Popper Coffee Roaster Motor Replacement

A walkthrough of DIY motor replacement for the Popper Coffee Roaster

With one screwdriver, a small pair of pliers, and some patience, you can replace the fan motor in the “Popper is a Coffee Roaster” in about 20 minutes! If the fan motor started misbehaving, that can bring a Popper coffee roaster back to life for another 250+ roasts!

The process does mean taking apart the machine more so than other minor tweaks people make to the Popper. If you aren’t familiar with these kinds of repairs, or losing tiny screws is in your DNA (like me) you might find someone else to do this for you.

But, as you see in the video, it’s pretty cool to rescue an appliance from the trash bin and get a bunch more use out of it.

(Remember when appliances were worth fixing, and every neighborhood had a repair shop … like a lawn mower repair or a TV repair shop. Or even a radio shack! Sigh)

(By the way, most people experience a small bump in the amount of coffee they can roast after the motor replacement. If your roast is not getting as dark as before using the same settings, try roast 5-15 grams more coffee).

Here’s the product link to Motor Replacement Kit for Popper

Popper Coffee Roaster Motor Replacement Video on YouTube

Listed instructions from the Video Captions

If it’s helpful, here are the instructions listed out, as they are shown in the video. If there is extra clarification you need or a photo that would be helpful, please comment and we will try to add that.

1- remove the 4 rubber feet to reveal screws beneath.

2- remove the 2 larger front face screws with the No. 1 driver.

3- remove the 4 screws under the rubber feet to release the base from the body shroud.

4- separate base from shroud gently tilting at angle toward the  the ribbon wire

5- disconnect ribbon wire and put the body aside.

6 – remove thermal switch connectors and remove insulation jacket.

7 – remove 3 screws holding roast chamber assembly to base plate

8 – remove 3 machine screws holding white fan shroud to metal roast chamber.

9 – remove 3 ceramic spacers to prevent damaging them.

10 – pull the fan off the splined motor shaft 

11 – remove 2 small motor mount machine screws – motor is free now

12 – pinch the insulation above the spade connector to help release, while gently pulling side to side and upward. 

13 – apply the 2 strips as in the video, not covering any openings in motor casing

14 – insert motor back into white housing, lining up holes in motor with where the 2 mounting screws will go.

14a – (oops) reattach motor with 2 screws, and tighten while pushing motor in place from the back. Don’t overtighten…

15 – push fan down with firm even pressure. test that it moves smoothly

16 – replace ceramic spacers. (added: These are very important to hold fan and heat coil in proper position!)

17 – replace 3 machine screws holding metal chamber to white motor mount.

17a – (added: You will be connecting the red and black wires on the new motor back to the PCB board exactly as they came off; black wire on the lower connector, red wire on upper connector. If you reverse these the motor functions but cannot roast much coffee because (I am pretty sure) the fan will be spinning backwards!

18 – slide thermal jacket on and re attach connectors to thermal switch, pinching them on if they feel lose at all. (added: if they seem loose at all, crip them on a but with pliers. If they aren’t well connected, full power is not getting to the heat coil, and your roasts will take too long / bake.)

19 – Inverting popper, attach base to chamber with 3 screws.

20 – reconnect ribbon cable.

21 – Reseat the shroud on the base, keeping one hand in top hole of roaster to guide it. Don’t force it!

22 – Replace the 2 larger front screws and 4 screws under the rubber feet, and replace rubber feet.

23 – Test your work… hopefully that motor purrs at an even clip and you have 250+ roasts more…

Some people can increase their batch size slightly after the install, depending on how the coffee spins in the Popper. The motor has better carbon brushes, and has equal or more power than the original, but it depends on your electric line specs and many other factors too.

21 Responses

  1. Thompson,
    Great demonstration video on replacing the old Popper motor with the V2 version, looks easy enough. I wasn’t aware we could move the thermal sensor above the flat portion of the roast chamber, any estimate on how many degrees that mod buys us if we move it just above the flat portion? Great tip BTW it’s nice to get a roast where you want it without a chamber cool-down period added in.
    Ordered my new V2 motor this evening, can’t wait to get back to roasting! I’ve kind of gotten used to my style of coffee.
    Thanks again for this helpful info.
    Best, Gary

  2. The enhancements mentioned: is this the same motor that will be in your newer version that will support darker roasts?

