Turntable chip ID help

[drewl]

Got a pretty looking Marley Stir it up turntable, model EM -JT-000
Speed control doesn't work, stuck at 45rpm

Real cheap boards inside.

The speed switch changes 5v to two different pins of a 14 pin DIP,

It's part # is WB7P314
Not finding anything on it.

Also the three pin driver/transistor/fet???

It's pn# is LSP52.

Either of those familiar to youse guys?


Thanks all.

[Enzo]

Those would be house numbers. try contacting the company, couldn't hurt.

[J M Fahey]

A turntable made out of .... BAMBOO?

"For every product we sell we´ll plant a tree in Kenya?

If it weren´t for the brand I´d think those guys are smoking something



Back to the turntable problemk, scope what the IC and (presumably) pass transistor do.

In principle I guess transistor either supplies 2 different DC voltages for 33 and 45 *or* it´s some pulse width/duty cycle modulation .
Scoping will confirm/denie one of them.

All under IC control, of course, which "should" also incorporate some kind of speed sensing and feedback to make it stable.

Your problem might be "logic" as in a bad IC or simply drive transistor shorted and supplies full voltage all the time.
Either one would explain it being stuck at the highest speed.

Doubt they discovered the wheel or gunpowder (although they are slick marketers) , while waiting for an answer I would also google "turntable speed control IC" or similar, given the vinyl resurgence "somebody" must be making a dedicated IC, which should have a datasheet and even suggested application circuit available.

EDIT:it might be as simple as this:

[drewl]

Hey, thanks guys.

I quickly checked the chip for changes in output while switching speeds with a voltmeter and only the two input pins changed from 5 to zero volts.

Just thought maybe someone was familiar with those part numbers.

I'll look up speed control chips and those schematics should do the trick.

It was just a quick look so I can give an estimate.

Thanks again.

[J M Fahey]

Cool.

First find the proper part and availability before giving an estimate.
The turntable is probably a generic OEM made one in large quantities, only clad in Bamboo Mojo, meaning you might get lucky and find a twin sister, different makeup but same guts, whose schematic IS avilable.
Elektrotanya?
Any inscriptions on PCB?