Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems DSP 8.2K BUZZ

Dr.Bill& Jerry,

good news.I dit remove my power plarte and check that out for you:
You can tighten the cap head screws but in different way as I described in my private mail.
You dont have to remove the powerplate, just take a 5mm hex key and CAREFULLY turn the screw clockwise about 1/8 of a turn.
Then try if the hum is gone.
If not you can try once again but not more as on 1/8 turn clockwise.
If you feel more resistance before 1/8 turn dont turn further.

One thing is to check that the whole power plate is not to deep mounted on the cabinet.
If this happened,then the bigger transformer touches the cabinet inside the cabinett opening.
The correct height is when there is a small gap between the top edge of the power plate and the cooling case of the electronics(not more then 2 mm.
Also the lower edge of the power plate have to be at the same height or above-never below-
the bottom of the cabinet.

If that is the case,you have to loosen the 3upper and 3 lower screws and push the power plate up to the correct height(heavy !!) and then tighten it.
Take care at the same time to make equal gaps on the left and right edges.

Also check the six screws that holding the power plate if they are tight,but dont overtighten it.
In this area of the cabinett "only" wood is there.Take care.

If the hum is still there,then it could be

a) DC on the power line(but a DC Voltmeter in the range of 700 VDC-not less as then your measurent is wrong!!) as one transformer is maybe more sensitive as another.

b) Transformer is "biased" (could happened)

c)As George described, loose connection-I have no experiences with that.

Good luck

Robert