RISC PC CMOS layout

[Footie]

I've been spending some time tracing the RISC PC CMOS circuit with the aim to repairing motherboards with battery damage. The image below shows a MKIII board and how I believe the circuit is laid out. The MKII is similar. I have managed to repair 2 boards so far based on this.
Hopefully it's of use to others and it should be similar to the A7000 and older machines.

Cheers,

Mike.

[razz177]

I've been spending some time tracing the RISC PC CMOS circuit with the aim to repairing motherboards with battery damage. The image below shows a MKIII board and how I believe the circuit is laid out. The MKII is similar. I have managed to repair 2 boards so far based on this.
Hopefully it's of use to others and it should be similar to the A7000 and older machines.

RISCPCCMOS.jpg

Cheers,

Mike.

Hi
I will solder the 0V lead to point 16
This is a great picture, I hope you do not mind I have added numbers to it to help me explain things,at position 1 4.45v / 2 4.45v / 3 5.09v bottom leg top leg variable / continuity between 4 5 6 7 8 9 but not between 9 & 10 continuity between 10 11 12 but not between 12 & 13 continuity between 13 & 6 16 is not present on my board
thanks Mike

[razz177]

I've been spending some time tracing the RISC PC CMOS circuit with the aim to repairing motherboards with battery damage. The image below shows a MKIII board and how I believe the circuit is laid out. The MKII is similar. I have managed to repair 2 boards so far based on this.
Hopefully it's of use to others and it should be similar to the A7000 and older machines.

RISCPCCMOS.jpg

Cheers,

Mike.

can you please look at my original post the picture you directed me to is great, I have replied on my original post with some reading I got but I have not tried doing this before & not sure what I should be getting but I believe 5v at pin 8 on 8583T is a must.
Thanks Raymond

[SKS1]

I've been spending some time tracing the RISC PC CMOS circuit with the aim to repairing motherboards with battery damage. The image below shows a MKIII board and how I believe the circuit is laid out. The MKII is similar. I have managed to repair 2 boards so far based on this.
Hopefully it's of use to others and it should be similar to the A7000 and older machines.

RISCPCCMOS.jpg

Cheers,

Mike.

can you please look at my original post the picture you directed me to is great, I have replied on my original post with some reading I got but I have not tried doing this before & not sure what I should be getting but I believe 5v at pin 8 on 8583T is a must.
Thanks Raymond

When powered on, you won't quite get 5V at pin 8 of the RTC as it's dropped slightly by the diode. Have you looked at the circuit diagram in the Tech Ref Manual? I don't know if the Rev 3 circuit is too different even if the board layout may be.

[razz177]

I've been spending some time tracing the RISC PC CMOS circuit with the aim to repairing motherboards with battery damage. The image below shows a MKIII board and how I believe the circuit is laid out. The MKII is similar. I have managed to repair 2 boards so far based on this.
Hopefully it's of use to others and it should be similar to the A7000 and older machines.

RISCPCCMOS.jpg

Cheers,

Mike.

can you please look at my original post the picture you directed me to is great, I have replied on my original post with some reading I got but I have not tried doing this before & not sure what I should be getting but I believe 5v at pin 8 on 8583T is a must.
Thanks Raymond

When powered on, you won't quite get 5V at pin 8 of the RTC as it's dropped slightly by the diode. Have you looked at the circuit diagram in the Tech Ref Manual? I don't know if the Rev 3 circuit is too different even if the board layout may be.

Mine looks almost identical to the picture Mike did It looks like one resistor less.
There is a picture of Mikes in my post plus a picture of mine it is numbered to go with text as I have not learned then names of components yet.
Look in here RiscPC Battery earth missing & not booting