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Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

My Transistors, original or copy?
My Transistors, original or copy?
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Old 9th August 2008, 12:02 PM   #181
viktor1986 is offline viktor1986  Serbia
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Thank's for information.
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Old 16th August 2008, 07:51 PM   #182
lefteyeyblue is offline lefteyeyblue  United States
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Thanks for the info. Very insightful
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Old 16th August 2008, 10:13 PM   #183
viktor1986 is offline viktor1986  Serbia
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I recognize transistor on the right side,it is ON.I had some 2BC556B(ON) from farnell and because that I know.

Here is picture of 2SC3117 and 2SA1249.I bought them in my country(Serbia) and I think that they are original.I paid 0.69euro for one piece.
Hfe is from 220-260,Ube(Uce=(-)6V,Ie=(-)11mA) is 0.6V for NPN and -0.602V for PNP.

Here is picture...Are they original?

Click the image to open in full size.
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Old 17th August 2008, 02:40 PM   #184
pjp is offline pjp  India
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I bought a pair of AD149 (Germanium Power) transistors.

When I tested them out on a multimeter I found:
1) Junction voltage = 0.5 Volt. (B-E and B-C).
2) Gain 180. (datasheet specifies 30-100)
3) No measurable Leakage current. (C-E).

Based on this I think what I have is a Silicon transistor.

However, I bought them from an old established retailer and he assures me that he has sold these very same transistors to other people who have used them to repair old amps successfully.
I had to search long and hard to find these devices and I would very much like to use them.

I have a theory that there might have been a time when production of Germanium AD149s had ceased, but there was still demand for the devices, so someone marketed a Silicon equivalent.

What do you think ?
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Old 25th August 2008, 05:52 AM   #185
artcarmo is offline artcarmo  Costa Rica
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Hi ,i heard about a SOAR curve or something like that for test Tr's.does anyone have info or link about how i can do that ,and its can be done by a DIY? ....as many others i have the bad feel when a tr...puff...blow in normal operation and realize that is a fake one, can i test it "rude" before i replace ?thanks
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Old 25th August 2008, 05:55 AM   #186
artcarmo is offline artcarmo  Costa Rica
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i post a pic of "test" i been made to identify fakes...
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Old 25th August 2008, 04:25 PM   #187
AndrewT is offline AndrewT  Scotland
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I don't think many of us amateurs would be prepared to invest in the resources necessary to carry out SOAR testing/validation.
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Old 26th August 2008, 06:40 AM   #188
artcarmo is offline artcarmo  Costa Rica
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yea i been reading and its expensive...i found i match test in the ESP web that s intersting.anyone know about a pulsing test or any link about it
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Old 27th August 2008, 12:08 PM   #189
linuxguru is offline linuxguru  India
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BEL-manufactured AD149s (red text) are most probably authentic NOS devices, while those marked Toshiba AD149 (red text) could be fakes. There's no reliable info on whether Toshiba ever produced TO-3 AD149s.

I have a pair of each in Bangalore, contact me offline if you want to buy them.
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Old 27th August 2008, 01:41 PM   #190
pjp is offline pjp  India
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Hi Linuxguru,
These just have "AD149" in red text. Doesn't say BEL anywhere.

The point is, all the other germanium devices I found had a junction voltage of 0.1 V (measured on a multimeter) and significant leakage current (measurable on the same multimeter).

Can this be a Germanium device at all with a 0.5 V junction voltage ?
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