Philips Norelco QT4085 beard trimmer disassembly and battery replacement

My trusty (yet old) beard trimmer has needed to be plugged in to use for a long while now, but the batteries finally degraded so much (I suspect they were a direct short) that even plugging it into its charger failed to make it work. So, I took it apart and replaced the batteries. (They needed it, I believe they were from 2001.)

This video distills what I learned (the hard way) about the proper order of operations for disassembling this model to get to the battery to replace it.

7 thoughts on “Philips Norelco QT4085 beard trimmer disassembly and battery replacement

    • I found them on Amazon (from a 3rd party seller), but I can’t recommend that seller because they shipped me NiMH batteries even though the listing claimed they were NiCD batteries. They work well enough to run the trimmer when plugged in, but the charging voltages levels are wrong, and the trimmer refuses to fully charge them. It’s better than the completely shorted out batteries that I replaced, which kept the trimmer from running even when plugged in.

  1. Great video, my problem is when I pulled the adjustment ring up these two little spring loaded pins fell out. Do you know where they go? Thanks

    • The pins go into the back of the razer, behind the flat plastic piece that cogs into the adjustment ring. (There are indents in the black plastic strip that the pins fit into to hold it at each of the 0-9 height adjustment levels.) The springs go in first, then the pins (with the pointy ends out) then you fit the rectangular plastic piece in.

  2. Hi, Jay!!
    I found your YouTube video showing and explaining how to replace the “NiCD” batteries in the T980. It was GREAT…Thank you!!
    Well, while I would attempt to replace the batteries in my T 980 (which are now shorted out), I feel better if I could have someone experienced””like you””doing that for me as a paid service.
    So, Jay, would you consider helping with that?
    If so, I’d pay the shipping to you and for the return, and if you could let me know what you’d charge for the service and the PROPER batteries, I’d send you the payment with the T 980 trimmer.
    I REALLY love this trimmer!! I’ve even kept the original packaging.
    Except for the failed batteries, it’s in like-new condition. I hope you can offer me your help with this.
    Please let me know whether you’d be willing to help me with this.

  3. I noticed, when I used your very helpful guide, that you actually don’t need to take out those 4 screws to get the “depth” ring off — just pull it up, and it comes off.

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