JBL DSC500 home cinema, restarts every few seconds

[Chungalin]

Just to document this failure, because I see it's not the first case (other cases in Fixya, with no solutions).

JBL home cinema, DSC 500. It starts fine, plays a DVD, but after a minute it resets itself, restarts again. Plays again, but then it restarts a bit sooner than first time. The process repeats again and again. It doesn't happen if not playing any disc.

No bloated caps anywhere. Back in 2008 I had another one with exactly the same symptom. Then I was able to order the power supply board and I did it. The problem was gone. Now the supplier is out of business and I'll have to repair it at component level, but at least I know that I have to look at PSU.

I suspect the problem is in primary section. I've replaced high voltage filter cap (68uF/400V), no change. The smaller ones too (1uF and 2.2uF, 50V), no change.

Since the problem seems related to heating (it resets sooner as it gets hotter), I've tried to heat the primary IC with the tip of the soldering iron. Starting from cold state, I've noticed that the reset time is notably faster if I heat that IC (NCP1002P, from ON Semiconductor).

I'll order it now and will report here the results of this operation. If I forget, please remind me with a reply.

By the way, I've seen that exists a CP1002PN from Power Integrations, but I've been unable to find a datasheet for it in order to check if they're equivalent or not.

[Chungalin]

Re: JBL DSC500 home cinema, restarts every few seconds

Not so easy.

First of all, CP1002PN from Power Integrations and NCP1002P from ON Semiconductor are not compatible. They do a similar duty but they're not pin-to-pin compatible.

Second, after replacing NCP1002P I thought I'd fixed it. It didn't reset after a few minutes like before. But an hour later, reset. Then it didn't repeat again, until an hour later...

I replaced all electrolytic capacitors from primary section. The same. I think I'll give up.

[budm]

Re: JBL DSC500 home cinema, restarts every few seconds

Service manual.

[Sparkey55]

Re: JBL DSC500 home cinema, restarts every few seconds

If you are using commercial dvd discs try them in another dvd player to see if the same problem happens. If you are using recordable media check it for errors or faulty playback on another unit. If the media is not at fault then it could also be the laser tracking mechanics in the dvd unit itself. Common issue with units of questionable quality. Sometimes the small nylon gears start to slip on shafts because of shrinkage of the nylon material used in the making of the gears. Cracked plastic gear hubs are hard to spot.

[Chungalin]

Re: JBL DSC500 home cinema, restarts every few seconds

@budm: thanks for the SM. I already had it from the beginning (I recommend ElectroTanya for SM).

@Sparkey: I ruled out the discs, because I always use the same pair of DVD for testing. They're in average state, I mean, they're not mint DVD discs, because I don't think it'd be a realistic test. I prefer relatively scratched discs to push the DVD drive to some degree of stress. I cannot assume that people will play mint DVDs all the time.

I also ruled out the DVD drive itself (a DSL-710A loader), because resets occur regardless of what the DVD drive is doing. It's a matter or time and heating. I've noticed that resets doesn't occur if you don't play any disc, but I assume that this is because the PSU only fails under a certain power demand when it gets hot.

[stj]

Re: JBL DSC500 home cinema, restarts every few seconds

could be a bad diode or other power emiconductor then.

[ben7]

Re: JBL DSC500 home cinema, restarts every few seconds

could be a bad diode or other power emiconductor then.

Yes, something is probably making the IC work too hard, or causing the IC to turn the power off (a protection feature).

[RJARRRPCGP]

Re: JBL DSC500 home cinema, restarts every few seconds

May be a bad solder joint.