[Coco] CoCo3 power short?

[dwight.bazinet]

I asked this question on the Facebook page a few days ago, but I hope you
don't mind e repeating it here?
I recently got a CoCo3 off EBay, a CoCo SDC from Ed (and had a case
printed) and a RGB to SCART to HDMI from Richard.  Everything was working
fine except a small video problem; ironically it was while I was talking to
Richard about the video that something went wrong.
I turned the computer off then on and it didn't come on, and started to
buzz.
I've isolated the buzz to the relay, it seems what is happening is that the
SALT is detecting an over current and dropping in and out.  The input to
the power transister is around 11.8V, the 5V output is around 2V.  The drop
over R19 is only 25mV, well under the 150mV the service manual says it
should be, indicating a short.
I thought maybe the RGB hadn't been used in a long time and one of the
transistors broke down to short, I removed all three, but that wasn't it.
There does look like glue around the bottom of the two large power
capacitors which has dried and cracked, so I may remove them and check them.
So I'm facing a failed component which is shorting power to ground, with
the only way to isolate being to remove each one in turn, with most of them
being soldered in...
Any suggestions on which ones to start with? I already tried the GIME.
Thanks