# Defective 24MHz crystal on teensy 4.1 board **URL:** \ **Category:** Teensy\ **Created:** [October 19, 2025, 12:20am UTC](https://community.sparkfun.com/t/defective-24mhz-crystal-on-teensy-4-1-board/67136 "2025-10-19T00:20:28Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![M3l](https://avatars.discourse-cdn.com/v4/letter/m/898d66/32.png) [@M3l](https://community.sparkfun.com/u/M3l)\ **Post date:** [October 19, 2025, 12:20am UTC](https://community.sparkfun.com/t/defective-24mhz-crystal-on-teensy-4-1-board/67136/1 "2025-10-19T00:20:28Z")
I recently got a teensy 4.1 from sparkfun. It works sometime, but after a while (few minutes) it stop responding and the board gives me 9 blinks. If I restart the board after that, I get 4 blinks which seem to point to “ARM JTAG & SWD Not Responding (Needs Crystal)”. Measuring the signal at C1 ([Teensy® 4.1](https://www.pjrc.com/store/teensy41.html)), I do not see the 24 MHz signal when the board is in this state (when the board is in a working state, I clearly get the 24 MHz signal). Is the Y1 crystal defective? ---
**Author:** ![TS-Russell](https://yyz1.discourse-cdn.com/sparkfun/user_avatar/community.sparkfun.com/ts-russell/32/6092_2.png) [@TS-Russell](https://community.sparkfun.com/u/TS-Russell)\ **Post date:** [October 20, 2025, 4:49pm UTC](https://community.sparkfun.com/t/defective-24mhz-crystal-on-teensy-4-1-board/67136/2 "2025-10-20T16:49:45Z")
It sounds like it; I found your order and will get a replacement sent out ASAP ---
**Author:** ![CoryDinkle](https://yyz1.discourse-cdn.com/sparkfun/user_avatar/community.sparkfun.com/corydinkle/32/12394_2.png) [@CoryDinkle](https://community.sparkfun.com/u/CoryDinkle)\ **Post date:** [April 10, 2026, 8:55pm UTC](https://community.sparkfun.com/t/defective-24mhz-crystal-on-teensy-4-1-board/67136/3 "2026-04-10T20:55:27Z")
Hello TS-Russell, I recently purchased a Teensy 4.1 from SparkFun, and am experiencing the same issue(s). Initially, the board worked, but then went into 4-red-blink mode. There was once instance when it did 9-red-blinks, but it’s been consistently 4-red-blinks otherwise. I’d be happy to send it back, if a replacement is possible. ---
**Author:** ![TS-Russell](https://yyz1.discourse-cdn.com/sparkfun/user_avatar/community.sparkfun.com/ts-russell/32/6092_2.png) [@TS-Russell](https://community.sparkfun.com/u/TS-Russell)\ **Post date:** [April 14, 2026, 4:12pm UTC](https://community.sparkfun.com/t/defective-24mhz-crystal-on-teensy-4-1-board/67136/4 "2026-04-14T16:12:18Z")
Was it purchased from us? If so head over to [Return Policy - SparkFun Electronics](http://www.sparkfun.com/returns) (contact vendor if purchased elsewhere) and we’ll get ya squared away ---
**Author:** ![CoryDinkle](https://yyz1.discourse-cdn.com/sparkfun/user_avatar/community.sparkfun.com/corydinkle/32/12394_2.png) [@CoryDinkle](https://community.sparkfun.com/u/CoryDinkle)\ **Post date:** [April 14, 2026, 7:02pm UTC](https://community.sparkfun.com/t/defective-24mhz-crystal-on-teensy-4-1-board/67136/5 "2026-04-14T19:02:53Z")
@TS-Russell yes, it was through your website. Thank you for the link, I initiated a refund. Would you be interested in having the unit back, to investigate? I have since ordered and received another, which is installed in my project and working without any hiccups! ---
**Author:** ![TS-Russell](https://yyz1.discourse-cdn.com/sparkfun/user_avatar/community.sparkfun.com/ts-russell/32/6092_2.png) [@TS-Russell](https://community.sparkfun.com/u/TS-Russell)\ **Post date:** [April 14, 2026, 9:35pm UTC](https://community.sparkfun.com/t/defective-24mhz-crystal-on-teensy-4-1-board/67136/6 "2026-04-14T21:35:08Z")
The CS rep will give any relevant instructions hereforth 🙂 ---
**Author:** ![JoshSan](https://avatars.discourse-cdn.com/v4/letter/j/2bfe46/32.png) [@JoshSan](https://community.sparkfun.com/u/JoshSan)\ **Post date:** [June 26, 2026, 1:34pm UTC](https://community.sparkfun.com/t/defective-24mhz-crystal-on-teensy-4-1-board/67136/7 "2026-06-26T13:34:51Z")
I’m seeing this too. Teensy 4.1 is part of a product we manufacture. One of the units was working and then suddenly bricked with a crystal failure - 4 flashes, no startup or response to button press. I hope Sparkfun will look into this. PJRC had incredible production quality and we need that to continue under Sparkfun - we can’t have our boards failing in the field. ---
**Author:** ![TS-Russell](https://yyz1.discourse-cdn.com/sparkfun/user_avatar/community.sparkfun.com/ts-russell/32/6092_2.png) [@TS-Russell](https://community.sparkfun.com/u/TS-Russell)\ **Post date:** [June 26, 2026, 9:59pm UTC](https://community.sparkfun.com/t/defective-24mhz-crystal-on-teensy-4-1-board/67136/8 "2026-06-26T21:59:44Z")
Sorry to hear you got unlucky…though there are always going to be some amount of defects; even the Raspberry Pi stuff which gets fully QC-verified and tested at production show 0.5-2% failures. SparkFun sells “hobby-grade” products…if any risk of failure is catastrophic for your use you might need to look at “industrial” MCUs/products We offer a [30-day no questions guarantee](http://www.sparkfun.com/returns) for situations where boards are deemed defective if that applies