Dead driver or dying board?

kazolar

@dc42 I figured it out -- the current sent to the stepper falls DRASTICALLY. This is reproducible even on drivers which are acting normally. I am running ldo nema 17s on X carriage steppers. I noticed all of a sudden one of the carriages can't home. It's trying, but it feels like it's basically running with a fraction of the current -- same behavior if I were to set the current to 0.5 or less. I tried M569 commands nothing is printed. I notice driver 2 is working fine, but when given 2 amps, the carriage is rather easy to move. So I gave it 2.5 these LDOs max is 2.8, I've run them at 2.5 on my voron. Even at 2.5 the stepper can be moved by hand with a bit more force. I then powercycled the machine, and 2.5 is now stepper is rock solid. This feels like the board driver current reg is failing? or Something of that ilk.

kazolar

Lots of timeouts.
Driver 0: standstill, SG min 0, mspos 216, reads 51266, writes 3696 timeouts 364
Driver 1: standstill, SG min 0, mspos 72, reads 51266, writes 3696 timeouts 364
Driver 2: ok, SG min 0, mspos 600, reads 51266, writes 3696 timeouts 364
Driver 3: standstill, SG min n/a, mspos 8, reads 51277, writes 3685 timeouts 364
Driver 4: standstill, SG min 0, mspos 936, reads 51266, writes 3696 timeouts 364
Driver 5: standstill, SG min n/a, mspos 8, reads 51277, writes 3685 timeouts 364
Phase step loop runtime (us): min=0, max=192, frequency (Hz): min=492, max=46875

And this is when the issue isn't happening
Updated the firmware to latest rc3, didn't help.

Reproduced the problem on 2 drivers now and other drivers show reduced current when the problem occurs. The drivers which are faulty drop current down 1 amp -- and the steppers I'm using need more than that to move.

Ordered a new board, clearly this one is not long for this world. Gonna get this print done, and will replace it over the weekend. Considering moving to SBC mode as well during the swap.
Will also be switching to 40-48v (need to do the math which is best for my steppers)

dc42

@kazolar this doesn't sound like a hardware fault to me. What M906 idle current setting do you use? If motor current is reducing on all drivers when this happens, perhaps the firmware is setting all motors to idle current incorrectly.

kazolar

@dc42 idle is 50% hasn't changed in 7 years I've had this printer. When the issue occurs. Restart cant even fix the current. Manually sending m906 isn't reflected in actual current. It seemed like now 2 drivers are pulling all current down. I was checking during the print yesterday and left over current was holding correctly. I ran 100s of hours with this config and Firmware. Only recent change was addition of szp. Nothing changed in drive config (until I had to stop using 2 of the drivers on the main board) Firmware reboot + reinstall would expect to restore any current settings, all the timeouts don't inspire confidence. Problems are only on the main board all expansions and toolboards are fine. Timeouts and current issues are main board only. Certainly looks like it's dying one driver at a time.

dc42

@kazolar if the idle current percentage is 50% then that would explain a drop in current from 2A to 1A. Have you really run 100s of hours using 3.6.0-rc.3 firmware before this issue started occurring?

You might like to change the idle current percentage to 100% to make sure that the issue isn't that the firmware is incorrectly changing drivers to idle current setting.

kazolar

@dc42 I had run 100s of hours on rc1. I had zero issues, i.e only thing i changed was add szp and that is connected to a toolboard, and basically proceeded to print another set of long prints and the issues started. Also issues started gradually. First it could go 15 hrs before there was a problem, then 5, then 3, then 1. Rc3 was updated just yesterday. Also when the problem occurs, it says it's 2 amps, but I can move the carriage by hand and the stepper skips, if I power cycle, it reports 2 amps again, and now the carriage would have belts slip before the stepper skips. Also the current problem on the main board only and expansion boards go in an out of idle and maintain current. I.e 2 amps is 2 amps. I reproduced it, i have 1 carriage on main board, one on expansion, both say 2 amps, 1 i can move by hand, one i cant. Hence why the main board seemed sus. I guess if the problem re-occurs with the 1.02 version of hardware (i am switching all to 48v capable) then we can hunt for idle or current issue as it connect to firmware. I have a big project coming up, we'll see. Board is of warranty, seems something not isolated to 1 driver is malfunctioning.

