Okay folks this one has me baffled! I was out with the detector a couple of weeks ago at the beach looking for a pair of glasses lost by a friend. The detector started playing up as in things missing from the display etc. I packed it in and went home. Got a chance to have a look at it last week and what was happening was the same as the beach. Also it was starting up with the rechargeable pack but it wouldn't with the C-Cell pack. Also when I switched it off and tried to switch it on again with the rechargeable pack it wouldn't come on again. I contacted White's through their Facebook page and explained what was happening. They said that it sounded like the didplay was shot and because of it's age they had no spares. Now I've had this machine from new and I'm 67 now and don't like change! So I decided to strip it down and see if there was anything loose or a dry joint or whatever. Took the control box to bits to the point where I was wishing I haden't but what the hell it was too late by that point. I found a ribbon cable that was loose at one side but wasn't sure if it had been loose or I had did it in the strip down. Checked for dry joints and found none. So after a few problems I got it all put back together and when I put the rechargeable pack in it started up okay. Connected the coil and it was working fine. Took the rechargeable pack out and put in the C-Cell pack, nothing. Wouldn't come on at all. I charged up both packs overnight and tried again with the same result. I used a battery checker to check the four batteries and they were fine. I used a voltmeter to check the voltage in each battery pack and the rechargeable one came in at 5.6 volts and the C-Cell one at 5.7 volts. The terminals in the control box are clean as I did them when I stripped it down. The contacts on the battery packs are good as I cleaned those up with a fibre brush. So can anyone suggest why a battery pack that measures 5.7 volts won't start the detector and one that measures 5.6 volts does? I'm out of ideas!