PCB: low voltage On-Off switch drives AC mains relay \ includes soft start .. H9KPXG

[sledwards12375]

Must have been one of the ICs was not seated properly. Delay is working now.

 

[Mark Johnson]

Q3 on both units are running at about 50C case temp

Drain current is about 21mA or so.
Rds_on is about 10 ohms.
Power dissipation is thus about 4.5 milliwatts
Theta_ja is 132 degrees C per watt
Thus junction temperature should be about 0.6 degrees C above ambient air temperature

One way to make it run a lot hotter is to replace R11 by a resistance a lot less than 180 ohms. Maybe your R11's are the wrong value?

 

[sledwards12375]

Mark:

I checked and R11 is 180 ohms as specified. Any thing else that could drive these so hard? My load is an 80W light bulb.

 

[RickRay]

Post a high resolution picture of front anf back of board.

 

[sledwards12375]

R11 is scorching hot. Just measured voltage across it...13.5V. Into 180 ohms that is 1 watt of power. All advice is welcome.

 

[sledwards12375]

Problem solved... wrong Meanwell converter, 15V instead of specified 5V. Hope I didn't damage anything.

 

[Mark Johnson]

It looks like you haven't installed any of the AC mains voltage selection jumpers.

_

 

[sledwards12375]

Yes, you are correct. I will be using a single 120V primary transformer. Connecting to PR1_DOT and PR2_ND works fine for my scenario without the use of jumpers.