    1. The main issue for darker roast is the thermal sensor placement, which I go into in the video. But yes the new motor will be more durable due to higher density carbon brushes mainly. Wish we could use a brushless motors but they are nearly the cost of the Popper!

  3. I noticed what appears to be black carbon brush residue expelled from the motor.
    Some of this probably gets on beans while roasting.
    Do you know if the brushes are a non-toxic formulation?
    In my experience as an electrical engineer, brush formulations can include lead for conductive/lubricating properties.

    1. Hi Roger – I can look into this more but my understanding was the motor carbons are just that, being a small simple motor and not a highly specialized type. The “domestic” carbons are rated at lower density which is why the new motors have more durable carbons (off the top of my head the specification is 24p). I do have pretty full motor spec that is part of UL certification process and will check tomorrow on that

  4. Not sure if I didn’t fully press down on the the blower fan but after having reassemled the Popper, plugging it in and powering up, it sounded great; seemed to work fine again EXCEPT for the fact that an initial 85g roast cooked up (smoked and burned) in less than three minutes, way too fast even while using a medium heat setting. I’d noticed there was very little movement of the beans even though I did feel air coming out and the replacement motor sounded like it was operating at full RPM. Not so long story made even shorter, a quick disassembly and a more firmly planted blower fan on the motor’s shaft ended up solving that issue. Had been a little too gentle I’m thinking. Regardless, that replacement motor does appear to have given my Popper a 2nd life. Thanks for having supplied the motor as well as all the helpful replacement steps and procedures in both text and video. I’m enjoying a cup o” joe as I write this thanks to Tom and all at Sweet Maria’s, stimulated in a tasty way.

    Me so happy.

    1. Glad it ended well and you figured it out! Do you think my instructions need to be clearer on pushing down the fan firmly and evenly onto the motor shaft? It’s a drag to have to take it apart again but glad you found the issue. My experience has been that it roasts a bit more with the new motor, maybe +10 grams … but cant say for sure that is always the case.

  5. I followed the video instructions and my popper was brought back to life. Thanks -the steps were easy to follow and took no time at all.

    1. That’s great. Thanks for the report … you may notice that the fan has a little more power. To keep the same roast level settings you are used to you might need to offset that by adding a little more coffee to the batch. For me I found that, if I was roasting 95 grams before, with the new motor I could get same roast level at same heat setting by adding 10 grams, so 105 grams.

  6. I did it!! Finally had an open afternoon to play “grownup Legos”. Had a great time, the instructions were very easy to follow, and apart from a bit of fear around busting the connectors when detaching the wires, everything went smooth. Runs like new again! I’m so glad I held onto it for the last year as if expecting y’all to come out with a spare motor. Back to roasting!

    1. Great – glad to hear it worked – the motor is improved and should perform better and last…

  7. I just swapped out the motor and it’s not roasting at all for me! It just spins the coffee and the coffee just burns. What could be the problem and what did I do wrong? I know that around 7 or 6 minutes on the countdown timer my coffee should be roasting. Did I connect something wrong or did I cross some wires.

    1. Oh no – thats not good. I’m trying to understand this – Lets assume you put in the same batch size as you used to … does the fan start to spin the full amount of coffee around the roast chamber in the first 15 seconds or so? One guess is that the fan blade isn’t fully pushed on to the new fan motor shaft. I did a swap and this happened to me – it didnt really spin the coffee, and I found when I pushed the fan evenly and firmly downward onto the new motor shaft, it worked great. In fact we have consistently found it has more air flow than before, so often you need to add an addition a 10-15 grams of coffee than the batches with the original motor. Perhaps it is possible to cross the wires from the fan motor to the control board, and perhaps that would have the fan motor spinning backwards. but I would have to check if that is even possible. In the video I tried to make it clear where they red and black wires go when you install the new motor.

