Apple B&W CRT monitor popping and clicking

[Tapley, Mark]

On Apr 3, 2018, at 3:48 PM, Phil Blundell via cctalk <cctalk at classiccmp.org> wrote:

> On Tue, 2018-04-03 at 21:07 +0100, Ian Frost via cctalk wrote:
>> 
>> Recently booted up my B&W Powermac G3, all came up fine including the
>> 17” CRT monitor. However after a second or so, the 
>> monitor gives a ‘popping’ sound and the image on the screen expands
>> then shrinks. This repeats every few seconds.
>> 
>> I’m guessing the monitor is on the way out - but as this is a
>> complete B&W system - I wondered what the likely cause is?
> That sounds like some sort of problem with the EHT supply. 

https://en.wikipedia.org/wiki/Apple_displays

indicates:

….The Apple Studio Display series of CRT displays were available in a 17" Diamondtron and a 21" Trinitron CRT, both driven by an LG-Manufactured chassis. These displays were notorious for faulty flybacks. …

</instant wikipedia expert >[

Would that be consistent with the symptoms, and is there a good way to test?
						- Mark