electronics, repairs, service manuals and datasheets discussion community for the repairs professionals and technicians
FAQSearchMembersGroupsRegisterProfilePM'sLogin/Out
SMD marking codes

 
Post new topic   Reply to topic    Electronic equipment repair and service manual search discussion Forum Index -> Equipment Repairs
View previous topic :: View next topic  
Author Message
evh



Joined: 06 Sep 2006
Posts: 12
Location: england

PostPosted: Mon Dec 14, 2009 8:08 pm    Post subject: SMD marking codes Reply with quote

I am trying to fix my Digital picture frame.The LCD back light lamp doesn't light on.Both end transistors of the inverter are gone.Both are the same SOT89 and there are 2 lines mark - DK and RN.
Searching on the Net gave me different results-PNP,NPN,MOSFET...
I looked the PCB and it seems they are NPN but not sure...I can see the "collectors" are connected to both terminals of the transformer's coil,which mid terminal goes to +9v.The "emitters" goes to ground...
How to find out the type and parameters of the transistors?
Back to top
View user's profile Send private message Send e-mail
joester



Joined: 03 Dec 2009
Posts: 35

PostPosted: Mon Dec 14, 2009 9:43 pm    Post subject: Reply with quote

There should be a manufacturers mark on it as well.

If you can post a reasonable photo of the component, I might be able to help you.

Joe
Back to top
View user's profile Send private message
evh



Joined: 06 Sep 2006
Posts: 12
Location: england

PostPosted: Tue Dec 15, 2009 1:40 pm    Post subject: Reply with quote

joester wrote:
There should be a manufacturers mark on it as well.

If you can post a reasonable photo of the component, I might be able to help you.

Joe

There is no manufacturers mark on it.It is too small (SOT89) and there are just these letters:
upper line- DK
lower line- RN
For now I am unable to make a good picture,my camera has no good zoom...
Back to top
View user's profile Send private message Send e-mail
joester



Joined: 03 Dec 2009
Posts: 35

PostPosted: Wed Dec 23, 2009 9:30 pm    Post subject: Reply with quote

Please don't think I've forgotten you... Not much to go on, but I'm trying...
Back to top
View user's profile Send private message
evh



Joined: 06 Sep 2006
Posts: 12
Location: england

PostPosted: Wed Dec 23, 2009 9:41 pm    Post subject: Reply with quote

joester wrote:
Please don't think I've forgotten you... Not much to go on, but I'm trying...

Thanks
Back to top
View user's profile Send private message Send e-mail
russ_connolly



Joined: 08 Jan 2010
Posts: 2

PostPosted: Fri Jan 08, 2010 10:32 am    Post subject: Similar problem Reply with quote

Hi I have a photo frame with the same problem, caused by using the wrong power supply. I have pictures of the components and will send them to the email address as I cant see how to attach to post
Back to top
View user's profile Send private message
evh



Joined: 06 Sep 2006
Posts: 12
Location: england

PostPosted: Fri Jan 08, 2010 11:51 am    Post subject: Re: Similar problem Reply with quote

russ_connolly wrote:
Hi I have a photo frame with the same problem, caused by using the wrong power supply. I have pictures of the components and will send them to the email address as I cant see how to attach to post

I didn't find the transistor codes.I found that can put any npn switching transistors.
I removed SMD transistors and connected spots by wires to external transistors BD385 which I removed from old TV.They are quite big but there is a lot of space.
For now everything is working fine.
Back to top
View user's profile Send private message Send e-mail
russ_connolly



Joined: 08 Jan 2010
Posts: 2

PostPosted: Sat Jan 09, 2010 8:42 pm    Post subject: Reply with quote

Thanks to the previous post I have also been able to fix the photo frame, I used 2 npn transistors labelled 9014 from an old BT answer machine.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Electronic equipment repair and service manual search discussion Forum Index -> Equipment Repairs All times are GMT
Page 1 of 1

 
Jump to:  
You can post new topics in this forum
You can reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Електроника София - Service Manuals Free Download - Prikachi - Service Diagrams

Free TV Schematics Download - HARDW.net - Pinout Master - Jabse Search - Jabse.InK  - Pulsator

Connector Pinout Forum - Новини - SnimkiOt.com - безплатен DNS - Whois разузнаване - Poblizo.com : пътешествия