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Old 17th April 2010, 07:06 PM   #31
fredlf is offline fredlf  United States
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Here are the original and an MCM part newly hack-sawed open. The MCM part is on the left, original part on the right.
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Old 17th April 2010, 07:10 PM   #32
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Here they are again, after I spudged off the white thermal (?) goo to reveal the die.

I should also repeat that the MCM part passed the IT-18 tests AND passed Vceo of 160vdc with 0 leakage. I'm not at all experienced, but I'd say this part is good.

What do you guys think?
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Last edited by fredlf; 17th April 2010 at 07:26 PM.
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Old 17th April 2010, 07:29 PM   #33
davada is offline davada  Canada
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Originally Posted by PB2 View Post
That is it, the real version of course!

Do you still have it?
I was young at the time and didn't have the knowledge to figure out what was causing the instability. I had replaced outputs on them a few times and they would last a few months then fail again.

My friend dropped them off to me one day and asked me to hang onto them for him. They sat in my basement for a number of years. By this time I had accumulated a lot of electronic odds and ends and decided it was time to clean up and dispose of some things. Thinking my friend had lost interest in them, I sent them off to another electronics enthusiast. That's the last time I saw them.

I never thought the tigers would become a vintage commodity.

David.
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Old 17th April 2010, 09:59 PM   #34
PB2 is offline PB2  United States
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Quote:
Originally Posted by fredlf View Post
This the first in a series of posts showing pictures of the original Toshiba parts on my Adcom and the replacement 2SD424 I obtained from MCM.

These two are of originals in my amp. Q17 is the transistor that failed. The other picture is of a transistor on the other channel. One side of this channel was obviously rebuilt at some point by the prior owner.
Right looks like what is currently in my Adcoms.

Left looks like what I pulled out of the Soundcraftsman - probably the older style marking.
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Old 17th April 2010, 10:02 PM   #35
PB2 is offline PB2  United States
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Originally Posted by fredlf View Post
Here are the original and an MCM part newly hack-sawed open. The MCM part is on the left, original part on the right.
The Soundcraftsman remarked part looks just like the left photo inside before I removed the sealer. Color is even about the same.
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Old 17th April 2010, 10:06 PM   #36
PB2 is offline PB2  United States
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Quote:
Originally Posted by fredlf View Post
Here they are again, after I spudged off the white thermal (?) goo to reveal the die.

I should also repeat that the MCM part passed the IT-18 tests AND passed Vceo of 160vdc with 0 leakage. I'm not at all experienced, but I'd say this part is good.

What do you guys think?
Die size and design looks just like what I have here, note that the size is about 1.5-2X what is shown for many fakes.

I'd say it is good but welcome input from others.

Does the beta code match your others?
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Old 17th April 2010, 10:08 PM   #37
PB2 is offline PB2  United States
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Quote:
Originally Posted by davada View Post
I was young at the time and didn't have the knowledge to figure out what was causing the instability. I had replaced outputs on them a few times and they would last a few months then fail again.

My friend dropped them off to me one day and asked me to hang onto them for him. They sat in my basement for a number of years. By this time I had accumulated a lot of electronic odds and ends and decided it was time to clean up and dispose of some things. Thinking my friend had lost interest in them, I sent them off to another electronics enthusiast. That's the last time I saw them.

I never thought the tigers would become a vintage commodity.

David.
I'm not sure if others are interested but I am since I scratch built one.

Maybe you did get some fake parts - hard to say.
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Old 17th April 2010, 10:10 PM   #38
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I agree. It looks like a good one.
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Old 17th April 2010, 11:12 PM   #39
fredlf is offline fredlf  United States
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Quote:
Originally Posted by PB2 View Post
Die size and design looks just like what I have here, note that the size is about 1.5-2X what is shown for many fakes.

I'd say it is good but welcome input from others.
Thanks for the confirmation, guys.

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Does the beta code match your others?
No. The originals are R. The MCM part is O. Interestingly, the parts list specifies O. At 50hfe, the MCM part does match the beta the of the others on the board very well.

Last edited by fredlf; 17th April 2010 at 11:21 PM.
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Old 18th April 2010, 12:05 AM   #40
PB2 is offline PB2  United States
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OK, I was just curious it's all you've got so try it out when you are ready. It is certainly better than the leaky part.
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