TNP #51 - Thorlabs PM320E Dual Channel Optical Power & Energy Meter Teardown, Repair & Experiments
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- Опубліковано 7 лют 2025
- In this episode Shahriar takes a look at faulty Thorlabs optical power meter which has been scored from eBay at a very low price. The listing shows the screen with a white background without any text. Upon close inspection however, it is clear that the screen contrast is the problem. The fault is traced to a basic voltage setting problem (230V versus 115V) which was causing the +/-15V supplies to be significantly under biased.
With the screen issue resolved, the unit is paired with two C-series optical detectors. Various laser power measurements & experiments demonstrate the full functionality of the unit.
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As a European, I've been taught to be extra careful and always double check those. Missing that setting here would end up in an interesting repair instead 😅
I work in a different unit within Thorlabs, love seeing people take apart our stuff!
Thank you for showing this repair. Despite it’s simplicity, we often purchase things for repair with the assumption that something needs to be fixed so highlighting this kind of situation where an overlooking something simple can lead to missing the issue.
Such an impressive find. We just recently bought their USB Power and Energy Meter together with a S120C sensor for my lab. Seeing that instrument at that price undamaged makes me so jealous haha. Nice video
Thorlabs may be the most vertically integrated company in the photonics business. More than 90 percent of the components in their products are made in house, down to every single active optoelectronic component which they make in two different wafer fabs.
It's a great pleasure to see you here again. I personally love your videos, your explanations, your overall knowledge. I hope you will continue. Greets!
I have the ThorLabs PM20, a small direct fiber input power meter. Optics is an interesting partner to electronics - great stuff!
While all of us would love to have abs like Thor, I think you may want to fix that title typo ;)
Lol - I almost want to leave it…
Finally a repair video I was able to keep up with!
Yay! Repair time! Power line is pretty boring. I'd be curious how much optical power comes out from generic lab communications SFP. There are many warning labels near them, but are they that dangerous, especially cheaper 1GbE/10GbE modules? Maybe something to try in future?
Depending on the distance the modules are rated for, they can definitely be dangerous.
Why are half of instruments on ebay **this** and the other half a blown unobtanium custom chip. Really lucky die roll 😁
That was Fun Thanks
Hey Shariar! Optical equipment is quite esoteric for many, maybe you could start a series or maybe even a new channel about Optics.
I am quite curios (also as a radioamateur with new sparked interest in GHz area) about the transition from microwave radiation to optical.
My first thought with you mentioning controle software, download and try remote setting controle….. then it was not necessary 😂
Why did Thor lose his lightning powers?
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Because his father grounded him. 🤣 ThorLabs
Now I'm busting to know if it was the sensor or channel - lol -, ie, it needed the channel swap.
Can you fit a laser table in your lab? Would be insteresting to use all kind of laser and optic stuff for studies and experiments.
I had a vacuum pump that didn't indicate if it was 110/230V and I accidentally plugged it into a 230V circuit when it was set to 110V and it tripped the breaker and few million dollars worth of equipment all shut off. oops. Silly design to not label the swtich.
So did you notice it was set to 230V before you started measuring the power supply? 🧐
No. My conclusion that something is off with the transformer was based on my measurements.
@@Thesignalpath I done the same mistake of plugging something in without ensuring the correct mains selection.
Except I live in Europe and lower voltage gear tends to have their transformers burn up when this mistake is done. Ie, always check before plugging any new gear into the wall.
Hola, tengo un analizador de espectro XSA1015-TG de Owon. Quisiera saber si puedes ayudarme?
Not sure how you found one for $40 when they're all well over $1K... but congrats!
Thorabs?
*Thorlabs PM320E Dual Channel Optical Power & Energy Meter: Teardown, Repair, and Experiments*
* *0:16** Esoteric Instrument:* The Thorlabs PM320E is a specialized instrument used in free-space optics and laser design for measuring optical power. It's capable of interfacing with both basic photodetectors and Thorlabs' "smart" C-Series sensors.
* *0:30** Versatile Interfaces:* The PM320E features analog inputs, DB9 connectors for smart sensors, analog outputs for use with external digitizers, and a USB port for computer control. [From joopterwijn's comment] Remote setting control via software might have negated the need for the repair detailed in the video.
* *1:05** Faulty Display:* The unit was acquired from eBay at a low price due to a display issue; the screen appeared completely white, suggesting a potential firmware or hardware problem.
* *1:14** Contrast Issue:* Closer inspection revealed that the display was actually very faint, not completely blank, indicating a problem with the display contrast.
* *2:30** Internal Layout:* The unit's internal layout shows a clear division between sensitive analog circuitry and digital/power supply sections. Thorlabs' expertise in optoelectronic devices is evident in the design. [From douro20's comment] Thorlabs is known for its vertical integration, manufacturing a majority of components in-house.
* *3:57** Power Supply Issues:* The display brightness initially surged and then dimmed, accompanied by beeping sounds, suggesting a power supply problem.
* *5:50** Voltage Regulator Investigation:* Measurements revealed that the +/- 15V supplies were significantly lower than their expected values, pointing to an issue upstream of the voltage regulators.
* *6:45** Voltage Selection Error:* The unit was mistakenly set to 230V operation instead of 115V. This incorrect setting caused the transformer to output the wrong voltage, leading to under-biased +/-15V supplies. [From pengiswe's comment] It's crucial to double-check voltage settings to avoid unexpected repairs. [From s0rc3's comment] Failing to check voltage settings can damage equipment and even cause widespread power outages.
* *7:28** Successful Repair:* Switching the voltage selector to 115V and ensuring the correct fuse was in place resolved the display issue, bringing the unit back to full functionality.
* *8:29** C-Series Sensors:* The video demonstrates the use of Thorlabs S121SE (0.5W) and S120C (50mW) sensors, highlighting their automatic detection and calibration data transfer capabilities. [From stevensworld14's comment] The S120C is a popular choice for lab applications, and its high price compared to the repaired unit highlights the deal obtained.
* *9:25** Ambient Light Measurement:* The sensors detected approximately 50 microwatts of ambient light, showcasing their sensitivity.
* *10:02** Laser Power Measurement:* A 670nm semiconductor laser was used to test the unit's accuracy. The laser's maximum output power was verified to be below its rated 5mW.
* *11:05** Sensor Discrepancies:* A slight difference (5.8%) in power readings was observed between the two sensors, potentially due to sensor-to-sensor variation or calibration drift in the PM320E itself.
* *11:42** Linearity Testing:* The laser's modulation capability was used to test its output power linearity, showing good results with a triangular wave modulation.
* *12:41** Future Experiments:* The repaired unit and acquired sensors will be used for future experiments in the lab. [From xDevscom_EE's Comment] A suggestion was made to explore the optical power output of generic lab communication SFP modules in a future video. [From OctavMandru's Comment] A request for a series or channel dedicated to optics, particularly the transition from microwave to optical frequencies, was made.
I used gemini-1.5-pro-exp-0801 on rocketrecap dot com to summarize the transcript.
Cost (if I didn't use the free tier): $0.07
Input tokens: 18188
Output tokens: 876
seriously
This is typical. One hopes to find an interesting cause for a fault... and it's too often dumb s**t like this. 40 bucks well spent.