  8. Long ago we made popcorn on the Poppery II. Then people started buying smelly popcorn that you put in the microwave right in the bag. When I took up self-roasting coffee, I tried the old P-II. It smelled a little un-coffee-ish at first but has It worked great ever since. Whenever we saw one at a garage sale, we would buy it for $5 give or take. We had three of them. Haven’t seen one lately. Sweet Maria has sold me every self-roast coffee bean I have ever tasted. I love the Central American coffees. A year or two ago the first P-II stopped being hot, so I tossed it and pulled another one out of the closet. The new one–very lightly used when I got it–runs cooler than it’s predecessor, so it takes 10 minutes instead of 3. Now I only drink it cold. I make it at night so it’s cool by morning. Drinking other coffees is a hardship, as when traveling, but I tough it out.

  9. Hi, I followed your excellent video – watching and re-watching various sections as I followed along step by step.
    Got my Popper reassembled, feeling kinda proud of myself, plugged it in, sounded good, finished bolting it all back together,
    did a roast – and no roast chamber movement at all. Took it apart, repositioned things a tad, put it back together, same.
    Can this only be the fan not pressed down on the motor shaft sufficiently, or is there some other possibility?
    I know the red and black fan motor to control board wires are correctly placed, but I wasn’t so clear about the
    set of wires that connect to that ring around the roast chamber – does it matter which goes where? Could not
    clearly see in the video – so that’s one thing that could be clarified. Or is it possible to too tightly tighten that ring?
    I’m getting close to having to go buy some roasted coffee, a fate I hope to avert – I am a devotee! Love what you are doing!

  10. P.S. Just took the Popper apart again. The fan blade was sitting nicely on the motor shaft, and it spins just fine.
    Having taken it apart again and seen how bolted-down everything is, what makes the coffee spin? I see no parts
    that could rotate anywhere above the shaft. Does the fan blade spin around underneath all the bolted-down parts?
    Looking forward to getting this working.

    1. Hi Eliana – sorry to hear this. So the fan spins freely, and when you power on the Popper after reassembly you hear it spinning? Do you feel air flow coming from the popper? Tomorrow I could make a small video to address this specifically for your question / issue. I am just not clear what you mean by “bolted down part”. It’s a rotary fan set on the motor shaft that pushes air upward past the heating elements and into the slotted vents of the roast chamber. I could also try to send a diagram of sorts.

  11. I came by the shop today to get some coffee and find out when the new improved Poppers will be arriving…since my old one gave up the ghost after 2 years of faithful service. The fan just stopped working, but I was worried some other component might faiukled as well. I was told the new model hadn’t arrived yet, but you had replacement motors for only $5 and thought why not see if that would bring her back to life… so I bought one and decided to install it when I got home. Thanks to your excellent instructional video the motor exchange was a snap. The hardest part was getting the plastic fan off the splined motor shaft. I was worried it would break, so I took it slow and it eventually came off. I determined from the carbon soot in the fan chamber that the old motor failed because the brushes burned out…

    Replaced the old motor, buttoned everything back up and plugged it in. Everything seemed to work so I went ahead and roasted a 90g batch of Mokha Matari.

    Observations: The motor is a bit louder. It sounds stronger, and it definitely swirls the beans more vigorously. I don’t imagine that the motor exchange did anything to make the heating element hotter, but I was able to reach first crack using low speed a lot quicker than before using either high or low speed. I guess that was made possible by a more powerful fan.

    1. Hi Nick – glad to hear the motor swap went well. Yes that fan can be stubborn! it’s a splined shaft and can resist a lot, and the fan kinda flexes making it harder.

      Your post-motor-swap results seem right on – it’s a little more RPM and you might compensate by using “low” fan speed, or by increasing the green coffee batch by perhaps 10 grams or so. Yemen is a bit hard as a test roast coffee since it’s harder to judge, and has a lot of chaff. But sounds like you figured it out.

      If you feel the fan is vibrating or notice it get worse, it’s possible it might need to be pushed a little more onto the shaft, with a little more force. I just want to mention it because I did a swap where I noticed some sound and vibration a little more than usual, so I checked and the fan was about 80% on the shaft. I used some more pressure and it solved this…

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