element14 Community
element14 Community
    Register Log In
  • Site
  • Search
  • Log In Register
  • About Us
  • Community Hub
    Community Hub
    • What's New on element14
    • Feedback and Support
    • Benefits of Membership
    • Personal Blogs
    • Members Area
    • Achievement Levels
  • Learn
    Learn
    • Ask an Expert
    • eBooks
    • element14 presents
    • Learning Center
    • Tech Spotlight
    • STEM Academy
    • Webinars, Training and Events
    • Learning Groups
  • Technologies
    Technologies
    • 3D Printing
    • FPGA
    • Industrial Automation
    • Internet of Things
    • Power & Energy
    • Sensors
    • Technology Groups
  • Challenges & Projects
    Challenges & Projects
    • Design Challenges
    • element14 presents Projects
    • Project14
    • Arduino Projects
    • Raspberry Pi Projects
    • Project Groups
  • Products
    Products
    • Arduino
    • Avnet Boards Community
    • Dev Tools
    • Manufacturers
    • Multicomp Pro
    • Product Groups
    • Raspberry Pi
    • RoadTests & Reviews
  • Store
    Store
    • Visit Your Store
    • Choose another store...
      • Europe
      •  Austria (German)
      •  Belgium (Dutch, French)
      •  Bulgaria (Bulgarian)
      •  Czech Republic (Czech)
      •  Denmark (Danish)
      •  Estonia (Estonian)
      •  Finland (Finnish)
      •  France (French)
      •  Germany (German)
      •  Hungary (Hungarian)
      •  Ireland
      •  Israel
      •  Italy (Italian)
      •  Latvia (Latvian)
      •  
      •  Lithuania (Lithuanian)
      •  Netherlands (Dutch)
      •  Norway (Norwegian)
      •  Poland (Polish)
      •  Portugal (Portuguese)
      •  Romania (Romanian)
      •  Russia (Russian)
      •  Slovakia (Slovak)
      •  Slovenia (Slovenian)
      •  Spain (Spanish)
      •  Sweden (Swedish)
      •  Switzerland(German, French)
      •  Turkey (Turkish)
      •  United Kingdom
      • Asia Pacific
      •  Australia
      •  China
      •  Hong Kong
      •  India
      •  Korea (Korean)
      •  Malaysia
      •  New Zealand
      •  Philippines
      •  Singapore
      •  Taiwan
      •  Thailand (Thai)
      • Americas
      •  Brazil (Portuguese)
      •  Canada
      •  Mexico (Spanish)
      •  United States
      Can't find the country/region you're looking for? Visit our export site or find a local distributor.
  • Translate
  • Profile
  • Settings
Raspberry Pi
  • Products
  • More
Raspberry Pi
Raspberry Pi Forum There is a broken chip on my Rpi3 motherboard labeled: 4R7. I just bought it and it broke while trying to install it inside the case. Will the board still work with that chip broken? Can I cover it with epoxy?
  • Blog
  • Forum
  • Documents
  • Quiz
  • Events
  • Polls
  • Files
  • Members
  • Mentions
  • Sub-Groups
  • Tags
  • More
  • Cancel
  • New
Join Raspberry Pi to participate - click to join for free!
Featured Articles
Announcing Pi
Technical Specifications
Raspberry Pi FAQs
Win a Pi
Raspberry Pi Wishlist
Actions
  • Share
  • More
  • Cancel
Forum Thread Details
  • State Suggested Answer
  • Replies 15 replies
  • Answers 12 answers
  • Subscribers 665 subscribers
  • Views 11023 views
  • Users 0 members are here
  • broken chip
Related

There is a broken chip on my Rpi3 motherboard labeled: 4R7. I just bought it and it broke while trying to install it inside the case. Will the board still work with that chip broken? Can I cover it with epoxy?

unsagicois
unsagicois over 8 years ago

There is a broken chip on my Rpi3 labeled: "4R7". I just bought it and it broke while while trying to install inside the case.

