Short??

[Jesse14]

Polling the hive in hopes I can finally resolve this: I have a fully professionally restored Harman Kardon 730 that looks and sounds gorgeous. I use it mostly for vinyl, for which I use a Realistic Lab 400 which was professionally serviced prior to adding to my setup. The issue is that - frequently - my right speaker shorts out (?) during playback. The R400 has hardwired RCA's but I don't believe those are the problem (and I have switched pos/neg inputs and the problem is consistent with the right speaker). When this happens, it seems the only thing I can do is fiddle with the turntable ground wire at the receiver ground knob. I always have the exposed wire-end snugly turned around the ground pole with the knob securely tightened. When the speaker shorts, I usually have to pull the ground wire from the ground pole on the receiver. As soon as I break the ground circuit, the right speaker pops back on - but always (and obviously) with ground hum. Then I halfway re-attach the ground wire to the post and the stereo image returns for a period of time before inevitably shorting (?) out again, and I must start over. This problem has been consistent across 3 sets of different speakers. I am honestly at my wit's end with this, and my hunch is the fix is probably something pretty basic. Any thoughts or suggestions would be welcome!

 

[Warren-Oates]

If your speaker was to short you would be blowing fuses or devices. I think you mean your sound is lost? You seem to say that it is only on the Phono setting, and that manipulating the turntable ground wire attached to the rear chassis of the HK restores the sound for a while? First thing I would due is clean up the ground terminal on the chassis. I had an HK430 that produced strange buzzes and dropouts from a TT, the ground connection turned out to be very poor. I would remove the terminal, lightly sand where the nut is inside the chassis to nice fresh shiny metal, a film of d5 if you have it, then snug everything back up. You could also test your ground lug with an ohm meter, just to get an idea if it is bad. If your ground lug is working and you still have this problem next I would suspect something is off with the turntable or it's cable.

 

[Jesse14]

These

If your speaker was to short you would be blowing fuses or devices. I think you mean your sound is lost? You seem to say that it is only on the Phono setting, and that manipulating the turntable ground wire attached to the rear chassis of the HK restores the sound for a while? First thing I would due is clean up the ground terminal on the chassis. I had an HK430 that produced strange buzzes and dropouts from a TT, the ground connection turned out to be very poor. I would remove the terminal, lightly sand where the nut is inside the chassis to nice fresh shiny metal, a film of d5 if you have it, then snug everything back up. You could also test your ground lug with an ohm meter, just to get an idea if it is bad. If your ground lug is working and you still have this problem next I would suspect something is off with the turntable or it's cable.

These are great suggestions, W-O! I will do these and let you know how it works.