Sir JPfx . . . . .
" Mah fren " . . . and you are my friend . . . . you do realize that you have yourself , one overall COMMMM - PLEXXXXX piece of equipment there . . . do you not ?
Along with all of the hollow feelings, in the pit of your stomach, when u see its schematics and documentations prolific use of " NO REPLACEMENT PART AVAILABLE. "
Now, does any thing light up on the front of your unit, if even only blinking for just an instant, at your attempted turn on with the main power switch ?
You can just hope that this units problem, relates to a power supply, audio power output / overload protection circuit fault. ( Most do ! )
Since this units design, incorporates a discrete part build up of its audio power output stages circuitry, why not look for sometthing simple first, even before checking the main power supply(s).
Find the units . . . . . " HEAT SINK CITY " . . . . . and on it, there should be ~ 6 sets of complementary PNP/NPN power output transistors being found heatsinked.
They will be of part numbers 2SA1695 and 2SC4468 markings.
In a NO POWER TO THE UNIT test . . . . . .
Place your meter in its lowest ohms test range . . . short its probes to see how a dead short displays . . . . and then test from Collector-to-Emitter on all of the units aforementioned power output transistors, to see if you might be ever so lucky as to find a shorted one(s).
Initially performing that test , see how you come out on that ?
FIO . . . . in later testing, you will be expecting a 2 .7Vdc logic ON level to activate the base of the Q 3702 relay driver transistor for its relay, which you are already being familiar with.
Considering the speed of the DC voltage blip that you might just find initially popping up . . . . on and then off . . . . . in case of default, on that Q3702 base . . . . .are you a scope person . . . familiar with + triggered, vert DC coupling mode analysis of a + going pulse ?
If not, I will give you a work-around.
AFTER THOUGHT . . . .
Has THIS unit been successfully working previously, with the same 220-120 power converter ?
ZUJ ing . . . . .
73's de Edd . . . . .
All syllogisms have three parts; therefore this is not being a syllogism.