A1200 screen flicker
 

Ive got 2 A1200s, both recapped by the same technician. Ive been using one with a standard 4GB HDD which works well, I got the other one out with a rear panel ide CF Reader and the screen flickers whenever I do anything ie access hard drive, access floppy drive. What could be causing this issue? Im using the same peripheral components and a new psu from centuriontech.eu so its non of these that are doing it.

From the symptoms I'd say that you're overloading the power traces on the motherboard of the 2nd 1200 or have an issue with the 1200's power socket connections to either the motherboard or the power plug.

As an initial test, try disconnecting the floppy power connector from the floppy drive side and see if the screen flicker disappears when you use the hard disk drive, etc. (except for the floppy functions of course). Also try to clean the 1200's power socket connectors and/or resolder its pcb connections with a bit of fresh solder.

Note - If disconnecting the power cable from the floppy drive stops the flicker and you're planning on refreshing the motherboard solder connections to the 1200 power socket then you may want to add wires that directly connect the +5V, +12V, and 0V on the 1200 power socket pins direct to the corresponding 1200's floppy power connector +5V, +12V, and 0V pins near the floppy drive and then retest for the flicker with the floppy drive power connected this time.

Hmmm ok, its a stock 1200 but with an Amitek 8mb board. Im away until tomorrow night. Ill have a go monday. Thinking about it, how do you clean the psu socket connector?

spray it with electrical contact cleaner and insert and remove the power lug several times