My JVC HD-61G887 went dark- was dark when turned on. There is no sound also. I have a spare bulb. When the bulb goes out do you lose the sound also or do I have a major problem?? Thanks Bill

Yes, in that case it's a problem in the ballast or the image processor. To find which you must open the tv and test the voltages at the bulb - if they are ok then the ballast is ok and the image processor is faulty. If the voltage is lower than normal but still present then the power source is in protected mode because there's a short on one of its outputs. You must find out that short and replaced the failed part. Again a good experience is needed. If you don't know how to do it then call a repairman. Yes, in that case it's a problem in the ballast or the image processor. To find which you must open the tv and test the voltages at the bulb - if they are ok then the ballast is ok and the image processor is faulty. If the voltage is lower than normal but still present then the power source is in protected mode because there's a short on one of its outputs. You must find out that short and replaced the failed part. Again a good experience is needed. If you don't know how to do it then call a repairman.

That's the light engine - totally different part. A new mainboard (on which the processor is soldered upon) will cost you around $250 new or $100 used, if you can find one. The tv  can be fixed, in the end all that counts is if you think that the tv is worth the money you will spend on it ; and you will spend more, be sure of that - it has started to fail apart of old age. Personally, if it would be mine, since it has never been that great from the start, i  would just junk it. That's the light engine - totally different part. A new mainboard (on which the processor is soldered upon) will cost you around $250 new or $100 used, if you can find one. The tv  can be fixed, in the end all that counts is if you think that the tv is worth the money you will spend on it ; and you will spend more, be sure of that - it has started to fail apart of old age. Personally, if it would be mine, since it has never been that great from the start, i  would just junk it.