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Yamaha B-6 Repair attempt and then we'll see...

Asmodeus2112 said:
I am going to put Toshiba 2SA1943 and 2SC5200 in for the outputs and progress. If all works, I'll pull them out and put the original Toshibas back in and put subs in for the power rail TRs. Interested to see how you mount your outputs, as they are the same package type. I'm hoping mine will only be temporary though.
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Yes was going to mention be careful the package types seem to be all over the place. Seems Toshiba are changing from TO-3P to 2-21F1A now. Ive got 2 ideas of how to mount them, 1 should work fine. Either ill 3D print carbon/nylon brackets to mount them or ill drill and tap new holes. Bottom row is easy as they fit fine, top row a little more difficult, could go sideways if needed but the die sits under the middle portion anyway so it doesn’t matter much in the real world as long as the centre portion is mounted…

The interesting part is the Sanken rail switching transistors survived this time so I do wonder how strong those old Toshiba outputs are as they blew in a split second.

Interesting to see the Sankens have a different bandwidth for a complementary pair also…

I did look at those transistors also but the saturation voltage is an odd one between typical and max values listed, what made you choose those ones?
 
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WCGW said:
I did look at those transistors also but the saturation voltage is an odd one between typical and max values listed, what made you choose those ones?
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They get mentioned a lot as good options. I am still learning though.

I don't recall all the threads that I read, and I purchased them before this thread, but here is an example:

Working on Repair Yamaha M85

I don't think it matters much for outputs, when I was doing my B6 I was worried about the hFe between outputs and was told for outputs it doesn't matter much . So I am going by what someone who knows more than I ;) Athanasios I was talking about complimentary pairs , I don't think its that...
audiokarma.org

They are listed as subs for a lot of TRs here:

Transistor Substitutions

I am not sure if there is another list like this on the forum or for that matter how many more there are, but I thought I would share this one. I stumbled on it while searching for trannies replacements. First I want to thank Mike from Hudson Valley HI FI for posting this on his site (no...
audiokarma.org
 
Asmodeus2112 said:
As I have been looking for higher bandwidth outputs I have come across this often.
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I was going to stock up on them, saw they’re in stock but weird they have a 60mhz/35mhz on a complementary pairing.

I think those other transistors are an older product line which is why they’re mentioned so much :) I think they will all sub fine with each other but the saturation voltage is a bit different between them all
 
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WCGW said:
I think those other transistors are an older product line which is why they’re mentioned so much :) I think they will all sub fine with each other but the saturation voltage is a bit different between them all
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You are probably right that those are older. I see Toshiba has TTA1942 and TTC5200 as well. I bet those are the same TRs with new part numbers.

Did you see the TTA0001 that is the same as the TTA0002 but in a smaller package? (But no stock I guess...)

I find myself going to the manufacturers websites more and more as I learn about transistors. Toshiba has a nice parametric search tool.

Bipolar Transistors Product List | Parametric Search | Toshiba Electronic Devices & Storage Corporation | Americas – United States

toshiba.semicon-storage.com toshiba.semicon-storage.com
 
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Asmodeus2112 said:
You are probably right that those are older. I see Toshiba has TTA1942 and TTC5200 as well. I bet those are the same TRs with new part numbers.

Did you see the TTA0001 that is the same as the TTA0002 but in a smaller package? (But no stock I guess...)

I find myself going to the manufacturers websites more and more as I learn about transistors. Toshiba has a nice parametric search tool.

Bipolar Transistors Product List | Parametric Search | Toshiba Electronic Devices & Storage Corporation | Americas – United States

toshiba.semicon-storage.com toshiba.semicon-storage.com
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Honestly I thought I was getting TO-3P parts as Mouser had the wrong package type listed, seems they’re switching over to the larger packages for most now. Anyways I ordered already so ill work with them.

Did a prototype mount last night in Markforged ONYX with another transistor in the same package, the packages overhang the top row but doesn’t really matter as the die area is still covered properly.

IMG_5260.jpegIMG_5267.jpegIMG_5261.jpeg
 
I did find this thread also discussing die size changes etc between all of them, cannot speak to it but an interesting read

2SC5200 and TTC5200

What is the reason that Toshiba rebuild the 2SC5200? Is the TTC5200 better? I can't see any advantages in the datasheet. The diagram Ic-Vbe looks even a little bit worse then as the of 2SC5200. OK, the output capacitor is only 145pF but else? Has anyone experience or knows more accurate?
www.diyaudio.com www.diyaudio.com
 
There is still residual stock of the Sanken ones also, not a lot left but yeah. I think TO-3P will always have a home because of their smaller size. Not sure if Toshi and Sanken are interchangeable for the most part.

My alternative is to CNC copper plates to MT-200 size and solder them directly to the plate. If my mounts don’t work out
 
Asmodeus2112 said:
I bet those mounts work great. That filament has a deflection temp of 145C, should be way more than enough.
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Hopefully, there are some heigh issues with the base plate also, mainly concerned with the compression of the filament as they do tend to yield over time with constant force. Ill keep refining it :)

I ordered a decent price break batch of 2SC5200N / 2SA1943N tonight after some research also, just to put away as I don't think the package will last much longer.
 
Spent the last couple days refining the design, clearances are definitely an issue. Using the 2nd extruder to add support and recess the bolts which gained back about 4mm. Still need a bit more by the looks of it. TO-3P arrive on the weekend so ill play with those also :whip:

Could just make my life easy and drill the plate lol.

IMG_5324.jpegIMG_5326.jpegIMG_5329.jpegIMG_5327.jpegIMG_5317.jpegIMG_5314.jpeg
 
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