No function including no LEDs.
Failed 3.3V VR, ominously tested no load as 4V, maybe normal , will
have to try some known gooders
About 1.5 ohm ground to 3.3V rail. Found where the confusing inner 3.3V
plane came off (near IC9) cutting either side of there and a couple of
other places, limited to one area of board.
Powering with V and A limited bench ps set for 3V limit, taking .2A,
dropped .4V and .3A dropped .7V.
With IR thermometer I would have thought 0.2W would shine out , about 1
degree C only above, around IC4 and AKM 4552VT codec, Japanese datasheet
out there. From that I think I know where to cut its supply trace,
despite being under the IC.
Anyone been here before ?, the main Roland chips are dead cold.
Anyone know what 5 pin SC70-5 or SOT416 format IC top coded JAPN is,
just in passing, googling got nowhere ?
Reminder to myself when using IR thermometer - use a distant LED torch
to illuminate the board. Misled into "finding" a faulty main cap , as
heating up a few degrees in one area of the cap, despite no normal
connection to any 3V line. My flourescent lamp was reflecting heat off
the cap top. Even turning off the lamp made no difference , retained
heat of course.
Also handled a switch and 3 seconds later found a (phantom) hot spot
there.
No change in ohmage heating or freezing.
I don't fancy removing a 16p IC, where it is, even if a replacement was
available, but now I've got this far I have to follow it through to the end