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Old 30th May 2014, 07:47 AM   #541
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Fairchild SSS6N80 MOSFETs - it looks authentic, with copper lead frame and a reasonable-sized die (the one on the left is unused, the one on the right is from the same batch but failed - probably destructively avalanched.)
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Old 30th May 2014, 10:28 AM   #542
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Quote:
Originally Posted by jcdrisc View Post
Linear Systems make the LSK389 which is a current equivalent of the Toshiba part
No need for hand wringing about counterfeits
Correct. I'm waiting for samples. However, not available in the ZIP7 package but the TO-71 package will probably fit the lay-out of my Borbely power amp.
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Old 6th June 2014, 11:49 AM   #543
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Default MJ15003

Anyone know if this is a genuine Motorola MJ15003 or a fake.
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Old 6th June 2014, 02:41 PM   #544
davada is offline davada  Canada
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Anyone know if this is a genuine Motorola MJ15003 or a fake.
The simplest test is a breakdown test. I seem to remember the die being squared up on originals. It's been more than thirty years since I had one of those oped up. Something doesn't look right about that one.
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Old 6th June 2014, 02:46 PM   #545
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This from a quick google. RHS one is a "fake"

Believe at your own risk - but yours does look clean and professional!
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Old 26th June 2014, 07:46 PM   #546
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I bought 2SC3600E / 2SA1406E pair from Japan (Wakamatsu). It doesn't look like tradition Sanyo transitor. So:
- Any one can tell if they are fake or real.
- Guide me through some tests to identify that?
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Old 27th June 2014, 12:05 AM   #547
davada is offline davada  Canada
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Originally Posted by ilkafrv View Post
I bought 2SC3600E / 2SA1406E pair from Japan (Wakamatsu). It doesn't look like tradition Sanyo transitor. So:
- Any one can tell if they are fake or real.
- Guide me through some tests to identify that?
First test is to put some acetone or lacquer thinner on a Qtip and see if you can remove the lettering. If they're fake the ink will likely come off. This test is not full prof.

Do some electrical tests.
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Old 27th June 2014, 02:26 AM   #548
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Originally Posted by davada View Post
First test is to put some acetone or lacquer thinner on a Qtip and see if you can remove the lettering. If they're fake the ink will likely come off. This test is not full prof.

Do some electrical tests.
Thanks!

I used Qtip with acetone with a little hard on the lettering but it still remains.

So electrical tests next. Which one do I need to test on this bjt?
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Old 27th June 2014, 04:33 AM   #549
davada is offline davada  Canada
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Thanks!

I used Qtip with acetone with a little hard on the lettering but it still remains.

So electrical tests next. Which one do I need to test on this bjt?
I would do a breakdown test. There is some disagreement as to whether this should be done with the base open or shorted to emitter. You will need some form of current limiting. A 1k resistor will do. Insert a current probe into the circuit and you can test for leakage at the same time. For an NPN connect the emitter to ground and place the 1k resistor in series with the collector. Apply a positive voltage to the 1k resistor and vary the voltage from 0 to 10V greater than the collector breakdown voltage. Verify your transistor becomes a zener diode at the voltage the data sheet specifies. If it breaks down early then you have a fake. You might see smoke from the resistor.
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Old 27th June 2014, 06:19 AM   #550
gman76 is offline gman76  United States
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Originally Posted by davada View Post
I would do a breakdown test. There is some disagreement as to whether this should be done with the base open or shorted to emitter. You will need some form of current limiting. A 1k resistor will do. Insert a current probe into the circuit and you can test for leakage at the same time. For an NPN connect the emitter to ground and place the 1k resistor in series with the collector. Apply a positive voltage to the 1k resistor and vary the voltage from 0 to 10V greater than the collector breakdown voltage. Verify your transistor becomes a zener diode at the voltage the data sheet specifies. If it breaks down early then you have a fake. You might see smoke from the resistor.
I wouldn't leave the base open, tie it to GND. Seems more dangerous to leave base floating. It's best to do this on a curve tracer which will limit the power delivered to the DUT. I guess a series resistor will do. What's the max Vce spec? Also don't you want to check the beta? A crappy transistor will likely have a low beta.

Edit: just looked up specs. 200v Vceo and Vcbo. hFE 40 min at 10mA Ic. I would say you should measure beta in the 60 to 80 range. The collector breakdown should be > 200v (which could a bit difficult to test).

Last edited by gman76; 27th June 2014 at 06:28 AM.
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