Sir pjnjune . . . . .
Did you get in enough initial testing time to see if your new LED pilot lamp(s) lit up O.K.
Plus . . . . the replacement lamp units have to be AC compatible as 7.5V RAW 60~ A.C. voltage is being their power source
Look . . . and you can see that the AC input to the main power transformer has a principal 5 A fuse that is assigned as F1.
Just your panel lamps and two very minor power supplies are further isolated thru a 1.5 A fuse . . . . labeled as F6.
Is that F6 blown ? if not, your lamp circuitry is very likely not being the fault.
If it was /is the MAIN F1 5A blowing, dont even think of putting in yet another . . . your 2nd ? . . .or 3rd ? , or then we'll KNOW exactly, that we are dealing with a totally brainless person.
Instead, find a table lamp or mechanics drop cord / lamp that will take a screw in old fashioned 60-100 watt incandescant lamp.
Plug it into AC power to confirm that it is now
turned on and
will light up.
If all is in order, then use two wire test leads with their clip lead ends . . . on both ends . . . for making temporary electrical interconnects.
Clip onto each of the two AC male plug blades and the other clip lead ends . . . .go across where the now pulled F1 fuse was clipped in..
Then you plug in the Pioneer to AC power and manually try to turn on the unit . . . .
JUST for an instant, for evaluation of the lamps response.
If you have a serious power supply or audio output power amplifier short problem, your . . . . now newly installed . . . . series test light . . .will come on approaching full brilliance.
Report back if the wires pass thru and are soldered, or if 10 or so TIGHT and close wound wire wraps around square stakes were being used by the factory for making the transformer wires to power supply circuit board connections. ?
Then you could ? . . . . selectively start disconnecting transformer wires that lead into the POWER supply board at its terminals 27-25----28-26 entry points and also the 26-19 terminals. Evaluating the lamp after each disconnect.
OR if you have the techno experience in using an analog or digital meter . . .you could ohm out connections, expecting a shorted diode resulting from the power flashover / Boo- Boo that you created.
Report back with the type of further techno directing that you will need now .
ITS A MIRACLE ! . . . . now instead of a total 48 pages of complex circuitry . . . look what just showed up down below !
It's including just your probable involved circuitry
Le Schematique ( petite ! )
https://i.ibb.co/LkcVPc3/Pioneer-SX-850-Lamp-Supply.png
73's de Edd . . . . .
.
