ADC-VDB770 working then not

I bought a ADC-VDB770 from another vendor in February and finally got around to installing it. It worked fine for a few hours and then just stopped and the door bell chime started shorting when connected. Tested all voltage and everything is good 19v and a paperclip will trigger the chime when put across the two round terminals. I tried to adjust the wiring a number of times with no luck. It doesn’t power on at all anymore.

I have it plugged into a micro USB right now and it won’t seem to boot at all. Is there any kind of hard reset?

Other thoughts welcome too.

This same transformer, wiring, and chime worked fine with the older model video door bell.


I have it plugged into a micro USB right now and it won’t seem to boot at all. Is there any kind of hard reset?

Devices can be damaged from an extended period of too little amperage. With the video doorbells this is a concern because not all transformers have the same specs. Can you confirm the specs on that transformer, or the model number of the one used? Voltage and VA rating.

Also, did you use the mount or is the back plate attached directly to the wall?

The back plate is a heat sink and one of the mounting wedges must be used (even the 0 degree one), otherwise it is easy to short the wiring behind the doorbell. Given the description, this may have occurred.

Thanks for the reply @jwcsurety!

I am using the ‘A’ mount with the wires tucked nicely behind it. I double checked the wires a few times. Can the wires short on the housing itself?

I am using the following transformer: C907 NuTone® 16V, 30VA Doorbell Transformer

I will note that the unit was very warm when it died. I suspect heat is going to be a constant issue with this design.


Ok, thank you for confirming the transformer and installation. It is possible that the unit is dead and experienced hardware failure. Try leaving it powered off for about 20 minutes, then try again by the USB port. If the VDB770 does not power up via the micro usb port, it will probably need to be replaced.

The back plate is expected to be very warm. If you are looking for a wider temperature range without a battery, look at the ADC VDB750.

Thank you for confirming. It appears to be dead as I’ve had it unplugged for over a day and after connecting, still dead and non responsive to a long hold of the button. Unfortunately I am out of luck as I never realized until the other day researching this that ADC doesn’t offer warranty to consumers and the vendor was an eBay store even though it was unopened and factory sealed.

That is pretty common. Warranty is between the seller and buyer. Buying equipment through ebay sellers can be risky. Even if it is not a used device, it is often old stock.

For something essentially DOA like this you might reach out to the seller, or ebay, for recourse. I cannot provide advice or guidance on their processes though.