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Marantz 2230 - different to SM

bluehills5

bluehills5

Active Member
I'm re-capping a 2230 I got (that I basically got for free off Ebay) and on the power amp boards P750 I notice there are a few differences to the service manual.
1. Cap C757 is listed as 22uF 35v in SM but mine had a 22uF 50v installed.
2. Mine is missing C761 on the back side of the board.
3. Between resistors R754 and R762 mine has a capacitor that I cannot read. It is not in the SM diagram or parts list but the board has the holes and space for it.
4. H757 is listed as a varistor and some photos of others show this as a glass pack. Mine is wired to a thermal switch(?) on the H755 transistor's heatsink.

Note that C753 is listed as 0.1uF in SM but is actually 10uF.

My question is are all these anomalies normal running changes or has someone been in here before me and done some upgrades? note my serial number is high (157000's)

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c753 in this schematic i have is 1uf 50v .
c757 22uf 35v ... 50v was likely a better choice here or they ran out of 35v ones .
it should be noticeable if it has been worked on before ..look for date codes on the caps
 
I know for sure the C753 error is listed in the Marantz service manual error sticky. Some of the others I'm not sure on.
 
Marantz equipment is rife with differences between what you find and the service manual. Best bet is to do what you did and pay close attention to what you remove and it's orientation. Replace with what you find with the exception that going up a little in cap voltage rating value is OK. Also, don't trust the silkscreen. The Marantz Service Manual error thread is full of these kinds of errors. For example, on the 2230 AM tuner board, C183 has the polarity reversed on the silkscreen. Pay attention, like you have been doing and you will be fine. Of course, all of this assumes there isn't evidence someone has been in there earlier hacking it up.
 
Sounds like good advice. A good illustration of the weirdness is the C753 which is 1uF on the schematic, 0.1 in the parts list but 10 on the actual item - it certainly keeps you on your toes!
 
SNIP -
bluehills5 said:
I'm re-capping a 2230 I got (that I basically got for free off Ebay) and on the power amp boards P750 I notice there are a few differences to the service manual.
4. H757 is listed as a varistor and some photos of others show this as a glass pack. Mine is wired to a thermal switch(?) on the H755 transistor's heatsink.
View attachment 844585
Click to expand...
H757 was replaced by a thermistor and series resistor in M-2230-2 .

Tom
 

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