Pioneer PL-L800 button problems.

[QSilver]

I recently picked up one of these with some problems. The linear arm seems to be okay and will work when I manually move it around. My problem was that none of the auto functions would work at all.

I went through it with the SM and tested the relevant pins to check if signalling to the various ICs was good or not. I had signals from the tracking buttons but nothing coming out of the main chip. Then suddenly, I got some movement on the scope and it started to work properly for a few operations, then died again.

I decided to double check the push buttons on the elevations system and I found that one of the switches is jammed in. This, I'm guessing could be causing most of the problems. Auto functions won't work it it doesn't know that the arm is raised...

So it looks like I need to replace them. They look to be push-to-make type switches but does anyone have any idea what to replace them with? Anything specific?

 

[Balifly]

I decided to double check the push buttons on the elevations system and I found that one of the switches is jammed in. This, I'm guessing could be causing most of the problems. Auto functions won't work it it doesn't know that the arm is raised...

So it looks like I need to replace them. They look to be push-to-make type switches but does anyone have any idea what to replace them with? Anything specific?

The service manual may have the parts number for the switch.
http://www.vinylengine.com/library/pioneer/pl-l800.shtml

 

[QSilver]

Thanks, I've been using that to check the operation of the chips. By chance, I was looking around and found the exact push button for replacement. For posterity, it's an ALPS SKEGACA010. i'm gonna order some and see if that gets the deck going. I do have a quartz lock issue to address with the Hall motor too... I'll look at that next....

 

[interalian]

I'm working on one that will quickly whiz toward center by itself, but if I grab the tone arm I can make it move back, only to whiz toward the center again when released. One of these I'll conquer it.

You could have a cracked circuit board or cold solder joint on yours.

 

[QSilver]

Yes I was thinking that too... but ill see where the new button gets me.

For ur self, have you tried changing or adjusting vr 2?

 

[interalian]

Yeah, VR2 doesn't do diddly. I think it might be a broken wire to the head. The CDS/lamp sensor tells the computer where the head is...

 

[QSilver]

Solved - The down detector and up detector switches were both dead. Replaced them with those ALPS switches that I mentioned before and its working! Had to clean out the gearbox too as it was full of thick gunk that had built up which made the motor stall.

Next up was sorting the flashing quartz lock lamp - rebuilt the motor board with new trimmers and capacitors and that's working well now. Next will be recapping and fitting new trimmers to the rest of the system, setting it up and trying it out.

 

[interalian]

Ahhh, those buttons. Aren't they carbon puck/elastomer for the originals?

 

[QSilver]

The photo I posted originally was the original buttons. They do have ALPS written on them and amazingly I got identical ones. Taken from the datasheet:

Product Details
Alps SKEG Series Tactile Switch
Alps Tactile or Tact switches are SPST snap action switches to be used with small currents. This series also provide a minimum rating of 10 μA at 1 V dc and a maximum rating of 50 mA at 12 V dc. These Tact switches have SMT terminals, low contact resistance, high contact reliability and come in a wide selection of operating forces and switching travels.

Suitable for use in a wide variety of applications, such as audio & visual equipment and automotive applications.
Available in various actuator types, such as flat stems & joint stems.
Various actuator colours are also available, to ensure your application is covered.

I think these are carbon contact as mentioned in this data sheet...

They are used to ground a logic signal in the turntable.

Word of warning when removing them - those pcb leads are sharp, got one right in my finger and now I have quite a deep and painful slit in the side of my index finger...