Whirlpool oven timer problem

[MDJolley]

Hello everyone, I am new here, and so I hope I am posting in the correct section. I have a little background in electronics testing and repairing, but it's been a really long time since I have done anything with it. I have since bought some basic tools, a multimeter, etc. I'm real good at soldering, and I am learning to test individual electronic components. Currently I am troubleshooting a Whirlpool oven timer. The oven is just a bit under 2 years old, and it has developed a strange problem. One time when I was using the oven, I noticed stuff inside was burning. I had no idea what happened and didn't think about it until the next time I used it. I then noticed that there is power going to the selected heating elements at all times, no matter what the temperature selector is set at. At first I thought it has to be the thermostat/probe. But this is not the problem, and it works as intended. The next suspect was the timer control board. The timer in this model is very simple, and I do believe I have found the problem, but I just wanted to talk it over with the community here and get some feedback from more experienced electronics test technicians.

I have taken the timer out, and I put a multimeter on the relay because that seemed like the logical culprit. I just hope I am testing the relay correctly...like I said it's been about 35 years since I have done any of this. When I put my multimeter on the two connectors of the relay, I have continuity, and so believe it is frozen in the closed position. I am testing this part pulled out of the oven and disconnected. I wanted to know if someone can verify I am testing this correctly. Also, there is another relay looking thing that is gray colored with the part number C42E, I have no idea what that part is, but I am guessing it's also a relay. Online searches have returned nothing. Perhaps someone here knows.

I appreciate any and all help I can get. I live in Ukraine and this timer is not available probably due to the war, and if it was, it's $100. Therefore, I am trying to fix the problem on my own.

Thanks in advance for any help, it is greatly appreciated.

 

[kellys_eye]

The two red arrows should read open circuit unless the element is ON in which case it will read as a short circuit.

 

[Bluejets]

I noticed stuff inside was burning.

Is that in relation to what was cooking in the oven or to some suspect electrical component.
Almost 99% of oven problems are related to the oven heater element be it burnt out or the spade terminal connections being bad.
Very seldom will a timer die especially with no physical signs.(so far at least)

If you pop the tabs on the pcb case (grey clear plastic)and show the other side of the pcb, there may be a different story.
Just may have to take care at what the construction is on the other side, things like spring loaded contacts etc.

 

[MDJolley]

Is that in relation to what was cooking in the oven or to some suspect electrical component.
Almost 99% of oven problems are related to the oven heater element be it burnt out or the spade terminal connections being bad.
Very seldom will a timer die especially with no physical signs.(so far at least)

If you pop the tabs on the pcb case (grey clear plastic)and show the other side of the pcb, there may be a different story.
Just may have to take care at what the construction is on the other side, things like spring loaded contacts etc.

Hi, thanks for the reply. Missed your question at first 'Is that in relation to what was cooking in the oven or to some suspect electrical component.' Not electrical...just about burned a batch of cookies I had in there and was bewildered as to why

The elements are in very good condition including the connection terminals. No problem there since they both work really good...the problem is they wont turn off when reaching the desired temperature. I did take the PCB out of the case. It looks clean with no broken solder joints or burns.

 

[MDJolley]

The two red arrows should read open circuit unless the element is ON in which case it will read as a short circuit.

Yep, this is also what I understood. Well, I think that was the answer I was looking for. I have ordered the replacement part. It was $6. Thanks very much for your time and the reply.

 

[Martaine2005]

The grey device has refdes of a capacitor or a small bank of capacitors. The white device is clearly marked as a relay.
As already stated above, should read open circuit when no power to the element/s.
That relay is a typical failure point as a large current arcs across the contacts, eventually welding them together.

Martin

 

[MDJolley]

The grey device has refdes of a capacitor or a small bank of capacitors. The white device is clearly marked as a relay.
As already stated above, should read open circuit when no power to the element/s.
That relay is a typical failure point as a large current arcs across the contacts, eventually welding them together.

Martin

Thank you, Martin. Your reply is very much appreciated. That was the confirmation I was looking for

 

[Harald Kapp]

I have ordered the replacement part. It was

I hope you get the right relay. There are different versions of the Hongfa HF115F relay. You need the HF115F-Q type which has the Faston connectors attached (datasheet).

