Marantz 250M Power Amp Service Bulletins

Pete B

AK Member
Subscriber
I found Service Bulletins (SB) 2-5 for the 250M not the 250 in the digital database Marantz (page 10)
section of AK, they are free for download: http://akdatabase.com/AKview/index.php
M-250-2 Mar 26, 1975 New part numbers for specific transistors and rules for beta selection
M-250-3 Aug 16, 1976 Increased reliability by replacing pre, driver, and output transistors.
Add flyback diodes, bias and test unit.
M-250-4 Sept 24, 1976 Correction to bias setting in M-250-3, sets current to 1/2 of previous.
M-250-5 Nov 15, 1977 New part number for power transformer and how to replace a failed one.

The 250 manuals can also be found there but much earlier in the database.

Anyone have SB M-250-1 ?
 
Pete, I have form No. 199-1074. Not sure if this is what you are looking for or this is something listed above.
 

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  • Marantz 250 Addendum 1.pdf
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I found Service Bulletins (SB) 2-5 for the 250M not the 250 in the digital database Marantz (page 10)
section of AK, they are free for download: http://akdatabase.com/AKview/index.php
M-250-2 Mar 26, 1975 New part numbers for specific transistors and rules for beta selection
M-250-3 Aug 16, 1976 Increased reliability by replacing pre, driver, and output transistors.
Add flyback diodes, bias and test unit.
M-250-4 Sept 24, 1976 Correction to bias setting in M-250-3, sets current to 1/2 of previous.
M-250-5 Nov 15, 1977 New part number for power transformer and how to replace a failed one.

The 250 manuals can also be found there but much earlier in the database.

Anyone have SB M-250-1 ?


M-250-1 is just about a meter p/n change....
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BTW , there are 2 addendums for the 250 amp (which also apply to the 240) are are useful for the 1200 and 250M amps.

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Bob
 
Pete,I am the a newer member of classic speakers pages.I was the guy asking all those recapping questions about AR's,From Montana.
 
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