# Spindel stuck at 7500 manual and automatic **URL:** \ **Category:** ❓ Something's Up\ **Created:** [August 10, 2026, 8:40pm UTC](https://forum.sienci.com/t/spindel-stuck-at-7500-manual-and-automatic/26883 "2026-08-10T20:40:16Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![SlimeTime](https://forum.sienci.com/letter_avatar_proxy/v4/letter/s/278dde/32.png) [@SlimeTime](https://forum.sienci.com/u/SlimeTime)\ **Post date:** [August 10, 2026, 8:40pm UTC](https://forum.sienci.com/t/spindel-stuck-at-7500-manual-and-automatic/26883/1 "2026-08-10T20:40:16Z")
Spindle locked at 7500 RPM Altmill 4x4 with 2.2kw Spindle and VFD I have everything set up but the spindle will not run at any speed other than 7500 RPM. I can turn it on, reverse it, and stop it with no issues. If I set my lower limit to 3000 RPM and try any setting under 7500, it just revs to 7500 and stays there. Same result when trying to go higher. After this I get error code 14, and both lights are blinking on the SuperLongBoard EXT. **Setup:** - Altmill 4x4 - 2.2kw Sienci’s Spindle and VFD - gController - GSender (latest version, updated firmware) **What I’ve tried:** - Followed the [Spindle stuck at 7500 RPM](https://sienci.zendesk.com/hc/en-us/articles/41563823576468-Spindle-stuck-at-7500-RPM) guide - Followed the [Alarm 14 / Alarm 19](https://sienci.zendesk.com/hc/en-us/articles/34779231810964-Alarm-14-Alarm-19) guide (everything except switching to MODVFD and checking internal cables, as I can’t find instructions for opening the enclosed VFD) - Updated firmware and GSender - Reset settings to default on the SuperLongBoard and GSender - same issue over both USB and Ethernet - Rebooted everything multiple times - Unplugged and reseated all electronics - Adjusted baud rate in both GSender and the VFD - no change - Increased timeout to 15 - no change - Triple checked outlet - confirmed running at 220V - All motion axes working correctly **Key observation:** I switched the VFD to manual mode to control speed with the front panel knob and got the same result, I can watch it ramp up and then it just hits 7500 RPM and stops there. Everything has its own correctly sized breaker. Next step I plan to try is switching to MODVFD. I have a support ticket open and am waiting to hear back. Any other suggestions in the meantime would be appreciated. Sorry if this isn’t the correct format for this forum I just stuck with how I add to tickets at work. Followed this as well [How-to-Diagnose-Spindle](https://sienci.zendesk.com/hc/en-us/articles/45561647001492--Training-How-to-Diagnose-Spindle-Issues?input_string=2.2kw+spindle+alarm+14) ---
**Author:** ![Chucky\_ott](https://forum.sienci.com/user_avatar/forum.sienci.com/chucky_ott/32/8692_2.png) [@Chucky\_ott](https://forum.sienci.com/u/Chucky_ott)\ **Post date:** [August 10, 2026, 10:59pm UTC](https://forum.sienci.com/t/spindel-stuck-at-7500-manual-and-automatic/26883/2 "2026-08-10T22:59:22Z")
@SlimeTime Looks like you did every troubleshooting steps except open the power connector to the spindle and check for a broken connection (making sure it’s not plugged in first) ---
**Author:** ![SlimeTime](https://forum.sienci.com/letter_avatar_proxy/v4/letter/s/278dde/32.png) [@SlimeTime](https://forum.sienci.com/u/SlimeTime)\ **Post date:** [August 11, 2026, 12:29am UTC](https://forum.sienci.com/t/spindel-stuck-at-7500-manual-and-automatic/26883/3 "2026-08-11T00:29:15Z")
Update: MODVFD Same issue. I’ll grab my multi meter and check er out tomorrow Thanks @Chucky_ott. Was going to have so by’s over to check er out but now its just going to be a good old shed party. ---
