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Another KA-9100 with issue's.

Discussion in 'Kenwood-Trio/Kensonic-Accuphase' started by Kenny*G, Jul 18, 2018.

  1. Kenny*G

    Kenny*G AK Subscriber Subscriber

    Messages:
    68
    Location:
    Dickinson, Texas
    I picked up a KA-9100 several months back and just got around to tinkering with it. Power light comes on, wait 10 sec and relay clicks but I'm getting no out put. Using my tablet for a music source, tried it on the AUX input and TAPE 1 input and still nothing. Tried moving all switches around and no luck. This unit has been sitting for several years at least. Anything I should be looking for first off that may be an easy fix ?
     

     

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  2. gort69

    gort69 AK Subscriber Subscriber

    Messages:
    1,118
    Location:
    Vancouver, WA
    Make sure the switch on the rear panel labeled NORMAL/SEPARATE is set to NORMAL.

    Make sure the speaker switch setting corresponds with the terminals terminals chosen where you connected the speakers.

    Remove the top covers and make sure someone didn't pilfer the outputs and/or amp boards!
     
    Last edited: Jul 18, 2018
  3. hopjohn

    hopjohn Silver Face Subscriber

    Messages:
    1,104
    Location:
    Dallas, TX
    Edit: Cross posted with gort69...

    One quick thing you can try if you haven't already is to clean or at least work back 'n forth the normal/separate switch on the back panel which is known to cause problems. Do the cleaning with the power off. When you operate the amp, do it with the switch set to the normal position.
     
  4. Kenny*G

    Kenny*G AK Subscriber Subscriber

    Messages:
    68
    Location:
    Dickinson, Texas
    Thanks for the reply's first off ! I will dig in deeper tomorrow after work. I did make sure the speakers were on the correct terminals / switch position, The NORMAL/SEPERATE switch is in normal, has a tab that locks it in the position. I will pull the lock tab, clean the switch and try it again. Going to pull the wood cover off tomorrow and clean the inside and have a look around, pretty sure this unit has never been opened up. Is there any fuses internal that may cause an issue ?
     
  5. hopjohn

    hopjohn Silver Face Subscriber

    Messages:
    1,104
    Location:
    Dallas, TX
    Sure, you'll have several fuses you can check. They will vary depending on whether you have a multi-voltage model or not. Be warned that if a fuse is blown it could very well mean some internal failure has caused it to do so. If in replacing a fuse it quickly blows again it means there's something else in need of attention, do NOT keep putting in new fuses in this case as it is not a fix, but rather a symptom of a bigger problem.

    [​IMG]
     
  6. Kenny*G

    Kenny*G AK Subscriber Subscriber

    Messages:
    68
    Location:
    Dickinson, Texas
    John, I completely understand what you are saying about the fuses. I was thinking more along the line of corroded fuse holders not making connection instead of an actual blown fuse. I'm going to dig into it shortly, just got home from work.
     

     

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  7. Kenny*G

    Kenny*G AK Subscriber Subscriber

    Messages:
    68
    Location:
    Dickinson, Texas
    Well I tried working the Normal/Separate switch numerous times, with the unit unplugged of course, and still nothing. I started working all the switched back & forth and all of a sudden wham ! The volume/balance switch seems to be a lot of the problem. It has sound coming from the right channel only and that is with the volume turned up pretty high and it has a lot of static and popping to the point I was afraid it was going to damage the speaker so I powered it off. I've tried it on the AUX, TAPE 1 & 2 and no difference. I tried with the speakers connect on A & B with no difference. This unit is pretty dirty inside, a bunch of small dead roaches. I have a feeling this is going to turn into a project above my pay grade, I don't have a scope etc. , only volt meters, pretty decent with a soldering iron. I know what capacitors, resistors etc. look like, but not much experience with small detailed components prints.
     
  8. Kenny*G

    Kenny*G AK Subscriber Subscriber

    Messages:
    68
    Location:
    Dickinson, Texas
    Well on second thought since I have $0 dollars invested in this unit I'm going to dive in head first. Plan on removing the front panel first, try removing the volume/balance pot and take it apart for a serious cleaning. I've tried deoxit 4 times along with working the switch and that is what got it to working to start with. As mention previously there is no volume on the left channel and the right channel has to be turned up almost 3/4 the way then shortly after it starts getting static & popping with faint music in the back ground. If deep cleaning the vol/bal pot fixes this issue I will move on to cleaning the rest of them. Who knows, I may even dive in to a full recap later.
     
  9. gort69

    gort69 AK Subscriber Subscriber

    Messages:
    1,118
    Location:
    Vancouver, WA
    - The vol/bal pot is soldered to a small PCB via 14 pins, several of which are bent over flush to the board. 9 wires connect to the board Removing the pot from the board and disassembling would be a last resort.

    - You can get cleaner into the pot by leaving everything attached and bring the pot out through the bottom. The access into the pot for the cleaner is from the bottom of the pot between the board and the opening for the pins. It's tight, but can be done. The square sections at the rear are volume, the round sections are balance. The rearmost volume section has huge openings on the side where you can introduce cleaner

    - The faceplate can stay put. Remove the bottom cover, the vol knob and the balance ring, then remove the nut holding the pot to the frame and maneuver it out through the bottom.

