What about all those sparks? Can you tell if the flex wire is poorly connected and may be the problem, instead of the LCD display itself. If the sets were poorly assembled on the factory line, there may be problems with the connector wiring itself. Possible breaking or shorting of wiring(?)...
My question is, are you going to use this for mobile use, or in-home/office use?
That'd affect whatever I recommended.
Maybe even more specific than that, .... is it going to be exposed to vibration, like in a motorcycle, boat, or dune buggy?
Now submit a proposal to the manufacturer asking for compensation for designing an add-on to their laser-cutter that customers will want as a valued feature.
MAKE SURE THE POWER IS DISCONNECTED FOR THIS:
As long as you've got a meter (I assume a digital multimeter). You might want to check that potentiometer in the second picture you posted, just to make sure it's still providing a variable resistance.
Sometimes they crack or otherwise fail...
Cool, hevans1944. I see the model you reference is 'temperature controlled' by a change in heater elements.
The miserable SOBs I work for keep buying me these $1,000 get-ups with digital set-ups and LCD displays (then require me to use specific temp settings for specific jobs). But no...
As if you don't have enough advice already, my input is to be very careful about what you decide to use. With all of the enviro-friendly changes to the old tried-and-true chemicals that are now banned because they might harm the environment, the marketplace is flooded with new chemicals that...
I find myself on kellys_eye's side on this. But like dorke and hevans1944 noted: are you a hobbyist and do you really have a requirement for a temperature-controlled solder station?
If you do work for manufacturers, they often have specs you need to meet for their product requirements. ie...
What Externet means, is that you can take an ohmmeter reading across the bottom lead and the top lead (the center lead is the wiper for variable resistance), and you will have the value of the pot in ohms.
My daughter had me look at one of those. Her problem was the switch assembly itself.
You might check that, just to be sure it's actually 'switching'.
Next thing I'd do is what you've probably already done. Look carefully for any physical damage to components.
Darned plastic parts often...
This may have no bearing on your problem at all, but I'll input an observation:
I don't know your vehicle/electrical system.
My experience with trying to jump a car battery that results in damage to the battery, is that in the old cars I've worked on, the diodes in the alternator are often...
Are you kidding? With all those other components on that board?
Get yourself a oscilloscope and compare readings on the good board with the readings on the bad board to isolate the problem.
I'm going to mention this because I've been sucker-punched before by it.
When resistors over-heat, those painted colors can change on you.
Looks like Black, Red, Black, Silver, Orange to me,. but having been fooled before, I don't bet on them anymore.
Can you get an ohmmeter reading across it...
The Chinese stuff is getting better-quality, I'll concede that.
Most all of the Chinese knock-offs I've dealt with work when you get them, they just don't last.
That's just my experience, and may not reflect the experiences of others.
Switches I've used fail far to quickly, components 'work'...
What you're looking at is an industrial standard interface module. In the States the most-used standard is 4-20ma, 0-5V. You get one with the other, not either/or. The old original standard was 5-50ma, 0-10V. Looks like you're looking at one that does 4-20ma, 0-10V.
The reason I'm going over...