Sony PS-x75 coil/cam removal

[brinsmead]

Sony PS-x75 Turntable. Removal of cam/coil holder 1-867-113-00 to allow arm lifter to operate freely, and to stop

Arm related issues such as the arm swinging wildly before setting down.

1…unsolder all coil termination wires

2…unsolder cartridge wiring

3…unscrew and lift head wiring shield cover over cartridge wiring.

4…unscrew PCB board position detection sensor. 1-601-927-00

5…unscrew shutter and remove 4-867-111-00 from coil holder x-4867-102-0

6…unscrew 2 x grub screws on the x-4867-102-0 M3 x 4 with suitable size Alan key

7….before removing the grub screws, mark with texta pen, the arm tube and coil holder (above) and try to use the same idents where the existing screws have touched the shaft.

8…. Remove coil holder.

9….remove 2 x brass mounting posts

10..Remove 2 x magnet assembly. ( Yoke 4-867-108 ) identify the marking as they are to be fitted as taken off. ( lift vertically as ferrite magnetism is strong)

11…Remove the surclip on the shaft.

12…Ease the coil holder/cam 4-867-113-00 from the shaft.

13..Gently with coil wires still attached place upside down to expose Sony Grease ……remove all old grease from bearing

14..REMOVE all Sony Grease from shaft.

15.. Use white grease such as MOLYKOTE on bearing surface and on lifter ident.

16..When refitting the shutter make sure its centralised in the housing

 

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The start and finish result picture

 

[brinsmead]

Additional Info.....
Between steps 4 and 5 remove the top 2 x yoke plates....
Use good JIS screwdrivers on this job.......for removing the brass supports use a good flat blade ideally this would not be tapered
I used cotton thread to bunch the coil wires together as these rotate with the cam/coil holder
Check the continuity of the 3 switches, Deoxit if necessary
Keep magnet assembly together and aligned
Put a smear of white grease on the cam/coil holder where the switches make contact
use a set of tweezers to hold LITZ wiring

 

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Ive redone the exploded diagram poor resolution

Note regarding the cracks on the coil holder /Cam ; it would appear every that every PSx-75 will have suffered fatigue cracks from the bearing, I don't consider this to be an issue at this time,In the future I may re-enforce the bearing surround plastic.

This Arm not dropping fault explained here is one of two main issues effecting the Sony PS-x75. the other being the failure of the MB8841-209 4bit Micro replaced with the MB8841-327

These two issues were expounded by the inactivity of the PS-x75 for many years.

One point I noticed that only after 2 or 3 years from new the PS-x75 would take longer and longer to drop to the record........it was worse in the cold weather, when the grease got harder

 

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Lastly...a adjustment to the drop point may be necessary

 

[Lastplace]

My beloved PSX-65 is on the ropes. Perfect condition and everything works except the queing/auto mute. It takes forever to drop and when it does touch the record, no sound. Midsummer it seems to work better, when it gets cold outside forget it. I suspect old grease on the auto mute drive.

 

[brinsmead]

The PS-x65 has the same set up, keep arm at rest position and clipped in place.
Follow the instructions for dismantling, mark coil wires and Litz wiring to cartridge.
remove old grease and re-grease as indicated, and also check the 3 switches for continuity one of which is muting.

Final notes.....This is not a real difficult job....use tweezers to hold Litz wiring when re-soldering,
if it helps.

Take off the platter, invert Sony and straddle across a suitable box, to clear arm.

Take plenty of pictures for reference.

 

[ebk231]

Hello

I have completed this procedure and it cured most of the problems. My grease was actually still good and looking back I think my main issue was loose grub screws.The arm does not act erratic anymore and all the buttons do what they should. I still have the issue of the tone arm not dropping when using the start button. When I hit the start button the arm moves towards the record and continues without stopping til it reaches the center of the record. When I press stop it returns to the rest and when I press the up/down button the lifter does exactly what it should. Im thinking it has something to do with the detection of arm position, maybe one of the leds out in that system? Anyone got a suggestion?

