Macintosh LCII - Starts to boot with friendly face and then restarts

[RetroGinger]

With a Macintosh LCII machine it was working ok but following an attempt to start from an external drive it now does not boot properly.

Model: Macintosh LC II - AP1455-03

The drive showed the following start-up error:

Which I think it a software error... I think that it was from a PowerPC and therefore could not run on the 68k CPU

Using either the internal SCSI or floppy it starts ok and you get the friendly screen.
Starts to boot but within a couple of seconds there is a click from the speaker and it restarts.
The next screen shows the floppy icon with flashing ?

So you get this:

And then:

Re-seated all RAM and socketed ROM with contact cleaner.

Tried with no RAM (just onboard RAM) and with floppy/SCSI/second floppy (it is the older board type)

Any ideas?

I feel I have blown something up somewhere

 

[retrotechtive]

Sorry if it sounds like an obvious question, but has this machine been recapped? Just thinking a partial short from leakage could perhaps be the culprit, and these era machines probably all have leaky caps (as did my Macintosh IIci).