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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. |
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P61310JX4 blacks out on extreme whites.
You know some breaks the "rules" by going whiter than whites (above
the standard max on the video color contents signals? Well on dish and on certain DVD that has too bright images and extreme flashes like "Blizzards" the opening before menu comes up is powerful white than standard whites upsets this chassis DTV307 to black out and return normally. The error log says code 7 (I know what it is but forgot the exact message). Picture simply blinks out then back on once the whites is gone. I tried many ways to stop this blacking out episodes by decrease the pemeters 21 (for all CRT cut offs), even R, G, B cutoffs without decreasing the picture quality. The user picture settings are at their defaults. Only way according to customer is decrease the contrast which stops this blacking out episodes which is bandaiding that problem. Background: changed one CRT for spotty picture complaint then ended up changed all CRT just to get acceptable picture and hopefully to stop the blacking out which did not work out and I have bought out my big guns to customer's and tried few things suggested in the training sections which turned out be wrong one even it was right off the website for the DTV307. I think the set of papers was for other chassis. The service manual for DTV307 on CD is correct and followed their CRT setting up instructions exactly. HELP! Aside: To Art who replied eariler: I copied and pasted his message: "Pay attention to lousy solder connections every where on the main chassis assembly, including the stand up daughter board and the inter-connect between it and the processor board that connects at the rear apron. Agreed, these sets are an absolute Bow Wow to work on and fix. Thank the electronic gods that Thomson dumped them and their near cousins. Hopefully you have their diagnostic procedures and training materials. If not E_Mail me and I'll see if there is an archive that can be made available for you." BARK BARK BARK!!! RIGHT on! I should have DTV307 in book form somewhere but my point is that it is a major pain to work on because way chassis is designed. I HAVE serviced several of them, all were physical broken traces early on 2 years ago or on going rebuild standby SMPSes that went up in smoke when a diode became a wire. What a biggest idiot to put little 10 ohm 1/8W UNDER a SMPS transformer. Egards! And few needed pair of caps to get them going. But this time this latest barker really got the stinky cake for biggest mean dog of the neighbourhood. }: Cheers, Wizard |
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?? Jason, have you tried changing values for sub brite, etc parameters just
to see if they have any variance with your specific blanking at high brite symptom? IMHO the current sense for the beam to all three crts may be causing the intermittent blanking. I hate the AKB on some of these sets, esp when they cause strange problems like this one. Agreed, the engineer who put that fuse resistor under the smps transformer should be required to change a few hundred under on-site conditions!! www.wa6ati.com site, post your status, may get some hits via a group of techs from "the other side"!!! "Jason D." wrote in message ... You know some breaks the "rules" by going whiter than whites (above the standard max on the video color contents signals? Well on dish and on certain DVD that has too bright images and extreme flashes like "Blizzards" the opening before menu comes up is powerful white than standard whites upsets this chassis DTV307 to black out and return normally. The error log says code 7 (I know what it is but forgot the exact message). Picture simply blinks out then back on once the whites is gone. I tried many ways to stop this blacking out episodes by decrease the pemeters 21 (for all CRT cut offs), even R, G, B cutoffs without decreasing the picture quality. The user picture settings are at their defaults. Only way according to customer is decrease the contrast which stops this blacking out episodes which is bandaiding that problem. Background: changed one CRT for spotty picture complaint then ended up changed all CRT just to get acceptable picture and hopefully to stop the blacking out which did not work out and I have bought out my big guns to customer's and tried few things suggested in the training sections which turned out be wrong one even it was right off the website for the DTV307. I think the set of papers was for other chassis. The service manual for DTV307 on CD is correct and followed their CRT setting up instructions exactly. HELP! Aside: To Art who replied eariler: I copied and pasted his message: "Pay attention to lousy solder connections every where on the main chassis assembly, including the stand up daughter board and the inter-connect between it and the processor board that connects at the rear apron. Agreed, these sets are an absolute Bow Wow to work on and fix. Thank the electronic gods that Thomson dumped them and their near cousins. Hopefully you have their diagnostic procedures and training materials. If not E_Mail me and I'll see if there is an archive that can be made available for you." BARK BARK BARK!!! RIGHT on! I should have DTV307 in book form somewhere but my point is that it is a major pain to work on because way chassis is designed. I HAVE serviced several of them, all were physical broken traces early on 2 years ago or on going rebuild standby SMPSes that went up in smoke when a diode became a wire. What a biggest idiot to put little 10 ohm 1/8W UNDER a SMPS transformer. Egards! And few needed pair of caps to get them going. But this time this latest barker really got the stinky cake for biggest mean dog of the neighbourhood. }: Cheers, Wizard |
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