I’ve had the 100w JPT fibre laser for about 7 months, all working fine.
Today I did 2 engravings…seemed ok apart from the middle seemingly loosing resolution.
On the 3rd, I hit the Frame button and in stead of a rectangle the red dot preview went mental, making a very strange noise like the mirrors were going round in circles very fast.
After a few restarts of lightburn and the laser the red dot now just dows the rectangle but kind of all over the place, backwards and forwards, not to scale sometimes 5 times the size.
If I hit Start it will then fire the laser but it will go where the red dot was and creat a right mess.
Any ideas?
I have contacted Aliexpress but my hopes are low of getting a resolution from them as they only say 15 day warrenty, but you never know!
15 day warranty does not sound good. You can check the DB15 cable connection at either end. Sounds like the galvo head though. What is the brand/ model number of the head? They do fail from time to time, new or old.
For the 1st 10 mins of the day it seems to work ok,
then it might do half the job, or start moving the mirrors at about 1mm/s instead of 1000mm/s, or it might just stop alltogether. the laser stops firing as well, don’t know if they are in contact with each other so if the mirror doesn’t move to the next position the laser doesn’t fire…
Sorry, I’m probably not going to be much help. So that said, this is what I think:
Can’t find that galvo with that brand and numbers. not a confidence builder.
Assuming a misspelling, Mode: is really Model. (L is right next to : on my keyboard) Not a confidence builder.
15 day warranty, not a confidence builder.
I’m a throw parts at it kind of guy, first I would open the case up and put a voltmeter on the power supply and run the laser, see if voltage goes bad same time problems start. New PS inexpensive fix. Lucky!
While open verify the board and laser manufacturer looking for misspellings or off brand. I can’t really advise on a test procedure. The BJJCZ board and galvo head can be replaced with genuine parts less then $1000 US. Not so lucky.
Hopefully the laser source is a genuine unit in good working order, those are expensive enough I would scrap the machine and get one with name brand source, board, and scan head. Worst case.
Keep us posted and good luck!
I had a very similar problem with my machine with an SG7110 head.
At first I noted a whine with it at idle, but I assumed that was normal. It’s not normal. That’s a high speed oscillation in the control system.
Then it started legit oscillating right after I started running it at high speed. Once it started, it would continue oscillating even while stopped, the red dot was a line. And also I saw the mirror stop completely (control card probably went into overcurrent and cycled off but no error signal tied in to stop the laser source or job)
If power was cycled quickly it stayed like this, if cycled off for 30 min or whatever it would power back on and make a dot initially but then start oscillating right after starting a high speed job.
Fortunately the mfg replaced mine under warranty. There was a warranty seal they needed back intact and I wasn’t able to do an autopsy on it. The problem was fixed by replacing the galvo head which contains the motors and drivers but not the DC power supply or DB cable,
From what I read, this is likely due to a bad ground, or maybe just a poorly seated connector. I do know there’s like 5 trimpots or so on each controller card which mostly adjust for overshoot and things but one of them might be capable of causing oscillation.
It is not in the BJJCZ board. The DC power supply is not in the scan head but the big MOPA source box, mine was fixed without replacing that.
I just discovered the SG7210 upgrade which cost me $560 offers DOUBLE the scan speeds. I have the 300W and the higher scan speed should drastically improve by throughput. If this works out I may have an almost new SG7110 to set you up with.
If not under warranty, I would break the warranty seal and check the cabling, probably put the DC power line under an oscilloscope, but AFAIK they share the same power rail and it wouldn’t make sense for my prob for it to be oscillation in the DC power rail. The mirrors should have encoders AFAIK and a prob with the encoder feedback would totally cause this too.
I really appreciate your time in the reply thank you.
If ou have a RC7110 going cheap I would love to take if off your hands.
I’m in the UK if that causes any issues re postage though.
I contacted the supplier of the laser, they did reply but are very slow, he originally though from the despcription that the main board was at fault, I have since sent him a video, but no reply yet.
I think the scan head also is faulty as I took it off, had a look inside (to many bits for me to know what is going on). and put it back on…It worksed for about 5 minutes all ok, then messed up again.
I think you can put an SG7110 in there instead of that RC7110.
It looks like SG7110 is a bit faster. More sellers of SG on AliExpress suggests it’s the more common one
It looks like the SG7110 is only about $300 from AliExpress so it would probably make the most sense to just get a new one.
Like I say, the SG7210 looks like a valuable upgrade since it delivers twice the speed. If I were you, I’d try to fix the RC7110- open it up, make sure the cables are seated, put an oscilloscope on the DC supply to make sure it’s smooth DC, look up the RC7110 manual and the trim pot functions. But actually I doubt the trim pots are an issue since you said both channels went wonky. I wouldn’t consider messing with those unless all other options were gone.
I did see a Chinese-made video online of “how to fix problem” that showed installing a thick external ground wire zip tied to the fiber cable going from the galvo head to the DC power supply and on to the case.
That’s plausible, a galvo draws high current spikes and the cable is just a DB25. The pinout shows they allocated 2 for GND and 1 for COM. Since this is a DB25, it’s likely the wiring going back to the source is thin-gauge stuff and 2 grounds isn’t much.
If they did their design well, COM would be the ground for all the signals but isolated from the power GND. That should make it “mostly” insensitive to IR drops along the GND wire but there can be exceptions when the IR drop on the ground is really high. But I don’t know.
If you think the RG7110 isn’t serviceable and looking for a replacement, I would definitely spend the extra $ for the SG7210
I got a reply from the supplier, I sent the video of what it’s doing.
He said was definitely the main board. It is under warranty and he’s going to send a new one.
Of course Chinese new year so everything shut for 2 weeks.
Will see if the main board fixes it.
Then will look into changing the head if it doesn’t or at a later time when i can save for the 7210.
