Rotel RC 995

Having trouble with this unit and need some help ( schematic is available )

All voltage are present the unit is in mint condition and i trace the problem around TC 9173P and TC 9174P problem is that these seem to be very obsolete plus that it seems that i cannot get any datasheet for them in order to start checking a few things around .

Any ideas ???

Kind Regards
Even though i have fixed the unit i forgot to update the thread plus i have fixed a few more in between so here is what i found

One unit had a capacitor that actually measured very properly replacing the working capacitor started the unit that was stacked on stand by 2.200 uf cap rated 6.3 Volts next to CPU that will be C 701

Other unit had 7805 faulty regulator on stand by board ( but also no stand by indicator)

And the other unit had a poor soldering on the resonator next to CPu

Kind regards
I have a RC-995 that gives a popping sound when I switch sources. The pop is loudest when it is just turned on and used for the first time but there is also a slight pop when the source is switched again. Is this a familiar issue? Maybe it is not a real problem but it annoys me. I have a service manual with the schematic but it is very hard to read so don't know where to begin. Perhaps a faulthy capacitor somewhere? Thank you!