QL Service Manual Update

[Derek_Stewart]

This a thread for the update of the QL Service Manual.

I have drawn all the scanned diagram images into Libre Office grouped objects.

I have traced the component positions in the Issue 5 Layout diagram, just need to annotate the values. Which, I will validate from a UK Issue 5 board.

I have converted all the scanned image PDF files into a Libre Office Writer file, with diagrams drawn as grouped graphics line drawings.

I have the Issue 6 layout to do, which should be just a modification to the issue 5 board.

The Issue 5 & Issue 6 schematics have been updated in Xcircuit CAD software.

Maybe the Xcircuit files want to converted into a more up to date CAD package, like Kicad, is a large job, but PCB reproduction would easier.

The is outstanding tasks:

Change Issue 5 & Issue 6 Bill Of Materials to standard format
Microdrive schematic & Layout, including Head Board
Description of the non-UK QL board
Issue 7: Schematic & Layout drawings, Bill Of Materials.

Does the Service Manual, want to go onto Github?

[Popopo]

Hi Derek,

I think all you said is a must to do.
Moreover, it could be great in order to upgrade some thumbs for components, later modifications (for example to change memory type for another more accurate without +12V or +5V, etc etc.

So yes,
How would you like to organize the work?
I am learning to use KiCAD.
Such a pity we cannot use some developed like Tetroid did.

[Pr0f]

All the memory in the QL is 5V only.

The +12v is used for the RS232 transceiver, and the -12V is used for this chip also, plus it's used via 2 resistors (normally found on top of the ZX8302) to provide bias on the RAW read data lines.

I am not aware these voltages are used for anything else? +12v and -12V come from the 15V AC line via diodes and regulators.

The +9V from the power supply feeds the main regulator on the heatsink, the 2 microdrive boards, the external microdrive edge connector and the main edge connector where expansions go.

[tofro]

The MC 1377 is connected to +12V as well. No need to care if you don't use composite video or RF.

[Pr0f]

good spot