 

[MDJolley]

I hope you get the right relay. There are different versions of the Hongfa HF115F relay. You need the HF115F-Q type which has the Faston connectors attached (datasheet).

Hello, yes. I have the datasheet for this oven and have ordered the exact relay: HF115F-Q-048-1H, (48VDC) - Incidentally, I have seen this exact oven timer use another relay, which is the Chinese brand 'SCHRACK' part number RFH54006WG. I was going to replace the entire timer, until I found out that it was not only unavailable, but also quite expensive at 100 dollars. This new timer had the SCHRACK relay in photos. They look identical, and have the same voltage characteristics. That said, I wonder if one is better than the other? The SCHRACK relay is twice as expensive at 12 dollars. I guess that is anyone's guess. Thank you for the reply.

 

[Bluejets]

HF115F-Q-048-1H, (48VDC

Don't mean to be picky but that looks like 8vdc to me....not 48vdc

 

[Harald Kapp]

which is the Chinese brand 'SCHRACK'

As far as I know Schrack is or used to be an Austrian company, not Chinese.
Hongfa is chinese, this probably explains the price difference.

This kind of relay is more or less a standard for e.g. household appliances. There are many similar if not identical models on the market. Hongfa seems to be a quality brand, as is Schrack. I doubt that one is better than the other in this application.

 

[MDJolley]

Don't mean to be picky but that looks like 8vdc to me....not 48vdc

Oops! No, sir...you are correct. I just copy/pasta'd the wrong information. This is the relay I ordered.

 

[MDJolley]

As far as I know Schrack is or used to be an Austrian company, not Chinese.
Hongfa is chinese, this probably explains the price difference.

This kind of relay is more or less a standard for e.g. household appliances. There are many similar if not identical models on the market. Hongfa seems to be a quality brand, as is Schrack. I doubt that one is better than the other in this application.

Well, if that is the case, it's definitely Chinese now

 

[Harald Kapp]

it's definitely Chinese now

Not necessarily. Made in China: yes, but the company is still European. Not uncommon.

 

[MDJolley]

Not necessarily. Made in China: yes, but the company is still European. Not uncommon.

Ah yes, and then there is that

 

[MDJolley]

The two red arrows should read open circuit unless the element is ON in which case it will read as a short circuit.

Yeah, I made a mistake... and just now only realized the mistake when I got the new part as saw the open/closed diagram. It is a normally closed relay as per the tiny diagram. So... Now I am back at square one on diagnosis.

 

[kellys_eye]

I then noticed that there is power going to the selected heating elements at all times, no matter what the temperature selector is set at.

How did you 'notice' that? When an oven is in normal use the element doesn't glow (as such) but you can feel it getting hot. It should only 'glow' when the grill setting is used.

I then noticed that there is power going to the selected heating elements at all times, no matter what the temperature selector is set at.

Heating selector switch?

 

[MDJolley]

How did you 'notice' that? When an oven is in normal use the element doesn't glow (as such) but you can feel it getting hot. It should only 'glow' when the grill setting is used.


Heating selector switch?

The heating element light is on at all times no matter what the element selection setting is set to, aside from the 'fan' and 'light' only options. This is with the temperature selector in the OFF position. That is how I noticed this... not to mention the last batch of cookies I used the oven for started to burn because they weren't shutting off. However, and so there is no confusion, only the elements that are selected will come on. So if I turn on the bottom roast setting, only the bottom element will come on. The top grill/toast element will come on when selected, and also the bake with BOTH elements. So it seems the selector is working as intended. The problem is that whichever element setting is selected, the heating elements will stay on no matter what temperature is reached.


Heating selector switch? <-- This is the thermostat/probe. I tested it and it works fine. And just so I was completely sure about that, I replaced it. It was so cheap that I had nothing to lose. Or did you mean the element selector? This I don't know.. as I said it seems to be functioning properly. All selections work as intended, and a visual inspection shows no damaged or burned wires.

What I think it is now is one of those heating elements is faulty. I need to check the ohms reading on them to see what I get. It could also be that one of the elements has become grounded to the chassis. I haven't checked, but this could be it as someone here previously mentioned that 99% of all oven problems like this are due to faulty elements. The bizarre thing is that the 2-year-old oven is still as new. I have only used it maybe 30 times. It's anyone's guess at this point what the problem is. So place your bets. In the mean time, I am having fun

 

[kellys_eye]

As you say.... if the thermostat is working then the only other thing left is the heating element itself.

