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Old 15th Nov 2017, 2:48 pm   #33
Vintage Engr
Heptode
 
Join Date: Jan 2008
Location: Shrewsbury, Shropshire, UK.
Posts: 824
Default Re: Philips PM5519 Service info

Thanks again Hugo,

Have tried decoupling IC's 356/365, but this has not made any improvement.
I will try adding some more caps at relevant points.

I totally agree with you in respect of the analog/ digital power rails, first principles really.

I recently tried to use a tiny encapsulated "Quiet" (according to the manufacturers) SMPS on a vintage valve guitar amplifier. I was going to use it to supply a few miliamps at 12v to the reverb driver unit, which was transistor.
This was to replace a rather hideous w/wound resistor & power zener, that was dissipating too much heat.
The spikes on the 12v rail had to be seen to be believed, and nothing would get rid of them, so I went for a miniscule 'real' transformer & linear regulator, - problem solved.

I am beginning to think I should adopt a similar approach & feed the analog parts of the PM5519 from an entirely separate supply.
Too much hassle though!

I'll let you know how I get on.

Thanks again.
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