Technics SA-700 one channel dead

[flyingfinngt]

Hi all,

I just purchased a Technics SA-700 which only works on the left channel. On the rear panel there are two speaker protection fuses visible, and the one for the right channel is blown.

I don't know for sure, but I assume I would be risking damaging something if I just try replacing the fuse without knowing what caused it to blow in the first place. I also don't know what I should check first.

Can anyone offer any assistance? Could it be harmful to blindly replace the fuse? What would be the first things to check?

Thanks in advance.

 

[gmphadte]

You have to replace the fuse of the same rating and type once only. If it blows, then go for repairs.

Gajanan Phadte

 

[shredhead]

Someone probably shorted the output terminals or connected to small of a load to blow the fuse so who knows if there is damage or not. In my experience sometimes a fuse stops damage and sometimes not. You can look at it this way: if you replace the fuse and there IS damage, either way, it will need repaired so F it.

If it was me, I'd at least check the output transistors for shorts before wasting the fuse. Checking the power rails to the output stage never hurts. If the fuse didn't catch the thing from getting zapped to death on that channel then be on the look out for any visible damage (brown stuff on PCB) while you're in there looking around.

Before you hook speakers up, check for DC on the speaker outs for sure though. People do some pretty crazy crap with receivers that leads to damage so who knows what the real story is. Looks like a pretty neat piece though, LED VU's and whatnot.

 

[flyingfinngt]

Thanks for the info. That gives me a good starting point.

 

[gmphadte]

If you replace the fuse and it blows, it will blow due to the faulty components. This will happen instantly. Sometimes a fatigued fuse will blow for no reason.

Gajanan Phadte

 

[flyingfinngt]

I swapped the two fuses, and the problem switched sides. The left channel went dead and the right channel worked fine. So it looks like it's just the fuse. The only other thing on the receiver that doesn't seem to work is the FM tuning meter. It just sits in the middle and never moves. That's a minor problem though, I'm not too worried about it.

Thanks for the advice!