**Author:** ![Karver\_One](https://forum.sienci.com/user_avatar/forum.sienci.com/karver_one/32/11233_2.png) [@Karver\_One](https://forum.sienci.com/u/Karver_One)\ **Post date:** [August 11, 2026, 1:05am UTC](https://forum.sienci.com/t/spindel-stuck-at-7500-manual-and-automatic/26883/4 "2026-08-11T01:05:25Z")
Not sure if this would be a help but I found this: **The “Hz Display” Communication Reset** A known firmware bug occurs when enabling RS485 Modbus control where the VFD display defaults to an arbitrary internal threshold (7500). 1. **Power cycle the entire system:** Turn off the SLB-EXT via the toggle switch, then unplug the VFD completely from its outlet. 2. **Boot back up:** Plug the VFD back in, and flip the SLB-EXT back on. 3. **Change Display Metric:** Look at the front face of your VFD. Press the **SHIFT** key repeatedly. Look for the display unit options and change it so the active monitoring screen is explicitly set to display **Hertz (Hz)** instead of RPM. 4. On Sienci VFDs, shifting the display mode to Hz often forces the internal EEPROM to flush the 7500 loop error and restores communication ---
**Author:** ![SlimeTime](https://forum.sienci.com/letter_avatar_proxy/v4/letter/s/278dde/32.png) [@SlimeTime](https://forum.sienci.com/u/SlimeTime)\ **Post date:** [August 11, 2026, 6:33pm UTC](https://forum.sienci.com/t/spindel-stuck-at-7500-manual-and-automatic/26883/5 "2026-08-11T18:33:26Z")
I did try this but I gave it another go with your instruction’s same issue. I gave the VFD parameters another look based on some suggestions and made some progress, though the issue isn’t resolved yet. F011 was set to 125 — I changed it to 0 and the spindle now runs at 300 RPM instead of 7500, so something is shifting but it’s still locked to a single speed. It looks like the spindle may be receiving a fixed minimum voltage rather than responding to the control signal. A few things that would help me move forward: 1. Does anyone know where I can find a full parameter list for the VFD that ships with the Altmill? I want to go through it systematically rather than guessing at parameter numbers. 2. Does anyone have instructions or a guide for opening the enclosed Ontario VFD? I can’t find anything on how to access it and I’d like to check the internal wiring. Still waiting on my support ticket as well. Any help appreciated. ---
**Author:** ![Chucky\_ott](https://forum.sienci.com/user_avatar/forum.sienci.com/chucky_ott/32/8692_2.png) [@Chucky\_ott](https://forum.sienci.com/u/Chucky_ott)\ **Post date:** [August 11, 2026, 7:48pm UTC](https://forum.sienci.com/t/spindel-stuck-at-7500-manual-and-automatic/26883/6 "2026-08-11T19:48:04Z")
@SlimeTime Are you sure that the minimum and maximum spindle speeds are set properly? See this article for the firmware settings > **[AltMill - Sienci Labs Spindle Reset Process](https://sienci.zendesk.com/hc/en-us/articles/36880180392468-AltMill-Sienci-Labs-Spindle-Reset-Process)** > > If customers are having issues connecting the Sienci Labs spindle to the AltMill (e.g. Alarm 14 on gSender, r00.0 on VFD), have them follow the steps below.  > Open gSender and run the attached setup... ---
