Connect with us

Help identifiying these burnt resistors

Discussion in 'Troubleshooting and Repair' started by OVERPOPULATION, May 7, 2018.

Scroll to continue with content
  1. OVERPOPULATION

    OVERPOPULATION

    2
    0
    May 7, 2018
    For a set of Logitech speakers Z906 resistors R79 and R80. Both are identical and both are fried. I ask because im unsure about the colors. I went to a local electronic components shop and the guy was unsure also. I think light is better on the pictures. Ive found ppl saying they are 5,6Ohm but found also some contradictory info.
    [​IMG]
    [​IMG]
    [​IMG]
     
    Last edited by a moderator: May 7, 2018
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,452
    2,812
    Jan 21, 2010
    Are they open circuit? If not, measure their value. It may have shifted a little but it will put you in the ballpark.

    If they are open, try measuring from one end to a part of the exposed helical resistance track. If you can't funny any of it, carefully scrape off some of the costing near the middle of the resistor. If you can get a reading from one end to the middle, you can double it as an estimate.

    You might also try taking a picture against a white background so your camera screws with the colours less. That will make it much easier for the eagle eyed amongst us.
     
  3. ramussons

    ramussons

    374
    71
    Jun 10, 2014
    It would help more if we get an idea of where these resistors were in the circuit. Can we get a photo of the PCB where these resistors were? And the corresponding Track side if possible.
     
  4. Harald Kapp

    Harald Kapp Moderator Moderator

    10,839
    2,445
    Nov 17, 2011
    According to this Polish website these resistors are 5.6 Ω / 3 W.
    5.6 Ω, 5 % would be > green | blue | gold | gold <. We can see the green band and two brown bands which could be meant to be gold. The second band, looking silver, should be blue. Can you confirm this by visual inspection? It could also be a variation of grey in which case the resistor would be 5.8 Ω. Not a crucial difference, I think.

    These seem to burn quite often, so better replace by ones with a higher power rating, e.g. 5 W.
     
  5. OVERPOPULATION

    OVERPOPULATION

    2
    0
    May 7, 2018
    Multimeter says 6.1 Ohm so with a 1.2% error margin in the specification and the difficulty to measure those short cables, i suppose someones guess i heard is should be right at 5.8 Ohm 5% non standard value. But if thats true, and considering ive already tried a bit to find that without success. Should i try a 6.2 Ohm and if it does not work go for a 5.6 Ohm which is what people were suggesting.
    Ive also though that i could get a cheap amp or receiver, dismantle the subwoofer removing all the pcbs and look for the actual subwoofer inner pair of cables then connect a longer pair and route those to the back of the subwoofer so i can use all the speakers of the set in a non propietary amplifier or receiver. Because thats basically the issue, that as a set of pc speakers you cannot simple connect them to a standard receiver. Im already looking at the specs of the speakers to be sure they match a standard receiver.
     
  6. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,452
    2,812
    Jan 21, 2010
    Resistors often shift in value when they get very hot, so a small difference is to be expected. It's also not unusual to have anything to to half an ohm in lead and contact resistance.

    I would get a couple of 5.6Ω 5W resistors as replacements (as per Harald's suggestion).

    When you mount them, leave them standing off the board by a couple of mm to both protect the boat from heat and to provide a little more airflow for cooling.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-