Blown fuse in a 5d

In most cases, when a camera is not working after turned on, there is a blown fuse on the DC board. You change it (Canon uses – as I know – oly two types of fuses, the K and the P), You turn it on , and that’s it.

This time I measured the fuse in the 5d – interrupted. I changed it. No sign of life. I measured, interrupted. I changed it again – nothing.
After the third change and assembling I realized, that the fuse made exactly, what he is pretended to do: protects the camera in case of a shortcircuit.The DC-board had a resistance of 2 ohms between the plus and the GND…..

So, next time before the fuse change – I have to measure the board.

If I don’t forget to read my own blog.

About canonrepair

Ruzsa János. Amatőr fotós, Canon DSLR váz. Amateur photographer. Canon DSLR user.
This entry was posted in 5d, Canon camera, General topics. Bookmark the permalink.

25 Responses to Blown fuse in a 5d

  1. Zakaria says:

    Hello Can you tell me the full specs of smd p fuse ? I am not good at this but i can solder and mess a little bit with it around but my wisdom of gettings specs of thease items is very bad ….
    So i found out it is a
    SMD fuse of size 0603 with 3 amps … but what voltage ?

    Could you send me an ebay link with the exact example of it ?

  2. Andrew says:

    Interesting! I now try to repair my Sony and got shorts on pretty much ALL power rails. Just 0.4 ohms. Can you share from your experience, what’s rather considered “normal” resistance in power lines of an “average” camera?

  3. kkuboa says:

    Dear sir, I have problem with my canon camera. It is old Canon 5D classic. Once I was trying to update firmware, thats why I saved to my CF card file for update. When I took CF card into my camera and try to power up, it doesn´t do anything. It was daed. I didnt do update. If Im trying to push microswitches on CF doors or on battery doors, nothing happens. Can it be the fuse, that you are describing in text above? I have another LPU PCB. Can it work again, If I will try to change whole PCB? Thank you. Bye.
    P.S. Do you think, that I can use this CF card that was inserted in when it happened?

    • canonrepair says:


      the most probably is, that You damaged the CF pins with the CF card. Check them! They can make a short.
      In the 5d you have some fuses on the Dc DC board. Check them too.

  4. Simon says:


    I’ve got a dead 5d mark II. Trying to figure out which of the 3 boards to order.
    It’s completely dead, no lights, nothing.

    Continuity checked all fuses on the dc-dc board and they seem ok.
    Are there any more fuses on bottom or main bord too? Have only taken apart the dc-dc board so far.

    Any tips on how to troubleshooting would be very appreciated.. Don’t want to order all three boards if only one of them is broken.

    • canonrepair says:

      i didn’t have to check fuses yet. i can do it for you, in a few days.

    • canonrepair says:

      another option is, if you send me the camera, as i have a full broken camera as sparepart, and a working one, which i have to repair anyway.

      • sharplinger says:

        Thank you for your answer.

        I’ve checked most cables, can do it again but I don’t think that’s the problem.
        Also I noticed that the small button with the blue lamp gives a very very very faint light for half a second when pulling out the battery (not putting in), so it’s not completely dead.

        I was thinking about that, buying another camera to test with and then sell it. Then it would be very easy.. as long as I don’t break that one too =)

        I’m interested in learning this, don’t learn that much if sending it away =)

    • canonrepair says:

      and chechk the flex cables – only one failing bit can make no life on the camera

  5. Juan says:

    Hi. tks for the info. Can you clear my doubt on the K fuses and P canon? What value amp have? i found Smd “K” fuses with very diferents values… same with fuse P. 😦

  6. vic says:

    Mda posibil ca placa de alimentare (dc-dc board) a lui lucian sa fii ajuns la mine, caci am cumparat inca una in speranta ca nu are decat siguranta arsa.

    Ideeea e ca daca faci scurt nasol pe montura intre 5v logic si gnd de alimentare sau ceva de genu asta se arde siguranga si apoi chiar daca o schimbi e ceva pe placa care consuma multicel si se incinge. Am doua placi cu aceasta problema :(.

  7. Lucian Mihai says:

    Salut, am uitat sa ai verific blogul pentru ca m-am lasat pagubas.
    Astazi am cumparat un 5D cu shutterul distrus. Am inlocuit initial placa de alimentare cu siguranta F103, dar tot nu pornea aparatul. Asa ca am inlocuit placa de alimentare de sub status display si a functionat.
    Acum am nevoie de un shutter si aceasta placa si voi avea doua 5D :)) primul lucru pe care l-am facut apoi a fost sa scot cipul de confirmare focus de pe adaptor.

    Multumesc mult pentru sfaturi si sper sa nu mai fie nevoie niciodata sa umblu in el.

  8. Lucian Mihai says:

    Pana astazi am crezut ca power board-ul e cel de sub displayul superior, unde se afla o singura siguranta K si contactele cu acumulatorul.
    Cautant pe ebay aceasta piesa mi-am dat seama ca e de fapt placa de langa contactele pentru USB/flash etc. Asa ca am masurat toate cele 4 ( ? ) sigurante (p, p, h, p) daca nu ma insel si toate sunt bune. Pana acum singura siguranta arsa e K, de sub displayul superior.
    Am mai citit despre un caz in care un traseu de pe un flatcable a ars in urma unui scurt circuit, dar deocamdata nu am gasit nimic.

