Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 155
  • Last Modified:

surface mount device codes

has any body got any idea what a surface mount device is with marking GFN 38 and also a diode symbol with its legs wrapped around to form a capital S. the device is 7mm long 5.5 mm wide and 2 mm deep, the two connections are on the short ends. it measures 4 ohms. It is in a dog perimeter minder circuit board , no bar marking on either end . just the symbol and text . the low value of ohms is causing over current draw on the 12 volt supply . i have extensive google search with  no success . removing the device from the board has solved the problem and it appears to work correctly . but mave not tried it with the dog collar.
Thanks for assistance in advance.
0
TopTed
Asked:
TopTed
  • 4
  • 3
1 Solution
 
d-glitchCommented:
Presumably the circuit was working, then it stopped working, and you noticed the suspect part was getting hot.  I think what you have is a failed protection diode.  The circuit will work fine without it, but it will be at increased risk of damage from line voltage surges.
0
 
dbruntonCommented:
I believe FN means Flat No-Lead.

However I can't get any further than that.
0
 
d-glitchCommented:
A close-up photo of the circuit, suspect part, and logo could help a lot.  
There are dozens (if not hundreds) of possible manufacturers and many thousands of possible part numbers.

I believe the part is something like one of these:  http://www.vishay.com/diodes/protection-tvs-esd/do-214ab/
Bipolar protection devices would not require an indicator band.
The suspect device probably wouldn't have measured 4 ohms when it was new and working.
0
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
TopTedAuthor Commented:
0
 
d-glitchCommented:
Thanks.  That isn't the official logo for ST, but they would probably be irked if another company used that mark.
I'll resume the search there.
0
 
TopTedAuthor Commented:
If there is no further comment , i think i will put it back into service and hope there are no surges. thanks for looking , I have had no further success either.
0
 
d-glitchCommented:
I have looked at the ST website and found more than a hundred of these parts with 3-letter codes, but none of them is a match for yours.  Some of the relevant data sheets are attached.  The 3-letter codes are on page 8.  The middle letter is always U or B (for unipolar and bipolar).  And the logo looks different too.
CD00001333.pdf
CD00001366.pdf
0
 
TopTedAuthor Commented:
I chose one of the vishay bidirectional devices as they were the same dimensins . i have put it in the pcb  and returned it to the customer and it is working ok. Thanks
0

Featured Post

What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

  • 4
  • 3
Tackle projects and never again get stuck behind a technical roadblock.
Join Now