Need help troubleshooting new Dayton SPA1000 sub amp

[tomzarbo]

Glad it turned out to be something simple.
TomZ

[rkj]

Thankfully, it turned out to be something simple. Parts Express tech support had me open up the amp and check the wiring. Turns out a pair of wires had become disconnected during shipping. I guess I should have just checked that to start with.

[rkj]

The Dayton SPA1000 sub amp is a drop-in replacement for the original amp in my old AV123 UFW-12 subwoofer. I cannot seem to get the new SPA1000 amp to work. It appears that the amp is stuck in standby. I tested the amp using an RCA Y adaptor with one output going to amp LFE input and I used the other output to measure the signal level with an AC voltmeter. I used REW signal generator to send a 60 Hz signal to the LFE channel at various levels. REW level was set at -3 dBFS and Denon AVR-X4200W sub trim was 0 dB. With AVR main volume at -20 dB, I measured an AC voltage of 1.03V. With AVR main volume at -5 dB, I measured an AC voltage of 3.4V. Amp LED stayed green the whole time with no activity or sound from the 12 inch driver. The manual states that the LED should turn yellow once the LFE input level exceeds about 3 mV. The driver measures about 4 ohms resistance as expected. I also tried the left and right amp inputs with same behaviour.

I have not yet tried separating the amp from its plastic enclosure to look for something obvious like loose wires, etc. Other than that, any suggestions for what to look for before arranging to send back under RMA?