I've been asked to repair a handheld laser diode 'probe' with a status LED included.
The original had been mangled - and basically all old connections were physically ripped apart (under epoxy & hot glue!)
The attached drawing is what I 'think' the original wiring was set up as, but it doesn't work.
Interestingly - the unit's controller also shows a strange symptom...
If the pushbutton is pressed (to start the timed cycle), and there is no LED or laser diode in circuit - the controller displays 000... If the diodes are in circuit (paralleled across the 2V line) the controller shows a different value*... so I guess it's displaying some error or status measuring the current draw ??
Any ideas what the circuit is likely to have been?
It was a real dog's breakfast - apart from being totally trashed internally!
(* the values displayed are even more confusing -- I have four completely separate controllers, and three of them show different numeric values when the LEDs are in circuit!)
-- and sadly, no manual or schematics of any sort. Just an (old) micro on each controller board.