New Element in a 1957 Hotpoint wall oven

wcs2

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Thanks! That's the first time in a long time I've encountered someone else who knows what microfiche are. I'll be sure to report back when I've conducted my hunt.
 

wcs2

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Hi again,
I managed to find a replacement thermostat. I realize it's either that or the 4 position bake switch, but I'm starting with the one I could find the replacement for. This leads me to two questions:
First, does anyone know the replacement part number for the 4 position, 3 heat time bake switch #601837? (Also, is there a more appropriate name for it? I'm pulling this off the schematic).

Second, the new thermostat has spade terminals instead of screws, but multiple wires were screwed in at each screw. Is there any harm or disadvantage to double crimping the wires into one female connector?
Better safe than sorry!

Thanks again!
 

Dan O.

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does anyone know the replacement part number for the 4 position, 3 heat time bake switch #601837?
Hotpoint part number 601837 subbed to GE # WB22X5049 and then to WB22X5131. Although all are discontinued, there are currently a couple available at this link

LINK > 601837/WB22X5049/WB22X5131 Selector Switch

From the pictures of that replacement switch, it looks like it no longer has a terminal market "TN" (the abbreviation might be for 'Timer Neutral'). The rest of the terminal markings look the same. I don't know what would be needed to adapt the replacement switch.


is there a more appropriate name for it?
Generally it is just referred to as an "oven selector switch" or "bake/broil selector switch".


Is there any harm or disadvantage to double crimping the wires into one female connector?
As long as the connector is an appropriate size to accommodate multiple wires, it shouldn't be a problem unless one of those wires ever needs to be disconnected or changed in which case the connector might need to be cut off again.

Dan O.
 
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wcs2

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Thanks as always, Dan. Your help is keeping me on track with this. Is there any way to test a thermostat when it's been pulled to see if it's the culprit? Or is it just better to switch it out, give it all a try and then, if need be, switch out the selector switch?
I'm a little nervous about shoving that catheter through the hole into the oven. It was tough to pull the old one out and I don't want to break this thing. Is it just a patience game?
 

Dan O.

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Continuity test contacts

Is there any way to test a thermostat when it's been pulled to see if it's the culprit?
It could have been tested in place. It looks like the two contacts on each side of the thermostat should close between each other when turned on. I assume they should both be open when OFF. If either set show continuity between them when OFF, the control is likely defective.

image.png

By looking at the wiring diagram I can't just the selector switch causing the indicator to be on all the time.

JMO

Dan O.
 

wcs2

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Sorry for being dumb, but when you say the control, do you mean the thermostat or the switch?
I've been wondering if it has to be the switch that's fried simply because the oven is on even when it's off, so since it has the "Off" setting and that's not working, that's where the problem is.
But you definitely have a more informed opinion than me - I'm just muddling my way through and slowly catching on.
 

Dan O.

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when you say the control, do you mean the thermostat or the switch?
The thermostat is often referred to as an "oven control" and as near as I can tell it (the thermostat/oven control) would have to be malfunctioning for the oven light to be staying on.

I've been wondering if it has to be the switch that's fried simply because the oven is on even when it's off
You said previously the LIGHT was ON, not the "oven".

I can't tell fom the wiring diagram if the selector switch would stop the indicator light or not. As near as I can tell a defective thermostat contact would have to be closed for the light to be ON. I would assume those contacts should be open when set to OFF.

It's also possible both thermostat and selector switch were damaged by the short at the same time.

Dan O.
 

wcs2

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Thanks for the clarification. I will keep you posted on the status. I'm close.
I did, however, just find an old wiring puzzle. In the wiring diagram, one wire from the Rota Grill switch is shown going to terminal C on the selector switch. In reality, that wire is connected to the top right screw of the thermostat (see the picture below). Since I have it all pulled apart, do you think I should wire it according to the diagram or the way it has been wired (and working) for who-knows-how-long?

puzzle.jpg

Just found a slightly better angle on a picture I took.
20190303_173520.jpg
 

Dan O.

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Rota Grill switch is shown going to terminal C on the selector switch. In reality, that wire is connected to the top right screw of the thermostat
Since according to the wiring diagram a wire goes from terminal C to the same terminal on the thermostat, either terminal is essentially the same thing. If it will prevent a dual wire in a single push-on terminal, it could be moved back to the selector switch terminal if it's not too much trouble. Otherwise it shouldn't hurt anything staying where it is.

Dan O.
 

wcs2

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Success!!! It took a bit to figure out whether everythign was going according to plan or not, but it seems like it's done. The new thermostat has an "off" setting, which the old one did not. It used to be that the selector switch alone turned the oven off. Once I figured that part out, I realized the new thermostat was doing everything it should.

Now to calibrate it, but to do that, I have to find a way to lock in the semi-circular stem into the circular hole of the knob. I haven't started googling that yet, as I wanted to let you. Thanks again, Dan. This is amazing.
 

