ELK 930/960 Combo and SkyBell HD integration


New Member
I’m desperate and am asking for your help. Previous weeks I’ve been trying to use the ELK 930 & 960 relay & timer combination to use an existing mech doorbell AND activate a wireless door sensor which will to sound a local “ding-dong” chime from my alarm panel.  The panel's speaker essentially becomes a 2nd doorbell chime. Why? - I intend to replace the doorbell switch with an Alarm.com Skybell HD video doorbell (Skybell circuit only allows for one 16V, 10VA mech doorbell) after I've got the circuit integration working. Initially I got some good ideas from this forum on how to do this, but ultimately have been unable to make it work.  I hope you can comment on my final config below:

I’m using the wiring diagram “Doorbell Circuit ELK 930 (A,'B to ELK 960 Hookup”.  I’ve replicated the wiring precisely on a breadboard (I had a friend independently confirm the wiring is per the diagram) using these components:
- Typical Doorbell Transformer: 16V, 10 VA
- Mechanical doorbell with illuminated push button doorbell switch. This will be replaced by the SkyBell HD from Alarm.com
- To power the 960: a 12V, 1 AMP wall wart, striped side of cable wired directly to the "+" terminal on the 960.  Using a voltmeter, I've confirmed that this wall wart creates "-12.4" volts
- Rectifier Diode “1N4004”, 1 AMP rated at 400V, diode stripe facing power source (not facing 960's blue terminal block)
- Wireless sensor 2GIG DW10-345 (default is N/C) "learned" into this zone, using wired leads (not reed switch). The leads are wired directly into the 960’s "N/C" and "Com" terminals.  This sensor is powered by two coin cell batteries which I tested to confirm that they have a full charge
- On my 2GIG panel, I've programmed an unused wireless zone (Zone 020); Equip code 0862 which corresponds to this sensor, Sensor type: “23-No response” (won't send an alarm when activated), Sensor equip type is “contact”, Loop 1 of 3 selected, Sensor supervised: disabled.

When I power up both transformers and test the circuit, I'm getting illumination on the doorbell switch (which goes dark when I depress the switch as expected) and the mech doorbell creates the "ding-dong" chime as expected, but that's it. I’m not even getting the 960’s LED to illuminate when I press the doorbell switch, nor any chime sound from the panel. The panel programming seems to be correct because when I remove the DW10 sensor leads from the 960 terminals, the panel chimes once, regardless of whether there is power to the 960 or not.

Thinking I had a defective ELK 960, I returned and bought a replacement. Since the ELK 930 includes two doorbell sensors, I swapped one for the other and also replaced the diode - no change.  The ELK components don't seem to be working (it's my fault); what am I doing wrong?
Not sure what wiring diagram you've used.  It would help if you posted a link to it, or post a copy of the diagram in this thread.  Then maybe we can help you.
One thing that jumps out at me... you said you've confirmed that the wall wart produces "-12V."  Do you really mean a negative voltage, or was that just a typo?   Usually, the striped wire on a wall wart indicates the positive side.  If you connected that to the "+" terminal on the 960, you've probably got it right.  But not every wall wart follows the convention, so best to measure it with a volt meter to be sure.
Attached is the wiring diagram "doorbell.jpg". I tested the wall wart with my voltmeter and yes, I did get a negative 12.4 volts after touching the red voltmeter lead to the striped side of the cable and the black lead to the non-striped side of the cable.  Hmm, I then swapped the voltmeter lead contacts: black to striped and red to non-striped and got the expected reading of a positive value of 12.4 volts.
Can you take a look at the attached file, then consider my config?  If it's as simple as swapping the leads, I'm thrilled, if not, I'd appreciate your feedback - thxdoorbell.jpg
It sounds like maybe you've got the power supply wiring to the 960 backwards.   But before you change anything, follow these steps:
1.  Make sure you have the black lead plugged into the COMMON jack on the voltmeter and the red lead into the V(olts) jack.
2.  Connect the probe tip to the black lead to the "-" terminal of the 960.
3.  Connect the probe tip of the red lead to the "+" terminal of the 960
Do you read +12V or -12V?   It might actually read something around 0V if the wiring was backwards. If you get +12V, then things are ok.
If you had the power wiring backwards, that would explain why you're having trouble.  You probably didn't damage the 960 since the diode would have prevented the reversed voltage from reaching the board.
Ah-ha - yes, I definitely wired the 960's 12V wall wart power supply backwards.
Before making any change, I followed your troubleshooting instructions and yes, this time the voltmeter reported a negative 11.8V when I touched the respective voltmeter leads onto the screw contact head on the 960 (red lead to "+" and black lead to "-"),  That was the problem.  In anticipating your next thought, I swapped the striped side of the wall wart cable to the  960's "-" contact with the diode and the non-striped side of the cable to the "+" on the 960.  Now, the 930/960 combo works exactly as expected.  So I didn't think to check the polarity on the wall wart cable.
This is great.  In my two story house, I can (1) install my SkyBell HD at the front door by replacing the lighted doorbell switch, next (2) use the original mechanical doorbell downstairs, and (3) have the "ding-dong" chime through my panel upstairs thanks to the ELK 930/960 combo solution.  This essentially overcomes the SkyBell HD's "one 16V, 10 VA doorbell per circuit" restriction and I've got a ding-dong chime throughout the house.  Yippee!
From your experience in helping others, do you have any more thoughts that i should consider?
Thanks for the objective review and helping me solve this challenge. I'll install the SkyBell tomorrow and report back. :)
I don't have a Skybell, so I can't speak from firsthand experience.  But others here who have installed Skybells and Ring doorbells have run into problems with the the combo of the Elk 930, the camera and their doorbells.  The camera in the doorbell button can draw enough power to falsely trigger the doorbell.  Not all doorbells have this problem, however.   There are ways around this, so try installing it and see what happens.
OK, thanks for the heads-up.  I'll install the SkyBell HD tomorrow and report back so others can benefit from my experience on this project.  I'll keep this topic open until I report back tomorrow. 
How did it go with the installation of your Skybell HD?
I have a similiar set up here with the Elk 930/960 except that it is connected to an OmniPro 2 such that it is using the 12VDC from the Omni2 panel and the original AC transformer for the old doorbell. (door bell ring triggers old mechanical doorbell and a chime / TTS via zoned audio).
I used this drawing to configure my 930/960 years ago.

Can you list the step by step you utilized to connect the Skybell HD?