My Transistors, original or copy? - Page 21 - diyAudio
Go Back   Home > Forums > Design & Build > Parts

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

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 5th December 2008, 07:15 AM   #201
diyAudio Member
 
EchoWars's Avatar
 
Join Date: Dec 2002
Location: Left of the Dial
/OT

If you need more than 10, you better have an armed friend, or an escape route.

Back on topic: No, I certainly don't recommend doing business with Match-a-Knob. I got perhaps a dozen original, good transistors, and several dozen bad fakes (some with two dies...had pics around here at one time). I gave up on sourcing out-of-production transistors right about then.
  Reply With Quote
Old 12th March 2009, 07:58 PM   #202
diyAudio Member
 
Join Date: Jul 2005
Location: Podkarpacie, Poland
Are they real or fakes? I bought them in local shop couple months ago. I measured them with simple multimeter, and beta for one of them was about 40 - little too low. I've destroyed one, and die is 4x4.5mm (need daylight to make photo, so i'll try post it tomorrow).
Attached Images
File Type: jpg toshiba1-2.jpg (77.2 KB, 720 views)
__________________
Wojtek
  Reply With Quote
Old 12th March 2009, 11:16 PM   #203
diyAudio Member
 
unclejed613's Avatar
 
Join Date: Dec 2006
a few pages back, there's a pic of a pair of C5200's which look real. i'm beginning to make a list of the date code styles different manufacturers use. i'm getting my info either from data sheets when available, or from known original devices when i can find them. Toshiba uses a dot and two alphanumerics for their date code on the right side under the part number. so since it doesn't have a toshiba date code, the devices in your pic are fakes based on the date code characteristics. toshiba also has two beta ranges in their data sheet, R and O. since the beta range designator is not on your devices, or even the ones in the pic a few pages back, they are most likely fakes (yours and the ones a few pages back.)
__________________
Vintage Audio and Pro-Audio repair ampz(removethis)@sohonet.net
spammer trap: spammers must die
  Reply With Quote
Old 13th March 2009, 01:27 AM   #204
diyAudio Member
 
Join Date: Jul 2005
Location: Podkarpacie, Poland
Another picture of 2SC3280
Attached Images
File Type: jpg z009.jpg (60.8 KB, 701 views)
__________________
Wojtek
  Reply With Quote
Old 13th March 2009, 02:13 AM   #205
diyAudio Member
 
unclejed613's Avatar
 
Join Date: Dec 2006
that does look like a correctly sized die, but still with the beta code missing from the package, i would tend to think they're not original devices.
__________________
Vintage Audio and Pro-Audio repair ampz(removethis)@sohonet.net
spammer trap: spammers must die
  Reply With Quote
Old 23rd March 2009, 03:06 PM   #206
wg_ski is offline wg_ski  United States
diyAudio Member
 
Join Date: Oct 2007
Usually the die doesn't make it intact when taking apart a real TO-247/TO-264. Bash the case apart and the die comes out in pieces if the passivation is worth anything. And I haven't seen real PNPs in green packages since since the early days of white silk-screened logos (with "Toshiba" in the old script font).
  Reply With Quote
Old 24th March 2009, 03:08 AM   #207
diyAudio Member
 
unclejed613's Avatar
 
Join Date: Dec 2006
i just downloaded Toshiba's Semiconductor Reliability Handbook. on pg 20 of chapter 1, they show the two date coding schemes they have in use, and i will fill in a small tidbit of info from actually looking at real toshiba devices. the two date coding schemes are the standard 4 digit one YYWW (year and week) and an abbreviated one using YM (last digit of the year, and a letter from A to L for the month). now for the undocumented tidbit.... they put a dot before the abbreviated date code (one up high like a degree(temp) mark). the date code is on the right hand side below the part number. the devices shown above have an S at the beginning of the date code, which is a bogus date code.

like i said, i have begun compiling (direct from manufacturer's publications where possible) the various date and lot code styles that they use to track reliability data. some of these markings are also logos, factory codes and such imprinted in the mold mark dimples (with sanken devices, the presence of an SK in the dimple above the collector lead actually indicates that it is a fake). from known good and original samples of sanken devices, i have found that sanken hasn't used an SK logo in the dimple at least as far back as 2005.
__________________
Vintage Audio and Pro-Audio repair ampz(removethis)@sohonet.net
spammer trap: spammers must die
  Reply With Quote
Old 2nd May 2009, 04:47 PM   #208
diyAudio Member
 
Join Date: Apr 2008
i recently bought a batch of 2n3055's from ST, price was pretty normal, but they keep blowing/shorting or acting strange.

last night i was so pissed i trashed a new one open, but i have no material to compare it with.

any opinions?
Attached Images
File Type: jpg dscf30912 (small).jpg (42.8 KB, 614 views)
  Reply With Quote
Old 3rd May 2009, 03:35 AM   #209
diyAudio Member
 
unclejed613's Avatar
 
Join Date: Dec 2006
looks a little small, even for a 3055 which is a 15a device. the bond wires even seem thin for a 15A device. ST publishes the same specs as MOT, 60V, 15A, hfe=20-70, Ft 2Mhz. what was your applied voltage?
__________________
Vintage Audio and Pro-Audio repair ampz(removethis)@sohonet.net
spammer trap: spammers must die
  Reply With Quote
Old 3rd May 2009, 02:12 PM   #210
diyAudio Member
 
Join Date: Apr 2008
somewhere between 43 and 50, but certainly not more.

the second channel is built up from old RCA 3055's and performs perfect, even under full load for hours
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
NTE transistors-->> Backwards from original case layout!! What the heck! 777funk Solid State 1 10th May 2009 02:49 AM
Need DVD copy software! Kyte_08 The Lounge 7 16th February 2008 01:48 PM
how to backup original cd as the same sound quality as original cd ctrn Music 3 16th May 2006 04:21 PM
Copy of Kore-Eda pre ? sinski Chip Amps 2 4th May 2006 12:03 PM


New To Site? Need Help?

All times are GMT. The time now is 10:50 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2