C2301 Temperature.

Discussion in 'Exclusively Sansui' started by JOMARK911, Jun 12, 2018.

  1. JOMARK911

    JOMARK911 Super Member

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    Hi guys .
    As an old owner of 2301's I have this , let's say uncertainty , my c2301 gets really warm after a couple of hours working, specially during summer. It is a 220v German version. I had it running on 230vac , and I thought that could be the problem. Recently I modified a big voltage regulator to act as fixed multi output transformer by reversing the cabling and taking the servo mech out of the way .
    So my c2301 now runs on 220vac. Still gets warm. Even the transformers get warm after a couple of hours.
    I mean warm like 50 degrees centigrade on the top cover.
    Inside it's more like 55 or even 60. Off course all pcb's are closed , or encapsulated on aluminum boxes to reduce noise , so some of the heat comes out of the venting holes from those. But in general this preamp runs warm.
    Anybody else here noticed the same behavior?
     

     

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  2. JOMARK911

    JOMARK911 Super Member

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    Anyone?
     
  3. kevzep

    kevzep Its all about the Music Subscriber

    I'll have a look at the schematic and see what I can learn from that........
     
  4. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    No experience of a C-2301 - but I can say that my C-2102 (pre-amp) PSU runs much hotter than I would like - 2 heatsinks on the (open) PSU PCB get extremely hot - the transformer is OK, just 'normal' temperature.
     
  5. JOMARK911

    JOMARK911 Super Member

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    :lurk:
     
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  6. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    In the PSU for the C-2301 - I see +/-75V DC regulated down to +/-48V DC - I think that must mean the series pass transistors are getting a continuous hammering, with consequent heat generated. (similar issue in the C-2102, but only +/- 45V regulated down to +/- 30V)

    If we assume the amount of heat John is seeing is 'normal' there are a fair number of small pilot lamps for front panel indicators and illumination, these could be converted to LED's without too much effort for some heat reduction. This would reduce the load on the transformer, and generate less heat inside the case which will reduce the heat around the electronics.

    Apart from the installation of fans, that's about it for practical solutions IMO.
     
    Last edited: Jun 14, 2018
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  7. JOMARK911

    JOMARK911 Super Member

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    John thanks for your time.
    The lamps that run on are very few , like 2 on the volume dial and one on the input selector. Apart from these there are a couple of leds. All these are at front just behind the faceplate.
    Most of the heat is coming from the rear off course. Also bare in mind that each line amplifier is on it's own closed vented box, and the phono equalizer also. There are two of those one for each channel , line and phono , and the one channel is at the bottom , below the first floor , kind like a sandwitch .
     
  8. kevzep

    kevzep Its all about the Music Subscriber

    John beat me to it, yeah well that is a lot of work for the Pass transistors to do, that is one hot regulated supply.
    In the Pioneer SX1980, they are doing similar mounts of regulation, and I was measuring 80˚C on some of the pass transistors.
    So I moved them by remote mounting them on the Main Power output transistor heatsinks and got them away from the enclosed area they were in.
    You wouldn't have that option.
    On my Pioneer SX1010, I actually mounted some extra heatsinking on what I considered quite a feeble factory heatsink, that took the temps down a lot.........
    There could be options for doing something like that but I'd have to see the unit....
     
  9. JOMARK911

    JOMARK911 Super Member

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    Yeah kev that could be done. But would take a tremendous amount of work.
     
  10. JOMARK911

    JOMARK911 Super Member

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    At the preset, I run a couple 120mm pc fans on the top to gently suck this amount of heat. Gently.
     
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  11. Hyperion

    Hyperion Roobarb & Custard Subscriber

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    I bet that sounds real cool now. :)
     

     

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  12. JOMARK911

    JOMARK911 Super Member

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    Yeah John. It runs much cooler.
     
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