 

[73's de Edd]

Sir MDJolley . . . . .

If you pop the tabs on the pcb case (grey clear plastic)and show the other side of the pcb, there may be a different story.

If you (press back)the 2 far rear tabs on the pcb case (tough LEXAN plastic) and then fight the 4 minor side tabs,you may find more discrete surface mount parts on the other, hidden side of the PCB.

REPEAT REFRESH . . . . . .OF YOUR PRIOR IMAGE . . .



I, also, am awaiting for . . . . the rest of the story . . . a la Paul Harvey
www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwiT_9L7ndCDAxVxnGoFHRjwBJkQwqsBegQIDhAF&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DjQy3s4Pp4YA&usg=AOvVaw3MHGdZzI-HYdnzMnDag5Ku&opi=89978449

www.youtube.com/watch?v=tYe_G0kfv7E

www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwiT_9L7ndCDAxVxnGoFHRjwBJkQwqsBegQICRAF&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DtYe_G0kfv7E&usg=AOvVaw0LPIsatDExU9bl3IIA1fnR&opi=89978449

The Solution . . . . .
Those closed ( fused /spot-welded together) contacts on that Hong Feng power relay seem to be your principal problem.

MY OBSERVATIONS . . . .
What I am seeing there (without benefit of the FULL viewing advantage of seeing the foil paths side of the PCB).
Is the top rear corners male Line / Neutral spade terminal . . . and assuredly, its companion male Line / Hot spade terminal that is just barely visible behind the left corner grey C2 poly cap.
Referring back to that Power relay, we see that it has a 6VDC coil.
That 6VDC low voltage supply is being derived by the 220 V 50~AC line voltage coming into the last AC HOT terminal ***and into the ~.68----1.0 ufd cap (C2) and out of it into a hidden ( to me ) diode rectifier / medium to then give rectified DC out of ~5v greater than 6VDC to one ( or both ) of the gold E-caps. (Fill us in on the capacitance and voltage specs) They then store up that slightly higher raw DC. It is then passed on up to the PVR1 regulator . . . highly being suspicioned as an LM7806 . . . . to let it then serve as the boards regulated 6V supply.
(Possibly that second gold E-cap was tied to the regulated 6VDC supply output .)( WHERE's da board foil pick-choor ? )

More detail on the C2 dropping cap . . . .
Its value was initially selected so that the incoming 220VAC @50~ power input initially encounted its capacitive reactance and then causeed a voltage drop thru it, but it is putting thru just a bit more loaded down power, than the boards max needs. Then the proper selection of additional series " trim " resistor(s) will drop down that excess voltage on down to the required raw voltage. ( Note the two 56 ohm metal film power resistors on board. )
The C2 poly cap is being a ruggedized X2 rated application type that can even be used wired directly across the AC line . . . . this one is only in series with the power. (Best that an AC line fuse's protection is also in circuit.)

THE REAL POWER SWITCHING . . . . . VIA POWER RELAY . . .

It looks like the Hong Feng HF115F-Q series relay at the bottom is the one that you want, as you can see its HEAVY-WIDE buss pairs are coming directly aside from the relay propers contacts and then folding up to become the push on terminals.
Now FAR better, that the limited current passage afforded by the old style, shown just above it.



HOW IS IT SUPPOSED TO WORK . . . . . . ? ? ? ? ?

I can see the L1N and L1HOT push on connectors receiving AC 220V@50~ line power input.
I can see an ISOLATED 1 and 1A push on connectors . . . . . only connecting to the separate heating element.
BEHOLD! . . .behind ye olde relay there is a Piezo sonalert alarm element .
Is the Piezo all self-contained, or does it require a driver ?
AND does it alert when the heater element turns off . . . . . or is the heating elements temp, pulse train controlled ?
With only the 4 AC power connections seen, how is this accomplished ?
(Wheredatpick-choorofdabackofadaboard?)

Whirlpool oven timer problem​

Lastly . . . . on your header, you should also have given that Pirlwhool's model number, so we could consult and check out its wiring diagram , for tracking down other routing and switching actions relative to your #18 post.

And lastly . . . . . . . . . . . . you ex-pat or contractor or Ukraine war husband​

SLAVA UKRAINE