 

[ebk231]

bump

 

[Yikescooby]

Hi, In my experience (I've restored four of the PS-x75 and absolutely love this table!) there are three critical things to address to restore proper function:

1 - Do the procedure in this post to address hardened grease in the lifter drive, and also verify that your lifter up and down switches (two of the three momentary switches around the lifter drive, the other one is the muting) are making contact like they should - up with continuity when the lifter is in the up position up and likewise down for down.
2 - Remove, disassemble and thoroughly clean the control panel. These buttons sit in the open and can get dirty, gummed up and stiff over time.
3 - Perform the calibrations on pages 15 through 17 of the service manual, particularly important for proper tonearm movement are the Slit A/B calibration (which requires an oscilloscope) and the tonearm horizontal motor offset adjustment. The offset adjustment can be confusing. What I found best is to use a blank record (the kind used to set anti-skate which lets the tonearm drift), set the VTF to 1.5 (centered) and adjust RV111 for zero drift (perfect anti-skate)

I haven't experienced any bad ICs. The initial condition of the four tables varied from totally unresponsive to a wildly erratic tonearm. I can't say my sample of four is totally random because I started with complete and cosmetically excellent or better tables.

These tables are totally worth it - one of the very best tables from the peak of the vinyl era.

 

[brinsmead]

Yes I concur the Sony PS-x75 are indeed a great turntable.

I fell in love with mine at a dealership where I was the resident service technician in the early 80’s, about the time they were first released in Australia.

With that purchase I had upgraded to include the XL45A Sony MM phono cartridge to replace the XL25A that was supplied as standard.

I was a Yamaha Service technician in those years, so to go to Sony was bit of a departure for me, something that I’ll never regret, as the Sony PS-x75 with its ease of operation and its ability to stay on track with warped records ( and there were many )was incredible. The detail from he Sony PS-x75 with XL45A is very satisfying , and its ability to shoot to higher register, of which can be attributed to the Shibata stylus is truely amazing.

A few years ago the the MB8841 micro failed, put very simply the word (Locked ) was missing in the Display and with that I thought the PS-x75 was finished as these were mostly unavailable , very surprisingly a small number of the newer version of the micro (MB8841-327) became available on eBay in the States and thankfully to an esteemed member “Vintage” on Audiokarma he helped me with the purchase, and the results were perfect.

A couple of other smaller issues developed over the years one being the grease issue which I gone into ( very common problem), and a motor drive dry solder joint.

Interestingly I purchased a Linn LP12 before the Sony PS-x75, and with a similar cartridge setup in the Linn I could not hear any discernible difference on my albums.
Most of my recordings are pre Digital

My system, is comprised of …………apart from the Sony is all Yamaha with NS2000 speakers, C2A pre, B2 amp. and others. All of which has been with me since the 1979.

In the 1980's I upgraded from Yamaha NS1000's to Yamaha NS2000 as well as upgrading to Yamaha C2A preamp.

 

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While I’m on the job another couple of points to be aware of :

Sony PS-x75….Found a Motor Drive Transistor dry joint on Q117, heat will contribute to a break down on their solder terminations ….

Check 2 x 2SC1419 ……

2 x 2SA755. ……

Q117-Q118-Q119-Q120

also found on PS-x75……Rotational Speed related issues before you suspect motor and or replace with donor motor check CX193 IC Comparator circuits ( IC106), check voltages and or replace this IC if necessary……….its fairly easy to obtain

 

[DualJon]

This is a super helpful thread. I wonder if you will let me jump in, even though I’m a PS-X700 owner.

My tonearm problems began when I had my lamp bulb replaced by a local audio repair shop. Before I took it in for repair, the arm balanced properly and the only problem was the auto speed/record size selection. Now that the bulb is replaced, the arm won’t balance (it blinks L, platter spins then stops). I have the extra Biotracer counterweight and it is not related to that or the weight of the headshell/cartridge.

What are the common culprits for this issue, does anyone know? Where should I focus my attention when I look at the service manual?

Please don’t say oscilloscope. I don’t have one of those! But I’m pretty handy with a soldering iron.