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Oct 6, 2008

Issues caused by incorrectly adjusted ESP power supply

Summary
We have seen cases where the internal power supply has been incorrectly adjusted causing a number of different issues with the ESP.

Possible symptoms include:
  • ESP fails to boot correctly, Status LED remains unlit and communication cannot be established
  • Some or all cards not detected correctly during a scan
  • ESP powers up with red Status LED and no audio passes.
  • Issues with serial communication via RS232 port.
Similar symptoms can also be caused by the power supply harness

Cause
The internal power supply for the ESP-88 should be adjusted to 5.2v during manufacture. If the voltage is incorrectly adjusted and is lower it can cause unexpected behaviour.

Product
ESP-88 (v1.001 or later)

Workaround
Not Applicable

Resolution
Initially the voltage can be measured on the GPO port (to avoid removing the cover unecessarily). With the ESP powered-up place the -ve probe on the GND terminal of the GPO port and the +ve probe on one of the GPO pins.

Note: that the GPO output needs to be 'OFF' or 'False' in order to be able to make the measurement otherwise there will be no voltage differential at the GPO pin.

At the GPO port the voltage should measure 5.1v (this equates to 5.2v at the power supply). If the voltage is lower then you will need to remove the cover and adjust the power supply output in accordance with the instructions below.

Two types of power supply have been used for the ESP-88/ESP-00 and the instructions are specific to each model. With the cover removed it is easy to identify the two versions by comparing with the pictures below:

Integrated Power Designs (IPD) Power Supply (used on earlier models)



Instructions for adjusting voltage on IPD Power Supplies

Astec Power Supply (used on later models)



Instructions for adjusting voltage on Astec Power Supplies

Voltage output adjustments on Astec PSUs


Links
Issues caused by power supply harness used on early ESPs
ESP fails to boot correctly - Status LED remains unlit
ESP fails to boot correctly - Red Status LED
One or more ESP expansion cards not detected correctly during scan
ESP is passing audio but has become unresponsive to changes made via CC-64
.