FAQ and troubleshooting
Stop imaging/guiding and inspect physical clearance before a check that can restart motion. If there is smoke, an electrical smell, damage or uncontrolled movement, isolate the system safely and contact support. Do not repeatedly retry a dangerous motion.
In this chapter
- 8.1 Before-use questions
- 8.2 Operating concepts
- 8.3 Power and start-up problems
- 8.4 Connection problems
- 8.5 Movement and GoTo problems
- 8.6 Tracking and guiding problems
- 8.7 Home, Park and safety problems
- 8.8 Contact technical support
8.1 Before-use questions
Which power supply should I use?
Use the supplied 24 V / 200 W adapter at the mount's 5.5 × 2.5 mm DC input, or a verified source meeting the WD-20EP 12–25 V DC, 10 A input specification and correct polarity. The included 12 V / 3 A and 12 V / 5 A PD-to-DC leads are saddle accessory outputs, not mount input leads. A lower-capacity source can limit saddle PD output or cause resets under load. See 1.6 and 4.9.
Do I need a counterweight?
Assess payload mass, its RA lever arm, tripod stability and brake holding. Counterweight-free operation is possible within the relevant limits, but a counterweight may improve stability or reduce unbalanced RA torque. Combined counterweight mass must not exceed 10 kg, independently of the torque result, to protect the M12 attachment thread. See 3.5.
Do I need guiding?
It depends on image scale, exposure length and conditions. Test actual star images. The output encoder does not remove polar-alignment error, seeing or optical flexure, and the specified drive error is not a universal exposure guarantee.
Is a hand controller required?
Computer control can use the mount's PC interface with a supported driver. The supplied AHC provides the advertised GPS, wireless bridge and convenient vendor-specific safety controls. It must be connected for its bridge to relay wireless commands.
Which accessories and software are supported?
Use the specified dovetail and counterweight interfaces, an approved tripod/adapter, and the supported OnStep-compatible software route in Chapter 04. Confirm special electrical adapters by model and pinout, not connector shape alone.
8.2 Operating concepts
How do polar alignment and Sync differ?
Polar alignment mechanically points the RA axis at the celestial pole. Sync associates the present telescope pointing with specified sky coordinates. One does not replace the other.
How do Home and Park differ?
Home is the reference position; Park is the stopping/stow operation. The default Park position physically matches Home, but the commands perform different functions. Returning to the AHC main screen with its HOME button is a third, unrelated action. See 5.4 and 5.9.
What should I check after a restart?
Check actual position, Home/reference state, Park, observing data, warning state, EC HA Limit and AEB. If a controller or imaging application reconnects, confirm that it has not changed the mount's data unexpectedly.
Before the first GoTo or manual slew after power-on, enable Tracking after verifying site/time. A Tracking ON indication alone does not prove that coordinate-based protection has been initialized; follow the GoTo/Sync initialization sequence.
How do EC HA Limit and meridian limits differ?
EC HA Limit is encoder/reference-based RA travel protection. Meridian limits govern coordinate-dependent GEM travel/flip behavior. Configure both consistently with physical clearance; neither setting describes every telescope obstruction.
When should I run AEB Auto Tune?
AEB is disabled at the factory by default; enable it if you intend to use it. Tune for the installed load using the supported workflow, and reassess after changes to the telescope, accessories or counterweights, or when diagnosis calls for recalibration. Do not start it merely to dismiss a warning. Follow 6.5, including compatibility and reduced-protection precautions.
