Author Topic: In case your EQP501 doesn't work as expected

January 06, 2021, 08:31:16 AM
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Check the usual suspects:
  • Forgotten solder joint,
  • Bad solder joint (reflow suspicious joints),
  • Reversed components (electrolytics, diodes, transistors, IC's). In case of IC's, probably destroyed, better replace,
  • Flipped IC's or transistors,
  • Trim all the component leads and test pins as short as possible. Nothing must touch the chassis plate.
Check the DC voltages:
First check the supply voltages as described in the setup guide.
Next, without any input signal, connect the voltmeter black probe to 0V and check you get no DC voltages on TP2. Any DC voltage higher than a few millivolts shows that the DOA is the issue.

Try to follow the signal
With all pots at 0, Send a constant 100Hz - 2 VAC sine signal on the input, measured between pins 2&3 of the input XLR.
Connect the voltmeter black probe to 0V and trace the signal.
- On TP1 you should get about 1.3 VAC- On TP2 you should get about 1.15 VAC
The reading should follow the input signal level.
The place where the signal drops will give you hints on where to look for.