Pioneer PL-7E idler - They're Stacking Up Now! My Next, Next Project

[mfrench]

Thanks, Nate.
I think its a really nice table; after giving it the extended tear apart, I see potential. I didn't expect to get this far with it already, but couldn't resist taking on that motor'ism. That would have eaten at me if I shelved it.
Now I can shelf it for a spell, and finish the record storage rack, the BP51HP project, the patio renovation project, the house painting,.... the massive honey-do list.

OK,... where this thing is at, as of yesterday:
new power supply board:


I had some acrylic, and put it to use as the mounting board for the power supply.  I drilled holes large enough for the legs of the caps to pass through, after they'd be "heat shrinked" to insulate them. I then weaved the legs back through another set of holes that act as strain relief. Where I connected the wires to the caps, I heat shrunk those connections and zip-tied them to the board for further strain relief.
I found that a 1" copper plumbing cap perfectly fit the existing capacitor clamp, so I drilled a 1" copper cap and used it as a mounting base. The board is insulated from the copper cap by a thick rubber washer (and the heat shrink on the capacitor legs). All of the connections within the motor circuit are soldered, with exception to the mains input leads, which are wire nutted until I get a better power cable.


My lucky find at the electronics shop. It fits perfectly. It will work really well until I can get a new threading into the original.
The platter o-ring is a left-over from my Bogen BP51 project, and I think it makes a really nice finish. I might add more.

[Chris65]

Hi Mike,

Nice work. Following with interest, as I have one of these too, although mine is designated PL-7 (no E).
Has the same arm, switches, bearing but slight differences in the top plate and motor. Picked it up earlier in the year, but haven't done anything with it (too busy). It seems to run ok, but haven't checked the speeds.
A bit of corrosion is coming through the top plate so needs repainting and the rubber motor mounts are shot.

Some pics:

[mfrench]

Hi Chris,

Thanks for posting that!
There is incredibly little information on these decks on the internet. It seems that we have a less common beast on our hands.
Strong similarities and some differences.

One of the strongest differences is the transformer that is in yours.  
I wonder if that is what really makes the diff between the 60hz and 50hz models? ooops,... never mind. That's for the 120/220v differences.
In truth, when I switch mine from 50 to 60hz, I do not realize a speed change, or any difference for that matter. It seems like maybe I'm hardwired for 60hz?

I'm not sure of what the designation of "E" stands for. These decks are precursory to the Exclusive line. So, maybe some reference towards that?

My motor mount plate is more covered by the top plate, making it impossible to adjust my idler spring tensioning. I was telling my wife that I felt like cutting the plate back to open it up in that area. I like what they did with yours far more.

[mfrench]

In keeping the info flowing for this somewhat uncommon deck,......

Tonearm

The tonearm wouldn't be too bad, except for the fact that it is constructed of tons of small non-captured ball bearings.
I expressed a feeling that the arm felt a bit like bad v-blocks earlier in this thread. Well, that's because some of the bearings had already disappeared from the arms vertical lift motion bearing.
There are two races of bearings that make up the vertical lift.
The horizontal sweep bearings are also in non-captured bearings in races (meaning loose balls). The races are loaded via nuts that are the outer race surface.
I'm already missing balls in these bearings, so its doubtful that this arm will be used.
I might use the components to make my own arm, so all is not lost.

[Graeme]

What size balls?

Local bike shop may be able to help out.

[mfrench]

Bike shop,... good idea.
They're specks, really tiny, like .3mm->.5mm small.
Thanks for that thought! I'll try that route.
Another thought might be to find a precision sealed bearing and retrofit it into the old race. I'm not sure how much time I want to spend trying to revive it. We'll see.

I think that someone might have lost a bearing screw (conical end), and replaced it with a standard machine screw which allowed the balls to escape, as the conical screw end is part of the bearing race, as inner race.

At any rate,... I boxed this Pioneer project up, and it's in now shelved in the garage now that the power supply has been sorted. I need to finish the soapstone tonearm, and, get back into the BP51HP project,.. and whatever else Sarge comes up with in her own list.

[Chris65]

What size balls?

Please!!......

Mike,
I received a photocopy of the turntable manual from the seller, let me know if you would like a copy.

There's also a very recent thread on AudioKarma on a PL-7. It's identical to mine apart from the nice headshell on the arm.
In much nicer condition as well:

[mfrench]

Thanks for the heads up to the AK thread. I'm not a member there, and have just signed up, and am awaiting approval

Manual,...
I'd love to get a copy if we could make that arrangement. Please and thanks.
I'll send you a PM in this regard.

