Issue 4 Electron - Won't power up

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KenLowe
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Issue 4 Electron - Won't power up

Post by KenLowe » Sun Mar 01, 2020 6:59 pm

A few weeks ago, I found some long lost hardware in my garage. Amongst them were 2 Electron. Today, I got around to switching them on to see if they were working. 50% success!

One is Issue 6 and it powers up fine. Light comes on and it responds to Ctrl-G. I've not plugged it into a monitor yet.
The other is Issue 4, but it doesn't power up at all. No light. No response to Ctrl-G. I'm using the same PSU as the one I used to test the Issue 6. I measure +5v and -5v on the 3 pin connector on the motherboard. I've swapped keyboards around. No difference. I've removed the ULA, and tried cleaning up the socket pins, and the chip contacts. No difference.

Any pointers as to what to try next?

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roland
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Re: Issue 4 Electron - Won't power up

Post by roland » Sun Mar 01, 2020 7:08 pm

I'd also reseat the 6502 and the ROM. If that does not help try to find out if the CPU is running by checking the SYNC pin, address and data lines with a scope (if you have one available).
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Re: Issue 4 Electron - Won't power up

Post by KenLowe » Sun Mar 01, 2020 7:15 pm

Sorry. Should have said that nothing else is socketed. I have a scope, so can certainly probe 6502 lines and see what they do.

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Re: Issue 4 Electron - Won't power up

Post by mr-macrisc » Sun Mar 01, 2020 8:55 pm

Inspect and reseat the ULA and inspect closely for loose/broken pins on socket. Check that your getting voltage coming out of psu as well.

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Re: Issue 4 Electron - Won't power up

Post by daveejhitchins » Sun Mar 01, 2020 9:15 pm

If you are getting NO screen output at all (?) then power connector first, Voltage measurements second then ULA socket, for broken pins then report back . . .

Dave H :D
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roland
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Re: Issue 4 Electron - Won't power up

Post by roland » Sun Mar 01, 2020 11:11 pm

As I understand, the power supply might be ok: I measure +5v and -5v on the 3 pin connector on the motherboard..
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KenLowe
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Re: Issue 4 Electron - Won't power up

Post by KenLowe » Sun Mar 01, 2020 11:18 pm

I did a fairly close inspection of the socket earlier today, and it looked okay, but I'll do a continuity check on it too, just to be sure. I've checked the voltage going to the board, and it looks okay; sitting at about 5v. I've also checked that there is voltage at various points on the board, and it's present everywhere I've tested. I've yet to connect it to a monitor, but given that I'm not getting the little yellow LED lighting up (and no Ctrl-G sound either), I'm not holding out much hope for the video. I'll get back to it tomorrow evening, and report back.

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Re: Issue 4 Electron - Won't power up

Post by KenLowe » Sun Mar 01, 2020 11:20 pm

roland wrote:
Sun Mar 01, 2020 11:11 pm
As I understand, the power supply might be ok: I measure +5v and -5v on the 3 pin connector on the motherboard..
That's correct. I've also just confirmed this in my previous post which I was writing as you posted!

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KenLowe
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Re: Issue 4 Electron - Won't power up

Post by KenLowe » Sun Mar 01, 2020 11:29 pm

Right. It turns out that I do have a broken pin in the socket. When I first saw the missing pin, I just assumed it was deliberately missing, but obviously not. I don't think I damaged this when I was trying to clean it, but I wouldn't bet on it!

What's the best way to fix this, or where can I get a replacement socket?

Edit: Just found some for sale on ebay for EUR15 from Poland delivered. Is that a reasonable price to pay?

And a follow on question... what's the easiest way to replace this socket? I'm guessing it might be easiest to break the socket apart, and then desolder the broken parts separately?
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Re: Issue 4 Electron - Won't power up

Post by daveejhitchins » Mon Mar 02, 2020 8:21 am

KenLowe wrote:
Sun Mar 01, 2020 11:29 pm
Right. It turns out that I do have a broken pin in the socket. When I first saw the missing pin, I just assumed it was deliberately missing, but obviously not. I don't think I damaged this when I was trying to clean it, but I wouldn't bet on it!

What's the best way to fix this, or where can I get a replacement socket?

Edit: Just found some for sale on ebay for EUR15 from Poland delivered. Is that a reasonable price to pay?

And a follow on question... what's the easiest way to replace this socket? I'm guessing it might be easiest to break the socket apart, and then desolder the broken parts separately?
Ken . . . A common fault! If you can remove the socket intact (?) I can either repair it for you (cost of postage here and back) or I can send a few pins for you to do the repair. I can also do the full repair, if needed - either way you chose . . .