Will that chip: "4R7 being cracked will prevent the Rpi3 from working properly? Can I simply coat the chip with epoxy?

This is my first experience with Raspberry. I never heard of it before until I saw an advertisement for Cayenne in Facebook last month.

image

  • Sign in to reply
  • Cancel
  • shabaz
    0 shabaz over 8 years ago

    Unfortunately it depends on precisely what is cracked or broken. If the pads are ripped off, or the wire inside is damaged then it won't work by securing with epoxy, it would need some soldering work and part replacement.

     

    However, if there is just a crack in the grey colored portion then it might work if the wire inside that part isn't damaged and the pads have not ripped off the board. But, there is no guarantee that it will work (and there might be some inefficiency in the power circuit introduced too). It is worth a try to just power it up if you have no way of replacing that part (it won't be a straightforward repair unless you've got some surface-mount soldering experience and the right tools, which will cost more than the Pi itself).

     

    If it works then yes you could apply a tiny dab of epoxy, it won't damage it any further.

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Verify Answer
    • Reject Answer
    • Cancel
  • rsc
    0 rsc over 8 years ago

    Does the PCB label read L1 or L2 next to the broken part? See lower left on image.

    Those parts are part of the power supply regulator circuit, and could cause problems with all the ICs if damaged.

    Take a picture of the damaged part and post it so we can see what's happening.

    image

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Verify Answer
    • Reject Answer
    • Cancel
  • COMPACT
    0 COMPACT over 8 years ago

    Epoxy is not conductive so just get someone with the right equipment to replace it to ensure it'll work properly.

    The price of the 4k7 is very cheap - can be low as fractions of cents.

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Verify Answer
    • Reject Answer
    • Cancel
  • rew
    0 rew over 8 years ago in reply to COMPACT

    Dear Compact,

    You are thinking of a resistor. The resistors on the raspberry pi are mostly so small that they do not have a marking. There are however two inductors prominently marked "4R7".  Resistors cost factions of a cent, the cheapest inductors that I can find are about 10 cents.


    Most before me haven't mentioned it, but the cracked component is not a chip, not a resistor but an inductor.

     

    The two inductors are involved in the power circuit. They make, I believe, 3.3V and 1.8V from the 5V input. Because they step the voltage down, I can predict how they are wired. If the inductor is broken, one of those power rails will simply remain at 0V. This COULD damage one of the chips on your raspberry, but it is unlikely.

     

    The inductor consists of a wire wrapped around a core. If that core is cracked, the inductor will not work as well as it should. On the other hand, it is usually not all that critical in the power circuit, so if things change a bit due to the crack there is a possibility that things still work. The continuity of the wire is essential though. So... if you power up your pi, and it works, then that continuity is ensured. In that case encasing it with epoxy might work. On the other hand, if it fails after you epoxy it, it will be impossible to fix.

     

    Replacing an SMD component is easy enough if you have the right tools. But having those tools and knowing how to use them is not trivial.

    • Cancel
    • Vote Up +1 Vote Down
    • Sign in to reply
    • Verify Answer
    • Reject Answer
    • Cancel
  • COMPACT
    0 COMPACT over 8 years ago in reply to rew

    Michel,

     

    Sorry, my mistake. It is actually shorthand for an Bourns SRN4018-4K7M 4.7uH (microhenry) inductor (or equivalent) and has a huge price tag of 13 US cents.

    So I'd replace it if it is cracked through the centre.

    No real worries if it's just a little bit of a corner.

    You can test the inductor to see if its coil is intact. When measured with a multimeter it'd read 0 ohms if ok (with the Pi turned off!).

     

    When the ferrite is in operation it is under mechanical stress from the constant charging and discharging.

    Epoxy is used to reduce buzzing from inductors but the epoxy is of a type not to affect its heat dissipation.

     

    If you play your cards right with an inductor manufacturer you may be able get one as a sample - Zero Cents!

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Verify Answer
    • Reject Answer
    • Cancel
  • rew
    0 rew over 8 years ago in reply to COMPACT

    IMHO the cost of the component is irrelevant.

