Kenmore 790.78672400 gas range

[profix]

I need info on this range. I installed new pc board ,and it worked for one day. I checked all connections, all seemed fine. Has anyone  had problems like this on a fairly new Kenmore?

[Samurai Appliance Repair Man]

What was the original problem?

Did you find the tech sheet in the range?

[profix]

The reported problem was, clock and digital controls not working. When I serviced the unit I first checked the power quality at the recepticle. This checked ok. Next, I   used  the tech sheet, found nothing leaving the board. I installed a new board, which worked for a whole day. I plan to go back in the morning and get a better diagnosis. I may stem from a external electrical problem?

[Samurai Appliance Repair Man]

You need to check the power supply inputs to the board. Inspect the wire harness connectors very carefully. Might find a loose connection in the harness or sloppy terminal. DO a live test, too, and measure the 120vac supply at the ERC while wiggling stuff. Need to rule out a power supply connection problem before we start suspecting the board.

[appl.tech.29501]

does the board also control the oven light? some of the newer amana line products have a problem with the light socket being bad and causing the board to go out. even though your socket looks different than the problem one externally it may be configured ths same way internally. Something to think about.

[profix]

Well, just came back from doing my service calls. I didnt find any problems that I thought could be causing the problem. The board was getting its 120v, the light socket, seemed ok. I did use the tech. sheet but, still could not find the problem. The only problem I found was a burned out motor on the vent hood. I could see where this could have caused a problem on the original board. I dont think it would have fried the second board, unless the switch had been used on a shorted motor. I plan to send for a new board and a light socket. I'll end up eating the cost of a new board. This time I will connect the range to another circuit, just temp. Thanks, Ron

 

[Samurai Appliance Repair Man]

[user=28041]profix[/user] wrote:

I didnt find any problems that I thought could be causing the problem.

I'm not clear on whether we're dealing with an intermittent problem or not. Does the original problem still exist?

The board was getting its 120v, the light socket, seemed ok. I did use the tech. sheet but, still could not find the problem.

Can you fax me the tech sheet at 866-315-4504? Alternatively, you could scan it in or take a really good picture and upload it to Flickr.

The only problem I found was a burned out motor on the vent hood. I could see where this could have caused a problem on the original board.

If this wiring diagram is accurate, then I don't see how the vent fan motor is connected to the EOC at all.

Check that neutral wire on pin 5 of the EOC harness connector. Examine it closely in comparison to the other wires in the harness looking for anything different in that wire: pulled back a little in the harness, loose, discolored, etc. Pull the harness connector and examine the pin sockets on the underside. Finally, ohm out that neutral wire from the harness connector to the neutral lug in the power terminal block.

 

[profix]

The fan motor is a vent hood which is on the same circuit as the range, which could have caused electrical problems to anything on that circuit. I will fax this tech. sheet.

[Samurai Appliance Repair Man]

Got your fax, same diagram as the one I linked to.

The fan motor is a vent hood which is on the same circuit as the range, which could have caused electrical problems to anything on that circuit. I will fax this tech. sheet.

While this is true, the board would only see RF noise produced by the failing fan motor. Possibly that would be enough to take it out, but I would eliminate other, more probable and obvious things first, such as a flakey neutral. If the fan motor failed short (again, unlikely but possible), then the circuit breaker would kill power to the circuit. If it failed open (most common), then it would simply no longer be a load on the circuit.

In general, unless there's a specific tech bulletin out on a subtle component interaction problem, I always troubleshoot the obvious things first. Maybe you have such a bulletin; I don't and so proceed on this rationale.

[profix]

Thanks for the info. I do plan as always, to go back and start from top to bottom. At times it seems frustrating, but it is part of learning this trade.

[appl.tech.29501]

[user=28041]profix[/user] wrote:

Thanks for the info. I do plan as always, to go back and start from top to bottom. At times it seems frustrating, but it is part of learning this trade.

it can be extremely frustrating at times, but once you have gone through a problem the "hard" way you will never forget it.