    -The signal passes through most every switch and pot and could be getting lost in any of them. Frequent offenders are the filter switches and norm/sep. The toggle switches are difficult to clean on this amp.

    - You can jumper around the normal/separate switch with a standard RCA cable going from pre-out to power in for both channels.

    - Popping is more indicative of a failing transistor, but who knows - cleaning switches might cure it.

    ka9100 volume pot.jpg
     
  10. Kenny*G

    Kenny*G AK Subscriber Subscriber

    Messages:
    68
    Location:
    Dickinson, Texas
    Made some serious progress, pulled the bottom plate off and did some serious cleaning on all switches with deoxit while working back & forth. NOW...I have music on both channels and all switches seem to somewhat work, subsonic filters seem to still have issues. Some times one channel starts to fade out, push the filter buttons and it comes back.

    How hard is it to remove the face plate, maybe get better access to all the switches for cleaning and I would like to do a serious cleaning on the face plate & knobs ?

    Since I got this far I figured I would try out the KT-7500 tuner I picked up at the same time as the amp, hooked it up and works like a champ ! Just needs a serious cleaning also.
    Oh I also scored a KX-830 cassette deck, need to pick up a tape or two so I can try it out. It lights up and the drive runs.
    Last but not least a KD-5077 Turn table, I spend 6hrs cleaning on it, replaced the cartridge with a new AT95E I had sitting here and it woks like a new one!
    And all of these have the walnut cabinets in pretty decent shape, I will be refinishing them.

    So far not bad for a $35 yard sale haul. :)
     
    Last edited: Jul 21, 2018
  11. Kenny*G

    Kenny*G AK Subscriber Subscriber

    Messages:
    68
    Location:
    Dickinson, Texas
    Well after taking the front panel off and going after the switches again with deoxit, everything works as its supposed to. :) Did a serious cleaning to the front panel and all knobs, cleaned the rear panel & all connections, pulled all fuses & cleaned fuses and holders. Only thing not working is the lamps for the meters, which I need to find somewhere to order them from. If anyone has a link to replacement bulbs I would greatly appreciate it.
     

     

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  12. gort69

    gort69 AK Subscriber Subscriber

    Messages:
    1,118
    Location:
    Vancouver, WA
  13. Kenny*G

    Kenny*G AK Subscriber Subscriber

    Messages:
    68
    Location:
    Dickinson, Texas
    Just sent him an email, see if he has the lamps for the KA-9100 & KT7500.

    I'm also in the hunt for one of the red(pos) speaker terminal screws if anyone has a spare from a parts unit.
     
  14. Kenny*G

    Kenny*G AK Subscriber Subscriber

    Messages:
    68
    Location:
    Dickinson, Texas
    Well with a closer inspection I need more than just the one red binding post screws, four are stripped out. Sooooo time to get creative and build a new binding post board with connections.
     
  15. gort69

    gort69 AK Subscriber Subscriber

    Messages:
    1,118
    Location:
    Vancouver, WA
    Pretty common to see that. The screws that thread into the terminal block are left hand thread, and I suspect folks don't realize it and force them in the wrong direction. It's a shame too, because - for the era - they are very good.

    I have repaired a couple of them by using a toothpick to get some JB Weld into the hole from the back side, threading the terminal back in and holding it in place with a spring clamp overnight while it cures.
     
  16. Kenny*G

    Kenny*G AK Subscriber Subscriber

    Messages:
    68
    Location:
    Dickinson, Texas
    Well it's officially ALIVE !!!!!! ended up modifying the speaker binding plate and installed new binding post, I should never have problems with these beast. Also got the new LED's from Dgwojo and they look real nice. Now that I have it hooked up to my listening speakers I'm using banana pin connectors on the speaker wires, really liking that set up.
     

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    Last edited: Aug 4, 2018
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  17. SicMan

    SicMan Fire up those speakers Subscriber

    Messages:
    2,974
    Location:
    Wolcott - CT. USA
    I use those exact binding posts.. great job :music:
     
  18. Sansushi

    Sansushi AK Subscriber Subscriber

    Messages:
    446
    Location:
    NW Arkansas
    nice looking 9100. i would love to run across a good deal on one. congrats!
     
  19. Kenny*G

    Kenny*G AK Subscriber Subscriber

    Messages:
    68
    Location:
    Dickinson, Texas
    Actually I'm pretty sure it was one of your post I saw about replacing the binding post with ones from Parts Express, founds these that looked like the ones you used and ordered them. They work great, Thanks !
     
  20. Kenny*G

    Kenny*G AK Subscriber Subscriber

    Messages:
    68
    Location:
    Dickinson, Texas
    Ok so I replaced the lamps with the white LED's from DGwojo, they are considerably brighter than I expected, they actually shine thru the top grill. The original bulbs had a blue tint cover over them, not sure what they looked like originally because they were all burned out when I got it. So do they actually have a blue tint to them originally ? Any way to cover the LED'S to tame them down a little ?
    I have my KT-7500 Tuner cleaned up and ready to install the same LED's in it, just afraid they will be to bright for my liking.
     

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