PS. If for whatever reason you want to investigate the main board, I won't be re-selling it, so it would go to e-waste, so if you want to cover shipping to UK, you can have it. All my expansion boards are perfectly functional, so I will try to sell them - since I'm switching to 1.02 versions to use 40-48v everywhere.

dc42

@kazolar M906 reports the configured current. The actual current may be lower than reported by M906 when the motors are not moving, either because of driver standstill current reduction, or because of RRF idle detection.

Did you ever run the test i described in this post https://forum.duet3d.com/post/355556 ? That checks for an unlikely error condition that the firmware doesn't check for.

kazolar

@dc42 yes M569 P5 R1 or in my case M569 P0.5 R1 shows no response -- I had the same issue reproduced on driver 3 also, I tried M569 P3 R1 and M569 P0.3 R1 -- no response. Tried on rc1 and rc3, no response.

dc42

@kazolar ~~why are you using the R1 parameter with M569? That parameter is for use with external drivers, and should not produce a response.~~

OK, my bad, I made a mistake in my post. The command to use is M569.2 not M569.

kazolar

@dc42 ok, I plugged the 2nd carriage into driver 3 -- it's set for 2 amps, but I can move it by hand easily
This is what I have in config
M906 Y1600:1600 U1600:1600 X2000 V2000 W2000 A2000 Z2000:2000:2000:2000 E750:750:750:750 I50 ; set motor currents (mA) and motor idle factor in per cent
5/23/2025, 1:18:38 PM M569 P0.3

Drive 3 runs forwards, active low enable, timing fast, mode spreadCycle, ccr 0x10024, toff 4, tblank 2, thigh 200 (375.0 mm/sec), gs=39, iRun=31, iHold=21, current=990.234, hstart/hend/hdec 2/0/0, pos 232
It didn't apply -- it was ignored. When I had V mapped to driver 0, it was reporting 2 amps.

5/23/2025, 1:19:19 PM M906 V2000
5/23/2025, 1:19:26 PM M906 P0.3
Drive 3 runs forwards, active low enable, timing fast, mode spreadCycle, ccr 0x10024, toff 4, tblank 2, thigh 200 (375.0 mm/sec), gs=79, iRun=31, iHold=21, current=2005.859, hstart/hend/hdec 2/0/0, pos 232

5/23/2025, 2:06:08 PM M569.2 P0.3 R1
Register 0x01 value 0x00000005

M569.2 P0.3 R1 V7

M569.2 P0.3 R1
Register 0x01 value 0x00000000

I'll try to reproduce it, but it requires a print of some sort, I'll try doing a number of test cycles with V axis mapped to driver 3

dc42

@kazolar thanks. This really doesn't sound like an issue with the stepper driver chip to me, which is why I'd prefer to identify the cause and rule out (or otherwise) a firmware issue.

dc42

@kazolar motors are not powered initially when you power up the system. if you enable the Y driver using M17 Y does the motor become hard to turn?

jay_s_uk

@kazolar said in Dead driver or dying board?:

M906 Y1600:1600 U1600:1600 X2000 V2000 W2000 A2000 Z2000:2000:2000:2000 E750:750:750:750 I50 ; set motor currents (mA) and motor idle factor in per cent

This line is wrong. You can't set a drive current per motor on an axis, only on extruders.

This would be the correct line to use

M906 Y1600 U1600 X2000 V2000 W2000 A2000 Z2000 E750:750:750:750 I50 ; set motor currents (mA) and motor idle factor in per cent

dc42

@kazolar it's as @jay_s_uk says; however the extra values you provided in the M906 command should be ignored and the first value provided should be used for all motors on that axis.

kazolar

@dc42 ok, all being the same -- Z wasn't ever the problem, and extra prams are ignored -- the issue was easier reproduce on my secondary X carriage (V axis) in this case there is no risk of damage to the machine -- carriage just doesn't home properly -- but as per usual it doesn't want to reproduce now. I'll keep trying today -- but gonna run out of time. New boards are coming tomorrow, so if the problem re-appears, I'll update the post.

kazolar

@dc42 just wondering. Is it possible that M906 implementation has changed and the impact is only on the main board, not the expansion boards, so my extra params are screwing up current assignments? Hence setting current on the expansion boards is working fine, but main board -- it's not, or at least not correctly (timeouts in triple digits on the main board are still unexplained though)