Marantz PM-35 schematic?

jaycee · 9th July 2009, 08:34 PM

Does anyone have one?

I've just picked up one of these and although the power amp section measures fine with no DC on it's output (at the junction of the emitter resistors), the protection relay isn't closing. The relay itself seems fine.

The toshiba datasheet i found for the TA7317 is rather crap but it gives me the basic gist that the chip should be grounding the relay to turn it on.

From the look of it, there should be a +15V supply, and there isn't. There is a JRC 2041D opamp that has no voltage on pin 8, but -15V on pin 4. Suspicious.

The amp also produces output through headphones, which is an attenuated output off of the power amp circuit, so i know the power amp's fine!

jaycee · 9th July 2009, 11:53 PM

Figured it out anyway

Protection circuit and +15V rail are derived from the output of a JRC 78M24, which is dead. Sometimes it works for about 10 seconds. From the look of it, it's ran very hot and had a poor amount of heatsink paste applied.

It'd still be nice to get the schematic for this amp. Oddly enough I can't find out much about it at all on Google. Marantz don't list it in their product archive!

9th July 2009, 08:34 PM	#1
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	Marantz PM-35 schematic? Does anyone have one? I've just picked up one of these and although the power amp section measures fine with no DC on it's output (at the junction of the emitter resistors), the protection relay isn't closing. The relay itself seems fine. The toshiba datasheet i found for the TA7317 is rather crap but it gives me the basic gist that the chip should be grounding the relay to turn it on. From the look of it, there should be a +15V supply, and there isn't. There is a JRC 2041D opamp that has no voltage on pin 8, but -15V on pin 4. Suspicious. The amp also produces output through headphones, which is an attenuated output off of the power amp circuit, so i know the power amp's fine!

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9th July 2009, 11:53 PM	#2
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	Figured it out anyway Protection circuit and +15V rail are derived from the output of a JRC 78M24, which is dead. Sometimes it works for about 10 seconds. From the look of it, it's ran very hot and had a poor amount of heatsink paste applied. It'd still be nice to get the schematic for this amp. Oddly enough I can't find out much about it at all on Google. Marantz don't list it in their product archive!

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