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May 12, 2017

Repair of an “Instant Pot” Pressure Cooker

Filed under: Uncategorized — admin @ 9:39 am

This post is about another case that reinforces my claim that “most repairs are easy” -especially when you know what to look for! One of my neighbours recently brought over a pressure cooker that had ceased to function. In quick initial tests, the unit powered up normally, and panel display and controls seemed functional, but the device heater did not come on. Other key observations were that the relay that supplies AC to the heater could be heard to “click” as expected. This relay is of a common type used in many appliances and electronic thermostats to supply relatively high currents to resistive heaters.

the patient, chest cavity opened

After opening up the base cover under the unit (just one screw needed to be removed, and the the cover rotated to removable position) I did a few quick electrical tests with a DVM (be careful of high voltages!). With the unit powered down and the heater quickly disconnected and out of circuit, I measured its resistance: about 15 ohms, appropriate for a heater of its power rating used at 120V. So, the heater seemed OK and not the cause of the unit not heating up. Next, I decided to look at the main power circuit board that contained the relay described above plus DC power supply for the display panel and some associated control circuitry. The board could be removed by taking out just 2 screws.

circuit board, in situ

Quick inspection of the underside of the circuit board revealed a highly suspect visible flaw in the solder at the common switch side of the relay. Essentially, there was a dark ring surrounding the relay pin between the pin and the solder on the board. Resistance measurements quickly confirmed no connection between the pin and the board. The suspect area is circled in red in the second photo below.

circuit board rolled over

circuit board, flaw circled

To perform the repair, I cleaned the pin of the relay with fine sandpaper, and then re-soldered it to the board. I left an especially thick cross-section of solder between pin and board, and along the full trace to the heater wire, since this is a high current path.

Quick reassembly and testing showed the pressure cooker to be heating and working fine again. One more appliance saved from disposal!

the repair

7 Comments »

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  1. Searching Instant Pot repair, found your page.
    Found the same spot solder looks almost the same with not enough solder surrounding the spot.
    Clean it and resolder, wife is happy got her pot working again.
    The pot is about 18 month old, hope the solder on this particular spot wasn’t done poorly on purpose :-)
    Can’t thank you enough for saving buying a new one.

    Comment by leho — July 13, 2017 @ 11:49 am

  2. Thanks for posting this. Our IP, is a little over 3 years old. It worked fine, twice last night, then when my wife added the final ingredients (vegetables) it, then it refused to work.

    I found the same problem and repaired it the same way.

    Thanks again,

    Butch

    Comment by Butch — July 18, 2017 @ 11:25 am

  3. Butch and leho, thanks for your comments. Nice to know these repair write-ups are useful. I’m considering telling the manufacturer, since this problem is clearly happening to a lot of these Instant Pots.

    Comment by admin — August 6, 2017 @ 1:28 pm

  4. Nice job with this. Mine just broke a couple nights ago and I had people over. Good thing I bought another during the holidays for backup. (They were half price on amazon)

    Until I saw this I was sure it was the heater. I tested it with my meter like you said and it was fine. I just soldered it a little while ago and it now works.

    Very useful post. Thanks

    Comment by Dave — October 27, 2017 @ 11:20 am

  5. Hey, Dave, you’re welcome and thanks for letting me know. Now that yours is at least the 4th that I know of with this exact same problem, I’m going to inform the manufacturer. I’ll post about that soon.

    Comment by admin — November 15, 2017 @ 2:29 pm

  6. Message I just sent the manufacturer:

    Hi. I do repairs of electronics and appliances as a hobby (to reduce waste, for environmental reasons).

    Recently, I’ve come across four instances of your Instant Pot products that have failed at exactly the same way at the same point on a PC board inside the units, at a connection to a high current relay. I’ve documented one of the failures, as well as my repair to it, on my repair blog here: http://media.davebaar.com/wordpress/?p=1368. See the photos of the problem especially. Note also the comments from owners of your products below that blog post who have experienced this exact same failure.

    Are you aware of any similar failures already, and do you have any comments in regard to this matter? Given the frequency of the same specific failure, I think it deserves your attention. It is likely that the problem could be easily solved in your future production by making that connection more capable of carrying high current, possibly via a larger cross-sectional area connection to the relay lead; it seems likely that self-heating at that point is what is causing the failures.

    Regards,
    David Baar

    2017 11 20 Update to this message and repair story:

    I’m happy to report that a support person for the manufacturer quickly got back to me after I sent them the information about the failed solder joint. That person has been diligently working to follow up and collect model number(s) and other information about any failed units. So, if anyone out there knows of Instant Pots that have failed similarly, please post model and serial number info here and I’ll send it on to the manufacturer.

    I think this reflects well on Instant Pot as a company. Here they have responded quickly to a customer problem, and have followed up diligently afterward to look for the cause.

    Comment by Dave B — November 15, 2017 @ 5:25 pm

  7. I came across this whilst searching for why my Instant Pot IP-LUX60 stopped getting hot but, whilst my circuit board looks similar from above, the underside is different and may be that’s because they updated it or because the one here is an IP-DUO60. Anyhow, mine was only 2 weeks old and I reported it as faulty and the supplier simply refunded it and didn’t want the old one back. Meanwhile the price has gone back up by 50%, so I decided to use my degree in electronics (35 years ago) to fix it. The first continuity test I did was between the neutral supply on the back of the mains input socket and the neutral post of the heating element (the one nearest the socket) with a blue wire. The live supply goes via the PCB whereas the neutral goes via a boss that is spring-biased against the base of the removable cooking pot. Anyhow, there was no connection to the neutral post of the heating element, so I stripped it down to find that the neutral simply goes via a 190 deg C bi-metallic disc thermostat (thermal switch / cut-out) rated at 16A 250v. I’d say here that the construction of that boss is very crude and everything is held inside by 2 thin metal discs that are pinched in place and are easily wedged out with a screw driver. There’s also a thermistor in there and some thermal paste. I struggled to find an exact replacement thermostat so got a 10A one because they are plentiful and I’d calculated that the max current of a 1000w element at 220v was 4.8 amps. The good news is that it works fine and I’m enjoying using the Instant Pot again, especially after the refund.

    Comment by Arthur Jackson — November 18, 2017 @ 7:06 am

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