Advanced Search

Picture 2, that looks like arcing across those two parts, moisture can do that, but the rest of the boards look like there is no moisture in quantities to cause that.

With Q1 open, what do you have between L1,L2,and L3?

Is the neutral wired on the machine?
What connector is used at the wall?
Was that connector or the wall socket changed before the incident?
-
Assuming using industrial 16A or 32A plugs, they can easily be miss wired by switching neutral and one of the phases, be it on the wall or on the machine plug.
When no neutral is used, usually not much happens, but when neutral is used that causes ... things to happen.
Mentioning this as it happens a lot where i live.

Does anyone use jmc integrated servos with a 7i77?
I know they work with pulse/dir but in the manual they mention some kind of external analog instruction, but nothing about +/-10v.
Or is there any other other possibility to drive them with a 7i77?

Manual:
www.rocketronics.de/download/datasheet/i...v_v6_2020_manual.pdf

Those should be a complete mechanical set, so no need for BOM.
One thing that i noticed just from a quick glance there, all those say weight is 140KG, impossible due to huge size differences, so that is lazy on their part. I feel bad for other Germans, i have a lot of respect for their punctuality, now this....and the bureaucracy.

Thank you for your response, Peter.
Is the NCV7608 still available? I only found one listing on Aliexpress, which makes me wonder if it’s becoming hard to source.

While taking a closer look at the board, I found a small piece of cut wire lying around in that area:
 
 

Could this have caused the issue?If not, what else could I check to resolve the 5V overvoltage?
The 7i85S is powered via the 25-pin connector from the 7i76E.
Thanks again for your help!
–
Max

Much better, move on to wiring and making chips!
Keep an eye when starting LinuxCNC if it complains about latency, it shows a warning usually when enabling it or later during use.

matasbuk wrote:

What about 100-120mb programs? Are they possible? LinuxCNC seems to crash then loading those.


 

i have no experience with very large programs.
There are commands to help with large preview by hiding some of it:
linuxcnc.org/docs/devel/html/gui/qtdragon.html#_preview_control
 

Not sure about the 7I76E outputs, but the 7I85S seems to have been damaged by an overvoltage on the the 5V
supply, possible related to the original fault. It appears that both the IS32174 step/dir driver and U11, the LMV342
have been damaged.

7I85 U11 is part of the encoder circuitry when TTL mode is used, it will not affect differential mode encoders
so the 7I85s will probably continue to function for encoder inputs if they are differential, BUT the 5V situation
needs to be checked.

On the 7I76E, the damaged driver chip (NCV7608) should be replaced as it may fail further and perhaps cause
further damage.

Seems to load and run here (master branch):
 

Okay, now I am getting inconsistent behavior. Yesterday, I switched on the machine, the PC booted, and I was able to check the 7i84 connected with it's 7i77, and also check the voltage of the 24V rail (204).

Today, I wanted to repeat that, but the PC gets no power. I receives 110VAC via pins 150 /151 from the same 3Ph  transformer (6T1) which also powers the 24V DC rails. The 110VAC secondary is protected by fuse 6F6 , which has not tripped.

 

The primary of the that transformer is only protected by that main fuse/breaker Q2. I measured the output of Q2. Between L1/L2--> 400V , L1/L3 -->240V,  L2/L3 --> 200V. WTF?

Shut down again, tripped the switch on Q2 to remove all loads, and measured on the input side of it. Same result... Between L1/L2--> 400V , L1/L3 -->240V,  L2/L3 --> 200V.

Shut down again, pulled the socket from the wall and measured. The supply is normal. 400V phase to phase between all three. There is no isolation transformer. None of the fuses or breakers has tripped.

 

I am kind of confused what could be pulling down the voltage on those lines, unless I have an open circuit on one and the multimeter is just picking up tiny current induced into the lines like an antenna?

The complete dmesg is more interresting as there a mention about qtvcp

Hello everyone,

Yesterday, I managed to blow up two Mesa boards within just a few minutes, and I’m still not sure why it happened or how to avoid this in the future.

The machine is a retrofitted Schaublin 125CNC lathe, which had been running flawlessly—until last Friday’s coffee break. When I came back, I found the central lubrication pump had burned out, apparently because it had been running continuously.

I discovered that output 6 and output 7 were permanently high as soon as the card was powered up. These outputs are connected to 400V 3-phase contactors (for the lubrication and coolant pumps), each with a 24V coil and a flyback diode directly across the coil. Each contactor draws about 275 mA.

I’m not sure which output failed first—or whether both failed at the same time. The coolant pump is already configured in HAL but hasn’t yet been wired to its contactor, so I can only confirm that the lubrication pump was not being controlled by LinuxCNC at all—it isn’t connected in HAL.

After powering down the machine and disconnecting the wire between the lubrication pump’s contactor and output 6, I turned the power back on. While sitting in front of the control cabinet and moving some wires around, I saw smoke coming from the 7i85S board next to the 7i76E. It appears that capacitors C22 and C24 have blown, and one IC also looks suspicious.

I’m only using the encoder inputs of the 7i85S, and those still seem to be functional. I suspect that one of the unconnected step/dir outputs may have been damaged.

While I can accept that switching contactors directly might not have been ideal (even if within spec), I don’t understand what could have caused the damage on the 7i85S—especially since nothing was connected to any of its outputs.

During my investigation, I also realized that I had used the VIN pin on the field power connector instead of pins 1, 2, 3, or 4—so field power was supplied through the internal jumper. Could that have caused issues?

By the way, this part of Norbert’s connection sheet (page 2) may be a bit misleading or unclear in that regard.

Both boards are still working, aside from the two damaged outputs and possibly one or more differential outputs on the 7i85S. Also worth noting: the 24V supply to the cards is not switched on the DC side; the PSU is switched on the AC side.

Should I replace the boards anyway, or are they still safe to use going forward?

Thanks in advance for any help or insights!

— Max