I have a fairly high end Infinity Prelude MTS powered subwoofer that suddenly stopped producing any sound. I confirmed that it is getting power and sound signal (RCA connection) - it even "wakes up" from stand by but still emits no sound.
This sub is a BASH amp but it does use high end transistors and is supposedly 850+ watts.
No authorized dealer will work on these anymore and parts are no longer available.
I took the amp out just to take a look see and I found this - see pics.
I have the service manual and they call it a "Surgistor" 4R 8A 70JSL154R008. It is located on the main power supply board (with the big caps) and it is directly next to the DC IN leads.
It looks bad and pitted but does it look like it failed? Do you think this could be the cause of the issue?
I might be able to fix this myself if I can find the surgistor somewhere. EDIT: I found the part. Digikey calls it a current inrush limiter and Mouser calls it a thermister so I guess it is a sort of surge protection.
Thanks for any suggestions and help.
Will
This sub is a BASH amp but it does use high end transistors and is supposedly 850+ watts.
No authorized dealer will work on these anymore and parts are no longer available.
I took the amp out just to take a look see and I found this - see pics.
I have the service manual and they call it a "Surgistor" 4R 8A 70JSL154R008. It is located on the main power supply board (with the big caps) and it is directly next to the DC IN leads.
It looks bad and pitted but does it look like it failed? Do you think this could be the cause of the issue?
I might be able to fix this myself if I can find the surgistor somewhere. EDIT: I found the part. Digikey calls it a current inrush limiter and Mouser calls it a thermister so I guess it is a sort of surge protection.
Thanks for any suggestions and help.
Will
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Measure it with an ohm meter, if it measures open it is bad. If you found the part at Digikey look at the data sheet for the cold temperature resistance. This is what it should measure.
For sure its blown, but the real question is, why?
Even if you replace it, this may not be the only problem.
Even if you replace it, this may not be the only problem.
Thanks for the reples.
I couldn't get a consistent reading with my ohm meter so I went ahead and ordered a few of these from Mouser.
As far as there being another problem that caused this, I don't see anything on the board that feeds this one that is obviously damaged so I will probably just swap a new one in and test it before putting it all back together.
I couldn't get a consistent reading with my ohm meter so I went ahead and ordered a few of these from Mouser.
As far as there being another problem that caused this, I don't see anything on the board that feeds this one that is obviously damaged so I will probably just swap a new one in and test it before putting it all back together.
I'm not following you here - put it before the surgistor board? There are a couple of leads that go to that board and if I am not mistaken, they are low voltage DC coming from a small torroidal type transformer so not sure if a 110v light bulb will work??? See pic.
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If something further down the chain shorted, a fuse should have blown before the inrush current limiter (NTC thermistor) went bad. They run hot when operating so failure is not uncommon.
The fuse was the 1st thing I checked and it is good.
No telling how long ago this happened; It may have been something that damaged it but not fatally, and then it only completely failed now or it just failed due to age. I have 2 of these subs that I bought new in 2007 and they were close-outs back then. The dates on the PCBs are 2000 so that gives you an indication of age ....
Will try to post back if this fixes the issue.
Thanks for all the replies.
No telling how long ago this happened; It may have been something that damaged it but not fatally, and then it only completely failed now or it just failed due to age. I have 2 of these subs that I bought new in 2007 and they were close-outs back then. The dates on the PCBs are 2000 so that gives you an indication of age ....
Will try to post back if this fixes the issue.
Thanks for all the replies.