**Author:** ![Karver\_One](https://forum.sienci.com/user_avatar/forum.sienci.com/karver_one/32/11233_2.png) [@Karver\_One](https://forum.sienci.com/u/Karver_One)\ **Post date:** [August 11, 2026, 9:35pm UTC](https://forum.sienci.com/t/spindel-stuck-at-7500-manual-and-automatic/26883/7 "2026-08-11T21:35:39Z")
@SlimeTime These are the settings I use: > **[Incorrect VFD Settings - Alarm 14 / Alarm 19](https://sienci.zendesk.com/hc/en-us/articles/34779231810964-Alarm-14-Alarm-19#h_01KHRQ39CQWAG56ER9C0WHY3TT)** > > This troubleshooting guide is for both the AltMill and LongMill using either the SLB or the SLB-EXT. Alarm 14 will appear on earlier firmware software.  If you have updated your firmware, have an A... ---
**Author:** ![SlimeTime](https://forum.sienci.com/letter_avatar_proxy/v4/letter/s/278dde/32.png) [@SlimeTime](https://forum.sienci.com/u/SlimeTime)\ **Post date:** [August 11, 2026, 10:58pm UTC](https://forum.sienci.com/t/spindel-stuck-at-7500-manual-and-automatic/26883/8 "2026-08-11T22:58:05Z")
Thank you I got to the video part and watched it and said got it I didnt scroll down. ---
**Author:** ![SlimeTime](https://forum.sienci.com/letter_avatar_proxy/v4/letter/s/278dde/32.png) [@SlimeTime](https://forum.sienci.com/u/SlimeTime)\ **Post date:** [August 11, 2026, 10:59pm UTC](https://forum.sienci.com/t/spindel-stuck-at-7500-manual-and-automatic/26883/9 "2026-08-11T22:59:41Z")
Yes everything is matching but I will check them once more just incase. Never unwilling to give things a secound shot. ---
**Author:** ![SlimeTime](https://forum.sienci.com/letter_avatar_proxy/v4/letter/s/278dde/32.png) [@SlimeTime](https://forum.sienci.com/u/SlimeTime)\ **Post date:** [August 22, 2026, 10:39pm UTC](https://forum.sienci.com/t/spindel-stuck-at-7500-manual-and-automatic/26883/10 "2026-08-22T22:39:18Z")
I think I found the issue there was a rattle in the vfd and a jumper fell out after shaking and routating it a bit. does anyone have a photo of the inside of one of these (control terminal area) or a schematic showing exactly where each jumper goes? I know there are at least a few in that area ---
**Author:** ![SlimeTime](https://forum.sienci.com/letter_avatar_proxy/v4/letter/s/278dde/32.png) [@SlimeTime](https://forum.sienci.com/u/SlimeTime)\ **Post date:** [August 22, 2026, 11:16pm UTC](https://forum.sienci.com/t/spindel-stuck-at-7500-manual-and-automatic/26883/11 "2026-08-22T23:16:47Z")
Found the jumper issue the NPN / PNP jumper fell off. I assume NPN is the correct jump for a longboard. but I will test it tomorrow and post. Support said not to open it but with a jumper falling out figured I would just send it. ![image](https://forum.sienci.com/uploads/default/original/2X/2/26cad19532a08d1cc128e4e22a335a20602bde12.jpeg) ---
**Author:** ![SlimeTime](https://forum.sienci.com/letter_avatar_proxy/v4/letter/s/278dde/32.png) [@SlimeTime](https://forum.sienci.com/u/SlimeTime)\ **Post date:** [August 24, 2026, 4:35pm UTC](https://forum.sienci.com/t/spindel-stuck-at-7500-manual-and-automatic/26883/12 "2026-08-24T16:35:11Z")
This worked the 0900 flashing numbers are now flashing 0000 even cleared from the VFD. Ran the Spindle Brake in just fine, it had no issues. ---
**Author:** ![gwilki](https://forum.sienci.com/user_avatar/forum.sienci.com/gwilki/32/366_2.png) [@gwilki](https://forum.sienci.com/u/gwilki)\ **Post date:** [August 24, 2026, 5:33pm UTC](https://forum.sienci.com/t/spindel-stuck-at-7500-manual-and-automatic/26883/13 "2026-08-24T17:33:19Z")
Closed on August 24, 2026, 5:33pm UTC