Kenwood SW900 now dead

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • roadrash
    Badcaps Veteran
    • Oct 2015
    • 490
    • U.K.

    #1

    Kenwood SW900 now dead

    I started having problems turning it on some time ago and it took quite a few attempts to get it to turn on and stay on. Now its no longer turning on at all.
    I notice its discoloured around some resistors and a 2200 Cap. I replaced the cap but still wont turn on. I would be very grateful if someone could guide me to getting this working again.
    Here are some pictures
  • roadrash
    Badcaps Veteran
    • Oct 2015
    • 490
    • U.K.

    #2
    The 5 light grey resistors in the fist photo have been getting very hot and some are not testing properly so its best i replace them first. Please can someone tell me what type of resistors these are?

    Comment

    • stj
      Great Sage 齊天大聖
      • Dec 2009
      • 31086
      • Albion

      #3
      did you check that power is comming out of the transformer?
      in old linear gear the power switch can fail because of the inrush.

      Comment

      • roadrash
        Badcaps Veteran
        • Oct 2015
        • 490
        • U.K.

        #4
        Originally posted by stj
        did you check that power is comming out of the transformer?
        in old linear gear the power switch can fail because of the inrush.
        Yes i am reading 240 vac in and various voltages coming from the 5 outputs.

        Comment

        • R_J
          Badcaps Legend
          • Jun 2012
          • 9555
          • Canada

          #5
          Have you checked any of the dc voltages? like +12vdc, -12vdc, 5.5v Based on the color of the board around those resistors (which are very likely ok) I would first resolder their connections as they are likely poor. There are many small electrolytics in that low voltage section that are likely bad, C116 (10µf/50) and C118 (1µf/50) are in the reset circuit and could cause strange operation.
          Last edited by R_J; 12-11-2024, 08:59 PM.

          Comment

          • roadrash
            Badcaps Veteran
            • Oct 2015
            • 490
            • U.K.

            #6
            Originally posted by R_J
            Have you checked any of the dc voltages? like +12vdc, -12vdc, 5.5v Based on the color of the board around those resistors (which are very likely ok) I would first resolder their connections as they are likely poor. There are many small electrolytics in that low voltage section that are likely bad, C116 (10µf/50) and C118 (1µf/50) are in the reset circuit and could cause strange operation.
            Thank you very much R_J there there a couple of those caps in that area that were not giving the correct value when tested. 1st of 2 jobs done.
            Cheers.

            Comment

            Related Topics

            Collapse

            • TinkerTron
              Schematic vs. Reality: Where Are the Resistors on My Sharp Clock Radio? Model FY-70CH
              by TinkerTron
              Hey everyone,

              I'm currently working on a mid-70s Sharp Electronic Digital Clock Radio, Model FY-70CH. I found the service manual online, printed it out, and have been studying it for a while. My main reasons for tackling this are: (1) I want to learn electronics and figured I'd start with something I had on hand, and (2) I want to fix its issues. Right now, the radio sounds awful, has about 5V DC at the speaker terminals, and the alarm time setting doesn't work. But I'm not asking how to fix these problems.

              Instead, here's what's been bugging me so far:
              The schematic...
              03-06-2025, 02:03 PM
            • MyronViegas
              A1466 Dead and Not turning on. Had repaired it before
              by MyronViegas
              Hi guys, I have an A1466 (820-00165-A) board which came in dead, had corrosion on R7181 near ISL6259 chip. I removed corrosion and replace R7181 and the macbook powered on.

              After sometime I didn't get any light on the charger but fan was spinning and I was getting battery charge logo on the screen, so I replaced the ISL6259 chip and it came on! everything was working fine.

              (NOTE: Customer had previously got the battery replaced from another shop and it was third party bad quality)

              I had used my test SSD and my known good original battery.
              ...
              11-10-2023, 03:29 AM
            • double_DD
              How can I be sure that my EC chip is dead?
              by double_DD
              Hi all,

              As the title suggests, how can I be sure that my EC chip is really dead?

              I've recently gotten into this hobby of laptop repairs, and have successfully brought back to life a couple with some easy fixes, mostly shorted caps.

              Now I'm working on HP Probook 455 G8, that had some "devil" run around on 3V line, burning a bunch of stuff. Luckily I have a dead 455G7 (for spare parts) so I managed to fix it (swapped burned parts) to a point that it will charge (both on barrel jack and usb-c), but it doesn't want to turn on. There is a 3V3 on a keyboard...
              03-12-2025, 07:47 AM
            • DrDos
              Kenwood KR-6030 vintage stereo ,Old Man Trying to Save a Buck
              by DrDos
              Hello all. I'll try to keep this short. I have no knowledge of electronics. I can use a multimeter and am familiar with caps to some extent. I bought a Kenwood KR-6030 vintage stereo. It need work and so I thought I would recap the thing since I get power to the on switch but nothing else is working. No lights, no sound and so forth. I went to Mouser to order caps and I find I am way over my head. I not only do not know the type of capacitors I need but Mouser and digikey do not accept Kenwood part numbers. I have the info such as 220uF 63v and such but no place to put it. I could buy a recap...
              08-08-2025, 03:16 AM
            • disorder
              ps5 edm-033 dead after hdmi/usb ports destroyed
              by disorder
              hello guys,

              i need help to repair a edm-033 ps2
              history : as always hdmi port and usb ports destroyed after unplugged
              after change them, ps5 dead too : 1 beep, no blue light. after inspection 1.8v power was shorted, and because of dead panasonic chip. after remove it : no short anymore
              so i changed it
              now i have got 5v stby,, 3.3v stby, 3.3v power, 1.8v power and no short on them
              but the ps5 is dead again : 1 beep, near 10 seconds with power lines and then off, no blue light ...

              i don't see any projection of liquid metal on pcb.
              ...
              01-14-2025, 12:48 PM
            • Loading...
            • No more items.
            Working...