€15 is probably a reasonable price as they're thin on the ground! If you do chose to go this route, please don't ditch the socket! I'll purchase it from you for the pins.

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
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Re: Issue 4 Electron - Won't power up

Post by 1024MAK » Mon Mar 02, 2020 2:02 pm

KenLowe wrote:
Sun Mar 01, 2020 11:18 pm
...but given that I'm not getting the little yellow LED lighting up..
That would be the caps lock indicator rather than a power on indicator.

Mark

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Re: Issue 4 Electron - Won't power up

Post by CMcDougall » Mon Mar 02, 2020 2:35 pm

^naaa, that comes on all the time at start up.

so, as he said, half the ULA pins are missing, hence dead :roll:
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Re: Issue 4 Electron - Won't power up

Post by KenLowe » Mon Mar 02, 2020 3:31 pm

1024MAK wrote:
Mon Mar 02, 2020 2:02 pm
KenLowe wrote:
Sun Mar 01, 2020 11:18 pm
...but given that I'm not getting the little yellow LED lighting up..
That would be the caps lock indicator rather than a power on indicator.

Mark
Ah. Okay. As you can probably tell, I'm a bit new to these Electrons! Not sure why I assumed it to be power light, particularly given that the Beeb has an equivalent caps lock light that comes on at power up.
CMcDougall wrote:
Mon Mar 02, 2020 2:35 pm
so, as he said, half the ULA pins are missing
I don't recall saying that. However, one pin is broken, for sure :roll:

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Re: Issue 4 Electron - Won't power up

Post by 1024MAK » Mon Mar 02, 2020 5:07 pm

CMcDougall wrote:
Mon Mar 02, 2020 2:35 pm
^naaa, that comes on all the time at start up.
In a machine where the 6502 is running the ROM code, yes...
CMcDougall wrote:
Mon Mar 02, 2020 2:35 pm
so, as he said, half the ULA pins are missing, hence dead :roll:
Hence, with a ULA socket contact missing, it’s unlikely that the 6502 is running the ROM code correctly... :roll:

Mark

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Re: Issue 4 Electron - Won't power up

Post by CMcDougall » Tue Mar 03, 2020 7:38 pm

have you tried the tin foil trick ??

would save all the hastle if something else is dead...
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Re: Issue 4 Electron - Won't power up

Post by KenLowe » Tue Mar 03, 2020 10:35 pm

CMcDougall wrote:
Tue Mar 03, 2020 7:38 pm
have you tried the tin foil trick ??

would save all the hastle if something else is dead...
I did think about trying something like that, but will probably just go straight for the repair. I've not had much time these last couple of days, but will hopefully get some time tomorrow to try and desolder the socket. What's the recommended method for removing the socket without causing further damage? Remove as much solder as possible, and then hot air gun?

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Re: Issue 4 Electron - Won't power up

Post by daveejhitchins » Wed Mar 04, 2020 8:34 am

KenLowe wrote:
Tue Mar 03, 2020 10:35 pm
CMcDougall wrote:
Tue Mar 03, 2020 7:38 pm
have you tried the tin foil trick ??

would save all the hastle if something else is dead...
I did think about trying something like that, but will probably just go straight for the repair. I've not had much time these last couple of days, but will hopefully get some time tomorrow to try and desolder the socket. What's the recommended method for removing the socket without causing further damage? Remove as much solder as possible, and then hot air gun?
I removed one yesterday . . . They are a pain :twisted: - I usually use my desolder station (vacuum pump) but it takes quite some time to get all the pins loose enough to extract the socket. But . . . Yesterday I used my new Aldi Hot Air tool :mrgreen: Set to 350C the socket came out within a few seconds =D>

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

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Re: Issue 4 Electron - Won't power up

Post by KenLowe » Wed Mar 04, 2020 8:44 pm

daveejhitchins wrote:
Wed Mar 04, 2020 8:34 am
I removed one yesterday . . . They are a pain :twisted: - I usually use my desolder station (vacuum pump) but it takes quite some time to get all the pins loose enough to extract the socket. But . . . Yesterday I used my new Aldi Hot Air tool :mrgreen: Set to 350C the socket came out within a few seconds =D>
Well, that's the socket out, but not without a bit of damage to some of the other pins on the socket. I've cleaned up the thru holes on the board, and everything else looks fine, so I'll order up a replacement socket and see how I get on from there...

