laser head to work

[bloody-orc]

has anyone some easy schematics or tutorials to get a gold plated 3jegged Laserhead to work? I cant give any more info, cause i don't know anything more... i know that one is GND but what are the other two?

The head came fom a laserprinter if that helps you...

and plz no schems with transformers or something... just a simple one...

 

[drrogla]

Usualy lasers require a high voltage supply, don`t know if this is the case with you...

 

[bloody-orc]

well as i cant see any high voltage makers on the original huge board then i thought that i dont nead it also...

 

[drrogla]

Do you still have the printer circut
Try using that, you might figure it out on your own...

 

[bloody-orc]

well i have... but only the board... i have no idea where what signal runs(there was a 80 line cable going in it) so it's hard... and the chps on it... i cant find no datasheets for them (chips are : [line]842 605 {8 pins and smd})

 

[Nigel Goodwin]

How big is it?, if it's a laser diode they are absolutely critical about the drive current - they only operate just before their destruction point, so the third contact could be an output monitor for feedback (like on a CD player).

 

[bloody-orc]

this board doesn't contain only this driver... also 100 other things... so only some of those components are connected to the Laser head...

on the board the GND pin is connected to GND
'
the LD pin is connected via 271 resistor to gnd and goes far away throug various of transistors

the MON pin is connected to pot and then disappears under a microchip mentioned before...

 

[Nigel Goodwin]

the LD pin is connected via 271 resistor to gnd and goes far away throug various of transistors

the MON pin is connected to pot and then disappears under a microchip mentioned before...

Following on from my previous reply, 'LD' sounds rather like 'Laser Diode' and 'MON' sounds like 'Monitor'.

As I mentioned before, applying slightly too much current to the diode will instantly destroy it! - you need to be VERY careful. These devices are also EXTREMELY static sensitive - you should apply strict static precautions at all times.

 

[bloody-orc]

yes that i know all... but hot to gt this thing to wark? i need a new schematic

 

[Nigel Goodwin]

yes that i know all... but hot to gt this thing to wark? i need a new schematic

As you have the board that originally fed the laser, you should follow the wires back and draw out the circuit they used to feed it. There's no point trying to give you a generic circuit, as I've explained previously, if the current is slightly too high you will destroy it instantly - you need the EXACT current for that diode - the easiest way is to copy the original circuit.

The circuit actually feeding the laser shouldn't be too complicated, it's usually an opamp or two in a feedback circuit, and probably a driver transistor or two.

 

[bloody-orc]

ok but then i need a data of a chip

842
605

is written on it
it's a 8 legged thingy

 

[Nigel Goodwin]

ok but then i need a data of a chip

842
605

is written on it
it's a 8 legged thingy

It may be an opamp?, if so the connections are usually standard - so try assuming it's a standard single opamp and see if the connections make sense - if not, assume it's a double opamp and try again.

 

[bloody-orc]

as i dont know the pins of an op amt could you gime me the names?
both single and double...

 

[Nigel Goodwin]

as i dont know the pins of an op amt could you gime me the names?
both single and double...

Most single opamps conform to the 741 connections, you can find them at , amongst a great many other places.

 

[bloody-orc]

nope... it cant be an op amp...

 

[theimperia]

Do BOTH "MON" and "LD" go to the same chip?

Can you give us a photo of the chip?
or
Could you rewrite EVERYTHING from the chip's top (all letters and numbers)?

If LD goes to ground through a resistor and there's another pin connected directly to ground, then what's the point of the resistor (assuming that LD is the diode).

I assume that you can't bring the diode to life with the original board, right?

TI|CP

 

[bloody-orc]

www.zone.ee/robz/laser
there are some pics of it
i hope you can find the chip there (only one there)

 

[bloody-orc]

well... any ideas... can't you see my pics? can't you find them there?