Cursitor Doom Wrote in message:r
On Wed, 06 Jan 2021 12:56:07 -0700, wrote:On Wed, 06 Jan 2021 13:44:19 -0600, Chuck wrote:On Wed, 06 Jan 2021 18:00:32 +0000, Cursitor Doom wrote:Hi all,I have a Roberts Stream 105 internet radio which I bought about 9years ago. It's been fine up until maybe 18 months ago when it couldno longer remember my preferred settings. I'm guessing it has a littlebackup cell in there somewhere that's gone way past its sell-by date.I've opened up the case and it must be very well hidden indeed. Iasked Roberts for info on where it is but they obfuscated and told meto return it to them and they'd fix it for 40 quid! There are nomanuals for this model on line (not service manuals anyway) and I *do*like to fix things for myself as a matter of course anyway. The insideconsists of only 3 boards apart from the display: an audio board (asit describes itself) the wireless card (I deduce from the fact thatalthough it's fully screened it's got a MAC address label on it) andcontroller board interfacing to the user controls.The only place this battery could be hiding is within a screenedenclosure on the "audio board". Now, I should have done this soonerobviously, but time shortages and whatnot, I've probed the undersideof the screened area and found a persistent 0.3V above ground on someof the joints. Does that sound like the sort of voltage a backup cellwould fall back to after 9 years? This 0.3V is with all external powerremoved and after shorting out any capacitances.Look for a 1/2 to1 farad electrolytic capacitor. Probably near theupc.Caps were used to retain voltage to a circuit. Some telephone systemsI worked on used them.What? Are you guys saying there may be no actual battery at all? Andthey've used an electro in place of one?

The .47 to 1F caps have been used for 30 years in stereo receivers.
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