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Re: Issue 4 Electron - Won't power up

Post by KenLowe » Fri Mar 13, 2020 1:19 pm

Replacement socket arrived today. I've soldered it in and we're back in action! Well, at least I think I am. The little yellow LED comes on, and I get a Beep when I press CTRL-Break, or do a CTRL-G. I've still to hook it up to a monitor, but that's a job for another day.

@Dave - Happy to send you the remains of my original socket if it would be of any use. It's in tact, apart from missing a few pins. PM me if interested.

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Re: Issue 4 Electron - Won't power up

Post by 1024MAK » Fri Mar 13, 2020 2:25 pm

I’m astonished that you have not yet connected up the video... :shock:
I mean, it’s not like Acorn did not give you any options...
  1. RGB socket wired exactly the same as the BBC Micro,
  2. Phono composite out (mono as standard) exactly the same as the BBC Micro,
  3. UHF TV output exactly the same as the BBC Micro,
[-X [-(

Mark

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Re: Issue 4 Electron - Won't power up

Post by KenLowe » Fri Mar 13, 2020 2:58 pm

It's not the video outputs that's the issue, particularly*. I need to clamber behind the TV or under desks to get to a power socket that's close to a TV / monitor to plug in the massive wall wart. Easier just to plug into a nearby socket for a quick test. I will do a fuller test soon.

*I've actually modified most of my beebs to use a 8 pin RGB socket to also carry the audio, so a cable swap is also required until I 'upgrade' the Electron socket too!

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Re: Issue 4 Electron - Won't power up

Post by KenLowe » Fri Apr 03, 2020 9:29 pm

1024MAK wrote:
Fri Mar 13, 2020 2:25 pm
I’m astonished that you have not yet connected up the video... :shock:
So, having previously replaced the ULA socket, I had some spare time this afternoon to look at this Electron in a bit more detail. It powered up ok, but half the keys weren't working, so stripped down the keyboard, removed the faulty key switches, cleaned the pins and soldered them back in again. I also took the opportunity to clean the case and all the key tops. Case is still a bit yellow, but there's not much I can do about that. Powered up, and now working perfectly. I now need to work out what to do with it...
20200403_211544.jpg
Repaired Issue 4 Electron
capture0.png
Screen capture using Hoglets RGB to HDMI via PI Adaptor

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Re: Issue 4 Electron - Won't power up

Post by 1024MAK » Fri Apr 03, 2020 9:32 pm

You can start by upgrading the Plus 1 OS ROM... :wink:

Mark

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Re: Issue 4 Electron - Won't power up

Post by rmbrowngr » Fri Apr 03, 2020 9:33 pm

Nice work. Another working Elk.
Richard B
Acorn Electrons issue 4 and 6, MRB, Plus 1, AP6, AP5, Pegasus 400, BeebSCSI, Gotek, Raspberry Pi, GoSDC MBE.
BBC B+ 64K (128K upgraded) with Duel OS, Raspberry Pi and Gotek.

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Re: Issue 4 Electron - Won't power up

Post by KenLowe » Fri Apr 03, 2020 10:41 pm

1024MAK wrote:
Fri Apr 03, 2020 9:32 pm
You can start by upgrading the Plus 1 OS ROM... :wink:
Think I've got quite a lot to learn about the Electron / Plus 1 :?

I've read a few posts about upgrading the ROM, and found a link to here. Is this what I should be upgrading to (the 16k ROM - AP6v131t.rom)? Is this just a drop in replacement, or do I need to make any hardware modifications? Is there any downside to upgrading to this ROM?

Thanks.

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Re: Issue 4 Electron - Won't power up

Post by daveejhitchins » Sat Apr 04, 2020 8:39 am

KenLowe wrote:
Fri Apr 03, 2020 10:41 pm
1024MAK wrote:
Fri Apr 03, 2020 9:32 pm
You can start by upgrading the Plus 1 OS ROM... :wink:
Think I've got quite a lot to learn about the Electron / Plus 1 :?

I've read a few posts about upgrading the ROM, and found a link to here. Is this what I should be upgrading to (the 16k ROM - AP6v131t.rom)? Is this just a drop in replacement, or do I need to make any hardware modifications? Is there any downside to upgrading to this ROM?

Thanks.
Unfortunately you can't use the AP6 ROM as it's a 16K Image and the Plus 1 only supports an 8K image. The version you want can be found here. I've attached the User Guide - Note: this ROM is currently being finalised, so keep you eyes on MDFS.NET and these pages for any updates.

