Initial checks on Marantz gear

Discussion in 'Marantz Audio' started by smokenguns22, Mar 8, 2018.

  1. smokenguns22

    smokenguns22 AK Subscriber Subscriber

    Messages:
    88
    Location:
    Lafayette LA
    Hi guys and gals-
    I have several pieces of vintage Marantz gear including
    2220
    4270
    4140
    140
    1250
    5025b
    And possibly 300DC - near future.

    Many of these have been fully restored by either Catrafter or wlhd1610. Mr. Tom and Mr.Bob never cease to amaze me with their skills and knowledge.
    I think I’m ready to start getting involved more in this hobby.

    My question is-
    Other than DC offset checks, what other initial checks are the norm for this Marantz gear?

    My 2220 has never been gone through-sounds amazing to me though- but I wanted to start on something small so I saved that one for me to tinker with.

    Any and all suggestions would be appreciated

    Thx
    Smokey
     

     

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  2. Steven Tate

    Steven Tate AK Subscriber Subscriber

    Messages:
    2,624
    Location:
    N. Richland Hills, TX
    I started in this hobby a year and a half ago with very little knowledge of vintage internals. With much mentoring by the AK experts, I’ve done major refurbishes on a dozen units. Best advice I got was to start with something like a 2220, which I did. First thing is to build a Dim Bulb Tester and use it every time you power up for the first time, and every time you make a change in the Electronics. This can save your bacon if there is a short somewhere. Next, download the service manual and become familiar with the layout. If it works and you want to see if adjustments are in spec, follow the Audio Adjustments section in the SM. On most units, you will be testing power supply voltage, DC Offset at the speaker terminals, and idle current (Bias). The lower powered units do not always have all of these adjustments, and capacitor coupled units like the 2230 and 2220 will not have the usual 0vDC Offset at the speaker terminals, so don’t be shocked if you try to measure Offset and find 20+ volts instead of mV. Hope this helps. These were some of the questions I had in the beginning. Good luck!
    Steve

    P.S. Also, Echowars thread should be your bible on how to get started in the hobby.

    http://audiokarma.org/forums/index....udio-gear-eh-heres-the-tools-you-need.333423/
     
    Last edited: Mar 8, 2018
  3. smokenguns22

    smokenguns22 AK Subscriber Subscriber

    Messages:
    88
    Location:
    Lafayette LA
    THanks Steve-
    Those suggestions were what I was thinking as well. Just like to have someone with more experience confirm my thinking as well.

    Been reading and learning here for 6 months or so and “tons” of great information here. Sometimes it seems overwhelming at times with all the info but it has been very interesting.

    Smokey
     
  4. wurlyman

    wurlyman Active Member

    Messages:
    236
    Location:
    Sacramento, CA
    Steven, Did you end up getting an oscilloscope and if so which one? - Stu
     
  5. Steven Tate

    Steven Tate AK Subscriber Subscriber

    Messages:
    2,624
    Location:
    N. Richland Hills, TX
    Yes, I got a Tektronix 1052B digital. It's an entry level scope that definitely does what I need it to do.
    Steve
     
  6. catrafter

    catrafter Marantz Specialist Subscriber

    Messages:
    6,064
    Location:
    Montana
    I like to check the functionality of each unit so that I have a good idea of what I am dealing with.
    Anytime something that is connected to the AC line (power switch, suppressor network, etc.) is touched, I perform an AC leakage test.
    I compare my measurements against the published specifications in the applicable service documents.

    For a 2 channel receiver it is usually something like this:
    AC leakage test!!!
    Listen, test all controls and switches for clean operation.
    No signal, check Power amp DC offset and make sure it is adjustable; cap coupled outputs, check DC Balance and make sure it is adjustable.
    No signal, check Power amp Bias and make sure it is adjustable.
    Signal into Aux, measure at tape out: Frequency response, total harmonic distortion + noise (THD+N) (this is mostly a sanity check).
    Signal into Phono (with a reverse RIAA adapter), measure at tape out; Frequency response, THD=N
    Signal into Aux, measure at Preout; Frequency response, THD+N, tone control, filter, loudness checks.
    Signal into Aux, measure at speaker outputs with dummy loads: Frequency response, THD+N, at rated power; max power before clipping.
    AM Tuner: Sensitivity, THD+N, Meter check, dial tracking.
    FM Tuner: Sensitivity, 30 and 50dB quieting on both Mono and Stereo, Frequency response, THD+N, Muting and meter checks, dial tracking.
    I also check that the front panel dubbing jacks and the headphone jacks to ensure that they work properly.

    When it's completed I perform all the same tests, plus I live with it for a week or so in my system.

    Smokey, If you have any specific questions about your 2220, be sure to let me know.:)
    Tom
     
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  7. smokenguns22

    smokenguns22 AK Subscriber Subscriber

    Messages:
    88
    Location:
    Lafayette LA
    Thanks Tom,

    This is some good info. I’ll start running some test on it when I get back home and if I have any questions I’ll shoot them your way.

    Smokey
     
  8. Steven Tate

    Steven Tate AK Subscriber Subscriber

    Messages:
    2,624
    Location:
    N. Richland Hills, TX
    I may post this on my wall. But I’ll have to break down and get a THD Tester before I can make much use of it.:thumbsup:
    Steve
     
  9. catrafter

    catrafter Marantz Specialist Subscriber

    Messages:
    6,064
    Location:
    Montana
    Oops, forgot two very important things:
    Inspect power cord for cuts and frayed areas.
    Check to make sure it has the proper sized fuse. I can't tell you how many times I've found a 20A fuse in place of what should be there.

    Tom
     
  10. smokenguns22

    smokenguns22 AK Subscriber Subscriber

    Messages:
    88
    Location:
    Lafayette LA
    Yea-
    That’s not good.
     

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