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Basic recap and restore BOM parts list on Kenwood KA-4002 integrated amp

Discussion in 'Kenwood-Trio/Kensonic-Accuphase' started by dlucy, Apr 24, 2017.

  1. dlucy

    dlucy dlucy67 (Doug) Subscriber

    Messages:
    1,784
    Location:
    Philadelphia, PA
    kenwood_ka-4002_solid_state_integrated_amplifier.jpg

    Performed a recap and basic restoration on a small Kenwood integrated amp KA-4002 and it sounds great. The KA-4002 has a cap-coupled output, so it has a warm sound kinda like tube gear and very much so the "1970's vintage sound".

    • All electrolytic caps and "noisy" small signal transistors replaced.
    • Electrolytics caps in audio path replaced with Nichicon KL series or metalized film.
    • All replacement caps chosen for 70% working voltage (or lower) and for best price-point (i.e. if a 50V replacement was more expensive than a 63V one, then I chose the 63V one).
    • Output caps replaced with same-capacitance-value to maintain the design's same low end rolloff.
    • Added snubber caps to the power reservoir and output caps.
    • High-stress resistors (e.g. output transistor emitter ones) replaced with high wattage metal film resistors.
    • Rectifier bridge replaced with modern version.

    I built a larger spreadsheet with ALL caps, all resistors, all diodes and all transistors... just in case someone needs a reference or I get bored and OCD and replace everything with modern versions.
     
    Kyocerafan, robthomp and Karl vd Berg like this.

     

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  2. dlucy

    dlucy dlucy67 (Doug) Subscriber

    Messages:
    1,784
    Location:
    Philadelphia, PA
    The BOM parts list for the recap and restore:

    Power supply

    C301 LKG1J472MESCCK
    C301(snubber) ECQ-E2104KB
    C302 ECQ-E2223KF
    C303 ECQ-E2223KF
    C311 667-ECQ-U2A104KLA
    D1 KBL02-E4/51
    R311 RN65D1002FRE6

    Tone amp

    Ce25 MKS2C041001F00KI00
    Ce26 MKS2C041001F00KI00
    Ce27 UKL1V100KDDANA
    Ce28 UKL1V100KDDANA
    Ce64 UPW1J221MPD
    Ce65 UPW1H221MPD
    Ce66 UPW1H101MPD
    Ce67 UKL1V470KPDANA
    Ce68 UKL1V470KPDANA
    Qe5 KSC1845FTA
    Qe6 KSC1845FTA

    RIAA or EQ or phono stage

    Ce1 ECQ-E1335KFB
    Ce10 UKL1V100KDDANA
    Ce11 UKL1V101KPDANA
    Ce12 UKL1V101KPDANA
    Ce15 UKL1V100KDDANA
    Ce16 UKL1V100KDDANA
    Ce2 ECQ-E1335KFB
    Ce69 UKL1J100KED
    Ce70 UKL1J100KED
    Ce70 UKL1V100KDDANA
    Ce8 UKL1V100KDDANA
    Ce9 UKL1V100KDDANA
    Qe1 KSC1845FTA
    Qe2 KSC1845FTA
    Qe3 KSC1845FTA
    Qe4 KSC1845FTA

    Main amp

    C121 UKL1H102KHD
    C121(snubber) ECQ-E2104KB
    C221 UKL1H102KHD
    C221(snubber) ECQ-E2104KB
    Ce45 MKS2C041001F00KI00
    Ce46 MKS2C041001F00KI00
    Ce47 UKL1V471MHD
    Ce48 UKL1V471MHD
    Ce49 UKL1V100KDDANA
    Ce50 UKL1V100KDDANA
    Ce51 UKL1J100KED
    Ce52 UKL1J100KED
    Ce55 UKL1V470KPDANA
    Ce56 UKL1V470KPDANA
    Ce57 UKL1J470KPD
    Ce58 UKL1J470KPD
    Ce59 FK22C0G1H224J
    Ce60 FK22C0G1H224J
    Ce61 UPW1J470MPD
    Ce62 UPW1H101MPD
    Ce63 UPW1H101MPD
    Qe10 KSC1845FTA
    Qe9 KSC1845FTA
    Re100 CPF3R47000JNB14
    Re91 CPF3R47000JNB14
    Re92 CPF3R47000JNB14
    Re93 CPF3R47000JNB14
    Re94 CPF3R47000JNB14
    Re95 CPF34R7000FKB14
    Re96 CPF34R7000FKB14
    Re99 CPF3R47000JNB14
    VRe1 3386W-1-102LF
    VRe2 3386W-1-102LF
     
    Kyocerafan likes this.
  3. dlucy

    dlucy dlucy67 (Doug) Subscriber

    Messages:
    1,784
    Location:
    Philadelphia, PA
    The before images:

    IMG_6294_AKsmall.png IMG_6334_AKsmall.png
     
  4. dlucy

    dlucy dlucy67 (Doug) Subscriber

    Messages:
    1,784
    Location:
    Philadelphia, PA
    And the results:

    IMG_6355_AKsmall.png
     
    Kyocerafan and Bassblaster like this.
  5. dlucy

    dlucy dlucy67 (Doug) Subscriber

    Messages:
    1,784
    Location:
    Philadelphia, PA
    Kyocerafan likes this.
  6. greenglass

    greenglass New Member

    Messages:
    1
    Location:
    West Hills, California
    Nice work sir. How many work hours to do it?
    I have 2, KA 4002's and 1, KA 2002. I do not have the skills to do what you do.
    I am looking for someone in Los Angeles to do some work if and when the amps need it.
    Thank You Sir
     

     

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  7. dlucy

    dlucy dlucy67 (Doug) Subscriber

    Messages:
    1,784
    Location:
    Philadelphia, PA
    The KA-4002 has a very simple layout and is physically small. The replacements are very straightforward and easy to access. I'd say I could do all the parts above in just 4 hours. If I was doing just the recapping, it would be 2 hours.

    That being said, I'm just a hobbyist. A professional could have a completely different approach to work and billing.
     

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