electronics, repairs, service manuals and datasheets discussion community for the repairs professionals and technicians
FAQSearchMembersGroupsRegisterProfilePM'sLogin/Out
Panasonic EURO-4H TX-32PK25D H-OUT missing

 
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
Guest






PostPosted: Tue Mar 04, 2008 12:27 pm    Post subject: Panasonic EURO-4H TX-32PK25D H-OUT missing Reply with quote

Panasonic TX-32PK25D
Chassis: EURO-4H

HOT (Q551, 2SC5144LB228) was defect [before this, the TV had already another defect: OSD and Teletext were hardly readable (dark, no colors, no contrast)].

Did not find any defect parts around the HOT. Replaced HOT with a 60W-lamp for test purposes. Test ok. Horizontal drive signal H-OUT was there for some minutes (but a bit dirty abraded square-pulse), then H-OUT dissapeared totally.

Tracing back brought out: HOUT is not delivered by the Digi-Modul (F Board, TNP8EF008, Pin16), respectively there from the deflection processor (IC1504, DDP3310BPSF5, Pin 8). Resoldering the Digi-Board and replacement of the 5 MHz quartz crystal X1502 (tip from panasonic service) -> no success.

Measurement at I2C bus (SDA: Pin22, SCL: Pin21, Reset: Pin23) brought out: 5 times in series data packets are sent, 5 times in series there is a reset. Then the TV switches to std.by. Same happens, when I dismount the Digi-board completely.

Does the traffic on the I2C-bus (5 tries, 5 resets) indicate, that the digi-board has (not only communication-)problems ? Does the OSD/teletext-problem harden this suspicion ? How would you proceed ? Thanks for every tip !
Back to top
Guest






PostPosted: Fri Mar 21, 2008 11:59 am    Post subject: Panasonic EURO-4H TX-32PK25D H-OUT missing Reply with quote

Defect disappeared after replacing the digi-modul (F Board, TNP8EF008) by a used one (new modules are not in stock since 2006). OSD/Videotext is functioning, too.

HOUT (measured at Gate of the line-preamplifier 2SK2962TPE6) was abraded a little bit and had a little knoll in the rising edge and two little overshooting oscillations on the upper plateau of the square-pulse. The oscillogram in the service-manual however shows a nearly perfect square-pulse. Checking every part from the digi-module to the line amplifier and replacing the 2SK2962TPE6 without success. Hence, this seems to be normal.

TV is functioning now for 1 week without problems.
Back to top
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


eServiceInfo on FB - Service Manuals Free Download - Service Diagrams

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

SnimkiOt.com - Poblizo.com : пътешествия