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ATTN: pseudonomen137

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drjohnny

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What gives? You haven't responded to any emails or PMs in over 2 weeks, yet I see you posting on this forum? :-?

I'd appreciate it if you could give an ETA for my RMA'd +150mW greenie.

It's been almost 2 months since I paid you and the only reason I haven't requested a chargeback with my credit card is because of your rep on this forum.
 





Sorry, just my sheer irresponsibility again. I have to admit it is frustrating to me though when I send a customer a laser that I test to be in spec with what I sold it to them as. Then when you receive it you tell me its not in spec - an unfortunate but occasional incident I have to deal with. However when I get it back, I again test it to be in spec, yet you refuse to accept it. That frustrates me and makes me lose hope of ever completing the transaction to both our satisfactions.

That said, I have been waiting on something to try to meet your extra needs that I was hoping would arrive weeks ago, but only showed up a few hours earlier today. I'll conduct tests later today and let you know what I can offer either tonight or tomorrow night. Sorry
 
I don't understand your frustration to the point of ignoring all my emails.

The first greenie you sent was underpowered and you verified that after I returned it. You then offered me a quick replacement unit that had some small scratches and I agreed to that. That one seemed a little more powerful but still underpowered according to my meter. You claimed otherwise when you retested with your new sensor.

So it seems my Lasercheck is off since you've tested with 2 different sensors, but you also verified my claim of the unit's poor thermal stability. It may be in spec for the first 30 seconds, but I think most people would agree with me that losing over half its power is unacceptable after a few 30 sec on / 30 sec off cycles.

Anyway, I'm glad you've finally responded to something and I hope you can offer me a suitable replacement soon.
 
laser checks arent all that accurate, and pen lasers do lose a lot of power after the first 30 seconds to 60 seconds because of the shear lack of hetsinking they are very unstable.
 
Diachi said:
laser checks arent all that accurate
Click to expand...

Says who? According to the specification it has a +5% accuracy in its measurement range. So for a 150mW the max error will be 142.5mW or 157.5mW. Fairly accurate imho.
 
it's pretty well known around here that laserchecks aren't the best measuring devices around - they're only handy because of their small size and (relative) low price

thermal meters are in many ways far superior to optical units since they are not affected by wavelength, dot size, etc
 
laserchecks are generally pretty accurate - I own one myself. Well, at least with a single-wavelength source. They aren't good for getting a true feel for the power tendencies of your laser because they do not provide logging capabilities, but as far as accuracy goes, they aren't bad. That's why it confused me so much. I did test the laser on multiple meters - both of which are, honestly, better than the lasercheck but the difference we were seeing was still a bit too high to believe. It seems like it couldve just been a fluke for the worse on different ends, but in any case its a very odd situation. As much as I like to remedy any mistakes I make, you gotta admit its difficult to try fixing a problem when you can't find a problem. hehe. In any case, I think dr johnny and I are working out an exchange that will work well for the both of us.
 
MarioMaster said:
it's pretty well known around here that laserchecks aren't the best measuring devices around
Click to expand...

How do you know this? Has somebody carried out a comparison test? With how many lasercheck units? From different batches? How did he/she calibrate the other power meter(s) used for comparison, ensuring the readout is accurate enough to be representative?

I'm sure a lasercheck not the best meter available for money, but unless somebody shows proof that complies to the above I'm going to believe the specifications given by the manufacturer. And +5% is simply fairly accurate.

As for the difference between a photodiode power meter and a thermal one: made me curious and search on the internet a bit. Both types seem to have their (dis)advantages, photodiode meters are indeed wavelength dependent, but that's not a problem if you know the wavelength of your laser. Which most of us do here. As for the dot size: when I measured my lasers with the optical power meter at my work, the dot size did not affect the readout. As long as the entire dot hits the detector surface it's fine. This was particularly demonstrated with the dilda, which has a focusable lens. There personal findings are backed up by Sam's laser FAQ, I discovered.
Thermal meters seem to suffer from thermal interference and drift. According to Sam's laser FAQ they cannot reliably measure low powered lasers, less then 20mW, unless the thermal head is sufficiently insulated from ambient temperature. Thermal meters on the other hand are more fit for high powered, multiline and pulsed lasers, and are recommended for laser powers over 50mW. But... in the same article it's mentioned that the calibration of a DIY thermal power meter is +10% at best. And the thermal power meters most people use here seem to be of the DIY kind.

http://www.repairfaq.org/sam/laserioi.htm#ioitlpm
 
Diachi said:
:-? Must have been misinformed then , oh well , my bad.
Click to expand...

No - you are quite correct. I am not going to go and dig up all the posts by folks that have been drastically disappointed in the performance of their Lasercheck, including myself. I now own a Coherent Fieldmaster II TO - and found it to be dead on accurate with the Kenometers I have been exposed to, as well as the Die4Thing meter I did own (since moved on to a nice home) and BOTH of those previous sources disagreed horribly with the LaserCheck. Check around on this forum, and do a search - you should find many examples. The MAIN issues with LaserCheck's are that the wavelength MUST be precise. If you own one - measure your 532nm laser at 533 or 531 (both of which CAN be common in most handhelds ) and close wavelengths to the 532 scale. you will see that your laser will measure in at a HUGE difference. Plus - there has been plenty of documentation regarding it's inability to measure 405nm with any accuracy at all. I am not posting this to argue with you, nor will I argue with you - believe what you wish (regarding manufacturer's specs) but the facts, and real life trials disagree HUGELY with the "manufacturer's claims", and you will have to search, and do some digging to find the referred to posts, sorry. My Fieldmaster is adequately thermally shielded, and I have had NO problems with measuring any wavelength, down to a 3mw HeNe I own.
 
Yeah thats what I thought, I was aware the LaserCheck was really sensitive to wavelength especially 405nm and that its better having a laser meter with a thermal sensor.
 
Diachi said:
Yeah thats what I thought, I was aware the LaserCheck was really sensitive to wavelength especially 405nm and that its better having a laser meter with a thermal sensor.
Click to expand...

;) Give that man a cigar !
 
pseudo, this is getting ridiculous! >:(

2 weeks ago you said you finally received an in-spec replacement and you needed a few days to take pics of it for a review.

Last week you said you'd ship it out.

I have yet to receive it.

Are you ever going to mail it????
 
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