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marantz 240

  1. James Cox

    Marantz 240 possibly blown

    So my friend called me up today and was very distraught. He purchased a Marantz 240 and 7t preamp a few months ago and was experimenting with some separate phone preamps he had. The problem came when he was switching around the phono preamps with the amp and stuff on and accidentally hit the RCA...
    • James Cox
    • Thread
    • marantz marantz 240 no sound power amp shorted rca
    • Replies: 5
    • Forum: Marantz Audio
  2. ocdecio

    MPSA65 Darlington hFE

    I followed lots of threads about the 240/250 and one thing I remember reading was Q503 can be a troublemaker, and it is a darlington MPSA65. I am having issues with the left channel slowly getting pops and cracks, then all of a sudden a "whoosh" and bam, the channel is out with rails DC in the...
  3. ocdecio

    Driver beta mismatch effects on 240's diff pair

    I am now replacing a diff pair on a 240 for the third time. I matched them before installing at 427 both, and now one of them is reporting 388 and there is DC imbalance and hiss/noise on that channel. Two previous times that was what I found as well, including the originals. As for the drivers...
  4. ocdecio

    Marantz 240 - Static/Hiss after hours of listening

    Please watch/listen to the following: https://drive.google.com/file/d/1KQaOjiNePiHS6m_5IobNnFOXsk87f6GF/view What type of component would usually be suspect in this case? I don't have a scope to get a waveform for it, but will get one if need be. I am inclined towards the small value caps (the...
  5. ocdecio

    Marantz 240 - bad transistor?

    I am chasing a high DC voltage at the left amp board on a 240, so I am checking each of the listed transistors in the SM list. When I pulled Q508 (SJ2582) this is how the collector looks like: Of course I will replace it, although the tester shows normal parameters and the DMM test passed as...
  6. ocdecio

    Marantz 240 - DC Offset unstable after recap

    Please take a look at this video: https://drive.google.com/file/d/141BK1ALmQPpahIRRAuvCNeKXTbZ8kvbB/view?usp=sharing This is the reading off the speaker terminals on left channel, after a full recap (no silicon was replaced though). I also added the flyback diodes as per service bulletin...
  7. ocdecio

    Marantz 240 question

    Just got a 240. It was sold as "working", and from the pictures I couldn't see anything unusual. Is there anything you would recommend doing before actually plugging it directly to the wall and trying it out? I connected it to a dim-bulb tester, and the light dims but not totally, which I think...
  8. ratatatwilly

    Best option for turning my amp on?

    Holla, So I got my self a Marantz Model 240 amp which doesn't have an on/off switch. My preamp is a Fisher 100t tuner/preamp. The issue I have is that the Marantz draws 480w of power and the Fisher 100t can only have a switched input max of 300w. Any suggestions how I can power the Marantz on...
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