Got these 2SB649/2SD669 transistors from ebay recently, and I assume that they're are fake. But since I don't have anything to compare them with and can't find anything about counterfeit 2SB649/2SD669 transistor at google, I started to doubt. Or at least considering to use them. So I'm asking you if anyone encounter fake 2SB649/2SD669 yet? And how do you tell?
So far I only tested the hfe of all 50 pcs with a multimeter;
Visual inspection looks good to me (but then again I don't have the original to compare with). Only thing I noticed is that the legs may not be as cleaned cut as the other (NOS) transistors in comparison. Also the casing at the top is not as smooth as the others. The ink doesn't come of with acetone btw.
What is there more to test? Brake down voltage?
So far I only tested the hfe of all 50 pcs with a multimeter;
- 2SD649 all tested between 112-123
- 2SD669 all tested between 150-163
Visual inspection looks good to me (but then again I don't have the original to compare with). Only thing I noticed is that the legs may not be as cleaned cut as the other (NOS) transistors in comparison. Also the casing at the top is not as smooth as the others. The ink doesn't come of with acetone btw.
What is there more to test? Brake down voltage?
Attachments
Today I received some transistor from another vendor. Compared to the other they look completely different (and well yes they're marked 2SB649AL instead. However these looks quite familiar to one in this thread. Also compared the the ones from ebay, the legs look not so shiny, which I guess indicates that they might be free from lead.
Anyone requognizes these transistor? Do they look real enough? Brand is UTC. DM me for supplier's name if you're interested.
hfe test as followng;
- 2SB649 128-133 (and one pcs 136)
- 2SD669 112-116 (and two pcs at 120 and 102)
Still working on a test equipment of some sort to test brakedown voltage. But I think I go for these second ones for the amp anyway.
Anyone requognizes these transistor? Do they look real enough? Brand is UTC. DM me for supplier's name if you're interested.
hfe test as followng;
- 2SB649 128-133 (and one pcs 136)
- 2SD669 112-116 (and two pcs at 120 and 102)
Still working on a test equipment of some sort to test brakedown voltage. But I think I go for these second ones for the amp anyway.
Attachments
Tested the break-down voltage of the transistors today, finally got some test equipment thrown together for this (scary stuff). Surprisingly the ebay transistors tested about same as the UTC brand.
- 2SB6649 (ebay) 215-225 V
- 2SB649 (UTC) 220-225 V
- 2SD669 (ebay) 200 V
- 2SD669 (UTC) 195 V
I thought this was going to be the test would tell which are fake or not, but I don't now what to think anymore. The are obviously some different between them (because them from different manufacturers) but still within the specs, so I guess that they might booth be real? Anyone who has actually bought some real parts (or at least believe so) from china/ebay/aliexpress?
- 2SB6649 (ebay) 215-225 V
- 2SB649 (UTC) 220-225 V
- 2SD669 (ebay) 200 V
- 2SD669 (UTC) 195 V
I thought this was going to be the test would tell which are fake or not, but I don't now what to think anymore. The are obviously some different between them (because them from different manufacturers) but still within the specs, so I guess that they might booth be real? Anyone who has actually bought some real parts (or at least believe so) from china/ebay/aliexpress?