I recently replaced the IC's and a single resistor that was shorted on my JVC AV-48WP74. The fix went fine - with everything working as normal for about two weeks. Then, the sound suddenly started going out and within a day it has stopped working completely. I've worked through the menu settings to ensure nothing was changed that would cause the sound to stop coming through the set's speakers and everything is set properly. There is sound from the cable box as it plays fine when routed through a receiver for a surround sound system. There is no sound from any of the A/V inputs to include those on the front of the TV. The problem exists even with the coax cable input. When the speakers are turned all the way up there is no buzz, nothing from them. Rechecked all my connections to ensure nothing was loose / etc. The problem started while watching a TV show and became intermittent for a couple hours. Worked fine the next morning, then quit working just as if mute was pressed on the remote. Any help would be greatly appreciated. The service manual for this TV can be found here for reference if needed.
Sam
check the voltage coming from the power board if you can trace it back from the audio board{(if it has a seperate one)also take that service manual and submit it on this site,so everyone knows its safe to download.
Good plan - will give it a go when I get the time in a few days. The service manual was submitted, hope it helps somebody else in the future. I'll post my results.
Thanks for the reply!
Because I'm at work for a few days, I tried to trace the circuit here using the schematics in an attempt to save time. For anybody else interested, I've attached the PDF files with my own notes and markup. There are 5 pages since the manual breaks the Main PWB into sections and I had to trace the circuit through each page. The last page has green squares around the components I'm planning on testing.
I don't know for sure if I did this right - I'm new to this, so if anybody takes a look at the PDFs and see an error - let me know, I'll correct it and repost so it might help others.
I'll post my troubleshooting results once I get the time to work on the TV (hopefully later this week).
Thanks!!
Here are links to download the PDFs:
http://rapidshare.com/files/406652401/01-Pg_16_-_Sheet_13_-_Receiver_PWB.pdf
http://rapidshare.com/files/406652402/02-Pg_04_-_Sheet_01_-_Main_PWB_AV_Tuner_Block.pdf
http://rapidshare.com/files/406652403/03-Pg_15_-_Sheet_12__-_Main_PWB_Regulator_Block.pdf
http://rapidshare.com/files/406652404/04-Pg_22_-_Sheet_19_-_Main_PWB_Power_DEF_PWB_Part_1.pdf
http://rapidshare.com/files/406652405/05-Pg_23_-_Sheet_20_-_Main_PWB_Power_DEF_PWB_Part_2.pdf
I was also able to locate the parts on the pattern schematic to make it easy to find once I start the testing. Here is that file with my notations:
http://rapidshare.com/files/406652406/Location.pdf
have you checked for (12) volts at pin 33 on the receiver.
temail,did you ever find the problem of no audio on the jvc?i have two of the same with same problem.