laser diode driver board with TEC from a 7w rgb source, unknown switch, help needed

[fbohmann]

Hi all!

i had to disassemble a 7w laser projector due to scanner failure, and due to dumb reasons, i started taking "before" pictures too late. the laser uses 3 almost identical driver boards for r, g and b, turns out, 2 of them run on 12v, and one on 5v, allthough all pcbs say 5v. (thanks). the boards might have been prduced by "Beijing Ranbond Technology", i asked them for help, and the seller, but in case somebody else knows something, it might be good to document this here as well.

the driver board is marked with GS082018 or GS08201B, that might be a date, or a spec. there are similar boards sold as 8v 20a oem ld driver with TEC or similar.

my main question is: there is a slide switch marked with A and the positions T- and T+. what is this switch for? my guess would be polarity inversion for the TEC driver part, but i dont know. my next step would be to run it and see if it changes the peltier direction.

does someone know something about these boards? (picture attached)

thanks and cheers,
felix from around hamburg, germany

[fbohmann]

i think i was a bit blind. my new guess is that the markings mean "analog" and 2 types of ttl modulation, probably meaning low or high meaning on for pwm modulation.

[mixedgas]

That looks like a what is in "Goldenstar", products switch is Analog up, TTL / off in the middle, inverted TTL (external pull down or open collector transistor turns beam off ) at the bottom. Leave the input floating, put the switch down from analog, beam will eventually beam on...

Analog is 0-5V in.

Messaging Mimi or Winnie at GS with a serial number might get you some info. "R" means red, and red drivers like 5V as red diodes have a lower Vf

I have four of them in a 5W projector , mine are one generation newer then that, but have never adjusted anything.





Steve

[fbohmann]

ah, thanks for the info. i am a step further now. turns out, the laser source uses 4x red in series, and thus 12v modded driver board, and 2x green in series, also 12v modded board, and one blue diode running off a 5v board. also, the failed reassembly attempt seems to have sent 12v to the blue diode, which is gone. i will replace it and hope the alignment is not too far off. i will contact gs with my serial, since i now also need to set up the blue driver for a new diode, and as always, no markings on the pots. i guess there is threshold and gaintrimmers for the diode, and 2 settings for the tec, but this is too much guesing. maybe gs can shed some light. thanks again!