He would have had to have gone out of his way to do this as the connector is keyed. I don’t think he’s mentioned anything about swapping pins or custom cables.
I also noticed the 0/5-12V spec which I thought was weird. I had the same question about 3.3V not being sufficient to drive but it’s clearly causing something to burn. Based on what he was saying about getting constant 3V at the laser driver board solder joints that explains why he’s not getting any power modulation and the burned traversal lines.
What I don’t understand is where 3V would be coming from at 0% power.
Exactly. And in message 23 it appeared to be modulated just fine, if it is 3.3V system. Then later modulation is no more.
This is why I asked if laser was connected at that time. It is possible that PWM is fine without laser but pulled high with laser connected.
Eric, please test that sequence, 0-50-100% with and without laser, what voltages do you see on PWM output. I hope you will use RMS DC meter and not a peak meter, later one will report 3V most of the time.
Both statements are true RE 23 & 29. Testing the wire, disconnected from the laser module resulted in the 0.0, 1.5, and 3.0 measurements. Reconnecting the module and testing using the soldered pins on the backside of the driver board resulted in an across the board 3.0 measurement. I will admit that 3 could be off as I was upside down on the far side of the laser trying to touch just the ground and PWM pins, I’ll test again this evening.
I think I erred and got the wires crossed in my explanation. The key on the connector allows for one connection configuration, PWM=White, GND=Black, VCC/12V=Red.
Laser pushing current back, pulling PWM signal up hard.
Controller board signal output not able to drive signal down.
Experiments:
Test laser: Disconnect PWM and instead solder to it 1K resistor to ground on laser board, essentially only use 12V power. Wear eye protection in case laser fires. Point it to some absorber.
If with 12V and 1K to ground laser is dark - it is probably OK. If it fires - laser driver board is bad.
Test controller without laser: Use same 1K or better 10K, on controller output connect resistor between PWM output and 12V, Run your progression 0-50-100 again and measure PWM voltages. If you see it changes as should - output is good. If you see it stuck high - output is blown. Any SMOS/TTL or any other output should have no problem driving 10K load.
Oscilloscope would be better but I have feeling you do not have one.
Soldering on working hardware is not a good or resonable suggestion. Likely ending up with more damage and questions as to what is and isn’t broke.
I’m not aware of his skills, but I cringe at the suggestion that he take a soldering iron to a working board to debug some other part. I have excellent hardware skills and I wouldn’t do that or even suggest it …
He is having trouble with three wires, now add a soldering iron …
The problem here, is we don’t know how things are set up when he tests them, then he changes them and posts, most of the time without a clear explanation of what’s happening or what’s been changed.
He has a control board specifically for that laser module and can test it at will any time he wishes, but he refuses to use that manual control to confirm or deny what is working and what is not.
I still don’t know if the basic cable from the original controller is ‘plug’ compatible with the laser module or not. And we’re at post 45…
Jack, I’ve never suggested to work on powered circuit. I omit that comment as obvious. Turn power off before soldering anything. I thought everybody knows that.
Now with your comment I understand that it might be not obvious to others. So Agreed.
Freudian thought: have it crossed your mind to work on it with power applied? Why do you think so? Tell us more?
Let’s make PSA:
NEVER WORK ON POWERED CIRCUITS!!!
Well, except when you have to, like taking measurements.
Following this, I understood the control board was OK. Works with the original laser. I meant modifying a board that is working to diagnose a laser issue.
Never even though about doing so with power on, so you are right there.
It only took me a couple of minutes to test the original JL1 laser. He could do the same with his laser and know if it’s the module or the control board without any soldering… at least to electronics we are unsure about.
Seems to me if he just put 12V and Ground, it would tell him if the pwm is working… mine stays off until I put 12V on the pwm pin…
Why do you think so? Tell us more?