Hamilton Beach 33103BC toaster oven - lower elements don't work, upper ones do - Page 1
Forum section: electronics / repair

author: Hogwild
author_rank: Regular Contributor
timestamp: February 04, 2021, 12:22:48 am
content: Hi everyone:Extreme newbie here, but like to take things apart. Hamilton Beach 31103DC toaster oven. Lower elements heat fine. Upper elements don't heat at all.I can't find any obvious signs of continuity problems anywhere. One multi-position switch controls both upper and lower elements.Switch is labelled Hua Li Lei FZ31-10. I'm not smart enough to understand the repercussion of the pinouts.One terminal on the switch seems to move up and down (but not left and right). On the same side, the switch casing seems to be not properly fastened to the rest of the switch. I can't find any thermistor or anything, but I guess it could be hidden.Should I assume elements or switch are broken, or am I even going in the right direction here? Remember, I'm a newbie.Thanks

author: bob91343
author_rank: Super Contributor
timestamp: February 04, 2021, 05:32:34 am
content: That symptom is usually caused by burned out elements. Disconnect them and measure their resistance. It is also possible that a switch is bad but then it wouldn't work at all.

author: Hogwild
author_rank: Regular Contributor
timestamp: February 04, 2021, 04:52:11 pm
content: I think the wires to the elements are actually welded on (not just soldered). Is there any way to tell for sure?Yes, that's what I was thinking about the switch. I don't know much, but this thing has a multi-position switch for which one position turns on the lower elements, the other position turns on the upper elements. Isn't it possible that the switch's contacts or inner mechanism are shot but for only one position and not others?

author: Hogwild
author_rank: Regular Contributor
timestamp: February 07, 2021, 04:22:39 am
content: If I do disconnect the elements, what resistance should they be?I can't find another switch to replace the bad one at a really reasonable price. $20.00 plus shipping. Hmmm...

author: WattsThat
author_rank: Frequent Contributor
timestamp: February 07, 2021, 04:58:38 am
content: Actual resistance really doesn't matter as you’re looking for an open circuit but... if it is a purely electro-mechanical device with no electronics in it, you should be able to measure the resistance of the good elements right at the plug with the timer turned on. Divide that by 2 for the resistance of one element.Or, the easy way if there is a wattage listed on the device, solve for R and divide by 4. R = E^2 / P

author: Hogwild
author_rank: Regular Contributor
timestamp: February 08, 2021, 03:20:48 pm
content: Sorry, being a newbie, I"m not sure what you mean. You mean one DMM probe on one AC plug terminal and the other probe on the other terminal? Or did you mean something else? Yes, I believe it's all electromechanical, I can't see any semiconductors.BTW, I don't know if it's relevant, but when I put the DMM probes on the element ends themselves, I measure somewhere in the 9.6 ohm region. OF course, since they're connected to other things, I don't know if those other things are affecting the measurement.

author: bob91343
author_rank: Super Contributor
timestamp: February 08, 2021, 11:21:25 pm
content: That doesn't tell much. The elements are probably in parallel so you won't find an open one that way. When you change switch settings do the readings change? Across the power plug, that is. Is this wired for 120 or 240?

author: Hogwild
author_rank: Regular Contributor
timestamp: February 09, 2021, 02:25:48 am
content: With DMM leads across the power plug, here's what I get with timer on:- Rotisserie (position 1) on switch: 2.674K- Bake (position 2) [bottom elements] on switch: 29.5-31M- Convection (position 3) : 0.465M- Broil (position 4) [ top elements] : OLDoes the very high resistance on Bake suggest something?

author: WattsThat
author_rank: Frequent Contributor
timestamp: February 09, 2021, 02:42:20 am
content: Assuming it’s 120v, 9.6 ohms sounds about right for an counter-top oven. That would approximately 12 amps and 1400 watts. That’s about the limit for a US standard outlet which is 15 amps max. Some are 20. I assume it’s the same up north.None of the ohm measurements at the plug make any sense.

author: Hogwild
author_rank: Regular Contributor
timestamp: February 09, 2021, 02:54:24 am
content: O-kay. Then, what do you suggest I do next?

