Sony PSX 600 electronic induced hum

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bernard1
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Sony PSX 600 electronic induced hum

Post by bernard1 » 30 Mar 2018 10:39

It's been about one year since I'm using a PSX 600.
Since the beginning, I noticed a hum, that I thought was caused by the grounding, as I'm using this turntable with a cheap phono preamp, the receiver it is plugged on having no phono entry.
But yesterday, I found what (or where) is really this hum coming from : when the TT is powered on, the platter not running and the stylus landed on the rubber platter cover, you can hear a quite loud hum, probably induced by the electronic of the TT, through the axis of the motor. Because, when the arm is down, and so the cell output going to the amp (this model has a switch that make the output silent until the cell is down on the record), but out of the platter, this hum is not audible.
I replaced two caps on the power supply board, a few months ago, for this table is aged 30 years, at least, and had some issues with starting, and the record size detector lamp.
In another post I exposed the issue with the VTF setting, which is only correct after a few minutes of heating, even after the caps change, so probably all electrolytic caps should be replaced, and a good servicing made, thanks to the service manual.
Also I noticed after one or two hours of use, a light "hot" smell, and the platter is warm, lightly warm but I think it's not normal.
Have you, users of similar Sony tables, been confronted to such problems and how did you managed them ? The biotracer arm on this PSX 600 table is rather good, so I would be pleased to be able to use it a few more years.

langer

Re: Sony PSX 600 electronic induced hum

Post by langer » 31 Mar 2018 00:32

Hello,

is it a European AEP model?
If so, what is the mains voltage in the house?
Some AEP models have a transformer with a primary winding which is also intended for UK.
These transformers have a 240V winding with an additional 220V tap.
If the mains voltage in your house to have the 230 V or even slightly exceed the 240 V winding should be used.
(A changeover is possible internally with an AEP model undocumented).

The voltage stabilization + - 14 V and + 5 V are applied to the input side with 30 V, the power loss in heat is high and can be significantly reduced with the changeover.
(Do not worry, the voltage regulation bias is still more than adequate with the 240 V secondary winding).

The electrolytic capacitors C101 and C103 are very close to the heat sink of the voltage regulation and have been very warm for a long time.
These should be exchanged for 105 °C types, preferably low esr.
With a new smaller size also like 1500 or even if short enough 2200 μF

A hum from the pickup when it is lowered on the plate
(yes then a relay disconnects the signal from ground) is still not normal.

Which pickup is it?

bernard1
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Re: Sony PSX 600 electronic induced hum

Post by bernard1 » 31 Mar 2018 14:43

I think it's an AEP model. The sticker says 220V AC, 50/60Hz. The UK model would say 240V.
Here is a picture of the power board :
PSX600owerboard2.jpg
You can see the power cord sheated wires, brown and light blue, and the three main transformer wires, red, white and purple.
The three secondary wires are on the left, two red and one black.
How should the main wires be rearranged to 240V ?

You can also see C101, an Elna Silmic II capacitor, 35V 1000 microF, 85° that replace the original Nichicon.

langer

Re: Sony PSX 600 electronic induced hum

Post by langer » 31 Mar 2018 23:54

Hello,

yes, it is clearly an AEP model for 220 volts but to 240 volts adjustable.

The pin on which now the red wire rests is an unused parking position.
The two wires red and purple of the transformer have to swap their places.
After that, the purple wire is in the park position, the red one is where the purple used to be. White stays where it is. That's all.

These capacitors are very large for their capacity and voltage strength.
It would have been synonymous in smaller design.

bernard1
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Re: Sony PSX 600 electronic induced hum

Post by bernard1 » 01 Apr 2018 12:21

Thanks for the tip, rewiring done :
PSX600powerboard3.jpg
I will now let the power on for some time and check the heat production.
Yes, those caps are so big, I had to rearrange them to close the bottom cover. There was only two types at my local store, low grade ones and those Elna. I will eventually change them for some smaller ones later.
I think there are other caps to replace, as I have issues with VTF setting.

Concerning the cart, it's an AT95E, I'll make a try with another preamp, to determine if the hum comes from the cart, table, or preamp.

bernard1
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Re: Sony PSX 600 electronic induced hum

Post by bernard1 » 02 Jun 2018 21:49

Hum is definitely coming from cheap preamp : when connected to a Quad 33 phono entry, this PSX-600 is totally quiet.

Gillingham57
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Joined: 28 Nov 2016 16:35

Re: Sony PSX 600 electronic induced hum

Post by Gillingham57 » 17 Feb 2019 23:00

Can anyone help my Sony Psx-600 has two major issues. First when i use my Coral MC81 low output MC Cart the Sony sounds very good until The Arm plays a quarter of the record, there is a loud pop through my speakers, I have tried manually moving the arm to the end of the record and waiting for the arm to auto return, then replay the record, the loud pop is heard on the last quarter of the record. the second issue and the more problematic is using a Nagoaka MP110 MM Cart as soon as the stylus hits the record there is loud audible hum, I have fitted monster rca plugs and new cart leads and the issues are still plaguing the Sony. My Denon DP45F has none of the above issues. My System consists of the Sony PSX-600, Denon DP45F Carts Denon DL103, Coral MC81 and a Nagoaka MP110, amplifier Musical Fidelity AI, Cd Denon DCD1420, Tuner Creek Cas 3140 And a set of Diy open baffle speakers. All Interconnects are Chord Company speaker cable are Transparent Company. All the components bar the Sony are faultless and extremely rewarding.

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