8.3 Power and start-up problems
| Symptom | Checks and next action |
|---|---|
| Mount does not start | Check the supplied 24 V adapter or other verified source, power switch, correct 5.5 × 2.5 mm input seating, polarity, cable condition and any upstream protection. Do not use a 12 V PD-to-DC saddle accessory lead as the input. Disconnect a damaged component before further use. |
| Unexpected restart | Check the supply remains within specification under load, connector retention, cable resistance/length, battery state and upstream power limits. Note whether it occurs during slewing. |
| AHC has a screen but no mount data | Check the mount's own power and controller cable; do not infer a successful data connection from the display being lit. |
AHC Power page is unavailable or shows -- | Confirm the AHC has identified WD-20EP and has live mount data. The two-channel display requires compatible AHC and mount firmware; -- indicates unavailable telemetry, not necessarily failed DC input or a failed accessory. Check the actual device, port and cable. |
| Saddle accessory stays on after the front-panel switch is turned off | This is expected while a live supply remains connected to the mount's DC input. The switch does not control Port A/B PD output. After stopping motion, shut down any Port B-powered mini PC cleanly, disconnect its USB cable, then disconnect the mount's DC input to turn off saddle power. |
| A saddle accessory requiring more than 12 V does not power on | Port A/B are step-down outputs, so a 12 V mount input cannot provide a 15 V or 20 V saddle output. The 12 V PD-to-DC leads also cannot boost a low input voltage. Check the required PD profile and actual output, then use an appropriate higher-voltage mount supply within specification. |
| Saddle accessory does not start | Verify device voltage, polarity and current, correct A/B port, a working USB-PD or PD-to-DC trigger cable, and input-supply capacity. For the included 12 V / 5 A lead use Port A. A passive USB-C-to-barrel cable is not equivalent. Check actual negotiated output and CH1/CH2 telemetry before retrying. |
| Accessory resets or power drops during a slew | Reduce combined saddle loads, check the 24 V adapter and input connector for sag or intermittent contact, inspect cable ratings/strain relief and retest one accessory at a time. Stop if any connection heats or shows damage. |
| Computer does not detect mount through saddle Port B | For data-only control, use a USB-A-to-USB-C data cable. For simultaneous power and data with a compatible mini PC, use a data-capable USB-C-to-USB-C cable and verify that the mini PC's USB-C port accepts PD input and USB data. A charge-only cable will not work. Connect mount DC and switch on the mount before the computer cable. Port B exposes its own mount USB serial channel; it is not a bridge from the front-panel PC port or a USB hub. |
For recurring resets, stop and collect the versions, supply information and reproduction steps. Do not diagnose by repeatedly running maximum-speed slews.
8.4 Connection problems
Computer does not detect the mount
- Verify the cable is connected to PC, not the controller/ST4 interface.
- Try a known data cable and a direct computer port without an intervening hub.
- Check the actual detected USB/serial device and install only its matching driver.
- Record the assigned COM/device port and use it in the telescope driver.
Port exists but the application cannot connect
Check the chosen OnStep profile, actual baud rate and whether another program owns the serial port. Close other direct-port clients, reconnect one application and read status before any movement. Check firmware-specific connection requirements if 9600 baud does not apply.
Why does AHC fail to connect to a PC?
Use a fully wired (full-pin) USB-C to USB-C cable compliant with USB 3.2. A charge-only or USB 2.0-only C-to-C cable will not provide the required AHC-to-PC connection. Try a known compliant cable and a direct PC port before reinstalling software. Check the intended connection route and port: AHC-to-PC, AHC-to-mount and direct mount-to-PC are different connections. See 4.3 and 7.2.
AHC mount icon stays gray
Inspect the supplied controller cable and its designated port, mount power and identification. Reseat with the equipment safely stopped; try an approved replacement cable if available. Check that the mount/AHC firmware combination is supported. Do not use a random powered USB cable at the controller port.
Wi-Fi is connected but mount control fails
Check the AHC is itself connected to the mount. Verify AP/STA mode, the current IP address, TCP port 9999, client protocol and local-network reachability. In STA mode, a DHCP address change or network client isolation can explain the failure. Light blue means the bridge service is ready; it does not mean a control client is connected.
BLE device appears but no control works
Confirm the client supports Nordic UART Service, the passkey requirement and the current device name. A generic Bluetooth serial-port expectation is not sufficient. Reconnect after Save & Restart.
8.5 Movement and GoTo problems
Unable to move or perform GoTo
After power-on, first verify the mount's site/time and enable Tracking before the first GoTo or manual slew. If a GoTo appears to produce no movement, check that tracking was enabled and that the mount received the command. Follow 5.6 Start-up initialization; Tracking ON alone does not confirm that coordinate-based limits are active.
Check Park/unpark state, current warning, EC HA/altitude/meridian boundaries, correct time/location and the target's altitude. On AHC Dashboard, check STICK is Active; once the startup prerequisites above are satisfied, use Motion for a supervised low-speed manual test in a clear direction. A disabled GoTo button can indicate Below Horizon or Waiting Mount Time.
Do not disable protection to find out whether it caused the refusal. Read the condition first, then use the appropriate recovery procedure.
Why do the N and S buttons sometimes appear reversed?
