Blown range circuit board


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Old 11-13-21, 03:11 PM
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Blown range circuit board

Oven was taking forever to heat up. Check voltage to elements and was only getting 120v on one plug off element other was zero. Pulled circuit board and completing blown where the solenoid is. Is there something else to check in wiring or could it be from the board itself shorting? Donít want to put new board in and have it blow. Thanks



 

Last edited by PJmax; 11-13-21 at 03:32 PM. Reason: cropped/reoriented pics
  #2  
Old 11-13-21, 03:37 PM
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Welcome to the forums.

A pretty common failure. You may actually be able to fix that board if you had solder and some minor parts.

I would use an ohmmeter and check from the end of each element to ground for shorts.
More than likely there won't be but I always check.

Usually what happens is there is a bad solder connection that starts to arc from the high current drawn thru it. As it arcs it melts/eats more of the pc board foil until finally the arc stops from the large gap.

 
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Old 11-14-21, 03:28 AM
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It looks to me like L1 blew out,
By the way it blew the track off the board I would say that you have a dead short somewhere in the unit.
Does not necessarily have to be an element if I am correct.
First look for scorch marks in the unit.
If all clear then check elements etc, for a short to ground.

Do you have the wiring diagram which may help.
 
bulova voted this post useful.
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Old 11-14-21, 07:14 AM
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Those three boxes are 30 amp relays with 12v[dc] coils. You could check that the relay coils are getting their voltage.

The total element wattage should then be less than 7200w & the total element resistance should be more than 8 ohms.

There is the control board, the elements & the connections between them.
The board could fail for a reason within itself or it can be overstressed by a shorted element or short circuit elsewhere.
A bad connection passing heavy current could fail to an open circuit.

A schematic will help narrow down the one or more possibilities.

So, in full, there is the control board, the relay coils, the relay contacts, the connections, the wiring & the elements.
 
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Old 11-14-21, 12:19 PM
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Hereís a wiring diagram. Does look like some one shorted the l2 plug off the bake element to the oven plate. The convection plugs have got hot before as you can see in the one picture. Donít know what thatís means but they were a bit loose so I tightened them up. Could that short from l2 be what blow the board?


L2 bake element

Convection element plugs
 
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Old 11-14-21, 12:21 PM
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Someone was giving it away for free because oven doesnít really work and the fan motors were blown. Got new fan motors in and working.
 
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Old 11-14-21, 12:38 PM
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Last pic shows overheated connectors due to connectors losing their spring temper. Need new [molex?] connectors.
Next to last pic shows arcing due to short circuit which might have ruined the contacts inside your relays.

How much time & mat'l have you spent so far & how much for a new unit?
 
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Old 11-14-21, 01:41 PM
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Yes..... the element touching ground blew the foil off the board.
The board may still be ok.
You can fix the burned foil.
You won't know if the board is still working until you fix that burned foil and fire it up.
 
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Old 11-14-21, 06:10 PM
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Only spent 150$ so far on the two fan motors and about 2 hrs figuring stuff out. It was a free stove and similar one is around 2000$. Itís about 6 or so years old I believe. New circuit board is about 150$ Donít know if Iíd trust myself fixing the blown section or not can maybe play with it and see or just pick up a new one. Iíll put some new ends on the connectors that got hot. Thanks for your help guys.
 
 

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