Opinions/options re: power loss on Lasever blue DPSS

[buffo]

Hi Fred;

Sorry - I didn't have time to post here earlier... (Busy day at work!)

David contacted me early this morning via PM. We've been talking back and fourth about the problem. He wants me to do one more test, but because I'm working an 18 hour shift today I won't be able to do the test 'till tomorrow evening.

David is thinking that the problem is in the TEC... Personally I think it's in the diode driver, but we'll see.

Either way though, he's aware of the problem and is working with me to nail it down. Thanks for helping to bring it to his attention! (And I know we'll get it sorted out one way or another; I know you stand behind your stuff.)

Adam

[buffo]

Hate to reply to my own post, but I've got an update:

David from Lasever contacted me and wanted me to perform another power test. He wanted me to run the laser for 30 minutes to 1 hour with +5 volts DC connected to the blanking lead, and to watch and see if the red overtemperature LED ever lit up. Well, this afternoon I performed the test. Below (in blue) are the results that I just PM'ed to David...

<paste>

Earlier this afternoon, I turned the laser on and conected +5 volts DC to the blanking lead. The laser came on and was drawing about 2.6 amps of current and making 28 mw of power. Both green LED's were lit up on the driver board. The red LED was off. The laser head was cool to the touch, and so was the heat sink on the driver board.

I let the laser run like that for about 10 minutes. The current draw increased to about 3.6 amps, and the power output went up to around 40 mw. The two green LED's on the driver board were still on, and the red LED stayed off. The laser head and the driver board were both still cool to the touch.

I checked back after another 30 minutes of operation. The current draw was 3.7 amps, the power output was 38 mw, the laser head and driver board were both cool, and the two green LED's were still on. (The red LED was still off.)

Finally, after 1 hour and 15 minutes of continuous operation, I did one final check. The output power was 39 mw, the current draw was 3.7 amps, the laser head was cool, the driver board was cool, the two green LED's were on, and the red LED was off.

I then disconnected the +5 volt signal to the blanking lead and turned off the power to the laser.

Based on this test (and the others), it seems clear to me that there is a problem with the driver board - specifically with the current limiting circuit for the laser diode.

</paste>

So that's where we stand. I'm waiting to hear from David (probably tomorrow sometime).

Adam

[allthatwhichis]

Hey Adam,

How'd this go? My 150mW green seems to be having a similar issue. I started it up when I got home "this morning" and it is only putting out 5 to 6mW per my small meter. No red LED either. I'm not into measring voltages yet, so I didn't try. I may do the test you did above. I emailed David and am awaiting a reply. Just curious about your adventure.

[buffo]

Hi Aaron;

David contacted me a couple days ago and agreed that the laser needs to be returned to China. He then asked me if it was OK if he replaced this unit with the larger head design. (The "U" model, where the head is in the shape of a brick, rather than the smaller design I have now with the round turret pointing out of the front.)

I told him that the larger "U" model would work just fine.

Since then, I haven't heard from him.

I still have the laser here, and while it's only making 40 mw, it does still work, so I'm still using it.

Adam

[allthatwhichis]

I sent an email last night and a PM today.

I also kinda did the same thing you did above. My little meter goes to 20mW but it also has the percentage setting that will goto 200. As this is putting out <20mW I have been using it, and if I set the percentage setting the same as the 20 or less measurment it has been staying fairly consistent on both readings. I had it on for almost 3 hours total. I don't know how to measure amps... so I didn't.

Here's what I got...

4:35 start up 10 to 12mW
4:45 8 to 9mW
4:55 13 to 15mW
5:15 16.5
5:25 20mW+
5:35 27mW
5:55 28mW
6:15 30mW
6:40 23mW
7:15 18mW
7:30 15mW

No red LED.

I also have it on now and am getting 12mW at the moment.

[buffo]

Hey Aaron;

Yeah, sounds like you've got problems there buddy...

To measure current, all you do is stick your multi-meter in series with the +5 volt power that feeds the driver module. That is, connect one lead of the meter to the + wire from the power supply, and connect the other lead from the meter to the +5v input on the module. Leave the ground wire connected as normal. (You can access these wires on the side of the driver module - there's a terminal block with +5 and gnd inputs.)

This forces all the current to travel through the meter on it's way to the driver module. (Remember to make sure it's set to measure current and not resistance or voltage.) That will tell you how much current the whole driver is drawing. (It won't tell you how much is going to the diode vs how much the TEC is pulling, but it's a start...)

Whatever you do, don't unplug the connector that runs from the driver module to the laser head. You could blow the diode if you don't take proper static precautions.

Adam

[allthatwhichis]

Whatever you do, don't unplug the connector that runs from the driver module to the laser head. You could blow the diode if you don't take proper static precautions.

Adam

You mean while it is running correct? I don't think they were connected when I got it... I also assume a blown diode produces no light...

[buffo]

Aaron;

No, I mean ever. When you pull that plug, it exposes the pins in side, and the pins are connected directly to the diode. There's nothing protecting it, so the slightest static charge on your fingers will blow the diode if you touch the right pin on the connector.

UPDATE:

David Wu got in touch with me, and we've decided to try the larger "U" series head instead. (I've got room inside my projector housing.) He's sending me a new laser with the larger head configuration. (Evidently those heads have a larger TEC and better heat-sinking.) I'll get it mounted and see how it performs. (The laser I have now will need to be sent back to China once I get the replacement.)

EDIT: My laser arrived on 6/19/2007. It's not the "U" series head, but rather one of the small MR series heads, though it looks like they used a new extrusion for the rectangular part of the head. It used to be smooth, but now it's got shallow grooves in it like a heat sink.

Adam

[redstorm]

hi people.
does anyone know about thease 4 adjusting resistors on a lasever LSR473-ML-100 driver unit? if known, please post their function destination and rotate direction (CW, anti-CW) to maximise value. i see later in this thread posts about it ...

I actually moved all 4 pots: the current limit, the current setpoint for the diode, the temperature limit, and the temperature setpoint pot.

but i cant figure about their order.

ADD:



please, add some information according to picture, if known thanks.

[mixedgas]

hi people.
does anyone know about thease 4 adjusting resistors on a lasever LSR473-ML-100 driver unit? if known, please post their function destination and rotate direction (CW, anti-CW) to maximise value. i see later in this thread posts about it ...

but i cant figure about their order.

ADD:



please, add some information according to picture, if known thanks.

you might want to repost this in help. you tagged onto a 2007 thread.
Steve