View Single Post
  #5   Report Post  
Posted to sci.electronics.repair
John Robertson John Robertson is offline
external usenet poster
 
Posts: 907
Default another dimmer smoked today outside thank goodness!

On 2020/11/23 12:50 p.m., Chuck wrote:
Well, I have one additional so called "30 amp" Chinese dimmer remaining
after the prior one smoked.Â* This one had a circuit breaker and it did
go today, but not before it started smoking.Â* As I said, I have a good
Astron power supply on the way to replace, but I still had the dimmer in
place until then and outdoors.

This time, I decided to open it up and see what's going on.Â* As others
have said, the Chinese tend to exaggerate ratings so "30 amp" was
probably far from it, but I was surprised what I saw internally:

two HY1707 Mosfets
an LM358
a 78L05
a 555 timer

At 12V, 7 amp load, it seems like it should have been able to handle the
load, but I am wondering that since I was driving it with a switching
supply, maybe that somehow affected the dimmer?Â* By the way, the burnout
was one of the HY1707's.Â* Perhaps they actually need a heatsink instead
of just being attached to the circuit board?

That's absolutely all for the Chinese stuff.Â* I had a constant voltage/
current module on the way, but not even going to open it.Â* Can't trust
it anymore.




No UL approval I'm sure.

Why would you trust it then?

Unregulated electrical junk sold on Amazon can be hazardous to your
house or your family.

John :-#(#