author: bob91343
author_rank: Super Contributor
timestamp: February 09, 2021, 06:28:59 am
content: All your measurements are high, in the megohms. I would expect them to be under 100 Ohms.

author: Hogwild
author_rank: Regular Contributor
timestamp: February 09, 2021, 02:49:48 pm
content: Yeah, that's what I was thinking. Maybe my meter is dying?

author: tunk
author_rank: Super Contributor
timestamp: February 09, 2021, 03:41:08 pm
content: Short your multimeter test leads, you should get a readingclose to zero (less than 1 ohm). If not, check each testlead by disconnecting one of them, and then putting the tipof the other into the socket of the test lead you just tookout. If one of them shows a high resistance, it's bad.If both is high, then both leads are bad, or your meteris bad.If your meter is ok, then it could be the owen switch.

author: Hogwild
author_rank: Regular Contributor
timestamp: February 09, 2021, 03:50:02 pm
content: Thanks. I already did that, but I'll do it again. It is showing 0 resistance. I've used the DMM on other things recently, and it has been accurate.So, likely the switch?

author: drussell
author_rank: Super Contributor
timestamp: February 09, 2021, 04:29:26 pm
content: Quote from: Hogwild on February 09, 2021, 03:50:02 pmNo, we don't know that yet...The readings you are getting on your DMM make no sense for the observed behavior of the bake element working but broil elementnotworking.Itmightbe the switch not turning on the broil element (top) in thetoastandbroilmodes, but you should still be seeing the bake element (lower) in circuit in non-broil modes with your meter, since it does heat up.Something is wrong with your measurements. Until your measurements agree with the observed behavior in operation, do not hastily jump to conclusions about where the actual fault lies!More sleuthing is required!Edit:Some good, clear photos of the guts of the unit would be helpful for us guide you.

author: Hogwild
author_rank: Regular Contributor
timestamp: February 09, 2021, 05:25:12 pm
content: When I meausred the elements directly, the bottom ones and top ones were both somewhere near the 10R area. The bottom ones measured slightly differently than the top ones.I'll get some pics and post back with them. My camera battery just died, so I'll do that later today or tomorrow. Thanks for all this. If I can fix this, I'll make my 95-year-old Mom very happy.

author: Hogwild
author_rank: Regular Contributor
timestamp: February 10, 2021, 04:11:10 pm
content: Do these help at all?1.2.3.4.5.6.7.8.9.

author: tunk
author_rank: Super Contributor
timestamp: February 10, 2021, 05:02:55 pm
content: Looks like there's no electronics.Use your multimeter to check for continuity everywhere:elements, cables, connectors, switch(es) etc. NB: Spadeconnectors can go bad. The timer should be ok - if it'sbad, I guess nothing would work.

author: drussell
author_rank: Super Contributor
timestamp: February 10, 2021, 05:15:34 pm
content: The contacts on the A terminal on the switch (blue wire) are burned.You might be able to disassemble the switch and clean up the contacts if they're not beyond repair, otherwise you'll need a new switch.Edit:

author: Hogwild
author_rank: Regular Contributor
timestamp: February 10, 2021, 05:21:55 pm
content: That's what I thought. Glad my instincts were good. Does one just pry open the side of the switch that's already not flush? As I said earlier, that same terminal is also moving up and down in the switch. What does one use to clean the switch? Contact cleaner?

author: drussell
author_rank: Super Contributor
timestamp: February 10, 2021, 05:28:50 pm
content: You will need to file it down, or sandpaper or something, it will be quite charred.First remove the switch from the toaster oven and see if you can figure out how it snaps together and post a picture of how bad that contact is. It was obviously making poor connection and got super hot, melting the case of the switch.Depending on how long it was like that there may not be much left of the contact to try to repair.

author: Hogwild
author_rank: Regular Contributor
timestamp: February 10, 2021, 05:33:15 pm
content: After what you described, I think it might be better/safer to just buy a new switch. I see them in a few places but $USD 24.00-28.00 !That's crazy. I bet they sell them in China for 60 cents.

author: drussell
author_rank: Super Contributor
timestamp: February 10, 2021, 05:33:33 pm
content: Quote from: Hogwild on February 10, 2021, 05:21:55 pmIt looks like there are little clips on the end caps that pop into holes in the main switch body, if you press on those with a small screwdriver or something you should be able to pop them free and open the switch.

