I need help identifying SMT components of a laser pointer driver.

I recently dismantled my 5mW green laser pointer because I was sick of feeding it AAA batteries. I'm using 4 18650 Li Ion batteries now. I found a little trim pot that increases the power output and when I turn it up, two of the driver components get really hot. I would like to build my own laser driver based on the original, but I need help reverse engineering it. I've attached a few photos, including the circuit I determined so far. The node voltages when the laser is operating normally are included in blue.

The two main (I'm guessing) components are marked Y2 and MY and I have no idea what they are. MY becomes very hot at high load. Please help me ID them!!

Oh right, and I had to put the big resistor on there. It's a 1Mohm. Somehow it's necessary for the circuit to turn on without the pointer body. It's connected from battery positive to the bottom of Y2.

Picture of I need help identifying SMT components of a laser pointer driver.
Its a constnat current source. Start from scratch with an LM317 regulator and a circuit like this one.

Measure the diode current, and use that to set the resistor you need.

LED driver.JPG
laserjocky (author)  steveastrouk5 years ago
Yeah, I've seen the LM317 driver before, I was hoping to use the original design but I may have to resort to this. I eventually want to be able to hook a DVD burner diode to a similar driver and my guess is I'll need something a little more robust. I've seen nice driving circuits that use a large transistor to control current but they require a low voltage op amp and I'd rather use radio shack parts for this. Maybe I'm just being snobby. Thanks for the post!
An lm317 IS a large transistor with an opamp...
laserjocky (author)  steveastrouk5 years ago
well, yeah. But it's cheating :) ok, ok I'll try it out.