Trouble shooting on a Pioneer SK 757L

[teisco]

My new box is arrieved, the Pioneer is in a very good condition, but the tape running occasional to slow !!

Now, i open the box, and i found this trouble !! The belt moves sometimes from the motor collar. Why ???
I have a another pioneer box (sk 300) for parts only and i compare the collars. See the photos, it´s grazy

Now, i install the collar from SK300 and the tape running perfectly

It`s a great box with a 30watt power amplifier !!

 

[2steppa]

Very nice sounding box, I have two of these - one just a scrapper really but the other pretty nice.
Lots of features and a heap of controls under that top flap
Cool LEDs too.

I believe it's more like 5w per channel, the power consumption on the rating plate says 30w.

 

[Fatdog]

That flat belt looks really old. I bet that is why it was slipping.

 

[baddboybill]

That flat belt looks really old. I bet that is why it was slipping.

you should do a complete belt change

 

[teisco]

o.k. the belt is very old ( the first) , i check the www. for a new one.

But see the different collars. With the collar from the SK 300 the tape runs perfect. the collar has the same dimension except the additional ring. With this wall, the belt can`t slipping.

 

[Superduper]

Well, actually, it's not the same size. The SK-757 one is larger in diameter where the flat belt normally rides. The belt needs to be tight or else it slides down the pinion. When it's tight, it naturally "climbs" the pulley to the high spot. Installing the SK-300 one with the guardrail might keep it from slipping off the pulley but the edge will be riding the rail until it grinds down into a powdery mess. And it might slip too. And I dunno on this one but if the belt slips during a play session and refuses to disengage the heads and reset -- then the door might not be able to eject and the boombox might not be splittable making it near impossible to repair without exercising a risky pry the door manuever and snap off the counter reset knob.

 

[Fatdog]

When it's tight, it naturally "climbs" the pulley to the high spot.

Yep. That's why the plastic is shaped like that. I suggest getting new belts and replacing the original 757 collar. It should work perfectly then.

 

[beatbox]

The SK757L NEVER had the extra ring part, but it worked once... when the belt wasn't old.

Don't replace the collar, replace the belt!!!!!!!!!!!!!

 

[teisco]

O.K Thank you for your help, i will install the original collar and a new belt. I found a belt for the sk 700 . If it is the same ?