[hotrod]

Hey Guys,
 Some photos of a PL-7 in my possesion.I don't know if it's an "E" version I cannot find a model # anywhere also,the motor on mine looks chinsy compared to yours and the mounts have completely melted.Not sure if I will do anything with this one or not but anyways....

[Chris65]

Hi Hotrod,

Thanks for chiming in. (do you have a name?) I think yours is a PL6A - if you go to the Japanese site that Mike mentioned at the start of this thread, it shows various Pioneer turntables. And judging by your arm and the 'earlier' look to the underside of your table, it is most likely this earlier incarnation which then became the PL7.

Being an idler, I am keen to hear how it sounds. Don't think it will match a Lenco though.

[mfrench]

I renovated the arm last night and this morning.
To fix this arm required a bit of 'ciphering. It was made up of ball races with non-caged balls. on the outer side of the tonearm turret, there were races on either side that created the vertical lift. The balls were loaded into the race, the arm inserted into the turret, then a screw with a conical end was inserted from the outside edge of the turret, inward. The conical end of the screw was supposed to enter the bearing race, and with tensioning, allow for smooth vertical lift.
Well, someone lost the ball bearings on one side, and just stick a normal machine screw into the hole. This allowed the arm to appear somewhat normal, but it had a nasty ghetto lean to it.
So I started studying on the ball race, and saw that it had been drilled to cause the sharp end of the race screw to not touch the arm.  The recessed area was the same size as one of the balls from the race.  I still had a good race with the balls in it. So I extracted the balls, and placed a single ball within the recessed area for the race screw. The ball was slightly taller than the recess is deep - perfect!
So I took a dot of grease and "glued" a ball in each race, and reloaded the arm into the turret. I then took an allen screw (4-40) for each side and screwed them in until the *cupped end of the screw contacted the ball bearing.
So I adjusted the arm until it became a touch too tight, and then backed it off a touch, just enough for free movement.

I also converted the output wiring from DIN plug at the base of the arm, to RCA jacks on the rear of the box plinth.

At any rate,.... she spins again!
I'm now listening to a Beethoven chamber music record (started with a tired out Buck Owens LP), and it really sounds great. Really a nice little deck.

* The end of screws are cupped in manufacturing by the pinching of the rod stock as it passes through two thread plates. The threading plates distort the metal leaving the ends cupped.

just to get into the system spot,....

[willbewill]

That really is a pretty deck Mike, I'm getting to like plinths that are same size as top plate. Nice work.

[mfrench]

thanks Malcolm!
I agree,... it a pretty little deck. Its definitely an idler with massive punch. The bass passages have attack, rather than a retreat feeling to them (listening to Pachabel chamber right now on it).
Sarge loves it as well.  She was all over it again last night when I had it out to get the arm out (had it boxed in the garage since fixing the motor).
With the exception of a couple of other clean up upgrades,... this one might just be a finished project. The plinth is quite nice, and in nice shape. The deck runs quietly in it too.
I'm going to put a more substantial base enclosure on it, a grounded power cable, and a couple of other slight bits - then its off to the bedroom system.

[colin]

Hi Mike,

The 7 is a nice deck, altogether the heavy platter version to the 6's more lightweight chassis etc.  The controls are very similar on both, here's a 6 I bought a few years back for the fun of getting it working  .................   

http://www.freewebs.com/strictly_vinyl/idlersfromtheeast.htm

Very user friendly for it's time, and the only one I've seen in the UK so far.

 

[GP49]

I renovated the arm last night and this morning...I started studying on the ball race, and saw that it had been drilled to cause the sharp end of the race screw to not touch the arm.  The recessed area was the same size as one of the balls from the race.  I still had a good race with the balls in it. So I extracted the balls, and placed a single ball within the recessed area for the race screw. The ball was slightly taller than the recess is deep - perfect!
So I took a dot of grease and "glued" a ball in each race, and reloaded the arm into the turret. I then took an allen screw (4-40) for each side and screwed them in until the *cupped end of the screw contacted the ball bearing.
So I adjusted the arm until it became a touch too tight, and then backed it off a touch, just enough for free movement.

EXCELLENT! That is exactly what several real manufacturers did for vertical tone-arm movement in the early 1960s: a cupped screw onto a ball.  It works, and very well if set up properly (the proper procedure is yours, exactly).

Some makers eliminated individual adjustment of the screws and balls by putting tiny springs behind them, providing preload.