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Marantz 1120 Transistor Replacement Help Needed

MrIgotNomoney

MrIgotNomoney

Well-Known Member
Hello Guys
Im starting on a rebuild of my Marantz 1120 that I just got and was wondering if you guys have a cross for the transistors, some are avaliable thru Digikey but quite a few aren't even listed, I wanted to avoid NTE if I can.
I have a service manual on the way but here is a list of silicon that I pulled off the schematic that came with it.
Thanks for any help
bob

I have to go thru it and find out what has failed, but was wondering if you guys have crosses for the transistors ? I have seen alot about Onsemi's for outputs, Im more of a tube guy so Im not that familliar with silicon.
bob
Im going to do a recap on her also.
The list I have so far is below.
What do you guys use for replacement transistors ?
POWER AMP SECTION
2N5210
MM5007
MM3007
MPSA20
MPSA05
MPSA70
SJ2519

POWER SUPPLY
S33370
S33369

PROTECTION CIRCUIT
SPS439
SS47

PHONO/SELECTOR BOARD
SPS1928
2N4250

TONE CONTROLL BOARD
SPS1928
2N4250

INTERCONNECT BOARD
SPS1928
2N5200
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I got your PM, and came here expecting that you needed a cross for one or two transistors...not every transistor in the amp!

You need to troubleshoot the problem first, and determine what you need. Data sheets can still be found for most of those transistors with Google, so once you have the bad guys rounded up, you can find their specs and I'd be happy to help look for a suitable replacement. On the ones where specs cannot be found, the circuit will need to be parsed to determine what the requirements of a replacement need to be (including the case style!).
 
Marantz transistors

Sorry my bad.
Ok starting with the outputs SJ2519
one is shorted EBC, pick any 2 terminals any polarity you have a short.
the second E to C short regardless of polarity.

Second pair collector + to base - high resistance
collector + to emitter - open

It looks to me that the first pair are toast,
If my thinking is right then the driver set are gone to.
they are mm3007 and mm5007, I will check those next.
bob
 
No apologies, but I don't think you quite understood the amount of work you were asking me (or anyone else) to do.

The original outputs are NLA, as you probably surmise. I can't find a schematic on the web to tell me if you have a full complementary output stage, or quasi-complementary output stage. If the amp is full complementary (uses both NPN and PNP outputs) and uses the old-style TO-3 transistors, then I'd probably use the On-Semi MJ15003 (NPN) and MJ15004 (PNP). If it is a quasi design, then all MJ15003's will do. You will have to replace them all, since mixing the new and old is a no-go.

I don't know what to recommend for drivers, since I don't know the form factor of the current drivers.

http://www.audiokarma.org/forums/showthread.php?t=116021
 
Most of the TO-39 packages are JEDEC numbered parts, and I'm not well versed in these. I can recommend some parts with Japanese numbers (TO-126 or TO-220 case style), but there ought to be some good US-numbered parts around in the TO-39 package. Perhaps some guys with more familiarity with these parts might chime in.
 
Hello
I'm not sure they are bad, I havent tested them.
I was thinking that types 2N5320 & 2N5322 should be compatable, or 2N5321 & 2N5323
from Central Semiconductor and at less than $2 a pop aint too bad either.
And lo and behold NTE has a cross NTE 323,324.
My thoughts are the Marantz is 34 years old, Im thinking that it would be a shame not to give her new silicon, at least in the poweramp, I'd hate for a dodgy driver to blow out a new set of outputs.

bob
 
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Outputs, yes 1 side gone.
I have ordered new outputs mj15003, Since this guy is 30+ years old, I am going to go thru the amplifier board and rebuild it. I have found 2 resistors that have heated up.
So Im thinking that to make this good as new it's my only choice.
The only expensive parts are going to be the drivers part #mm3007 and mm5007 they do cross to an nte the 323 and 324. 4 bucks each. Still looking for suitable crosses for these, but if I can't find any ill go with the nte parts.
One thing I notice on the board is there are a second set of holes for a different type of driver transistor TO126 or TO220.
Power supply, preamp,tone circuits seem fine, I am going to re cap the power supply just to be on the safe side.
And change any electrolytics throughout.
Id like to use the 1120 as a daily driver, looks wise it is near perfect, the face and knobs are perfect.

bob
 
Hello 1 pair seem to be good, the other are dodgy.
makes sense since one of the outputs was a total short.
So I think I will go on and find replacements/substitutes.
Im also looking for 2 different diodes, they are MZ2360 and MZ2361.
The MZ2361 are mounted so they touch the heatsink for the output transistors, both these diodes cross to an NTE 177 this dosent make sense, they are differend diodes.
The MZ2361 acts as a thermal sensor, on my multi meter diode test, I get different readings reversing the lead polarity, but the diodes do match in readings.
Any ideas on these diodes?
schematic located at
http://www.pbase.com/rjones5296/image/112709125/original
part reference numbers CR601/CR602 for the MZ2361
part reference numbers CR503/CH504 for the MZ2360
bob
 
You can replace the MZ2360 by ONE 1N4148, and the MZ2361 by TWO 1N4148 connected in series. Take care to isolate (electrically) the diodes from the heat sink.

You can also replace the MZ2361 by one diode connected (base and collector connected together) low power darlington transistor. It is usually easier to fix, more ruged and presents less chance of accidental short to the heat sink.
 
Well guys, finished the Marantz this evening, I decided to totally rebuild the amplifier board, new resistors and silicon.
I did end up using NTE for the MM3007 and MM5007. Variac'd it no fireworks just came up and was good.
Set offset to <7mv on both channels. Set the bias per the service manual.
I did notice that after a good while the heat sink was pretty warm, so going to run it for a while tomorrow and recheck the bias, just to make sure it is within spec.
A buddy that is a service tech, cautioned me about Q507 and Q508 (MPSA20) that this was a common failure part in this amp.
But it lives and sounds pretty good.
Thanks for the help !
bob
 
I know this is an old thread......but, I need some replacements for the mm5007 and mm3007.
Any suggestions would be excellent. If possible I'd like to use KSC/KSA equivalents.
 
In my Marantz 1120 Power Amplifier Board :
MM5007 = 2N5679 - PNP - 100V/4V/1A
MM3007 = 2N5781 - NPN - 100V/4V/1A
You can also use 2N3440/2N5415
 
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Welcome to AK...Alex..
 
avionic said:
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Click to expand...

But good that it showed up as I have an 1120 here that Steve gave me that he was told is a bit down or off in one channel. Cracked it open and found no output transistors, so I have thread watched this one for the eventual review when I finally get inside that amp to see what is going on.
 
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