HELP! with Pioneer SX-253R AKA Optimus STA-3180

[Ronald W. Coon, Jr.]

I need to know if someone has a schematic of this unit (Pioneer
SX-253R) AKA Optimus STA-3180. I need to know which power transistor
goes where... otherwise I don't wanna let any smoke out.

Thanks.

Ronald

Repsond to :

[email protected]

 

[Mark D. Zacharias]

The positive B+ voltage goes to the collector of the NPN output - the
Collector of the PNP output goes to the - supply line. There could well be
other parts bad though....

Mark Z.

 

[William R. Walsh]

Hi!

Do you have a manual for this unit? I have the Pioneer branded/made unit and
I'd like to know more about operating it. There are some buttons I do not
understand the function of. I'd also like to see a mapping of the display in
the unit.

The reply-to is valid and works after obvious repairs...or if not, let me
know and I'll tell you what to do.

William

 

[Sofie]

William R. Walsh:
What buttons do you want more information about??

 

[Ronald W. Coon, Jr.]

Sounds easy... how can I test this without the schematic.

--Ron

 

[Mark D. Zacharias]

You can measure with an ohmmeter or visually trace the connections from the
collector of an output transistor (the center of the three solder pads) to
each of the outputs on the other channel. Each one will be connected
directly to the its equivalent on the other channel via a foil-run and / or
jumpers.

Or you can look at the two main filter caps. One will have the positive side
ungrounded - that goes to the NPN collectors of the outputs. That cap which
has the negative lead ungrounded makes that connection to the PNP outputs'
collector.
This applies to your model, but is not totally consistent across brands.
Marantz for example would sometimes connect power to the emitter leads, and
even place emitter resistors in the collector leg of the circuit.

Mark Z.

 

[William R. Walsh]

Hi!

There's really only button I'm curious about--the RETURN button. I can see
that it kicks off the "Super Bass" setting, but beyond that I don't know
what it does.

I'm working on figuring out how to store stations 11+, but that's more of a
curiousity than anything else. I only need the first three station presets.

I have noticed that the display face has some colons (indicating a clock
perhaps? If so, how?) and some stuff for RDS. Do these features exist or are
they for other models?

William

 

[Mark D. Zacharias]

The Return button cancels all user settings, wipes the station memory, and
returns it to the factory "out-of-box" condition.

Mark Z.