Frigidaire microwave wiring diagram needed

[psteichen]

I have searched everywhere online, and cannot find the service manual for a Frigidaire cfmv154clsa. Not even a payed download. And not only for this machine, but it seems that service manuals for all microwaves are pretty much nonexistent online. (found some for Daewoo only).

A few diagrams are available on parts sites, but they're such low resolution as to be unreadable. Anyone have a paper diagram they could scan?

The machine has an automatic vent fan that comes on if the unit gets hot (which it does because it is mounted over a stove). That feature works fine, but when it gets really hot the fan shuts off again. Like when cooking or using the self cleaning oven.

I'm assuming it has some sort of overtemp cutout, but it seems that it is cutting out far too easily (I mean it is an over-the-range microwave afterall, it's going to get hot).

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[hermit]

Well, many of these aren't located the minimum distance spec'd above the range.  Thermal cutouts are generally on top of the cavity, sometimes called flame switches.  Not surprising many won't reset because the 'assume' something went terribly wrong and should be looked at.   The mag tube will have another.

Does anything else go off when the fan cuts off?  Most of these other devices will shut down everything as a precaution.

[Bushougoma]

Here:

ftp://ftp.electrolux-na.com/prodinfo_pdf/springfield/5995641239.pdf

Wiring diagrams on the last page.

[psteichen]

Well, many of these aren't located the minimum distance spec'd above the range.  Thermal cutouts are generally on top of the cavity, sometimes called flame switches.  Not surprising many won't reset because the 'assume' something went terribly wrong and should be looked at.   The mag tube will have another.

Does anything else go off when the fan cuts off?  Most of these other devices will shut down everything as a precaution.

No, nothing else stops. The microwave still works, interior and stove illumination lights, just the vent fan turns off until it cools.

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[psteichen]

Here:

ftp://ftp.electrolux-na.com/prodinfo_pdf/springfield/5995641239.pdf

Wiring diagrams on the last page.

Great clear diagram. Thanks!

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[psteichen]

I'm confused a bit by the diagram. What is labeled "hood thermal cut-out" seems by the diagram to actually be the thermal "cut-in" that turns on the fan automatically during hot conditions. The way it's drawn, I don't see how it would act as a "cut-out". I don't see anything else in the diagram either that would remove power from the fan only in high heat conditions.

Although, the "Thermidtor" drawn on the top left of the diagram is ambiguous, considering that no electrical connections are drawn to it. Could this be signaling the microchip to open both relays 4 & 5 to cut power?

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[hermit]

I read the diagram pretty much the same.  Remember, the motor has an internal safety.    It could also be that the 'cut-out' is located in such a way that it cools down faster than you think it ought to.  Only way to know for sure would be to check it when the fan stops.  Of course stuff is going to be pretty damned hot then.

[amyk]

And not only for this machine, but it seems that service manuals for all microwaves are pretty much nonexistent online. (found some for Daewoo only).

Panasonic microwave service manuals are pretty easy to find.

[psteichen]

Hey everyone, thanks for the help. I figured out the problem. During installation a year ago a small low voltage wire from our LED under counter lights got caught over the baffle plate in the vent exhaust duct. As a result the baffle has been stuck shut preventing 90% of the air flow from passing. The vent fan motor was overheating due to the workload combined with the hot exhaust it was trying to pass. The motor must have an internal thermal cut-out that is not described in the schematic. The whole thing was always hot to the touch when operating the stove or using it's convection oven features. Now it is much cooler. Stupid wire!

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[hermit]

The motor must have an internal thermal cut-out that is not described in the schematic.

Yes, I mentioned that above.  If that flap is on the mircowave you can usually hear it close if it exhaust up.  There are all sorts of subtle clues  that became automatic when you've done it for years.  The sound is different when it doesn't vent because of the air flow.  Mostly the complaint for blocked airflow was that the fan 'wouldn't change speeds'.  I used to take a paper towel and check the airflow.  On the ones I worked for the vent fans needed to be turned during installation depending on whether it would recirculate internally through a filter or exhaust up or out the back.  I've been retired for close to 7 years though so no longer 'second nature'.

[psteichen]

The motor must have an internal thermal cut-out that is not described in the schematic.

Yes, I mentioned that above.  If that flap is on the mircowave you can usually hear it close if it exhaust up.  There are all sorts of subtle clues  that became automatic when you've done it for years.  The sound is different when it doesn't vent because of the air flow.  Mostly the complaint for blocked airflow was that the fan 'wouldn't change speeds'.  I used to take a paper towel and check the airflow.  On the ones I worked for the vent fans needed to be turned during installation depending on whether it would recirculate internally through a filter or exhaust up or out the back.  I've been retired for close to 7 years though so no longer 'second nature'.

I did the paper towel thing with a page from a magazine It wouldn't hold it up. Now that I freed up the baffle plate it sucks the page up from 2 inches below. Also, you mentioned that people complain that they don't have two speeds. We thought exactly that all year. Many times I commented on how pathetic the high setting was, because it sounded almost exactly like low

Should have had a pro install it!

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[hermit]

I've had to do mop up on plenty of 'pro' installations.