author: drussell
author_rank: Super Contributor
timestamp: February 10, 2021, 05:36:30 pm
content: Quote from: Hogwild on February 10, 2021, 05:33:15 pmWell a new switch is certainly the best way to go but since it is toast anyway (har har) there's nothing to lose by at least trying to open it and see justhowcharred it is, how badly it failed.

author: tunk
author_rank: Super Contributor
timestamp: February 10, 2021, 05:38:42 pm
content: To open it: I guess there's four tabs, one to theright of "A", one above "16A" and two on the otherside. And you may have to replace the spade connector,it may have been weakened, loosing it's tension.It could possibly also have been the cause of theproblem.

author: drussell
author_rank: Super Contributor
timestamp: February 10, 2021, 06:55:01 pm
content: Quote from: tunk on February 10, 2021, 05:38:42 pmYes, that is why it is interesting to open it to see. If it was the connection at the spade terminal that got hot and melted the case, the contact will probably still look pretty good and the switch just quit working mostly from the melted case allowing the contact to come out of alignment and therefore no longer make connection. In that case, some judicious of some epoxy or something might well be able to repair the housing and then with the spade terminal cleaned up well and possibly a new female connector on the wire if required would be able to be returned to service.On the other hand, if the heat was coming from the switch contact and working its way outward, the contact itself will probably be pretty messed up. It is impossible to know until it is opened so an autopsy can be performed and deduce where the problem actually started and what condition the parts are actually in.

author: drussell
author_rank: Super Contributor
timestamp: February 10, 2021, 07:00:59 pm
content: Quote from: Hogwild on February 10, 2021, 05:33:15 pmIndeed.This one is under $18 USD including shipping but you have to wait for it to get here from China.https://www.ebay.com/itm/1x-HUA-LI-LAI-Rotary-Switch-FZ31-9-6-Pins-16A-250V-13A-125V-AC-T125-55-/254766220784Edit:Wrong switch

author: Hogwild
author_rank: Regular Contributor
timestamp: February 10, 2021, 07:02:51 pm
content: Thanks, but that's not the same switch. I don't know how to tell if that switch will work in this oven. I need an FZ31-10, that's an FZ31-9. Any way to tell? I can't even find specs on the -10 model, except the voltage and current ratings on the switch itself.

author: drussell
author_rank: Super Contributor
timestamp: February 10, 2021, 07:12:45 pm
content: Quote from: Hogwild on February 10, 2021, 07:02:51 pmOh, oops, sorry... I didn't look closely enough, obviously, was just doing a quick google search.Regardless, I would take the burned switch out and at least open it up, post some photos for us and we'll see if you can just rebuild that one reliably anyway. It may not actually be that badly damaged, who knows.If you do end up ordering and waiting for a new switch, you could temporarily wire it up into one position, say regular "Bake" or whatever function gets used most often until your new switch arrives. The timer and thermostat would still work but you'd be stuck in whatever mode you wired it up for while waiting for a new switch.

author: Hogwild
author_rank: Regular Contributor
timestamp: February 21, 2021, 04:26:54 pm
content: I had little success in finding another switch. I would be comfortable doing the repairs you guys described if this weren't an oven. However, knowing that insurance companies are just looking for a way to blame it on me if anything goes wrong, I'm not comfortable repairing the current switch.So sadly, this goes in the garbage. What a waste. Thanks so much for all your help. You folks are wonderful.

author: EE-digger
author_rank: Frequent Contributor
timestamp: January 11, 2022, 07:03:13 pm
content: Late to the party but the same problem on a Cuisinart TOA-60 air fryer oven. On ebay, the switch is called both FZ31-10 and as shown below.The switch has two stacked decks. Each deck is labeled FZ31-9E but on ebay, a stack of two is called the same thing. If you're going to spring for the crazy replacement price, be sure the vendor has photos from multiple angles to insure the right part.But there should be laws against:1. crap like this in the Chinese made products ... I know, I know, the stainless steel housing will contain the flames2. crazy replacement price from China, as already mentioned.