GE Cafe CT9050SH1SS intermittently won't heat to desired temperature

[GVlog]

Our GE Cafe in-wall electric oven CT9050SH1SS has these symptoms:   Will intermittently heat-up to 20-50 degrees below desired temperature. Oven light will intermittently not respond to the panel button. Have to press button 3-5 times before light would turn off. The buttons on the glass panel sound when pressed. No error codes have ever been displayed. All homes in this development had GE appliances installed and some have reported that their ovens, microwaves, refrigerators, dishwashers, and washers needed repairs after just 1-2 years. One home had the "control panel" of their oven replaced but they did not elaborate on what problems they encountered. Our oven is nearly 5 years old but has been used only about 20 times since it's in a vacation unit. It worked fine (as far as we knew) until a few weeks ago when we first noticed the oven light not responding. Later we experienced the oven not heating-up as expected. Any suggestions as to what might be the cause? The board machine control (AP6040044 or WB27X25554)? The control board (AP6301308 or WB27X29602)?

[WOOKIE]

to start with, Find you mini manual and ,with a oven theometer check the temperature in the oven against what you have it set to.  You can also check the oven sensor resistance which is located on the broil unit mounting  plate to ensure it is within spec's 

[GVlog]

Thanks. The inside temperature varies about 10-15 degrees over/under what is shown on the front panel. That might be due to differences in location of the oven sensor (back wall) and the oven thermometer we used (closer to the door). 

However the oven still (more often than not) fails to rise to the selected temperature.

Sensor resistance was about 1080 ohms so I assume that it’s okay. 

What should I investigate next?

[GVlog]

Replacing the control board (WB27X25554) did not fix the problem. 

I'm open to suggestions.

[Vance R]

3 hours ago, GVlog said:

control board (WB27X25554)

You have replaced the main control and oven is still 20 to 50 deg low intermittently. When looking this model up is it a single or double oven?  The user interface just communicates with main board.  Start by looking over the element wiring and terminals for loose connections. Were any of the terminals loose when replacing the board?

[GVlog]

Thanks for the reply, Vance. It's a single oven.

All terminals were secure when replacing the board and I saw nothing to suggest it could be a wiring issue.

In my tests, the gap between what temperature is set to and what the oven reaches seems to have narrowed to 5-25 degrees (where it used to be 40-100 degrees). An improvement, but still not fixed. The gap is bigger if I set it to a higher temperature like 475F.

Someone suggested that the control board might be overheating and that perhaps the cooling fan and board fan sensor need replacement. Is that a possibility?

[GVlog]

1 minute ago, GVlog said:

(where it used to be 40-100 degrees)

Sorry, I mistyped. The old gap was 20-50 degrees.

[Vance R]

20 hours ago, GVlog said:

Someone suggested that the control board might be overheating and that perhaps the cooling fan and board fan sensor need replacement. Is that a possibility?

 Could be possible. Have you adjusted the temp offset? instructions are usually in the owners manual.

[GVlog]

21 hours ago, Vance R said:

Have you adjusted the temp offset? instructions are usually in the owners manual.

Yes. With or without an offset, the oven will fail to reach the selected temperature.

I don't know if this is a clue, but I've also noticed that the oven light often will sometimes not turn off. When pressing the touch panel, I'll hear the single or double beeps that indicate on or off respectively; but the oven light will stay on. It's only after I open-and-close the oven door a few times that the light will respond to the touch panel.

[Vance R]

Since you have replaced the board and still having problem. May want to check voltages and ground of incoming power.