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  1. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    Ok! I did it and now adjusting the trim pots actually makes a difference. No more distortion while under load. Thanks Ylli and WHONOES for helping me figure this out. I appreciate it
  2. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    Before I do this, though.. What happens if the schematic has the jumper numbering wrong? I do still have the current limiter, but the "before" picture that I took of the back of the heat sink appears to have factory soldering on it. I had just removed the first two nuts/bolts, pulled the...
  3. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    I did have the output transistors removed. They're TO-3 ones that are mounting right to the heat sink with jumper wires going to them. At first I was like "there's no way", but the more I look at the schematic, the less I understand what pins jumper to where. For example, what pin does the...
  4. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    Ok, so.. stupid question time. What is R627 supposed to actually be adjusting? The service manual says to connect to both sides of R647 and adjust until you get 7.5mV. No matter what I do, it reads zero. But, if I check the resistor itself, I get 0.5 ohms
  5. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    Yes Yes These are at zero
  6. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    R621 doesn't appear damaged or anything. Brown, Black, Brown, Gold = 100 ohms. Tests at 101.5 ohms. It's counterpart at 99.5 ohms. The voltage at J605 is 49.6V if that's what you mean. As I adjust it, the waveform appears to smooth out a little, then goes back. I get the same result no matter...
  7. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    All the voltages listed in your drawing are within reason, if a little high. The one exception is the half a volt on H617 & H618 measures closer to 1.5V Also, I'm not really finding anything hot. H615 - H618 are warm, but they're also larger than the other transistors. None of them are hot...
  8. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    Sorry for the delayed response. New school year and all that. Base to base: H615 to H617 = 2.19V H616 to H618 = 2.14V
  9. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    Base to base: H611 to H613 = 400mV H612 to H614 = 388mV Base to ground: H615 = 25.78V H617 = 23.89V H616 = 27.65V H618 = 25.52 Base to base: H615 to H617 = 1.88V H616 to H618 = 2.02V 600mV Zero ohms at one extreme and 156.8 at the other. Switching the leads around gives pretty much the...
  10. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    Woops! I put my on willy-nilly pants before I found your message. Good news is, I figured out where the constant buzzing was coming from on the Marantz 2250 receiver. That's why it was a parts unit in the first place. Bad news is, I don't have a spare set of good SV-3A's after all. I'll put the...
  11. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    Ah ha! The Marantz 2250 has the same SV-3A's
  12. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    I have a small bag of mystery diodes. They appear to be zeners and have "j1 31 v" printed on them. Unfortunately, I have no idea what those codes mean. I do have a Marantz 2250B and a Marantz 2216 that I can pull parts from, but I would need to verify that they are good before using them
  13. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    You lost me on this one, I think. Getting to the bases of those transistors is easy enough, but did you mean 24 volts from ground to base or 2.4V from one base to another? Measuring from ground to base, here's what I show: H611 = 24.74 H613 = 24.4 H614 = 26.0 H612 = 26.35 They don't appear to...
  14. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    Hmm... I don't know if I have any 1N4148's on hand, but I do have some parts units that I can look into for something similar. I also have a current limiting setup that I built. Power has to run through a light bulb and a switch before it gets to the outlet. (Side note: the distortion is there...
  15. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    J606 = 24.15 J607 = 25.56 J620 = 25.90 J619 = 27.29 This stays the same whether there is a load or not
  16. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    There is, in fact, a small kink halfway up. I had previously wondered if I did something with the output transistors that could cause this, but as long as there is no load, everything sounds great through headphones. Very clear, no distortion.
  17. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    I'm getting some conflicting information about H701 and H702. They may not be diodes at all. According to the parts list in the service manual they're varistors. Part number SV-3A. In diode mode on my DMM, I get 0.L both directions on both parts. If I switch to resistance mode, I get 1.9M one...
  18. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    Thanks for all the replies! I'll try to go down the list in the proper order. Fairly certain. This isn't my first recap (if that means anything), but also, I took pictures prior to recapping and everything looks to be put in the right way. Measured from the positive side of the output...
  19. KilgoreCemetery

    Marantz 2015 Receiver Distortion

    Everything on this receiver seems to work fine except when you hook up a load to the speaker connects. I just finished recapping and replacing a couple of bjt's in the FM section and finally hooked it up to some speakers so I could start enjoying it, but the music sounds horrible. It's not just...
  20. KilgoreCemetery

    MPS U56 BJT Replacement Comparison and Options

    Thanks for the info, Edd, O Captain, my Captain! It seems I was looking for cross reference information in all the wrong places as it kept pulling up an 'all purpose' NTE transistor during my previous searches. As for the model number, I suppose I didn't think it was pertinent.. However, ask...
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