Sharp VZ Microcomputers

[Funkateer38]

I read your post but do you use the right belt because the VZ-2000 are different from the VZ-2500. The one from the 2000 are smaller and therefore increases the reading speed.

 

[floyd]

I can't remember if the 2500 has the 33/45 rpm electric eye inside the lp door if so I would check the position the selector. If its not firmly selected it will interfere with the sensor.

 

[caution]

Floyd, there's an RPM button, that's the thing docs is having trouble with

 

[floyd]

If what he needs is the lp door sensor then I have those parts . I took the turntable out of my 2500 so that's why I had a hard time remembering.

 

[caution]

Yeah Floyd maybe it's not the button, maybe the sensor circuit is the problem?

docs, check the circuit tied to pin 39 of the CPU, If that pin is sitting near 5V all the time, you may have a bad part in the sensor circuit.
If that pin always thinks you're in 45 mode, the 33/45 button may not do anything.

 

[docs]

Yeh it ties to a resistor leading to q508 which is new and all resistors read good.
The sensor on the door is firmly in situ on auto, I think those sensors are transistor like components according to the schematic. Hmm.

Might have been on to something Floyd, that sensor in the door feels a bit stiff, ive wiggled it some and it seems more stable...

 

[floyd]

I have complete boards for this turntable so just let me know if I can help with parts.

 

[docs]

Will do, thanks Floyd and thank you all for your invaluable help.

 

[floyd]

No problem , usually what happens is nobody plays 45's on these then crud build up and damn near locks the selector in place with little or no contact , sharp boxes seem to absorb moisture like no other brand.

 

[caution]

It seems strange though, that the sensor would override the selector switch, but it may work that way. So what happens then if you ground pin 39, does it cause the opposite, in that the selector switch seems stuck on 33rpm instead?

 

[floyd]

As far as I know you have to select between 33/45 on the top and by changing the 33/45 selector in lp door as well to play the different sizes at least that's the way it works on the vz 2000.