Repair Parts for ET312B

While you may never have a problem with your ErosTek ET312B, after a many years of use, some things may wear out. Like the output level pots. Or the battery. If it’s within warranty, let us know. Here’s a list of the most common repair parts and their sources:

Rechargeable Battery Module
Part: RP300 available from ErosTek
– Includes mounting bracket and instructions.

Output Potentiometers (Level A and B)
Part: RP302 available from ErosTek
– Replace if output levels become erratic or unreliable.

Battery Charging IC (U13#)
Part: LM2941CT available from DigiKey
– Replace whenever battery fails to charge.
– Connecting the wrong AC adapter is a normal cause of failure of this IC.
– Observe ESD precautions for handling static-sensitive components.

Output Transistors (Q3, Q4)
Part: IRF9Z24N available from DigiKey
– Replace both to resolve “Failure 20” errors.
– Observe ESD precautions for handling static-sensitive components.

Tact Switches (Up / Down / Menu / OK switches)
Part: TL1100CF160Q available from DigiKey
– These switches are rated for 100,000 presses but not if liquids get inside 🙂
– Replace as needed

For the more parts, visit our Spare Parts section.

13 responses to Repair Parts for ET312B

  1. Spirit

    I bought my unit in 2006 and had years of frequent use, apart from a battery replacement have had continuous use with out any malfunctions. The only thing that gives a great deal of trouble are the leads, and am continuously repairing them, finding a flexible lead that through bending that will not break is almost impossible.
    But all told I love the machine and would go into panic if it stopped working.
    My Question from 2006 have you changed the program initially installed, and is it possible if you have to upgrade mine.
    Thanking for a great product that is worth every penny.
    Gill./ Spirit

    • erostek

      I’m glad you love your ET312B! There are some (including one I use) that is over 10 years old. That’s pretty good value, I think 🙂

      The factory routines are the same as the version 1.2 up to the current version 1.6. The differences lie in the slight changes to components we’ve had to use to keep the units in production over time. Older units are usually “up to date” with version 1.3 and the latest versions are 1.6. There is no upgrade path since the ET312B operates more like hardware than computer software applications we’re used to having to upgrade every few months or so. I hope this helps! Thanks for the comment. –Eric

  2. Robert White

    My ET312b is no longer charging. Otherwise it seems to be working fine. I replaced the AC Adapter. I have ordered the battery charging IC from DigiKey. However, looking inside at the circuit board does not look like a DIY project for me, Is this part difficult to replace? I do not want to damage the unit.

    I was wondering if you recommend a repair facility? Can I take it to someplace local in the Baltimore, Maryland area..

    • erostek

      Hello Bob – I’m not sure who could do the repair for you in Baltimore. I would imagine any place that repairs VCRs and the like would be a good first place to look. You will need some equipment and skill in desoldering the part before you can replace it. It’s not a difficult repair, but does require some expertise to prevent overheating and lifting of the PC board traces. If you find a reputable repair person in Baltimore, let me know and I’ll list it here. Thanks! –Eric

  3. Russell Harmon

    The link to the battery charging IC returns multiple results on the Digikey site. Which is the correct one?

  4. Drew

    Hello. I need to replace the charging IC but Digikey lists five different parts. Are they all interchangeable or is there a specific one I should use?

  5. Harold N.

    Hello my battery too low indicator was on my et312 , I replaced the battery and the charging ic and they are still on. Any ideas? You should have a repair program for older et312s and if you cant fix them for say 200 – 250, a customer loyalty discount on a new unit could be applied. Thank you

    • Post Author

      Hello Harold: Have you replaced your AC adapter? It’s possible that it’s not outputting the correct voltage which would allow it to operate the ET312 but not charge the battery. I suggest getting a new Universal AC Adapter and see if that resolves the issue. Thanks! —Eric

  6. Denis D

    My ET-312 failed to charge after many years of service. I decided to try and repair it. I ordered the replacement part from DigiKey and soldered the replacement part. I’m no expert but did the best I could. The unit has a dead battery. I plugged it in. It turns on. ErosTek self test appears, then press any key. Charge % does not show. The programs work. Should I buy a new battery? Is the unit safe to use? I don’t want a battery to explode or electrocute myself. Thanks for any info.

    • Post Author

      Replacing the battery module will likely restore your ET312B back to normal. If the charging IC failed awhile ago, the battery is most likely beyond recovery (aka “dead”). You can verify this by testing the voltage (VDC) across the battery tabs. If it’s less than 11.5 VDC or so, it’s ready for the recycling center. You can get a new Replacement Battery Module for ET312B online from us. Thanks! -Eric

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