electronics, repairs, service manuals and datasheets discussion community for the repairs professionals and technicians
FAQSearchMembersGroupsRegisterProfilePM'sLogin/Out
Sharp DA-50W chassis, problem with horizontal output stage

 
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
torbjorn



Joined: 07 Jun 2007
Posts: 370
Location: Sweden

PostPosted: Thu Jun 07, 2007 8:24 am    Post subject: Sharp DA-50W chassis, problem with horizontal output stage Reply with quote

Horizontal output transistor Q601, BUH515 was shorted and resistor RA611 showed signs of overheating. Both those components were replaced and several bad solder joints repaired. When switching on the set, it worked normally for 1-2 minutes, then Q601 failed again. Q601 does not get hot prior to failing. A suggestion from another forum was that this could be caused by insufficient base drive to Q601 due to a bad C607. This capacitor has been replaced without success.
A strange thing is that the set runs so well before Q601 fails. If it had been, for example, a flyback capacitor problem, then the picture width would not have been correct and it would probably have shown E/W distortion.
Back to top
View user's profile Send private message
bbp1



Joined: 04 May 2007
Posts: 22

PostPosted: Sat Jun 09, 2007 6:42 am    Post subject: LOT failure Reply with quote

Check/change LOPT!I assume you have checked everything elseB+, electros, djs etc. And not to forget yoke. Confused Confused
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