Darn - I think I achieved dumbness - again


 
M

Mark Ten

New member
Hello All -

Well it's been a long time since I got back to finalizing my Heatermeterkit.

Out of sheer stupidity, I plugged my Ethernet cable into the black jack, instead of the silver Rasberry jack.

Yep - I let the smoke out of what i believe is the Mosfet Q3 FQU11P06TU - It looks cooked

Question is, Are there any other components I may have fried in the process?

Lastly (for now) does anyone have a mouser P/N for the mating connector to the power barrel jack on the Heatermeter? I'm using one from a cheap power supply I salvaged for a battery connection that doesn't seem to fit.

I will get this to work one day!

Mark
 
Mark,

Looking at the schematic you might want to check Q3, Q5, and Q1. The other components are probably fine. (To check my work look at the JP2 subassembly in grid A6/B6 and the blower pin 5 coming out of the ATMega(which breaks out to grid B5/B6). Looks like the DC jack is this one.

Hope this helps!
 
Drew -

I'll check Q3, Q5 & Q1 also.

The Mouser part was for the jack, I was actually looking for the mating plug.


Thanks for the assistance -

Mark
 
Do you have POE ( Power Over Ethernet ) switches? I'm pretty surprised that you nuked the HM board by doing that.

Are you sure Q3 wasn't blown as a result of your previously reverse polarity adventure?
 
Last edited:
Steve -

No POE on the switch.

I believe that Q3 was still OK, as Bryan mentioned that the fan would not operate if damaged, and it still did.
I didn't check fan op after this latest fiasco, in fear of further damage.

BTW - If anyone is in need of the Q3 FQU11P06TU, please let me know - It will cost me $8.00 in shipping for an .88C part, so if anyone needs spares, I'll ship in an envelope at no charge (Within reason, of course)

My way of giving back.

Mark
 
I have made that mistake without burning anything up, but don't have POE though.
As for recovering from the episode. If you can see a part that is damaged I would remove it first off, if it was in the blower circuit you might want to check Q1, D2 and R14 right off the bat. Then I would remove the rPi and power the board with nothing but power connected and measure your 12V, 5V and 3.3v. If all present the HM should boot and work except for the items where you removed the bad parts. (blower for instance if it is Q1 or Q3) You'll have to follow where the troubleshooting leads as you test these items.
 
Do you know if you have 100Mb or 1000Mb ( gigabit ) switches?

If 100Mb, then pin 5 ( blower ) isn't even used, as only wires 1,2,3 & 6 are needed for 100Mb ethernet.

You also need to get through a bunch of other stuff before getting to Q3 from the RJ45 jack. Seems highly improbable that you nuked Q3 this way.
 
Mark Ten said:
Steve -

No POE on the switch.
Click to expand...

That's odd, cause I have done the same without anything bad happening...
If you are ordering a new mosfet for the blower most of the cost is gonna be for shipping, so might as well order some of the smaller BS170 mosfets and the 3.3v regulator too, and even the diodes... the parts are really cheap so might as well make sure you have a spare for those other parts that could have blown rather than ordering again down the road.
If you just need a blower mosfet I have some here and could throw one in the mail to you tomorrow for free, no problem....
 
Ralph -

Thanks for the troubleshooting tips - I'll check all of that tomorrow - BTW - I don't have POE - It's an old Netgear 10/100 switch.
The HM still boots OK -

Mark
 
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