     

    Before Michel is able to replace the inductor the costs are many, many times more than just the 13 cents for the inductor.

     

    * Buy, or arrange to borrow the right desoldering equipment.

    * find time to desolder the component.

    * manage to solder on the new one without damage to the surrounding components.

     

    Factor in the chances of ruining the pi for good (IMHO about 50/50), the costs are WAY more than the 13 cents for the inductor. So his idea of epoxying the component in place sounds like the better bet. Just first test if the pi still works. Then you can be confident that it is electrically OK. Then apply the epoxy. (Because Michel comes with the suggestion of epoxy, I'm assuming that's easy for him because he has all the stuff to do that.)

     

    If the pi no longer works, it's a dead board. You can do anything with it, even: try to repair it. However, the replacing the inductor on a pi is not the easiest of "first projects" to try and learn such a task....

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Verify Answer
    • Reject Answer
    • Cancel
  • COMPACT
    0 COMPACT over 8 years ago in reply to rew

    Very Compact wrote previously:

     

     

    Epoxy is not conductive so just get someone with the right equipment to replace it to ensure it'll work properly.

     

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Verify Answer
    • Reject Answer
    • Cancel
  • unsagicois
    0 unsagicois over 8 years ago in reply to COMPACT

    I had to get some sunshine to get a good pic. It is the L2 - 4R7. The ohm meter reads 10 ohms, unless I'm reading it wrong, but it is not zero anyway. It does not look like the wires are broken or the contacts loose. I will not apply any power to this until I am sure there will be no further damage to the circuits. I have soldering equipment but I am not very proficient at soldering, but I have a friend how is more experienced at it than I am. Otherwise, I doubt I will find a replacement since I am stranded here in the boondocks of Asia, namely a province in the Philippines (pun intended). I thought it was a heat sink of some kind, so I have to ask to make sure if epoxy was safe to use. I really, really need this to work. It is my only chance. Thanks.

     

     

    image

     

    image

     

    Sent from my iPad

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Verify Answer
    • Cancel
  • unsagicois
    0 unsagicois over 8 years ago in reply to COMPACT

    imageimage

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Verify Answer
    • Cancel
  • shabaz
    0 shabaz over 8 years ago in reply to unsagicois

    Hi Michel,

     

    I will not apply any power to this until I am sure there will be no further damage to the circuits. I have soldering equipment but I am not very proficient at soldering, but I have a friend how is more experienced at it than I am

     

    If you're not confident at replacing this (it won't be easy without experience) and you cannot find someone with enough experience to replace the part (assuming you can get the part at a price you're willing to pay - most suppliers will expect a minimum order and/or postage costs) then you have not much further to lose if you apply power. Find a person to replace it and that is your best bet.

     

    Having said that, (and of course, I take no responsibility for it not functioning and getting damaged further if you apply power to it), if you've confirmed the wire isn't broken then in this situation, typically there is little harm in applying power. It is not a heat sink, but it will affect the power supply performance, but nothing to the extent of it not functioning; most likely it will run fine.

    • Cancel
    • Vote Up 0 Vote Down
    • Sign in to reply
    • Verify Answer
    • Reject Answer
    • Cancel
>
element14 Community

element14 is the first online community specifically for engineers. Connect with your peers and get expert answers to your questions.

  • Members
  • Learn
  • Technologies
  • Challenges & Projects
  • Products
  • Store
  • About Us
  • Feedback & Support
  • FAQs
  • Terms of Use
  • Privacy Policy
  • Legal and Copyright Notices
  • Sitemap
  • Cookies

An Avnet Company © 2025 Premier Farnell Limited. All Rights Reserved.

Premier Farnell Ltd, registered in England and Wales (no 00876412), registered office: Farnell House, Forge Lane, Leeds LS12 2NE.

ICP 备案号 10220084.

Follow element14

  • X
  • Facebook
  • linkedin
  • YouTube