Print Page - I Have a CPC 464 that I have Killed with 12 Volts ** FIXED **

Title: I Have a CPC 464 that I have Killed with 12 Volts ** FIXED **
Post by: Audronic on 07:05, 01 November 18

I Have a CPC 464 that I have Killed with 12 Volts Grrrrr

The Model info is :- Z70200, MC 0002C

No Raster displayed (Rectangle) Just a Blank screen.

The 16 Mhz clock works.

I have taken chips from the faulty machine and tested them in the working machine.

I have swapped the 40010. It is Ok
I have swapped the Z80 It is OK

I looks like I will have to cut out the 6845 , socket and see what happens ???
Any comments Please.

Thanks. Ray

Title: Re: I Have a CPC 464 that I have Killed with 12 Volts Grrrrr
Post by: llopis on 08:39, 01 November 18

Before you cut out anything, do some basic checks:
- 5V everywhere
- No shorts between 5V and grnd
- Clock signal on Z80 (pin 8).
- Vsync signals from GA
- Basic activity on address and data buses

I recently had a COC without video, but it has complete lack of activity, starting with a clock signal (even though the 16MHz crystal was working). It turns out it was part of the circuit that feeds back that clock signal and generates the signal to the GA.

Sent from my iPhone using Tapatalk

Title: Re: I Have a CPC 464 that I have Killed with 12 Volts Grrrrr
Post by: Audronic on 10:43, 01 November 18

Before you cut out anything, do some basic checks:

- 5V everywhere
@ Checked all OK

- No shorts between 5V and grnd
@ Checked all OK

- Clock signal on Z80 (pin 6 ).
@ Checked OK

- Vsync signals from GA
@ Not looked at yet

- Basic activity on address and data buses
@ On the Z80 3 lines Odd

See the tables ?
Thanks. Ray

Title: Re: I Have a CPC 464 that I have Killed with 12 Volts Grrrrr
Post by: 00WReX on 12:16, 01 November 18

Did you try Geralds 'Quick and Dirty RAM test'.

Cheers,
Shane

Title: Re: I Have a CPC 464 that I have Killed with 12 Volts Grrrrr
Post by: Audronic on 20:54, 01 November 18

@00WReX (http://www.cpcwiki.eu/forum/index.php?action=profile;u=518)

Hi Shane

No I have not used the Ram test yet.
If I don't have a raster, I have no video out and I thought that I will have to wait until I have a raster.

I have discovered that I have 1 (one) warmer than usual Ram chip, this morning I will replace that.
Had a quick look at the schematic and the 3 (Three) questionable data lines go " Everywhere ".

Thanks for the thought

Ray

Title: Re: I Have a CPC 464 that I have Killed with 12 Volts Grrrrr
Post by: gerald on 22:13, 01 November 18

Quote from: Audronic on 20:54, 01 November 18
No I have not used the Ram test yet.
If I don't have a raster, I have no video out and I thought that I will have to wait until I have a raster.

Running the RamTest also have the side effect of bypassing the internal lower ROM, which is initialising the CRTC.
If this one is nuked, you for sure will not have any video ;)

If the ram test start you will know that the internal ROM is bad and hopefully get a idea of the RAM state.
If you still have no video, then the CRTC can be bad, but also the ROM too, or anything else :-\ .

Title: Re: I Have a CPC 464 that I have Killed with 12 Volts Grrrrr
Post by: Audronic on 22:37, 01 November 18

@gerald (http://www.cpcwiki.eu/forum/index.php?action=profile;u=250)

Ok Thanks for the info.

I will do the RamTest.

Thanks. Ray

Title: Re: I Have a CPC 464 that I have Killed with 12 Volts Grrrrr
Post by: Audronic on 23:07, 01 November 18

@gerald (http://www.cpcwiki.eu/forum/index.php?action=profile;u=250)

Hi Gerald

I have plugged in the RamTest and still a Blank screen.

I tested the Ram test on an other 464 that I have here.

Thanks. Ray

Title: Re: I Have a CPC 464 that I have Killed with 12 Volts Grrrrr
Post by: Audronic on 00:45, 02 November 18

@gerald (http://www.cpcwiki.eu/forum/index.php?action=profile;u=250)

Ok I have cut out the 40009 fitted a socket.
I have NOT put a replacement 40009 in the socket.
Ran the " RAM Test "

and Voila. the screen shows this.:-

Just waiting for a 40009 file to burn.
Thanks
Ray

Title: Re: I Have a CPC 464 that I have Killed with 12 Volts Grrrrr
Post by: 00WReX on 06:54, 02 November 18

Oh, I just came back to this to see how you got on...and realised I had read your last post wrong.
I thought you going off to burn a 40009 EPROM, but realise you are waiting for the file to then burn :laugh:

So I have just done a quick search for the files.
Looks like you went down this path 3 years ago ;D

http://www.cpcwiki.eu/forum/hardware-related/wanted-a-dump-of-a-rom-40009/

That Grim link is dead now, so I grabbed the 2x 16k ROMs (OS+BASIC) from an emulator and concatenated them for you.
The checksum matches what you found last time (link above)...checksum F700

[attach=1]

Cheers,
Shane

Title: Re: I Have a CPC 464 that I have Killed with 12 Volts Grrrrr
Post by: Audronic on 07:06, 02 November 18

@00WReX (http://www.cpcwiki.eu/forum/index.php?action=profile;u=518)

Hi Shane

Thanks. for all the effort to remake the rom.

I have been looking in all my hard drives BUT could not find the File.
Thanks I will burn it NOW and see what happens.

Ray

Title: Re: I Have a CPC 464 that I have Killed with 12 Volts ** FIXED **
Post by: Audronic on 08:02, 02 November 18

@gerald (http://www.cpcwiki.eu/forum/index.php?action=profile;u=250)

@00WReX (http://www.cpcwiki.eu/forum/index.php?action=profile;u=518)

@llopis (http://www.cpcwiki.eu/forum/index.php?action=profile;u=1728)

Thanks for all the support it Works

Replaced 1 Ram chip and a 40009.

I will try NOT to put +12 Volts instead of +5 Volts in the future

Thanks again

Ray

Title: Re: I Have a CPC 464 that I have Killed with 12 Volts ** FIXED **
Post by: 00WReX on 08:12, 02 November 18

Cool ;)
So only 2 'fuses', that was lucky ;D

Cheers,
Shane

Title: Re: I Have a CPC 464 that I have Killed with 12 Volts ** FIXED **
Post by: LambdaMikel on 08:33, 11 November 18

Now I feel better that I am not the only one who did kill his 464 with 12 V :D Glad you fixed it, congrats!

CPCWiki forum

General Category => Technical support - Hardware related => Topic started by: Audronic on 07:05, 01 November 18