Magic Chef Oven problems
Posted 25 July 2005 - 06:57 AM
Okay, last week, my cub scout den was here, wanted take and bake pizza...It was hot in the house already, the oven wouldn't light. I called my home warranty co. and they scheduled a service call with a local repairman (one of the two previous companies) this morning. I just tried the oven, (the house is cool this morning) and it lit right up. I do have to turn the temperature up to "Broil" to get it to light whenever.
Is this a common problem? Is my oven just smarter than I am and knows summer is not the time to do any baking? Should cub scouts just eat peanut butter sandwiches for snack? Please help.
Posted 25 July 2005 - 12:13 PM
Currently serving EVERYTHING
Posted 25 July 2005 - 01:10 PM
Posted 26 July 2005 - 01:05 PM
Posted 26 July 2005 - 03:50 PM
As for ignitors, I've found that the most reliable one these days is the Maytag universal ignitor.
Posted 26 July 2005 - 09:31 PM
Thanks for the information.
Posted 27 July 2005 - 03:39 AM
Posted 06 November 2005 - 12:39 PM
Samurai san, nice site you have going. Thanks.
This topic is rather close to a problem I had just now... it may be the same cause.
Our oven failed to ignite... when the girls used it.
When they called me over it would work. (You've been there right?). Eventually it stopped igniting even for me.
So I apply the 6th Law of Appliance Repair: Begin troubleshooting right at the problem. ... Gas oven won't bake? Start at the ignitor. Go right to the main thing that ain't doing its thang. Ripped it out, measured it.. in range. Dang.
Ok, then clearly it must be the sensor... and here i failed to observe the 10th law. I thought I needed to disconnect it at the back, not realizing I could measure it, including the wiring, at the control module. Moved the appliance. Yikes. Found a long lost spoon though!
Anyway, the sensore nicely measure 1100 ohms at room, and 1300 or something when immersed in a hot cup of tea. So that was not it either. Obviously this was before reading up on repairs here, otherwise I would expect an exrror code to go with a broken sensor. Oh well. Now what? Apply a beer!
Next measure the igniter in circuit. Removed the oven control lead, feed into amp meter, other side of amp meter to the power.. works.
Ok... maybe the relay does not come on. Measure that voltage. A second or two after setting a temp, the relay click and 110 V appears.
Finally, measure the amps really in circuit with the relay: click... no amps. Add second multimeter to measure relay output.. a glitch, but not 110 V. Suspecting a bad contact or bad relay now, but since the broiler also did not come on (no one told me before!) a bad central contact.
Jank out the relay/power board, perform a visual, and bingo! A nice brown ring on the bake relay power-in solder point! And... a similar brown ring on the broil relay power-in solder point. Hard to believe, but the same problem twice on one board.
Solder it back up, and the oven ignites fine.
Xcept... that it starts to bleep after a while and reads -F8- in the display. Oh well, I'll have to crack an other beer before tackling that new detail.
Hope this helps someone out there,
Posted 06 November 2005 - 04:34 PM
Looks like I fixed a simple problem and somehow created a more expensive problem. This F8, as most readers here probably know is supposed to mean "Analog/Digital converter. 1. Replace clock assembly (also called the ERC)".
Closer observation shows the temperature reading to be erratic for a while, then it shuts down with F8.
From near cold, requesting hot, the display may show: 120, 125, 125, 120, 135, 140, 125, 130, 140, 140, 145, 140, 145, 125, ...
I suppose the measured temp going down while it is supposed to go up triggered a fault, or maybe an unexpected rate of change did it in.
Anyway... any component to suspect, or go hunt for a board?
Btw.. the board is kinda ugly, with lots of patches: diodes and resistors soldered accross the back and such. I tried jiggling it some, reseat it in its locks, and put pressure in different zones in case it was a bad track, but no luck.
Posted 06 November 2005 - 06:36 PM
I'm pretty sure it is not the ERC board, even with code F8.
If I connect a 1.3K resistor over the sensor contacts it reads a stable 175 degrees.
1.5K reads 275 and 1.8K reads 425. Solid. (1.3 was made by 2x2.7 in parallel).
The sensor mearures reasonable Ohms values, but when I hook it up the termperature reading still fluctuates. This is after tightning up the connectors some, and replacing the connector to the ERC with screw on clamps. Dang, so close, but still no go.
I'm convinced law #10 did me in. I moved it, and undid stiff (the sensor) where I could have measured in a smarter place directly on the ERC board, without touching any of that.
Still, I did find that spoon back, and also decided to exploit the unused electric range hookup for a 240 outlet for some European appliances I still have.
In an other topic I saw a request for pictures of potentially bad solder joints.
Well, I had already re-soldered them so I can not show what the bad ones looked like, but I can show where they were. See attached.
Posted 07 November 2005 - 10:55 AM
Posted 07 November 2005 - 12:45 PM
supply coltage + Igniter + valve + relay circuits are now certainly good.
If I ohm measure the sensor are the ERC connector, it nicely reflects the temperature.
So the sensor looks good, and I think is was good before, as the cause was bad relay to circuit board soldering.
If I fake the sensor with a resistor, then the ERC read a nice stable temp and is happy: calling for heat if, and only if, the selected temp is above resistor faked/suggested temperatur value.
So the ERC appears to function nicely it seems, but claims a fault when connected to the sensor
With a volt meter you sort of a 1 second cycle saw tooth voltage rise/drop over the sensor/resistor. I guess the ADC is a condensator charge/discharge time measurement depending on the resistance of the sensor. Also, when I can make teh ERC report F2 or F3 on demand, so that part works also.
Every component checks, but the whole fails.
At this point my money is on the sensor/wiring but I'm not sure enough.
Posted 07 November 2005 - 01:25 PM
Mine, too. Sensors can test fine with an ohm meter but act flakey under load. And they're alot less expensive than the ERC. You can buy a new sensor here.
At this point my money is on the sensor/wiring
Posted 24 November 2005 - 06:20 AM
Ordered sensor from repairclinic using clickthough as suggested.
The real problem was the solder joints behind the ignition relays on the power printed circuit board.
It is still somewhat odd how the sensor failed on me, after I 'touched it'. But I suppose ours is not to wonder why once it works again.
I'm also still somewhat proud to not have jumped the gun on the F8 error code suggesting that the controller board was toasted. The quick check with a normal, fixed value, resistor replacing the sensor was a good diagnostic tool. It showed the controller reading capable of reading a stable value when stable input was given.
Have a great Thanksgiving Day/weekend
Do not overfeed your insinkerators (sp?)
[NPR carried an item yesterday declaring the day after T-day being the busiest plumbers day of the year, not because of the you-know-what waste problem, but rather due to folks stuffing unused stuffing down the kitchen drains]
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