Sanyo STK handbook STK2028 for Technics SU-Z25

[chris.oates]

I wonder if anyone has a technical handbook for the Sanyo STK series of integrated amplifiers? I have been looking at a Technics SU-Z25 that I fear is beyond reasonable economic repair but in my research into the STK2028 the output stage hybrid pair of Darlington transistors which is one of several faulty components I discovered this youtube video from Peru showing a STK series manual.

https://youtu.be/55XSA-HI94E

Through my rudimentary Spanish and Google translate of associated comments and blogs I think the owner did post a pdf of the manual but was then required to remove it as it was copyright. As I have found it impossible to find a datasheet for the STK2028 anywhere I wondered if this book had the information? The STK2028 works with a pair of AN7060 but I've found a data sheet for it.

I have read lots and watched lots of videos about STK modules, Technics amplifiers etc. and there is a downloadable service manual for the amplifier which gives much useful fault finding information but I would like to see a proper original datasheet for a STK2028 which may show the internal schematic.

There are many posts decrying the Chinese copies of these modules available from the usual sources but as there are no originals available out of interest I have ordered one, if only to open it and see if they have been replicated using discretes.

So far, as well as the SU-Z25 service manual I have found a specification and circuit diagram for STK2025/2029 which may be similar, and a circuit diagram and internal layout for SVI2003 which is said to be pin compatible for the amplifier section but not the protection pins.

Thanks,

Chris