Marantz 18 Transistors

UncleBingo

UncleBingo

Super Member
Trying to source proper transistors for the driver and tone amplifier board for a Marantz 18.

I've checked schematics and service manuals only to find proprietary Marantz part #'s (Grrr...)

I even looked for an annotated schematic where someone perhaps wrote in some actual manufacturer numbers to no avail.

I'm trying to figure out what modern equivalents I can use. I'm willing to cross-reference from old manufacturer part numbers if need be, but these 34-10XX numbers are basically useless.

I'm trying to find replacements /equivalents for:
34-1004
34-1005
34-1007
34-1008
34-1010
and 34-1011 (or 34-1031 as noted in the service manual

Can anyone point me in a direction? If you don't want share the numbers publicly, I understand. A PM with whatever help you're willing to provide would be fantastic.

I really don't want to dig into this receiver without having some sort of replacement transistors in hand. It has a channel balance issue that cleaning and caps didn't fix (it isn't the volume control).

Many thanks!
 
I have tons of the standard Marantz and Pioneer sub transistors and some other stuff on hand (KSA992; 1845's 3503's, 2sc2240's,ksc2690,ksa1220's, BC549, BC560 and so on if that helps)
 
UncleBingo said:
Trying to source proper transistors for the driver and tone amplifier board for a Marantz 18.

I've checked schematics and service manuals only to find proprietary Marantz part #'s (Grrr...)

I even looked for an annotated schematic where someone perhaps wrote in some actual manufacturer numbers to no avail.

I'm trying to figure out what modern equivalents I can use. I'm willing to cross-reference from old manufacturer part numbers if need be, but these 34-10XX numbers are basically useless.

I'm trying to find replacements /equivalents for:
34-1004
34-1005
34-1007
34-1008
34-1010
and 34-1011 (or 34-1031 as noted in the service manual

Can anyone point me in a direction? If you don't want share the numbers publicly, I understand. A PM with whatever help you're willing to provide would be fantastic.

I really don't want to dig into this receiver without having some sort of replacement transistors in hand. It has a channel balance issue that cleaning and caps didn't fix (it isn't the volume control).

Many thanks!
Click to expand...

Perhaps John at Instrument Resources can help.

Tom
 
UncleBingo said:
Hopefully I'll hear back from him.
Click to expand...
Following this thread as I have a model 18 andd having same issues. One of the service bulletins states to replace cr 17 and cr 18 bias diodes part # 35-1002 which tells people nothing. I may have to replace a few transistors as well. So if you do find more info please let me know. Thanks!
 
In my admittedly limited experience I think Marantz tended to use these numbers across their product line from that era. I know the 1120 and 1200 have both the Marantz part numbers but also the actual transistor numbers on the schematics. Maybe you can match something up?

And it also seems like you have the actual receiver in your possession. Not knowing this model is there something that is preventing you from looking at the actual transistors on the board? They will always have the model number stamped or printed.

Good luck with your search. :thumbsup:
 
I have looked at the transistors on the board. They have the Marantz part # and that is it.

I'm not going to start pulling transistors without having some recourse to a substitute. If it was mine I'd probably find a way to extrapolate substitutions from measured data and the schematic.

I'm giving this back to the owner.
 
I talked to Marantz USA and to the lead tech at Adams Electronics, one of their service centers, Marantz has no documentation what so ever in their archives on the Model 18.
The tech at Adams spent a couple of hours trying to find actual component numbers instead of Marantz part numbers which is how I know that Marantz has nothing on this model not even the service bulletins. She contacted Marantz and found nothing at all. So bottom line unless some older tech or Marantz guru out there comes forward with actual component numbers we are sol. Marantz had their own part numbers instead of maufacturers numbers on all of the transistors as well as the diodes.
 
Pretty frustrating, really. I'm fairly certain a couple guys around here have at least some sub/replacement info but are holding it close. I understand it to a certain degree, but hopefully they don't take it to their graves. Not for my sake; I don't own one and at this point will avoid acquiring one, so I don't care a lick. I can't really justify the time and effort to reverse engineer it.
 
SN# 18-5591 came to me with voltage on the left output and hum in the right. All but one transistor in the left was damaged in some way. The left was causing the hum in the right. Here is what I used in the amp. I used spare originals for the driver. I have run out of spares so I listed what I have seen suggested in the driver.

Amp

34-1000 MJ21194G
34-1001 MJ21193G
34-1002 2N5192
34-1003 2N5195
34-1013 KSA733C
34-1014 KSC945C

Driver

34-1004 2N5320
34-1005 2N5322
34-1007 2N3906BU
34-1018 2N2857


driveramp2.png

Scope

CR5 UF4006
34-1006 TIP47G / KSC3503
34-1030 2N5116 (I found a note that suggest 34-1030 and 34-1012 are interchangeable)

Tuner MPX

34-1012 2N5460 (I found a note that suggest 34-1012 and 34-1030 are interchangeable)

Limiter

34-1018 2N2857 (txturbo)

Delay

CR13 35-1010 6.8 volt 1 watt / 1N5921BRLG 6.8 volt 3 watt

If you try or have tried any of these please let us know how it works out.out
 
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