Troubleshooting Non-Functional Servos Issue

@athena

test1 Start

PWM test starting on d23 PWM test complete Done (00:00:01.0896984)

test2 Start

Digital test on d23 Digital test complete Done (00:00:00.5458804)

voltage zero voltage on all ports

unplugged servo on d23 volt 0,01

i see no damage on the inside from the magnet .

You can't see inside microchips, resistors, or transistors for damage. Electronics can look okay, but not operate because something's broken internally. You are very experienced with EZBs and electronics, so you would have this working if it was ok

Good troubleshooting - your measurements confirm the problem.

Summary of what we know

• ARC connects to the EZ-B and firmware identifies correctly (top/comm board is working).
• Battery/VCC is present (~7.6 V) and stable.
• Servos themselves are known-good (you tested them on IoTiny).
• ARC script commands (PWM.set / Digital.set / Servo.setPosition) execute without script errors but there is effectively 0 V on the SIGNAL pins at the servo headers (you measured ~0.01 V).
• Web admin "Set all ports to 90" reboots the board but does not move servos.

What that indicates

• The communication/top board is fine (WiFi, camera, firmware handshake).
• The PWM / digital driver outputs on the bottom I/O board (the D0-D23 outputs) are not driving the signal lines.
• Most likely cause: the bottom I/O board (the lower PCB that contains the servo drivers / digital outputs) is failed or the electrical connection between the top and bottom boards is not making contact.

One last quick check (non-destructive)

1. Power OFF the EZB.
2. Remove the top board from the bottom board connectors and visually inspect the male/female header pins for any bent pins or missing pins.
3. Re-seat the top board firmly and evenly onto the header pins (press straight down so all pins are seated).
4. Power ON, then run this quick toggle test in ARC (copypaste and Run):

print("Digital test d0/d1 start");
Digital.set(d0, true); sleep(500); Digital.set(d0, false);
Digital.set(d1, true); sleep(500); Digital.set(d1, false);
print("Digital test complete");

Measure the SIGNAL pin while the test runs (signal vs GND). If still ~0 V across multiple ports, the I/O driver is not outputting.

If the signal pins remain dead after reseating

• That confirms the bottom I/O board (or the driver circuitry on it) is defective and should be replaced.

Repair / replacement options

• The EZB v4 is two boards (top = comm/wifi/camera; bottom = I/O). If the bottom board is damaged you can replace just the bottom I/O board and keep the top board.
• Parts / info:
  • EZB v4 support & hardware page: https://synthiam.com/Support/Hardware/EZ-B-v4
  • EZB v4 product/store pages (parts sold here if available):
    • EZ-B v4 product: https://synthiam.com/Products/ARC (navigate to hardware/shop)
      (If you tell me where you purchased the unit I can help find the exact replacement board link.)

Basic replacement steps (overview)

1. Remove power.
2. Remove any screws holding the case and separate the case halves.
3. Unplug camera, cables and note orientation of connectors.
4. Unscrew/remove top board from header, lift off.
5. Unscrew/mount the replacement bottom board (or swap bottom board under the top board).
6. Reassemble in reverse order, power up and test D0-D23 outputs with the Digital.set test above.

Safety & tips

• Work on a non-conductive surface; observe ESD precautions if possible.
• Keep track of screws and connectors; take photos before disassembly so you can reassemble exactly.
• Don’t force connectors-if pins look misaligned stop and tell me.

Would you like me to

• Walk you stepbystep through reseating and retesting now (I can list every screw/connector to remove)?
• Help find and order the correct bottom I/O board (tell me where you bought the unit or your country)?
• Provide a photoguided swap procedure and the exact tests to run immediately after replacing?

Tell me which option you want and whether you’re comfortable opening the EZB now. If you want to go ahead with a part order, paste your purchase/region and I’ll search for the correct replacement board and give the next steps.

@athena let see for a boart then . thank for the help .

Great - I’ll help you find the correct board and walk you through the replacement steps. Below are next actions, links, and what I’ll need from you to find an exact match and order the part.

1. What I need from you

• Where did you purchase the unit (EZ-Robot store, Amazon, reseller)?
• Your country/region (so I can find sellers that ship to you).
• Do you want me to search for a replacement bottom I/O board for you, or would you prefer a link so you can order?

2. What to search for (use these terms when looking for parts)

• "EZB v4 bottom I/O board"
• "EZB v4 I/O board replacement"
• "EZB v4 v4.x/2 I/O daughter board" These terms will find the PCB that contains the D0-D23 servo/digital drivers (the lower board). Match the board to the firmware ID your EZB reported (you had "EZB v4.x/2 Native Firmware") to avoid mismatched revisions.

3. Official reference & part info

• EZB v4 (hardware & support): https://synthiam.com/Support/Hardware/EZ-B-v4
  • Read the "Diagnosing a Damaged EZB v4" and the port/board overview - it explains top vs bottom board behavior and confirms the bottom board is the likely culprit.

4. Ordering tips

• Only replace the bottom I/O board (not the whole unit) if:
  • Camera, WiFi and firmware handshake work (they do for you), and
  • Signal pins remain at ~0 V across D0-D23 after reseating (you already measured ~0.01 V).
• When ordering, confirm the seller lists compatibility with "EZB v4.x/2" or shows photos of the same pin headers and connectors as your unit.
• If a seller offers "full EZB v4 main board" vs "I/O bottom board," choose the bottom/I/O board option if available. If not available, the whole EZB can be replaced.

5. After you receive the board - I will guide you stepbystep

• Tools and safety: small Phillips, ESD precaution (antistatic wrist strap if available), nonconductive work surface.
• Swap steps (I’ll provide full photo annotated steps if you want):
  1. Power OFF and disconnect battery.
  2. Remove case screws and open the case.
  3. Note / photo connector orientation (camera, headers).
  4. Unscrew and lift the top comm board straight off the header pins.
  5. Remove the bottom I/O board and install the replacement.
  6. Re-seat the top board evenly onto the new board (press straight down).
  7. Reassemble, power up, run the Digital.set / Servo.setPosition tests you already used.
• Postinstall verification I’ll walk you through:
  • Run the earlier digital/pwm/servo scripts and measure SIGNAL pin voltages.
  • Test the "Set All to 90" in the EZB web admin and in ARC.
  • Confirm servos physically move.

6. If you want, I’ll search now

• Tell me your region and where you bought the unit, and I’ll find compatible replacement boards and post links. I can also provide stepbystep photos for the swap and the exact tests to run immediately after installation.

Want me to search for replacement boards now (and do you prefer official EZRobot parts or used/spare boards)?