my 3d Print ate some 4.1 components

steveholder

steveholder

Member
Ok, so in my excitement I printed of a nice simple Teensy 4.1 enclosure, jammed the thing in and it was all working fine. After an a while I realized I would need to get the sd card out which my print didn't allow for, so I printed another enclose, bigger etc. Pulled out the Teensy, popped it into the enclosure, much nicer fit access to sd card, powered it up and got the double red flash.

Out came my iPhone, took a macro photo and saw I'd knocked off a number of parts, L3, C21, C28, C29, and C32, I also dislodged C7 but is still present, all others are lost to the carpet.

I think I have the values for all of these as follows, but not the voltage, can you correct or confirm for me please?

L3: Ferrite 120 ohm?
C21: 0.22 uF 3.5v? Package size?
C28: 2.2 uF 3.5v? Package size?
C29: 2.2 uF 3.5v? Package size?
C32: 10 uF 3.5v? Package size?

I have another 4.1 on the way but feel like the opportunity to practice some smd work and repairing an otherwise brand new 4.1 is worth the pursuit.
 

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You can get it working again by just using a wire to replace L3. The purpose of L3 is to keep the DC-DC switching noise from the CPU power from feeding back onto the 3.3V power line. Without it might have more high frequency noise on 3.3V, which probably isn't a major problem unless you've got a pretty sensitive application.

The bigger capacitors are 603 size and the little one is 402. Use 6.3V or 10V rated parts if you can. Buy X7R or X5R type ceramic. Don't use low quality Y5V or Z5U.
 
If there were T_4.1's that didn't pass QC - they'd be a good source of fresh parts. The bootloader and MCU could be pulled maybe and added to an order?
 
PaulStoffregen said:
You can get it working again by just using a wire to replace L3. The purpose of L3 is to keep the DC-DC switching noise from the CPU power from feeding back onto the 3.3V power line. Without it might have more high frequency noise on 3.3V, which probably isn't a major problem unless you've got a pretty sensitive application.

The bigger capacitors are 603 size and the little one is 402. Use 6.3V or 10V rated parts if you can. Buy X7R or X5R type ceramic. Don't use low quality Y5V or Z5U.
Click to expand...
Awesome thank you for this, I seem to have pulled out the right hand trace on the ferrite, would I get away with soldering that wire to one of the adjacent resistors?
 
steveholder said:
I do like the idea of recycling devices
Click to expand...
Only seen a few posts of missing/lost components - so not a huge thing.
But indeed, if PJRC does have some few NON-QC units the passives are ideally good and the trouble of ordering even one or two components adds up to an exacting low volume order.
The unit would need to be decommissioned - pulling MCU and Bootloader ? - so some extra work for PJRC ... as if they don't have enough. Of course if there were any BOM changes across boards that could be a fail even with extra effort to ID ...
 
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