    Am recurs la acel tip de siguranta deoarece am cumparat aparatul acum 2-3 saptamani si fix a2-a zi s-a stricat. Nu a fost tocmai un moment fericit avand in vedere ca mi-am vandut motocicleta pentru a avea bani sa il cumpar. Vanzatorul nu a mai raspuns la telefon dupa ce mi-a promis ca imi va inapoia banii. Asa ca am incercat o reparatie ieftina care daca nu reusea il expediat in service-ul autorizat din Bucuresti.

    Pana atunci am avut un 50D care a functionat superb cu acel adaptor si daca se intampla sa fie pozitionat gresit cipul aparea o eroare care disparea imediat dupa restart.

    Intr-un fel am fost inspirat si i-am cumparat prietenei mele un 40D, asa ca pot lucra in continuare.

    Insa 5D-ul a fost dorinta mea, eram disperat dupa un full frame. Am riscat avand in vedere varsta acestuia, cu toate ca din exterior pare a fi un body foarte intretinut si ingrijit.

    I hope that you understant what i wrote. I used romanian language so I can explain better my problem.

    I still hope that I will repair my 5D until you visit Iasi. Anyway, if I don’t, I hope that you can take a look.

    Thanks a lot and if you have some ideas, please tell me what can I do next.

    • canonrepair says:

      Avand in vedere, ca am terminat TCM-ul de la Cluj, da, am inteles ce ai scris :))
      5d-ul e un aparat foarte bun, am avut-o si eu (acum am un 5d MkII), dar e cam sensibil. din punct de vedere electronic. sunt o grmada pe piata, asa ca ai sanse sa gasesti piese folosite. cat de bine te descurci cu voltmetrul?

  9. canonrepair says:

    Lucian, do You really think, that a 5mm big glassfuse will have the same melting speed (and for this reason, characteristic) as a small 603 size SMD fuse?!? I am really sad when some people (like the guy from where You have got the ideea make some crazy things, and then the publish it, and after then a lot of others follow it.
    You should change the fuse with an exactly same type of fuse – and even than is not sure, that You will get the sam protection level. Now You probably have a blown DC board. If You have lot of time, You could search which part (probably a FET) has been damaged – or You can order a new board for the camera.
    Next time search for smd fuses on Not cheap, but they have a lot of thinkgs on stock.
    But be carefull, I dont know them, so I dont know, if they send really a good part. Or try for new part.

    şi data viitoare să nu mai foloseşti adaptoare necorespunzătoare 🙂

    Salut, János

    Independent de asta, putem să ne intalnim la Iasi, daca merg pe acolo.

  10. Lucian Mihai says:

    Hey, I changed the fuse on my 5D mk I with another type of fuse, it worked for two weeks and now is’t working again. I finded that the fuse was blowed (again), I installed a new one but now the camera don’t power up. The condensers are draining some electricity in them, just that.

    I don;t know what to do. Please give me an advice.

    • canonrepair says:

      check the security switches (battery door, cf-door, SW under the battery (if there is a switch in the battery compartment)), check the flex cables between the boards, check the on/off switch itself. try an another battery or check the voltage, check the voltage on the inner end of the battery contacts when battery is inserted.
      take off (desolder) the shielding of the DC board and other boards, search for some small metallic parts which could cause a short on the board (soldering alloy etc)
      in 1 month I will be probably in your city (Iasi) for 2 days, we can arrange a short meeting there

      • Lucian Mihai says:

        That would be very nice!
        I checked every switch, I tried 6 batteries, but I’m afraid to desolder the powerboard.
        Now I have a big glass fuse ( ). It was blowed up and after replace it is stil good beside the canon don’t power up.
        There is voltage in the battery connectors with the power board.
        All this probles because I use a m42 adaptor with AF confirmation cip…I glued that cip on the adaptor a little bit nasty. Both time the fuse blowed up when I changed this adaptor in a hurry.
        Where do I look to verify if there is a short circuit between EOS mount and the + circuit?

        Thanks for replay!

  11. sibi says:

    Hii.. i got a 550d. few weeks efore it stopped working. it is not even booting up. i opened the camera and when i disconnected the back panel which contains lcd in camera, the camera starts working. then i connected the backside again to main board and it again stopped working. then after few tries, camera stopped working completely even thowi i ddnt connect the back side… got any ideas to rescue my dslr?

    • canonrepair says:

      unfortunatelly the 550d has no fuses, as I remember. In this case if You haeve a short in the camera anywhere, the DC-DC board can be damaged easily. You should check the DC-DC board, this is possible only after taking it out of the body. sometimes its enough to get a few waterdrops on it, and will have critical corrosion. search on the cables, connectors – use a microscope or magnifier.

  12. vic says:

    Nice blog.
    Last winter i’ve tried to make a macro tube extension with contacts useing an old film camera mount( ef) and a lens baionet and some tube. The problem is that the wires made some short circuit and now the camera is dead. I have change de fuse from the top power board but the camera is still dead. When i put the battery in its draining some current for a very short period of time and then nothing. The fuse from the onther dc-dc board are ok too… any ideeas? tnx? it is a 5d mk1k

    • canonrepair says:

      hard to say anything. The problem is, that it’s enough to put back a flex cable in a wrong way, and will not start. (Once I made this failer – I worked 1 day after that, to find out, that the cable should be invertd….

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