My 6128 is not booting anymore. When I turn the CPC on, the welcome message will appear and then the CPC resets, shows the message and so on in an endless loop. Has anyone an idea/suggestion how to fix this ?
Maybe is the keyboard or Z80 needs to be pressed down or maybe just wait Bryce ;D
Do you have any expansions fitted? Are your system ROMs socketed?
Sadly, I think I exactly know why the CPC is damaged but not how and where:
I've put an extension at my Mother-X4 not exactly at the right pins (as you may know, these are not idiot (me ;) ) save).
After that the CPC showed this behaviour.
If the ROMs are socketed, I don't know. I didn't open it for years, it is my main and first CPC and because of that I especially love this one. I've put many things into this CPC, for example ABBA-Switch, Reset-Switch, CPM-Switch, Pause-Switch but I never did something with the chips. So if they are not socketed by default, they are not.
@Shining (http://www.cpcwiki.eu/forum/index.php?action=profile;u=922)
Remove all peripherals, Mother x etc including external floppy drives.
Just the 6128 Power up as normal. Is the fault still there. ?
Ray
It could be a few different parts causing this, but you've definitely damaged either the ROM or some of the TTL logic. Most likely by feeding 5V into any output. Send the board over if you want.
Bryce.
Sounds like a corrupt lower ROM (or the BASIC or AMSDOS ROM). Yes, Bryce can help. :)
Board just arrived. I'll report back later in the week when I've had a chance to look at it.
Bryce.
Ok, a quick round of diagnostics later... 40015 (AMSDOS ROM) has D3 jammed high (not good). I'll put a socket in and replace it with an EPROM.
Bryce.
Thank you very much. Also for the socket.... ;)
If you want to test it later, please note, that I soldered an ABBA switch to the board and sending it to you I just cut the cables.... Also there are two wires on the Jumper for the CPM-switch (AMSDOS to ROM 0).
Yes, I discovered that quite quickly, especially as you have also removed LK7 and added wires to that too.
Bryce.
All tests completed, your 6128 is back working as it should.
Bryce.
Wonderful, thank you very much :) .
Quote from: Shining on 12:12, 05 September 16
Thank you very much. Also for the socket.... ;)
If you want to test it later, please note, that I soldered an ABBA switch to the board and sending it to you I just cut the cables.... Also there are two wires on the Jumper for the CPM-switch (AMSDOS to ROM 0).
What is the advantage of amsdos in slot 0. Surely the machine don't boot then?
Quote from: CraigsBar on 21:39, 05 September 16
What is the advantage of amsdos in slot 0. Surely the machine don't boot then?
It boots directly to CP/M when you have the right disk inserted.
Bryce.
Quote from: CraigsBar on 21:39, 05 September 16
What is the advantage of amsdos in slot 0. Surely the machine don't boot then?
Autoboots CPM when in slot 0.
Quote from: Duke on 21:43, 05 September 16
Autoboots CPM when in slot 0.
Really? Have to try that lol.
Require a special jumper set on the mainboard, if I'm not wrong?!
You are right. Just cut a metal wire on the PCB (or add a switch). Also putting FutureOS ROM A in slot 0 will cause autoboot of it. And cutting LK seven just "moves" AMSDOS from slot 7 to 0. :)
Quote from: Shining on 12:12, 05 September 16
.... Also there are two wires on the Jumper for the CPM-switch (AMSDOS to ROM 0).
Do You have link to the detail for this CPM Modification Please.
Thanks Ray
Here is a description of the LKs on the CPC-Mainboard:
LK Links - CPCWiki (http://www.cpcwiki.eu/index.php/LK_Links)
The CPM-one is LK7. When you cut it AMSDOS is switched to ROM0 and autoboots CPM.
I did this modification as a child as it had also the advantage that some games (e.g. Gauntlet) auto booted with this modification....
For those who are interested just to list all modifications to my 6128 I found useful back then:
- Reset-Switch
- Pause-Switch (Z80-Halt on Expansion-Port)
- ABBA-Switch
- CPM-Switch
- Switching manufacturer from Schneider to Amstrad
- Replacing the internal Speaker with two external ones (Internal CPC amplifier did handle this)