In GEM mode, N and S refer to directions on the celestial coordinate system, not fixed directions of DEC motor rotation or directions in the camera image. Near a celestial pole, this can feel counterintuitive: after the telescope crosses the pole, the next command toward the pole may rotate the DEC axis the opposite physical way. OnStep describes this as the classic question of what lies “north of North” (or “south of South”) in its FAQ. WarpAstron support also explains why DEC motion near the north celestial pole can differ from an Alt/Az interpretation of north and south.
This behavior near the pole does not by itself indicate reversed wiring or a motor fault. Keep the mount in view and make only short, low-speed test movements with clear space around the telescope. If the direction changes unexpectedly away from the pole, the mount repeatedly moves back and forth, or its reported position disagrees with its physical position, press STOP and check the mount mode, hemisphere, Home/reference state, Sync history and any active safety warning before continuing.
Movement direction or physical position is unexpected
Press STOP. Check mount mode, hemisphere, reference/Home state, target identity and recent Sync operations. Remember that image orientation can invert the apparent direction. Do not change motor direction or encoder Home settings as the first response to an inverted camera view.
GoTo misses by a large amount
Check date, UTC/time zone, site coordinates, physical Home, Park state and polar alignment. Review any plate-solve/Sync result for consistency. Establish a verified pointing before synchronizing again; repeated Sync to an incorrectly identified field can worsen the problem.
8.6 Tracking and guiding problems
| Symptom | Checks |
|---|---|
| Tracking will not start or stops | Check enabled state/rate, Park, limits, warnings, supply and commands from other controllers. |
| Star drift | Check polar alignment, rate, time/location, actual tracking state and any camera/optical flexure. |
| Guiding calibration fails | Check camera focus/signal, entered pixel size/focal length, guide connection/rate, target region and that mount movement is permitted. |
| Guide graph is erratic | Inspect wind, seeing, star signal, cable drag, attachment flexure and power before changing motor settings. |
| Problem after a flip | Check pier side, guiding-calibration handling, target reacquisition and cable routing in the new orientation. |
Compare guide logs with star images; a graph alone does not identify mechanical or optical causes. Change one parameter at a time and preserve the original values.
8.7 Home, Park and safety problems
Homing or parking fails
Stop and inspect clearance, the actual axis position, warning and selected Park destination. For Home, check encoder/sensor status and whether the operation completed. Do not save the current arbitrary position as Home to bypass a failed return.
EC HA Limit is reached unexpectedly
Check the actual Home/reference state, east/west boundaries and encoder information. Inspect recent changes and the relationship to meridian settings. Recover away from a boundary only using a permitted, clearly safe route; see 6.4.
AEB activates unexpectedly
Wait for movement and any protective reversal to finish. Check for cable snagging, contact, changed payload, stiff motion, supply problems and the stored baseline/threshold. Do not repeatedly raise the trigger to hide an unexplained event.
AEB Auto Tune fails or is interrupted
Check compatible versions, physical Home, tracking off, required unparked state, EC/HA/AEB state and disconnected independent controllers. If a recovery screen offers Restore Speed, complete it. A run without actual preparation/return movement is not a valid calibration. Preserve error information and follow 6.5.
What do the front-panel lights mean?
- Power: red continuously lit during normal powered operation.
- STATUS: flashing blue during tracking; continuously lit blue during GoTo or slewing, including a Home return.
- EC: flashing green for normal encoder status; flashing red for an encoder fault.
If EC flashes red, stop movement, inspect the reported encoder/reference state and resolve the fault before relying on EC HA Limit or issuing Home, GoTo or Park. Do not clear the Home reference merely to remove a fault. See front-panel controls and indicators.
GPS or NTP does not synchronize
For GPS, check reception, valid fix and the selected sync controls. Confirm the observing site's correct time zone, including the result of Auto Timezone if enabled, and compare UTC and Local Time after synchronization; a valid GPS fix does not confirm the zone. For NTP, use an internet-connected STA network; AP alone is not sufficient. If the controller has time but shows Time ready - waiting mount, resolve the mount connection. Manual site/time entry remains available.
8.8 Contact technical support
Use WarpAstron support or support@warpastron.com. Provide:
- WD-20EP model/serial number, mount firmware and AHC firmware versions.
- Telescope, accessories, counterweights, tripod/pier and power-supply details.
- Connection method, driver/application versions and operating mode.
- Exact warning/error text, relevant settings and what happened immediately beforehand.
- Steps to reproduce, logs, screenshots and photographs showing the complete setup and cable paths.
Keep diagnostic records before changing settings or clearing event counts. Do not reproduce an unsafe collision for a video; describe it and provide safe stationary photographs instead.