Frigidaire Built-in range (FGDS3065KFB) oven relay failure question

[twalp]

When we start Bake mode our oven might eventually reach 150 degrees at the point when the controller beeps and the display says it has reached 350. Not a good sign.

The oven temp sensor measures approx 1080 ohms, which appears to be correct in the RTD Scale on the Tech Sheet/Wiring diagram. The oven circuit breaker is good. The 240v terminals where the power cord terminates measure 124V between ground and each side.

I understand that the voltage across the elements should be 240V when the front panel element indicator shows it in red. In my case, when the control panel's display shows the top element in red, its voltage measures 23 volts. When the lower element is shown in red it measures 124v. So neither is hitting 240V if that's the correct goal.

I removed the control board assy and then detached the relay board. On the traces side I see what looks like a problem. It's beneath K1, the DLB Relay. One of the relay's pins appears to have come unsoldered from the traces. See picture.

 

It would be easy to reflow some solder into the area but there's no point in doing that if something else caused it to come unsoldered, like a failure in the relay.  What's the wisdom from the crowd here?  To be much appreciated.

[16345Ed]

Relay is toast. Board needs replaced or repaired. 

[ECtoFix]

36 minutes ago, 16345Ed said:

Relay is toast. Board needs replaced or repaired. 

Agreed.  The relay's contacts are pitted & carboned up, thereby generating enough heat to melted that solder joint.

 

2 hours ago, twalp said:

When we start Bake mode our oven might eventually reach 150 degrees at the point when the controller beeps and the display says it has reached 350. Not a good sign.

If the temp control is satisfying at 150° when set point is 350°, then that's an unrelated problem to the failed relay. 

The way you'd described it, sounds like the temp control circuit isn't sensing/regulating temperature correctly.  Although the probe may ohm out as good when tested at room temperature, that doesn't mean it's good at 350°.  The temp probe lives a rough service life and can eventually give up after years of use.

FWIW:

• Be sure your resistance test of the probe is done while the probe is isolated (disconnected) from the board so you're not reading back through the board. 
• I also test probes to ground.  A probe should read OL (or an infinite amount of resistance [∞]).

Nevertheless, I suggest replacing the temp probe too.  It's relatively cheap to purchase and easily replaced while you have it apart.

[ECtoFix]

1 minute ago, ECtoFix said:

I also test probes to ground.  A probe should read OL (or an infinite amount of resistance [∞]).

WHEN read to GROUND.

***Sure wish I could edit my posts***

[Vance R]

Looks like at typical cold solder joint. Clean, flux and reflow solder, add solder if needed.  If that doesn't fix the board you'll have to decide aboit replacing board or trying compoent level repair.

[twalp]

Thank you @16345Ed, @ECtoFix and @Vance R.

I'll replace the relay and temp probe, and then give it a try.

BTW, why don't @ECtoFix's posts have the Like (clapping hands) option?

[ECtoFix]

7 hours ago, twalp said:

BTW, why don't @ECtoFix's posts have the Like (clapping hands) option?

Probably because I'm not a paying member.  I work on commercial appliances instead of residential.  Therefore I see no personal benefit to dish out the rather exorbitant annual membership fee (even if I was deemed qualified). 

However, I'm sure this website is a HUGE asset for those who are in the residential appliance repair field.  I think I would undoubtedly pay such dues to tap into the knowledge shared here if I was a domestic tech (there's no such place as this for folks in the COMMERCIAL field).

However I still come here to see if I can help folks like yourself.  My forty years of electrical troubleshooting experience (twenty working/teaching in my Marine Corps aviation specialty) is a my greatest asset in that regard.   My SECOND career gave me twenty years of also working on gas, refrigeration and steam (LIVE steam) equipment too, so I feel I have enough experience to lend a hand occasionally (when I feel qualified to).

[certified tech group 51]

I carry small file set..Riffler files, with nice curved ends.. they fit the area to be filed nicely....The DLB relay is closed all the time when in bake or broil..The bake or broil relays are the ones that cycles... Clean all the old solder and any contaminates off the relay post and board and resolder..The amount of solder i use  is about twice the original size...