My Yamaha M2 Output Transistor saga

brinsmead

Active Member
Every tech knows the frustration of not being able to get the correct parts, I thought I was going to be in that situation with a Yamaha M2.
I had the opportunity many times over the years to get Yamaha M2, high freq Toshiba TO3 output transistors and to stock up on them, but time passes and you put it all on the back burner, the alas comes the day and you need them.
China has got a lot to answer when it comes copies; they print part numbers like its going out of style, so be wary on ebay, it might not be fabricated with the same technique.
I tried just about everywhere for the Toshiba 2SA1051A and 2SC2461A, knowing this was going to be a challenge.
Dalbani had NPN only and they looked pretty motley so I gave that a miss..
I remembered I’d purchased from HB Electronics in CA, so I checked their stock, and low and behold they still had them on their stock list.
I ordered 3 of each but they had no brand listed and no “A” version.
It was important to me to get Toshiba “A” version printed on the device.
I waited eagerly for the package, thinking they were at best going to be at best, unsuitable Sumitomo , as I not sure whether Toshiba licensed that technology to 3rd parties.
This is what arrived for $40
 
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Every tech knows the frustration of not being able to get the correct parts, I thought I was going to be in that situation with a Yamaha M2.
I had the opportunity many times over the years to get Yamaha M2, high freq Toshiba TO3 output transistors and to stock up on them, but time passes and you put it all on the back burner, the alas comes the day and you need them.
China has got a lot to answer when it comes copies; they print part numbers like its going out of style, so be wary on ebay, it might will not be fabricated with the same technique.
I tried just about everywhere for the Toshiba 2SA1051A and 2SC2461A, knowing this was going to be a challenge.
Dalbani had NPN only and they looked pretty motley so I gave that a miss..
I remembered I’d purchased from HB Electronics in CA, so I checked their stock, and low and behold they still had them on their stock list.
I ordered 3 of each but they had no brand listed and no “A” version.
It was important to me to get Toshiba “A” version printed on the device.
I waited eagerly for the package, thinking they were at best going to be at best, unsuitable Sumitomo , as I not sure whether Toshiba licensed that technology to 3rd parties.
This is what arrived for $40

FIFY

Wow. Looks like the real deal there.

When are you going to install them?
 
Brutal,thankyou for correcting my comment.

The M2 has been sitting around for a time gathering dust, quietly waiting for this day. I was optimistic, but didn’t think this purchase was going to work.

This M2 is for a repair, but looking at my own position and as an owner of M2, I like to have a small stock of key parts on hand, something of which I overlooked when I ordered these transistors.
I will have to correct this fopaux.

My B2 was a very different story I stocked well on spares but I thought the M2 being more conventional, parts would be available well in to the future.
Having a stock of parts for your amps doesn’t always guarantee that you’ve got it right, like a power switch in the B2 that fails thru arcing.Very few manufactures make lever mains switches where as the push on/off mains switch in the M2 can be found in a lot of equipment.
 
thankyou clinicaudio for those words,on that recommendation I'll go for another 6,and put them away for a rainy day.
I was trepid at the start of this purchase, and considered it was more a matter of good luck rather than good management.
 
These outputs made by pct perfect crystal technology;is this process what gives them the Ft high freq 80 mhz ability
 
IMHO some of the best BJT's ever made.

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There's a bazillion Toshiba fakes out there...I'd want to see the other side of the device (and for NOS transistors, that lettering looks awfully good).
 
Hello Echowars !

In the picture of brinsmead , I don't need to see the other side of these devices to see if they are fake or not ....They are original

See my picture of some other original (above and under views ) :thmbsp:

They are new and never mounted and if I good remember 2SA1050 is output power transistor for M4
 

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You cannot tell a fake just by looking at the printing...that's easy to duplicate (I helped set up device printers at Motorola and Micron...simple stuff). I suggested looking at the backside since many (most) of the counterfeiters use the same emitter/base insulators and the same collector base. I recognize this style a mile away. Usually...
 
You cannot tell a fake just by looking at the printing...that's easy to duplicate I follow you and understand perfectly what you mean but I do

more than 35 years servicing Japanese unit help me to see the fake and not fake
transistor
:thmbsp:
 
Aren't all the fakes flat on top as opposed to a slight dome on the real Toshiba?



Sent from my subconscious mind.
 
Nope. I've seen them in all shapes and sizes, flat and round, thick and thin base, and even the 'speckled' base used on the Sanken trannies. Simply looking at a transistor and trying to guess if it's an original or a counterfeit is a fools game...any out-of-production Japanese transistor (especially a special-purpose wide-bandwidth one) is to be viewed with great skepticism. Doesn't mean they aren't out there, but the Chinese have flooded the market with so many fakes that the odds are stacked against you. And resellers are either ignorant of the problem or turn a blind eye to it.

"You need 2SAxxxx? Sure, we have that! Of course it's an original part! Says so right here."
 
...any out-of-production Japanese transistor (especially a special-purpose wide-bandwidth one) is to be viewed with great skepticism.

I no you already have to have them in hand to be able to do this but can you tell anything by examining the bottom and looking at where the base and emitter leads exist the case. The better Japanese semi's always had a nice fat lead and an encapsulated epoxy glass bead at the exit point as shown here ... or are they faking that too these days?

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