Dan O.

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semi-circular stem into the circular hole of the knob.
I'm not sure what you mean by that. The hole in the knob for the thermostat shaft is usually "D" shaped. It couldn't be round or it would just slip on the shaft.
 

wcs2

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Sorry for being unclear. The picture will hopefully make it clear. The old thermostat has a round shaft and a second, flat one in order to lock the knob in place for calibration (calibration is done on the knob with a toothed wheel and screws). The new shaft is D-shaped. So the old knob just slides around the new shaft without really grabbing on. I don't want to replace the knob as that's part of the aesthetic of this oven, so I'm hoping there is an adapter I can either buy or make to lock the knob in place on the shaft.

knob.jpg
 

Dan O.

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Sorry but I've never seen a control shaft like that original one. It must be even before my time.

The final replacement universal thermostat did come with some extra hardware. I wonder if it has anything to do with the knob mounting?


WB21X5212 Thermostat Pkg + accessories




Dan O.
 

wcs2

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Oh wow, I can't believe I stumped you. The link above doesn't work for me - it just takes me to the home page. I've tried searching for it but it's not coming up. Could I ask you to repost it? I'd like to take a close look at the picture to see the parts.

I was wondering if something like this might work - I could epoxy it in there and then calibrate the knob once it sets. What do you think?
 

Dan O.

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This page has similar pics of the control kit and accessories.

LINK > http://www.appliance411.com/data.php?ap=WB21X5212


that clip you linked to is for a dryer and their shaft sizes are considerably larger than GE thermostat shafts. It also fits into a knob that has a "D" shaped hole.

Are the temperature calibrations written on the knob or printed onto the panel? I might be able to find a knob to fit the thermostat shaft but finding one with the temperature gradations will be difficult.

Dan O.
 

wcs2

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Right, I know it's not the right part, I'm just thinking of something along those lines (that was simply the first thing I found that I thought I might be able to build into what I need).
The temperature calibration is done on the knob using what I can only describe as a pin and teeth set up.

It's not a fun job to get it just right, but basically you have to loosen the screws to turn the aluminum ring of the knob to lock in to the teeth of the knob. I've included a picture that shows how it's put together. I'm wondering if there's a spring insert that could replace the triangular one that would lock into the D shape. I'm not quite clear what this "spring" is actually for, but could it have been intended to be replaced based on the shape of the shaft?

knob angles.jpg
 

Dan O.

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Thermostat knobs

I'm not quite clear what this "spring" is actually for
I'm afraid i don't know either. It doesn't look to do anything unless it clipped into a horizontal groove in the shaft to hold the knob on??

The size of a GE thermostat shaft is unique in the industry in my experience. I don't know any knobs besides ones designed specifically for it that fit onto that shaft size. Most control shafts are larger diameter.

I found a couple of GE thermostat knobs that look to have the same temperature gradation as your knob and should accommodate the new control's shaft size but I don't know if the "D" shaped hole will have the same orientation as your control. That is responsible for having the OFF position at 3:00, 6:00, 9:00 or at the top at 12:00 position.

GE therm knobs.jpg

LINK > WB3X5481 Thermostat Knob

LINK > WB3X5638 Thermostat Knob

I don't know what the differences are between them.

The latter one is NLA but there are a couple of used one listed at the link below.

LINK > WB3X5481,WB3X5638 Thermostat Knobs


I don't know how you'd get the old knob to be used to on the new control if the knob's hole is totally round. That would require some ingenuity on your part. :(
 

wcs2

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So I went with the "ingenuity" route and it took about a week, but I think it's working. I basically clamped a small strip of middle under the metal plate at the back of the knob and that is now grabbing the stem effectively. Depending on which oven thermometer you believe, it's either exactly right or 50 degrees off. I suppose I need a third oven thermometer...
Below is a picture of my jury-rigged solution. I have, however, wondered if this knob would fit as a more permanent solution. It's closer in style to what is on the oven and the right shape. Of course that doesn't mean it's the right size, but it might be worth a shot. (I don't know if there are parts manuals for knobs).

This is my workaround:
20190318_221712~2.jpg
 

Dan O.

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wondered if this knob would fit as a more permanent solution. It's closer in style to what is on the oven and the right shape.
That knob could very possibly be a right shaft size and the temperature gradations look close. I mainly looked at the 300 mark bring directly opposite broil. I can't tell about the orientation to the flat on the shaft.

BTW Your solution looks fine if it holds up. Such an insert could be tapered so it tightened onto the shaft when pressed on. That might make initial installation simpler.

Dan O.
 
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Dan O.

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BTW of the used knobs at the "LINK > WB3X5481,WB3X5638 Thermostat Knobs" link i supplied previously there was one for $9 and one for $15
instead of the $24 dollar used at your link. If you were going to take a chance, cheaper might be the way to go?
 
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