Since 2009 I've had three units of these for repair. All the same nightmare of wasted time.
This home cinema has 5 independent modular digital amplifiers. Symptom is that it doesn't start, it returns to Standby in a few seconds without showing anything on display. F205 fuse blown (1,6A). If you replace fuse AND disconnect CN703, it starts OK, with no sound, of course, because you have removed ±B from digital amplifiers.
One of the digital amp modules (which are interchangeable) is short or about to short. The interesting part is that in all cases I've found, the culprit is the Surround Left module.
Too hard to repair these modules. Inside each there're 4 TO-263 (SMD) IRF530NS mosfets soldered to a 2mm thick solid aluminium PCB (!). I gave up to try to unsolder them, I don't have powerful enough tool. The complete modules were never sold by JVC, only component level repair. Thanks, great spare parts policy!!
In one case I was able to scrap one module from an aborted unit and this wasn't enough. On base board there're two big coils and several caps per channel. At least one coil was bad, almost exploded its ferrite cover. After replacing everything, the unit lasted one year before ending the same way, same channel.
The only solution was to extirpate Surround Left module. It's been about a year since that, no returns (this doesn't mean anything, you know).
Now I have another unit, same bad channel (not short, but I can see a toasted 47Ω SMD resistor [R1825] on that channel, I don't need more clues). I won't be silly this time: kick out Surround Left module and good bye.
For illustration purposes only (not my pictures), I attach a general view of this thing (see 5 amp modules to the left), and a view of the aluminium PCB with 4 mosfets. Inside each module there's also a daugherboard with its driver.
This home cinema has 5 independent modular digital amplifiers. Symptom is that it doesn't start, it returns to Standby in a few seconds without showing anything on display. F205 fuse blown (1,6A). If you replace fuse AND disconnect CN703, it starts OK, with no sound, of course, because you have removed ±B from digital amplifiers.
One of the digital amp modules (which are interchangeable) is short or about to short. The interesting part is that in all cases I've found, the culprit is the Surround Left module.
Too hard to repair these modules. Inside each there're 4 TO-263 (SMD) IRF530NS mosfets soldered to a 2mm thick solid aluminium PCB (!). I gave up to try to unsolder them, I don't have powerful enough tool. The complete modules were never sold by JVC, only component level repair. Thanks, great spare parts policy!!
In one case I was able to scrap one module from an aborted unit and this wasn't enough. On base board there're two big coils and several caps per channel. At least one coil was bad, almost exploded its ferrite cover. After replacing everything, the unit lasted one year before ending the same way, same channel.
The only solution was to extirpate Surround Left module. It's been about a year since that, no returns (this doesn't mean anything, you know).
Now I have another unit, same bad channel (not short, but I can see a toasted 47Ω SMD resistor [R1825] on that channel, I don't need more clues). I won't be silly this time: kick out Surround Left module and good bye.
For illustration purposes only (not my pictures), I attach a general view of this thing (see 5 amp modules to the left), and a view of the aluminium PCB with 4 mosfets. Inside each module there's also a daugherboard with its driver.
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