Plus 1 User Guide.pdf
(835.29 KiB) Downloaded 15 times

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

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Re: Issue 4 Electron - Won't power up

Post by KenLowe » Sat Apr 04, 2020 11:26 am

daveejhitchins wrote:
Sat Apr 04, 2020 8:39 am
Unfortunately you can't use the AP6 ROM as it's a 16K Image and the Plus 1 only supports an 8K image. The version you want can be found here. I've attached the User Guide - Note: this ROM is currently being finalised, so keep you eyes on MDFS.NET and these pages for any updates.
Hi Dave. Thanks for the information and the manual. I think I'm starting to get a better understanding of it all.

Would I be correct in understanding that I need one of your AP6 boards if I want to install multiple ROMs, and that this board fits inside the AP1?

If I also want to get PiTubeDirect running, then I would also need to also get on of your AP5 boards, which then gives me 2 user ports, tube port and 1mhz interface? And this AP5 board would plug into the cartridge slot on the AP1?

Are you still selling your AP5 & AP6 boards?

Finally, although not photographed, I also have a PRES AP3 board which gives me ADFS when plugged in. Is there a DFS equivalent? I assume my goteks will work fine with the AP3 board?

Thanks

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Re: Issue 4 Electron - Won't power up

Post by 1024MAK » Sat Apr 04, 2020 12:10 pm

It’s possible to upgrade an AP3 to an AP34 (AP3/4). An AP34 has both ADFS and DFS. See this link for photos of my upgraded AP3 ;-)

Mark

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Re: Issue 4 Electron - Won't power up

Post by daveejhitchins » Sat Apr 04, 2020 12:21 pm

Hi Dave. Thanks for the information and the manual. I think I'm starting to get a better understanding of it all.

Would I be correct in understanding that I need one of your AP6 boards if I want to install multiple ROMs, and that this board fits inside the AP1?

Yes you would and it does.

If I also want to get PiTubeDirect running, then I would also need to also get on of your AP5 boards, which then gives me 2 user ports, tube port and 1mhz interface? And this AP5 board would plug into the cartridge slot on the AP1?
Yes and Yes.

Are you still selling your AP5 & AP6 boards?

:oops: a second batch is overdue for both boards. AP5 first. AP6 still needs an extra feature adding.

Finally, although not photographed, I also have a PRES AP3 board which gives me ADFS when plugged in. Is there a DFS equivalent? I assume my goteks will work fine with the AP3 board?
Yes, the AP3 was ADFS (to match the Acorn Plus 3 numbering) and the AP4 was DFS - However, it was also sold as an AP3/4 or you could upgrade either the AP3 or AP4 to an AP3/4 by adding the appropriate ICs. Your AP3 'should' have a 2 pin header and jumper on the IC nearest the gold fingers (if not I can send you the parts to fit). The DFS (E00 version) is a ROM and RAM (2 x ICs) and a removal of the jumper. Gotek should work just fine :mrgreen:

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ARA III, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

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Re: Issue 4 Electron - Won't power up

Post by KenLowe » Sat Apr 04, 2020 12:28 pm

1024MAK wrote:
Sat Apr 04, 2020 12:10 pm
It’s possible to upgrade an AP3 to an AP34 (AP3/4). An AP34 has both ADFS and DFS. See this link for photos of my upgraded AP3 ;-)

Mark
daveejhitchins wrote:
Sat Apr 04, 2020 12:21 pm
Yes, the AP3 was ADFS (to match the Acorn Plus 3 numbering) and the AP4 was DFS - However, it was also sold as an AP3/4 or you could upgrade either the AP3 or AP4 to an AP3/4 by adding the appropriate ICs. Your AP3 'should' have a 2 pin header and jumper on the IC nearest the gold fingers (if not I can send you the parts to fit). The DFS (E00 version) is a ROM and RAM (2 x ICs) and a removal of the jumper. Gotek should work just fine :mrgreen:
Thanks Mark & Dave. That's helpful. I'll get to that shortly. However, firstly...
1024MAK wrote:
Fri Apr 03, 2020 9:32 pm
You can start by upgrading the Plus 1 OS ROM... :wink:
I'm looking at what I need to do to upgrade the Plus 1 ROM. The existing ROM is 24 pin. I understand it's a compact 8k ROM (2364?) that has a different pinout to the standard 2764. Do I need an adaptor board to use a standard 2764 / 27128 EPROM? This thread seems to suggest otherwise.

Sorry for all the questions. I'm confused!

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