Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 25
Default SM diode marking woes.

I'm noticing that some circuit boards I'm repairing have SM diodes marked
with the old General Semiconductor logo and the letters "SJ" or "S3".
These diodes have bodies about 4mm long.

I'm pretty sure "S3" is SS23, a 2A 30V DO-214AA (4mm) diode.

But according to Vishay (which bought out General Semiconductor),
marking code "SJ" means S3J, which is a 3A 600V DO-214AB (7mm) diode.
And yet the part on the board is 4mm, not 7mm. The Vishay data sheet
doesn't say anything about alternate packages.

So I wonder why the discrepancy? Did Vishay change General Semiconductor's
marking codes? Or did they just change the package of the S3J diode?
Anyone have any knowledge of this?

--
RH



  #2   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 5,247
Default SM diode marking woes.

Robbie Hatley wrote in message
...
I'm noticing that some circuit boards I'm repairing have SM diodes marked
with the old General Semiconductor logo and the letters "SJ" or "S3".
These diodes have bodies about 4mm long.

I'm pretty sure "S3" is SS23, a 2A 30V DO-214AA (4mm) diode.

But according to Vishay (which bought out General Semiconductor),
marking code "SJ" means S3J, which is a 3A 600V DO-214AB (7mm) diode.
And yet the part on the board is 4mm, not 7mm. The Vishay data sheet
doesn't say anything about alternate packages.

So I wonder why the discrepancy? Did Vishay change General

Semiconductor's
marking codes? Or did they just change the package of the S3J diode?
Anyone have any knowledge of this?

--
RH





So a matter of removing one and testing and plotting out what happens to the
knee above 1.5A and effect of reverse 25V


  #3   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 25
Default SM diode marking woes.


"N_Cook" wrote:

So a matter of removing one and testing and plotting out what happens to the
knee above 1.5A and effect of reverse 25V


Good idea, but I don't have the equipment on hand.

However, I've discovered on further research, that SM marking code "SJ" on
Gen Semi (now Vishay) diodes can mean any of several different 600V diodes
(the "J" means 600V but doesn't specify current). Fortunately, the current rating
is tied to package:
"SJ" on DO-214AC (SMA) package = S1J (1.0A, 600V)
"SJ" on DO-214AA (SMB) package = S2J (1.5A, 600V)
"SJ" on DO-214AB (SMC) package = S3J (3.0A, 600V)
"5J" on DO-214AB (SMC) package = S5J (5.0A, 600V)

Fortunately, it seems Vishay doesn't re-use same code on same package
for different parts. (Note that since their 5A diode has same package as
3A, they change code from "SJ" to "5J".) So as long as you're careful to
observe both the code *and* the exact package (measure carefully, as
some packages vary by only a millimeter or so!), finding the exact part
should be easy.

(In my case, it's "SJ" on SMA, hence S1J (1A, 600V).)

Caveat: the above is for Vishay only. For diodes made by others, such as
Diodes Inc or Nat Semi or Fairchild or International Rectifier or whatever,
all bets are off; likely same part has different code for each. And if there's
no maker mark, then the only way is to power it up and graph the V/I
response curve. (I wish I had suitable equipment here to do that.)

--
RH



  #4   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 5,247
Default SM diode marking woes.

Robbie Hatley wrote in message
...

"N_Cook" wrote:

So a matter of removing one and testing and plotting out what happens to

the
knee above 1.5A and effect of reverse 25V


Good idea, but I don't have the equipment on hand.

However, I've discovered on further research, that SM marking code "SJ" on
Gen Semi (now Vishay) diodes can mean any of several different 600V diodes
(the "J" means 600V but doesn't specify current). Fortunately, the

current rating
is tied to package:
"SJ" on DO-214AC (SMA) package = S1J (1.0A, 600V)
"SJ" on DO-214AA (SMB) package = S2J (1.5A, 600V)
"SJ" on DO-214AB (SMC) package = S3J (3.0A, 600V)
"5J" on DO-214AB (SMC) package = S5J (5.0A, 600V)

Fortunately, it seems Vishay doesn't re-use same code on same package
for different parts. (Note that since their 5A diode has same package as
3A, they change code from "SJ" to "5J".) So as long as you're careful to
observe both the code *and* the exact package (measure carefully, as
some packages vary by only a millimeter or so!), finding the exact part
should be easy.

(In my case, it's "SJ" on SMA, hence S1J (1A, 600V).)

Caveat: the above is for Vishay only. For diodes made by others, such as
Diodes Inc or Nat Semi or Fairchild or International Rectifier or

whatever,
all bets are off; likely same part has different code for each. And if

there's
no maker mark, then the only way is to power it up and graph the V/I
response curve. (I wish I had suitable equipment here to do that.)

--
RH





Just a bench ps and standard DVM for knee plot, a "nanoammeter" of some
resistors and 200mV DVM range and variac and transformer /rectifier for
going well above the ps voltage range in reverse plotting of leakage


Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
SMD marking A62 - any ideas please? martinlith Electronics Repair 0 November 1st 09 12:04 PM
Cable marking PM UK diy 15 April 20th 09 12:47 PM
Marking out flooring petercharlesfagg[_2_] UK diy 15 December 21st 07 04:56 PM
dovetail marking Gary DeWitt Woodworking 13 November 30th 04 02:15 PM
smd marking Matthieu Benoit Electronics Repair 1 April 3rd 04 11:31 PM


All times are GMT +1. The time now is 11:16 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"