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Sony PS-Q7 tonearm woes etc

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Sony PS-Q7 tonearm woes etc

Postby Laus » 21 Feb 2014 11:42

Hi,

Late last year I purchased a refurbished PS-Q7 from Ebay. I've had quite a lot of troubles with it, mainly with the tonearm, which is rather "limp". I also need to hook it up to my amp from the headphone jack in the front to be able to hear anything. The seller appeared to be helpful at first, but after I had to take a break because of family matters, he stopped responding to me. I came here for advice after trying to contact him via PM. Here are the two videos I made for the seller to demonstrate the problem with the tonearm:





I guess the tonearm belt is having some issues? What about the two built-in amps, is it normal that the one in the back puts out such a low signal?

Thank you for your time :)

Toni
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Re: Sony PS-Q7 tonearm woes etc

Postby ATHERMOS » 22 Feb 2014 16:09

Please note that the direct output from the cartridge is bound to be low ~ 2.5 mV or so, you would need a preamplifier capable of providing RIAA equalization to amplify it. There are 2 amps inside, one is the equalizer amp and the other the audio amp for driving the headphones both are necessarily in series As for the tonearm, you would need to clean the moving parts and adjust per the service manual.
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Re: Sony PS-Q7 tonearm woes etc

Postby Laus » 08 Nov 2015 19:25

So, I didn't get anything done about this and it was in storage until this weekend. I pulled it out and opened it to take a look at it. Excuse my ignorance, but where is the tonearm belt supposed to be located? I can't see a belt anywhere.
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Re: Sony PS-Q7 tonearm woes etc

Postby fscl » 10 Nov 2015 21:21

Laus wrote:So, I didn't get anything done about this and it was in storage until this weekend. I pulled it out and opened it to take a look at it. Excuse my ignorance, but where is the tonearm belt supposed to be located? I can't see a belt anywhere.


Download the service manual from the VE library:

https://www.vinylengine.com/library/Sony/ps-q7.shtml

Not sure if they were here when you originally posted.

From what I can see, there is no tonearm drive belt just the standard Sony drive gear and cams for tonearm movement. The exploded view shows a 90 deg space saving offset and not a linear tonearm.

It also appears just a few tweaks are needed to have the tonearm travel to the correct start, stop, reject and rest positions.

Good luck.

Fred
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Re: Sony PS-Q7 tonearm woes etc

Postby Laus » 31 May 2016 06:45

I'm glad to say that I finally got the tonearm throw fixed. I feel like an idiot for letting the Ebay auctions that sell belts for this thing influence my thinking... there is no belt! :lol:
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Re: Sony PS-Q7 tonearm woes etc

Postby henrydaly2 » 18 Sep 2017 20:59

Hi All,

This is my first post on vinylengine. I realize this thread is a few years old but there doesn't seem to be too many people talking about this deck anymore so I thought this might be a good place to post, apologies if it's in the wrong place.

I also recently bought a PSQ7 from ebay. Its working pretty well apart from the headphone port which only puts out sound at certain volume positions and only ever in one channel(alternates between L & R) at a time.

I don't currently have a phono stage with me so I haven't been able to test the phono out on the back but there is definitely signal to both channels.

I'm thinking that the volume potentiometer probably needs to be replaced so I downloaded the manual from here and identified the part. I also opened her up and had a quick look at the pot. But I'm struggling to find the part on-line.

In the manual its RV601 and the part no. is 1-228-169-00 RES,VAR, CARBON, 10k/10k.

The actual part in my TT has got 31103A printed on it as shown in the attached picture.

I can find plenty of 10k pcb mounted variable resistors but this one has a hole in the middle for a screw which the volume dial mounts to. (I've attached a screenshot from the manual showing the dial, screw & pot assembly)

Does anyone have any idea where I would find one of these parts? or is there a better way to fix it.

I would massively appreciate any opinions/criticisms/wisdoms on this
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Re: Sony PS-Q7 tonearm woes etc

Postby John Little » 21 Feb 2018 00:15

@henrydaly2, not sure if you are still monitoring this thread. I would love to hear what you did about the volume potentiometer on your PS-Q7.

I'm restoring mine at the minute and am facing the same issue. Broken potentiometer, no suitable replacement (that I could find) on ebay.

My potentiometer is labelled slightly differently. 3D103A instead of 31103A. The "103" part means 10KOhm, and the "A" may mean logarithmic scale, which would make sense for a volume knob.

The closest I could find is either RV12SK6 (right mini shaft with screw hole / general shape / height) but is mono so probably not good. Or "10PCS A103 10K Duplex Gear Potentiometer A10K 16x2.8mm 5pin for Radio MP3 MP4 UK" which potentially, I could solder to a bit of stripboard and fingers crossed, will fit instead of the original PCB. For reference, the original wheel is 23mm diameter x 2mm thick and the (smaller) wheel on the A103 looks like it's riveted in place. Fun fun fun.

Or I could try and "fix" the existing potentiometer which loses one of the channels if I press down on the wheel and generally makes a lot of cracking and hissing when turning.
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Re: Sony PS-Q7 tonearm woes etc

Postby henrydaly2 » 31 May 2018 23:48

@John Little

Didn't see your reply until now, I had a shot at the volume control this evening no good news though I'm afraid.

I picked up a 34 103G from a parts store in Helsinki, it has exactly the same form as the one from the Q7 and should be a 10K log pot. I fitted it and there was no improvement. I can still get loud audio in one channel when I play around with the dial for a while and press it inwards.

Because I can still get audio after changing it I'm half wondering if the problem is further up stream but hopefully not, these aren't too fun to take apart!

I was looking at the logo on the side of the potentiometer and it looks kind of like a 'P' but I don't know what brand that would be, I don't really know component manufacturers at all.

Be interested to hear how you got on and if you had any luck with your deck. How were you planning on fixing the existing potentiometer?
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