My Transistors, original or copy? - Page 37

Andy5112405 · 30th May 2011, 05:18 PM

If no-one answers within a few days the pictures become immaterial but point taken.

unclejed613 · 30th May 2011, 07:02 PM

they don't show any obvious signs of being fakes. is the printing inked or laser etched? it should be laser etched

Andy5112405 · 30th May 2011, 07:56 PM

How can you tell the difference ?

unclejed613 · 30th May 2011, 10:16 PM

laser etching goes into the surface, ink stays on the top of the surface. take a dab of heat sink grease and rub it into the lettering. if it goes into the letters and makes them show up better, it's etched. if it doesn't, they're printed.

nigelwright7557 · 30th May 2011, 10:25 PM

I wonder how often fake transistors have been blamed when the real problem was the design(er) ?
It takes a lot of money and know how to start up a fabrication unit.
Why bother if you cant sell your fakes easily ?

Andy5112405 · 31st May 2011, 04:12 PM

Quote:

Originally Posted by unclejed613

laser etching goes into the surface, ink stays on the top of the surface. take a dab of heat sink grease and rub it into the lettering. if it goes into the letters and makes them show up better, it's etched. if it doesn't, they're printed.

The Heatsink Compound enhanced the engraving so I guess these stand a reasonable chance of being genuine.

I'll try loading one of them up to 15A and see if it can hold its own.

Andy5112405 · 1st June 2011, 05:17 PM

I managed to get around to building six of the devices into my DIY-PASS Aleph 4 output stage having previously matched them.

Loading them up to 100mA each they seem OK. Next step will be to push them up to 4A.

Andy5112405 · 4th June 2011, 01:14 PM

Under SOA test these seem original. God Bless Genuine E-Bay vendors.

meanman1964 · 06:34 AM

I bought eight MJL4302A and eight MJL4281A trannies.
I measured them with a cap tester between E and C
Don't know if this is the right way and came out with the following result:

MJL4302A: 9,53
9.9
9,96
9.94
10,45
10,35
10,41
10,37

MJL4281A: 9,53
9,48
9,43
9,52
9,50
9,40
9,42
9,15
are those fake or not and what is the best way to find out please explane?
They all have the sign ON and the seller told me they are OnSemi

tiefbassuebertr · 15th June 2011, 06:44 AM

Quote:

Originally Posted by meanman1964

I bought eight MJL4302A and eight MJL4281A trannies.
are those fake or not and what is the best way to find out please explane?
They all have the sign ON and the seller told me they are OnSemi

check out this thread - especially post #22:
Possible fake Toshiba/Sanken transistors?

30th May 2011, 07:02 PM	#362
unclejed613 diyAudio Member Join Date: Dec 2006	they don't show any obvious signs of being fakes. is the printing inked or laser etched? it should be laser etched __________________ Vintage Audio and Pro-Audio repair ampz(removethis)@sohonet.net spammer trap: spammers must die

30th May 2011, 10:16 PM	#364
unclejed613 diyAudio Member Join Date: Dec 2006	laser etching goes into the surface, ink stays on the top of the surface. take a dab of heat sink grease and rub it into the lettering. if it goes into the letters and makes them show up better, it's etched. if it doesn't, they're printed. __________________ Vintage Audio and Pro-Audio repair ampz(removethis)@sohonet.net spammer trap: spammers must die

30th May 2011, 10:25 PM	#365
nigelwright7557 diyAudio Member Join Date: Apr 2008 Location: Carlisle, England	I wonder how often fake transistors have been blamed when the real problem was the design(er) ? It takes a lot of money and know how to start up a fabrication unit. Why bother if you cant sell your fakes easily ? __________________ http://www.murtonpikesystems.co.uk PCBCAD50 pcb design software.

15th June 2011, 06:30 AM	#369
meanman1964 diyAudio Member Join Date: Oct 2006 Location: Belgium the land of chocolate	I bought eight MJL4302A and eight MJL4281A trannies. I measured them with a cap tester between E and C Don't know if this is the right way and came out with the following result: MJL4302A: 9,53 9.9 9,96 9.94 10,45 10,35 10,41 10,37 MJL4281A: 9,53 9,48 9,43 9,52 9,50 9,40 9,42 9,15 are those fake or not and what is the best way to find out please explane? They all have the sign ON and the seller told me they are OnSemi Last edited by meanman1964; 15th June 2011 at 06:34 AM.

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30th May 2011, 05:18 PM	#361
Andy5112405 Banned Join Date: Nov 2006 Location: Torpoint	If no-one answers within a few days the pictures become immaterial but point taken.

30th May 2011, 07:56 PM	#363
Andy5112405 Banned Join Date: Nov 2006 Location: Torpoint	How can you tell the difference ?

1st June 2011, 05:17 PM	#367
Andy5112405 Banned Join Date: Nov 2006 Location: Torpoint	I managed to get around to building six of the devices into my DIY-PASS Aleph 4 output stage having previously matched them. Loading them up to 100mA each they seem OK. Next step will be to push them up to 4A.

4th June 2011, 01:14 PM	#368
Andy5112405 Banned Join Date: Nov 2006 Location: Torpoint	Under SOA test these seem original. God Bless Genuine E-Bay vendors.

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