PL310 power supply shows ofl on voltage display

[amateur_25]

I knocked my power supply off my bench

Now it shows ofl on the voltage display on power up.

What could I of broken?

[Chris56000]

Hi!

Have you got the earlier type PL series power supplies in a brown case?

The early PL310 uses an ADD3701 ±3.999 count DVM a/d converter & display driver IC, and one large control board in the chassis, whilst the later series uses a much more complex front panel display/control regulator board using an ICL7109/PIC16C55 combination for display, with a switchbank pcb mounted on the front panel, with a small 'driver' board in the chassis near the mains transformer.

Service Manuals for both types are available, but I'll need you to let me know which version you have first!

Chris Williams

[amateur_25]

it's the brown unit I have.

I just noticed two axial components were  broken off. Unfortunately the components that broke off must of dropped out when I took it apart.

Any chance someone can advise on  what they were?

[Chris56000]

Hi!

Here's the manual you need - unfortunately the schematic is atrocious, but the PCB layout-diagram is clear enough and the parts-lists are clear and complete!

The missing items are 1N4003 diodes if you've a lower current PL310 version, or 1N5402 if you've a higher-current PL320 version - your picture suggests thin wires so you need 1N4003s!

Chris Williams

PS!

I have a project in mind to draught new schematics for these but regrettably recent illness has prevented me beginning with it!