HM 4.2 LCD goes out when blower plugged in

[Todd E.]

I got my 4.2 board all soldered up. Strapped on the Pi and fired things up. Everything looked good and I changed the Pit0 setting to TC so the reading went from "The Sun" to ambient 73 degrees F. Plugged in the blower (blower only, no servo) and the LCD went blank. Adjust contrast didn't do anything. The blower did run. I noticed the the board(s) were getting pretty hot to the touch. I unplugged the blower and the LCD came back like nothing had happened. I was suspicious of my 12V 1A power supply so I used a 5V power supply plugged into the Pi to power things back up. Everything came back online but got nothing from the blower. LCD stayed on when the blower plug was inserted. I had to stop there and won't get to do any more troubleshooting until tonight. Sounds like a short but thought you all might give me some ideas about where to start looking.

Todd

 

[Bryan Mayland]

Sounds like you have a short somewhere in your blower wiring and it is killing the whole system. Does it work ok with 100% blower without the blower plugged in? If so then it is just a simple wiring issue. If the HeaterMeter turns off any time the output is on (even without a blower plugged in) then you should check the soldering around the giant MOSFET.

 

[Todd E.]

Sounds like you have a short somewhere in your blower wiring and it is killing the whole system. Does it work ok with 100% blower without the blower plugged in? If so then it is just a simple wiring issue. If the HeaterMeter turns off any time the output is on (even without a blower plugged in) then you should check the soldering around the giant MOSFET.

Yep. With blower disconnected and the HM calling for 100% blower it seems to be happy. I'll start with the blower wiring and MOFSET joints. I used a Cat5 cable for the blower with blowerBLK to CatBLUE and blowerRED to CatBLUE/WHITE. Thanks Bryan.

Todd

 

[Todd E.]

Started out by cleaning off the solder side of the PCB with alcohol. Rechecked that the blower was wired to the Cat5 properly and fired up the HM w/o the Pi. Everything worked and plugging in the blower cable didn't mess with the LCD. Also, none of the "hot" operating temps I had felt before. Shut down, attached the Pi and repeated. Everything OK there as well. I tried this with and w/o the Pi because I had melted one corner of the Pi connector a little during the assembly and thought I may have boogered it up. Since the blower wiring is so straight forward, I'm going with the solder/flux splatter clean up as the solution.

Todd