GE PHB920SJ induction range

[dca]

I have the mini manual / service sheets for this model, but am struggling with what seems to be a bad design, and/or lack of information. 

 

I am getting 13.20V to the left wing taco board (part of the multi-board top assy.  This 13.25V nominal voltage from the filter board.  My assumption here is that -50mV low can't be an issue.  (There also seems to be a typo that implies both 13.25 and 15V on same pin - I think the 15V was left over from the previous generation of controls.)

 

The left board puts puts out +5V and +10V for the other boards (main logic board, and right wing taco board.  Those supplies check out, too.  

 

Problem is that the main logic board assy display will not light up and go into service mode.  It only makes a double chime sound about every 10 secs or so.  

 

I see there are Gen boards and Filter boards under the cooktop, but from what I see in the schematic, aside from the main 13.25V supply, there shouldn't be anything there to prevent the top boards from booting and responding...but even with a new top assy, the same issue occurs.  It should be able to display an error code if it has correct power supply.  

 

Does anyone know anything more about this double chime and why the main board might not display due to a bad filter or gen board (ref top left of pg 4 of mini manual dated 2015-10)?

  

Thanks,

Dave

[kokomo]

ever get anything solved on this one, thks