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250m

  1. ocdecio

    250M Strange transistors

    I am working on what looks like a very original 250M. Inspecting the outputs on left side, this is what I found. The transistors are very oddly numbered (the HK ones have true Marantz part numbers on them, not transistor codes) and the others are 2N types which I had never seen before. The...
  2. ocdecio

    250M - ringing?

    Just finished repairing and restoring a 250M. While testing, I got same channels amplitude response to sinewave but when I test with a 15kHz square wave I am getting what seems to be ringing on right (top) channel: I'm wondering where should I start looking. It isn't bad but it is different...
  3. UrbaXter

    Output transistors for Marantz 250M

    Hi guys, I burned out the right channel output transistors of my 250M... :( According with the SM the right ones are SJ2519 and SJ2520, BUT, my unit has at the left channel, two pairs of A747A and C1116A, so my questions are: 1- We have today options available for the originals? 2- I found...
  4. goldswimmerb

    Marantz 250M Questions

    Hey guys, so I have a 250M on my hands that seems to be acting up, I actually had another local shop work on it while I was busy with other projects, however it's been in and out of their shop for 3 weeks now. It originally had a completely exploded channel. It is now at a usable state, though I...
  5. parkjv1

    Marantz 250M

    Hi, I purchased a Marantz 250M Amp from a seller on EBay! He sent a dated video of the Amp working! It went through FedEx hell, having reached a certain point in California and then for some unknown reason, it was returned to the sender twice! The third attempt it finally arrived on island...
  6. goldswimmerb

    250M replacement transistors

    Hey guys, I recently aquired a 250M with 1 blown output, which took out the corresponding predriver transistor as well as an exploded 2N4125 transistor. What are the recommended replacement transistors?
  7. goldswimmerb

    Marantz 250M help

    Hey guys, I recently acquired a working Marantz 250M, it appears to ll be original, I would like to upgrade it as per the service bulletins. What is recommended to make this amplifier more stable, as I have heard of the 250s being "conditionally stable". This unit appears to be a later model as...
  8. goldswimmerb

    250M DC offset question

    I recently got a 250M that was allegedly serviced, I can tell, to an extent, that that was true as many if the capacitors have been replaced. However, I was testing today and figured I would check the DC offset, one channel was at 15mv and the other was around 40mv, should I worry about this...
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