AF-540FGZ

Hi all. I have a 540 FGZ which is acting up. It is an intermittent fault. Sometimes it switches on perfectly first time. Sometimes it doesn't switch on at all. SO I give it a short swift tap with my hand and it switches on. I've asked SRS if they can help and they have said to send it to them and they would send it to Pentax to get an estimate for a repair. To me it would seem like a loose contact somewhere but I thought one of you whizz kid tech guys might be able to help me. I can see no way to get inside. No clips no screws. Someone help an old man out please.
CHEERS Vic.
P.S. I do have my two hammerheads with power packs and my 540 FGZ ii so I'm not desperate. It's just that I have a power pack for the problem one and the Mk ii doesn't have a power pack socket. ( except for mains which I don't want)
CHEERS again Vic.

Vic
Is this any use to you? It is a discussion on dismantling a 540https://www.dpreview.com/forums/thread/3028254

Mick

Thanks Mick. I shall have a good look later. It looks interesting. I must go for now and look after my wife and cook her dinner. (Not well. / Stroke.)
CHEERS Vic.

Thanks Mick. I had a look with the 4 screws removed from the bottom. It looks a bit complicated for me. I was a mechanical machine tool engineer not electronic. I think I'll just have to send it away for repair.
CHEERS Vic.

Hi Mick. Problem solved. Although no batteries had been left in the flash the contacts just needed cleaning. There was no nasty green muck on the contacts. I took a cotton bud soaked in vinegar and gave the contacts a good clean. Now as good as new and switches on first time no bother.
CHEERS Vic.