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Transistor Substitutions

trkyle said:
substitution suggestions for the transistors in the power supply of an marantz 1180dc:

original device:
  • 2SD313(D od E) Vceo 60; Ic 3A; Pc 1.75W; fT 4MHz; hFE D=60-120, E=100-200, TO-220 package, has a heatsink or no?, pinout BCE
possible subs:
  • KSC2334 Vceo 100; Ic 7A; Pc 1.5W; fT ?MHz; hFE Y=120-240, TO-220 package, pinout BCE, $0.99, complement is KSA940
  • KSC2073 Vceo 150; Ic 3A; Pc 1.5W; fT ?MHz; hFE H1=40-80 H2 60-125, TO-220 package, pinout BCE, $0.65, complement is KSA1010
  • MJE15028/30/32/34 Vceo 120-250; Ic 8A or 4A; Pc 25W; fT 30MHz; hFE 40,40,70,100, TO-220 package, pinout BCE, $1.31, complement is MJE15029,MJE15031,MJE15033,MJE15035
Click to expand...

You've done some good research!

In an application in a power supply, the hFE and fT won't matter as you aren't doing amplification (as I assume you're doing current or voltage regulation).

The pinout will matter:
  • If you select a device that is not the same as the original, BCE, then you can choose ECB and just spin the device around 180 degrees, but...
  • If you are attaching to a heatshink that cannot be spun around with the ECB device, then you have a problem that may no be solvable.

All three of the devices you chose have higher or equal Vcbo, Vceo, Vebo, Ic, and close-or-higher Pd. All three are pinout BCE and use package TO-220 just like the original. All three should work fine.

Personally, I'd choose KSC2073 as I've used it in power applications before and it worked well, and it is slightly cheaper, and it doesn't consume a MJE150xx device which I prefer to use for audio drivers or outputs.

Good luck!
 

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great! - thanks very much. the TO-220's are definitely on heat sinks so i'll watch the pinouts. good tip to remember.
 
Any thoughts on a replacement for 2SA1376?

and I am planning to replace the 2SA1380 with KSA 1381
 
Any thoughts on a replacement for 2SA1376?
and I am planning to replace the 2SA1380 with KSA 1381
Click to expand...
Hi there,
The KSA1381 is an excelent replacement for the 2SA1380. For the 2SA1376, you may want to go with the original: http://www.bdent.com/2sa1376a-nec-transistor.html
or this replacement (cheaper, similar specs): http://www.bdent.com/2sa1370-sanyo-video-transistor.html
You may still find the KSA1370 at a local shop. The last resource is to use another KSA1381 for the 2SA1376, but you need some room for the TO-126 package. There may be a 2SBXXXX part that may fit there like the 2SB1245 but it may be hard to find.
Another possibility is the KSA1013 which is only rated at 160V, and it has a transition frequency of only 50MHz,
 
Hi guys
I'm writing from Brazil.
I have an old R1040 Luxman receiver, original condition
I need to refresh the pre-amp board, because one channel is dead, and the other is very noise. The aux/ tuner is fine. So my plan now is to do a total recap on preamp board, and work on rest of receiver in next months.
The preamp board of my Luxman uses 2sc1345E and 2SA836E transistors.
At the moment, and next month, I can't buy any new transistors, due to a pandemic situation and the difficulty of finding these transistors here from reliable sources.
My two question is. I have here some BC547B.
Can I replace the 2SC1345E with BC547B, in preamp board?
Can I replace the 2SA836E with BC560, in preamp board?
Thank you for your help
Greetings from Brazil
 
havols said:
Hi guys
I'm writing from Brazil.
I have an old R1040 Luxman receiver, original condition
I need to refresh the pre-amp board, because one channel is dead, and the other is very noise. The aux/ tuner is fine. So my plan now is to do a total recap on preamp board, and work on rest of receiver in next months.
The preamp board of my Luxman uses 2sc1345E and 2SA836E transistors.
At the moment, and next month, I can't buy any new transistors, due to a pandemic situation and the difficulty of finding these transistors here from reliable sources.
My two question is. I have here some BC547B.
Can I replace the 2SC1345E with BC547B, in preamp board?
Can I replace the 2SA836E with BC560, in preamp board?
Thank you for your help
Greetings from Brazil
Click to expand...

Close match but it doesnt look like your replacements have enough hFE.

2SC1345-2SA836.jpg
 
UPDATED:

Yes, the BC547 with gain code B will work, it just won’t amplify as much. You can use your BC547B as a temporary replacement.

The problem you will have is twisting the leads of the BC5nn transistors to match the pinouts of the 2Sxnnnn transistors. The original transistors have an ECB pinout or pin order and the replacements you want to use, the BC series, have CBE pinouts.

if you are careful, you can put insulators on the leads and twist them so they go in the correct holes on the PCB. This is not optimal, but it will work and get you through until you can buy the right replacements.
 
Thank you very much for the quick response
Could be a better temporary wedding if I use a BC547B as 2sc1345E sub and if i use BC559C as a sub of 2sa836E?
Regards.
 
Unnecessary question. I checked ... the BC559 is for lower voltages. I will install the BC 547B and BC560
Thanks again
 
1 hour of work, and service done.
Tantalum replaced by polyester
Electrolytic caps replaced by electrolytic
2sc1345E by bc547B
2sa836E by bc560B
I put insulators on the transistors lead. Great idea.
It sounds very good. A bit lower than before, but enough to me.
greetings
:beerchug:
 

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Hi guys I have a Rotel RA1412 that has 2sd426 output transistors 4x per side .
Would the mj15022g be ok to use in this circuit or would there be a better substitute.
Peter
 
Pjp50l said:
Hi guys I have a Rotel RA1412 that has 2sd426 output transistors 4x per side .
Would the mj15022g be ok to use in this circuit or would there be a better substitute.
Peter
Click to expand...
the OnSemi is a better part than the original. There aren't that may choices for the good ol' TO-3
 
Can someone please confirm that 2N5416 and 2N3440 are good replacements for 2SA606 and 2SC959 as drivers in the power amp of my Marantz 2235b?

Any help or suggestions are greatly appreciated!!
 
eizner23 said:
KSA1220AY + KSC2690AY would work great we know that.
Click to expand...
They're certainly cheaper! I see they're a different form factor though, would they require a heat sink?
I know enough to do some basic diag and repair/get myself in trouble hahaha but I'm far better with machines than electronics.
 
LPStandard said:
They're certainly cheaper! I see they're a different form factor though, would they require a heat sink?
I know enough to do some basic diag and repair/get myself in trouble hahaha but I'm far better with machines than electronics.
Click to expand...
I used them on a 1060 with no heatsyncs and they work great
 
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