"Jerry" wrote in message
...
On Jan 26, 5:44 am, "Arfa Daily" wrote:
Anyone help me out with a copy of the schematics for a Marantz ST48 tuner
please ? One of those 'friend of a friend' jobs, so could really do with
getting a result on it ... :-\


A quick Google led me to ...

http://www.user-manuals.com/advanced...keywords=st-48

PDF scans of original manuals, US$14.99 each. Never dealt with them,
can't vouch for their service or the quality of the manual scans.

Hope this helps,

Jerry

Thanks both. I'd managed to find a couple of sites that claimed to have it,
but as you say, quality unknown, which is why I was hoping to find someone
on here that could do me a quick scan of one. I might not actually need one
when I get down to it properly. Looks a bit like the front panel system
control IC is not working. No drives to VFD, no signs of activity on push
button matrix lines, so I guess no clock being generated. There is a fixed
level of about 4.5v on the standby button, so I'm thinking maybe low 5v
rail - there is something of a few decimals over 5v going up there from the
main board, and I have had feeds like this going via diodes on the front
panel that have gone faulty by high forward drop - but of course, if it uses
a resistive divider and A-D input on the micro for button decoding, then
4.5v might be right.

Other possibilities might be a bad clock resonator or shunt padding caps,
something wrong holding the reset line, or maybe even a problem with
whatever it uses for memory backup - battery or GoldCap. I just thought that
a schematic for it, or even a similar model from the same stable, might help
to eliminate some of these whilst they were still just ideas. Never mind.
I'll just get the screwdriver out and strip the PCB off the front panel, and
see what we can find behind there ...

Arfa