Problem with Phase Linear PL-8000 - quartz lock LED always illuminated and plays slow

[ChopperCharles]

So I have one of the venerable Phase Linear PL-8000 linear turntables. I put new belts and lubed the gears a few years ago, and it's been working perfectly - or so I thought. Listening to blue suede today I realized it was playing slow. I investigate, and the quartz lock LED is always illuminated, even if I physically slow the platter down with my hand, and even when the platter isn't rotating at all. Is this a common problem and easy to fix?

Charles.

 

[orange]

Isn't it supposed to be on? So you are saying that you try to turn it off and it doesn't change the lamp status?

 

[orange]

Does this help? http://elektrotanya.com/phase-linear_8000_series_sm.pdf/download.html

 

[laatsch55]

Ed has a lot of experience with these perhaps he'll chime in....

 

[ChopperCharles]

It's only supposed to be illuminated when the platter is spinning at the correct speed, and is supposed to turn off when it's not at the proper speed. It's always on, the LED never shuts off even when the platter speed is incorrect. (ie, I'm stopping the platter with my hand).

I have the service manual.... but holy crap, I need a scope to adjust anything

Charles.

 

[oldphaser]

It's only supposed to be illuminated when the platter is spinning at the correct speed, and is supposed to turn off when it's not at the proper speed. It's always on, the LED never shuts off even when the platter speed is incorrect. (ie, I'm stopping the platter with my hand).

I have the service manual.... but holy crap, I need a scope to adjust anything

Charles.

Charles,

I would suggest you contact Dean Nissen (the last Phase Linear factory service manager at the Lynnwood Washington plant).
Dean is the only service department employee to receive first hand training at Pioneer's plant in Japan.
Dean still actively services these turntables and has all the necessary fixtures and extender cables.

Send me a private message and I'll send you his phone number.

Ed

 

[stuwee]

Hey Charles, I hope ya get it going again...it's a great TT! My old roomie had the Pioneer version and, these puppies do not like to be moved...as in just from the car to the house...very sensitive piece of gear. I think Dale spent close to $1,000.00 on it over the years keeping it running, when I last called him, it wouldn't turn on at all. Sad!!

Call Dean like oldphaser said, good luck!!

 

[ChopperCharles]

So I've been able to do a little testing with my voltmeter, and I've got a question. The manual says the crystal oscillator should have a 27.78Hz signal of 10V amplitude and 0.66ms pulse width at pin 15 of PD1003. Can I test this with a basic multimeter? In the AC position, I don't read 10v on pin 15. More like 0.2 volts. Not sure if I should be able to pick that up with a regular cheap voltmeter... I obviously don't have ability to test the signal Hz or pulse width, unfortunately. I don't have a scope.

Charles.

 

[laatsch55]

Without a scope you are SOL on that test...

 

[MarkWComer]

Yeah... you really need an adequate 'scope to fix these babys...

I had the opposite problem with my 8000- hit the start button, the arm moved toward the record, platter began to spin up, quartz lamp came on for a second and went out as the platter turned faster and faster. CRAZY fast! The logic circuit prevented needle drop, the arm returned to home position, but the platter continued to spin fast enough to create a gravitational field of its own.

The service manual calls this "runaway."

Don't know what I'm gonna do when this finally goes into failure (I now have the Pioneer version), but for the meantime it's the most delightful turntable I've owned.

 

[ChopperCharles]

Tried getting in contact with Dean. Got him on the phone once, but I've left several messages and I just can't get him to send me his address so I can mail him my motherboard. So it looks like I'll be needing another source for my turntable repair. Preferably on the East coast.

Charles.