2. amps-preamps
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Help with blown amp

I have a Plinius SA-102 amp which I have had for a few months. It sounds great and I have never had a problem with it. This evening, I was in another room, not listening to music. The amp was on as always, but no music was being played. All of a sudden I heard a loud hissing sound which lasted for about 3 or 4 seconds and then a click. The amp has an automatic mute switch which kicks in when there is a problem. When I checked out what was going on, the mute switch was on and I could smell burning plastic. The mute switch will not go off, and the amp will not work. I immediately unplugged the unit and tried to remove the top lid (per the instructions) to see if one of the fuses has blown. Unfortunately, I can't unscrew some of the allen nuts as they are too torqued.

Can someone please help me get a good night's sleep and tell me that it's only a fuse? Could it be worse? Any ideas on how to get overtorqued screws out?

Any help would be greatly appreciated.
gboren
7 responses Add your response
twl
3,251 posts
 
Hate to say it, but if you smelled burning plastic, the prognosis doesn't look good. If the amp is just a few months old, then send it back to the Mfr. They generally prefer that you don't take them apart yourself.

If you must take it apart yourself, then you just have to get a little more "gusto" into your allen wrench. That is what they will do at the factory. If you break a screw, then you can replace it after you get the cover off. Make sure that you are taking out the proper screws, that don't have nuts on the other side.
plato
1,543 posts
 
I agree with TWL that the burning plastic smell would seem to indicate some sort of fried part as opposed to just a popped fuse. Chances are that you probably will not be able to repair the amp yourself and since you can't seem to get the cover off sending it back makes the most sense. Remember: it's only an amplifier and it can be repaired. The downtime may pose an inconvenience, but I wouldn't lose any sleep over it.

Just another question -- do you also keep your preamp on all the time and are you sure the problem is isolated to the amp? Perhaps you have another amp you can substitute to check that everything else in the system is working properly...
gboren OP
143 posts
 
Thanks for the responses. The user's manual actually advises the owner to remove the top and see if there are any LED's that are lit, which indicates a blown fuse. I can see an LED through the slits in the top and I'm sure that at the very least, a fuse is blown.

The fried plastic was worrisome to me too. Fortunately, the unit is under warranty and I have a very good relationship with the distributor. My sense of urgency was due to the poor timing: on the eve of a nice long Thanksgiving weekend with a few new LP's ready to spin! Poor me! Add to that the thought of packing, shipping, unpacking, reinstalling, etc. I guess I've been lucky thus far and it's time to pay my dues.

Thanks for the advice.
sean
6,231 posts
 
All i would add to this conversation is that non-mechanical equipment failure is not normal, especially for a new unit. If the unit was 10+ years old and it went dead, i would not think too much of it. The fact that you leave the amp on and have reduced thermal cycling to a minimum and the amp has still developed a problem might have me worried about future operation.

Let's hope it was something simple and just a faulty part. Hopefully, you've got another amp to fall back on so that you won't be "tune-free" for the long weekend. Sean
>
fbi
92 posts
 
~~~~Glad you have the warranty, sorry you have to wait.
For anyone else: If a screw is torqued or seized, and won't cooperate, it can sometimes be coaxed by slightly tightening and slightly loosening repeatedly until oxidation crystals release their bond. Has worked numerous times for me.

Just the Facts

By
warrenh's avatar
warrenh
2,299 posts
 
I don't know about Plinius, but some manufacturers will nullify your warrantee if you mess with their stuff. Once you open it up you may have an additional problem. Burning plastic smell? Sounds like more than a scratch. Send that baby back. warren
gboren OP
143 posts
 
Thanks for all the advice guys. I finally got the lid open and none of the user accessible fuses are blown. That means something more serious. Back it goes.

As for the warranty, the user manual actually advises the user to open the device up and change the fuses. If only that were the problem.

Now to figure out why the thing blew.
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