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*UPDATE* Problem found LPM or Laser

Hap

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So, I just got my LPM in and decided to test my PL-E Pro and see what kind of power I was getting it from it. I checked all the following:

-Fully Charged battery
-Set the LPM to 0.000
-Gave it about a 6" to 12" distance

Is this right? Because if it is, this PL-E is underspec by about 25mW's, and Gray's reading of 180mW is way off.....



-Alex
 
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Razako

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Re: Am I doing this right?

I think you need a bigger sample size. If you measure multiple lasers and they're all underspec it means your meter has problems or you're doing it wrong. If only one of the lasers is underspec it means the laser is underspec. Personally I've had bad luck with LPM's in the past. I had a cheap LPM 4-5 years ago and tried using it to measure my collection. The LPM seemed to suggest that my RPL-300 was underspec, my RPL blue-30 was underspec, my laserglow lyra was underspec and my wickedlasers pulsar 125 was underspec. It showed everything underspec by 20-30%. Either I got scammed by literally EVERYONE, or there was just something fishy with the meter. Ended up selling it here after a while.
 
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Hap

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Re: Am I doing this right?

I think you need a bigger sample size. If you measure multiple lasers and they're all underspec it means your meter has problems or you're doing it wrong. If only one of the lasers is underspec it means the laser is underspec.
Maybe... I let it get used to room temperature and am only getting around 130mW....

-Alex
 

Razako

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Re: Am I doing this right?

Maybe... I let it get used to room temperature and am only getting around 130mW....

-Alex
Idk. Usually being underspec is commonly associated with DPSS lasers. I have a hard time seeing why a red 650nm would be underspec to begin with at the 150mw level. Practically the only thing they could do to make one underspec is set the driver current too low intentionally. No reason why the diode and driver shouldn't be able to put out 200mw easily. Basically there would be no real financial incentive to send out underspec 650nm lasers in the 100-200mw range.
 
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Hap

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Re: Am I doing this right?

Idk. Usually being underspec is commonly associated with DPSS lasers. I have a hard time seeing why a red 650nm would be underspec to begin with at the 150mw level. Practically the only thing they could do to make one underspec is set the driver current too low intentionally. No reason why the diode and driver shouldn't be able to put out 200mw easily. Basically there would be no real financial incentive to send out underspec 650nm lasers in the 100-200mw range.
Yes, understood!

I won't have time this afternoon but will run the test again later tonight. I'll let the LPM sit(turned on) for 1 hour and then fire up my PL-E at a distance of 6". If the readings are still low then something is very, very wrong, no?

-Alex
 

BowtieGuy

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Re: Am I doing this right?

Hap, is the whole dot in the sensor area, and not unfocused too much, how is the charge in your batteries?
I've never received anything from J/L that was underspec, usually 20~30% overspec.

Edit: don't get too close, you'll get false readings.
 
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grainde

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Re: Am I doing this right?

That looks like a laserbee lpm with a thermophile sensor. These take about 30 seconds to reach the max reading, often however the max power will have dropped by then and esp with heat sensitive diodes like the 638s. Did Gray say 180 mW was the max power, or average power over a set time? If you want to test the max ask someone with an Ophir head - these reach the max reading in 1-2 seconds. :beer:
 
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Hap

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Re: Am I doing this right?

Hap, is the whole dot in the sensor area, and not unfocused too much, how is the charge in your batteries?
I've never received anything from J/L that was underspec, usually 20~30% overspec.

Edit: don't get too close, you'll get false readings.
Hey Bowtie,

My battery charge was at 94%, and I tried with the dot both fully focused, and fully unfocused. Should it be better to have it slightly unfocused? Yes, the entire dot was on the sensor area, looked kind of like a square :(

-Alex
 
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Hap

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Re: Am I doing this right?

That looks like a laserbee lpm with a thermophile sensor. These take about 30 seconds to reach the max reading, often however the max power will have dropped by then and esp with heat sensitive diodes like the 638s. Did Gray say 180 mW was the max power, or average power over a set time? If you want to test the max ask someone with an Ophir head - these reach the max reading in 1-2 seconds. :beer:
Gray's graph was 180mW as peak reading, and it stayed there.... :/

Edit: I have to go for the afternoon soon but will try this tonight.

-Let the LPM sit for 45mins and adjust the reading to 0.000
-Place it on a Xbox game case
-Slightly unfocus the laser
-Make sure all air, windows are closed
-Fully charge the battery

-Alex
 
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grainde

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Re: Am I doing this right?

Also make sure that all the light falls on the sensor ie focus the laser to a 2-3 mm dot on the sensor. A couple of inches are fine, just don't go too close or you may skew the readings upwards due to heat from the laser. Last question; is the lens the same as the one Gray used?:beer:
 

Hap

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Re: Am I doing this right?

Also make sure that all the light falls on the sensor ie focus the laser to a 2-3 mm dot on the sensor. A couple of inches are fine, just don't go too close or you may skew the readings upwards due to heat from the laser. Last question; is the lens the same as the one Gray used?:beer:
I believe so, never asked him :(

The dot itself is about 2-3mm when fully focused. This is a non-corrected 650nm laser. Would the readings be better when unfocused then?

How should the LPM get used to room temperature? Should it automatically go to 0.000 when ready or should I do it(like I've been)?

-Alex
 

grainde

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Re: Am I doing this right?

A 2-3 mm dot is fine just make sure it's not too focused, or defocused and make sure all the light hits the sensor. If you see some light around the dot, you are loosing power. I once burnt my old laserbee sensor with a focused 2.8 W laser..here it shouldn't be a problem though. ;) Yes you should let the sensor equilibrate to room temp, just leave it on for 15-20 mins before taking the measurement.:beer:
 

InfinitusEquitas

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Re: Am I doing this right?

IMO, within 10-15% of advertised spec or so, is on spec.

It's also possible that Gray tests off of a bench PSU, not batteries, so do top off your batteries completely before testing.
 
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Hap

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Re: Am I doing this right?

IMO, within 10-15% of advertised spec or so, is on spec.

It's also possible that Gray tests off of a bench PSU, not batteries, so do top off your batteries completely before testing.
So 130mW is ok? I actually don't really care for my lasers being overspec. I'll try to charge my batteries up to 100% tonight and let the LPM sit for 30min.

If I still get 130mW should I return the laser? During my tests, it peaks at around 130 then slowly drops down by 1mW every 40sec..

-Alex
 

InfinitusEquitas

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Re: Am I doing this right?

It's completely your call, and Gray is easy to work with, but personally I wouldn't bother. 20mW +/- on a 150mW laser makes zero difference visually.

I definitely wouldn't bother if it means shelling out for tracked shipping to china. As Gray for a small discount on a future purchase instead.
 

Razako

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Re: Am I doing this right?

So 130mW is ok? I actually don't really care for my lasers being overspec. I'll try to charge my batteries up to 100% tonight and let the LPM sit for 30min.

If I still get 130mW should I return the laser? During my tests, it peaks at around 130 then slowly drops down by 1mW every 40sec..

-Alex
Depends on a variety of factors. If I was paying a lot for an exotic DPSS wavelength I'd be kinda angry about it. IE getting a spartan 50 and having it put out 30mw average.

I'd be a little annoyed about a 150mw red laser putting out 130mw, but it's not something I'd bother sending it back over.(especially sending it back to china). Perhaps let JL know about your issue and see if they'll offer you a slight refund or discount on a future purchase.
 




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