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KA-6100 restore

Discussion in 'Kenwood-Trio/Kensonic-Accuphase' started by rickl, Nov 6, 2018.

  1. rickl

    rickl Active Member

    Messages:
    107
    Location:
    Twin Cities
    I really hate to call this thread a restore but I recently picked up a KA-6100 and plan to get it working better.

    The thing is dirty. Restaurant or bar setting is my guess. I don't think it has been opened in a long time.

    I pulled the cover and checked out. All fuses were not burned out but 2 10A, 1 30A/32V, and a 250mA for the burned out lamps. They should be 4A and a 500mA for the lamp. They were coated in a sticky mess so they have been there for a long time.

    Got the SM from HifiEngine and started checking voltages.

    I pulled the fuses to check the transformer since too big of fuses can burn up the windings. All is good.
    I replaced the fuses with more appropriate size and powered it up on a DBT. No glow and the relay kicked in. +-35 volts on the rails (using the DBT).

    put a signal though it and got a crappy sine wave. Note the lower half is larger than the upper half.

    I read a few other posts on PS caps so I'll get an order pulled together but I'm encouraged.

    I'm missing an input selector knob (shaft might even be bent) and the power switch will need straightening.

    More to follow once I dig into this deeper. If anyone has worked on one of these and have suggestions, please share. I think this might be a fun project.
    6100-front-left.jpg 6100-fuses.jpg 6100-scope.jpg 6100-front-right.jpg
     
    Last edited: Nov 7, 2018
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  2. rickl

    rickl Active Member

    Messages:
    107
    Location:
    Twin Cities
    Nice to know the PS is working (even the preamp has +- 24v). I had to clean the face plate. I didn't want to touch it. found a few bent controls. if anyone has a input selector knob, please PM me. Or know what size I need (my guess it is the same size as the balance and tape knobs).

    Looks like fresh caps are the next step.
     
  3. hopjohn

    hopjohn Silver Face Subscriber

    Messages:
    1,092
    Location:
    Dallas, TX
    Yes, it is the same size as these two. Also the 6100 has knobs with a cosmetic design unique to itself which has a wider indication notch than the 7100, 8100 or 9100.
     
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  4. rickl

    rickl Active Member

    Messages:
    107
    Location:
    Twin Cities
    I pulled a BOM together and replaced a few caps I had on hand. I focused on power supply and coupling caps. I still have the original 6800uF/50v caps in there.

    What a difference. Kind of happy about this.

    ka-6100-after.jpg

    Once I get the part numbers for the PS caps, I'll post the BOM. I think these might work but need to verify lead spacing. I found hopjohn's mounting bracket post from Doug's resto thread.
     
  5. rickl

    rickl Active Member

    Messages:
    107
    Location:
    Twin Cities
    22mV/12mV DC offset and bias adjusted to 20mV per SM.

    ka6100-bias-adjust.jpg
     
    Last edited: Nov 9, 2018 at 4:14 PM
  6. hopjohn

    hopjohn Silver Face Subscriber

    Messages:
    1,092
    Location:
    Dallas, TX
    Those 6800uf 63V caps will work fine. The lead spacing is 12.5mm caps vs 14mm board ( I think) but it's not an issue since there's some wiggle room.
     
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  7. rickl

    rickl Active Member

    Messages:
    107
    Location:
    Twin Cities
    Here is a list of most of the caps in a 6100. I added hopjohns PS caps. If you plan to re-cap a 6100, I'd verify these caps before placing a mouser order. I had everything except the PS caps in my spare parts bin.

    CdXX caps are the phono section, CmXX caps are the pre, amp and PS caps. A few gaps but this should get you close. Note Cm81 is a pretty green bi-polar cap. All others are electrolytic caps unless otherwise noted.

    You should be able to copy and paste into Excel and text to column by space.

    RefDesg Value Voltage Desc MouserPN
    Cd11,12 10uF 25v 647-UFG1H100MDM
    Cd25,26 220uF 25v FG 647-UFG1E221MPM
    Cd3,4 100uF 10v 647-UFG1A101MEM
    Cd7,8 33uF 16v
    Cd9,10 470uF 6.3v
    Cm11,12 1uF 50v WIMA 505-MKS4B041002CJF00
    Cm13,14 4.7uF 25v 647-UKL1E4R7KDDANA
    Cm15,16 47uF 16v 667-EEU-FC1C470
    Cm17,18 10uF 25v 647-UFG1H100MDM
    Cm21~24 1uF 50v WIMA 505-MKS4B041002CJF00
    Cm25,26 47uF 16v 667-EEU-FC1C470
    Cm27,28 10uF 25v 647-UFG1H100MDM
    Cm29,30 .33uF 35v WIMA 505-MKS2C033301C00MI
    Cm3,4 220uF 10v 647-UPW1A221MED
    Cm41,42 3.3uF 50v WIMA 505-MKS2B043301HJSSD
    Cm45,46 47uF 35v 647-UKL1V470KPDANA
    Cm47,48 47uF 16v 667-EEU-FC1C470
    Cm5,6 100uF 16v 647-UPW1C101MED1TD
    Cm53,54 47uF 50v 647-UVR1H470MED
    Cm55,56 47uF 16v 667-EEU-FC1C470
    Cm61,62 47uF 6.3v
    Cm67~70 6800uF 50v 647-UFW1J682MRD
    Cm7,8 4.7uF 25v 647-UKL1E4R7KDDANA
    Cm71,72 1uF 50v WIMA 505-MKS4B041002CJF00
    Cm81 100uF 16v non polar 647-UES1C101MPM
    Cm82 100uF 16v 647-UPW1C101MED1TD
    Cm83 10uF 50v 647-UFG1H100MDM
    Cm84,85 220uF 35v
    Cm86~89 100uF 25v 647-UFG1E101MPM
     

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