with the mod carried out. I'll post here when I have an answer.

Dave H.

[daveejhitchins]

Well . . . That was easy!

The first first Plus 1 I pulled out of the cupboard had an original AP6 installed and had the MRB mod. carried out.

So, it removes the reset line from IC6 (74LS175 - Quad D Flip-Flops with Clear) and then the 470pF capacitor 'slugs' the reset line.

I'll give this a try when I find time and see if there's anything to report.

Dave H.

[Marvin]

I've found, and recommend, that when switching between modes you carry out a power cycle.

I am curious as to why you recommend power cycling as I've jumped back and forth between all 3 modes with only a Ctrl-Break for the last 30 odd years without any problems.

[daveejhitchins]

I've found, and recommend, that when switching between modes you carry out a power cycle.

I am curious as to why you recommend power cycling as I've jumped back and forth between all 3 modes with only a Ctrl-Break for the last 30 odd years without any problems.

Because, in my experience with dozens of different setups, it doesn't always work and as I always have an in-line power switch a few inches away from the Electron I know for certain that the Electron is going to be in a stable state for whatever testing I'm doing

Dave H.

[Marvin]

Because, in my experience with dozens of different setups, it doesn't always work and as I always have an in-line power switch a few inches away from the Electron I know for certain that the Electron is going to be in a stable state for whatever testing I'm doing

Fair enough, I'll bow to your experience but as I've never had a problem I'll continue as I always have done.