Finding the cmos battery

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Generally speaking, I've found that supercaps used as memory devices are ge nerally run *very* close to their voltage rating, so if your supercap is a

2.7V, there's a good chance there could be 2.5 volts on it. But, you don't need to make this complicated. Plug the radio in and see what the voltage is across the supercap. Most of the supercaps I've changed just go low va lue/high ESR and don't short. Whatever the voltage is under test, add that via cell. Since the value you need is unlikely (Murphy's Law) to be a dir ect value of a cell you want to add, you may have to add more than one diod e to drop the voltage to or even a bit below the memory voltage.

Thanks! Just the kind of details I wanted. Must admit I hadn't thought about using diodes to 'trim' the cell(s) to the correct voltage.

Do you know what the original back-up source is, yet?

You were just looking at it, in the last report.

You should be able to do a simple repair, without a lot of useless speculation.

RL

You forget who we're dealing with.

--
"I am a river to my people." 
Jeff-1.0 
WA6FWi 
http:foxsmercantile.com

No I don't! I've had it apart just a few moments ago. So far I have found NO supercaps. One of the ordinary electros 220uF tested over 5 ohms ESR so I'm going to replace that, but I very much doubt that's anything to do with the fault in question.

IME there's *rarely* any such thing!

I'll post some photos of the internals shortly....

Here's some photos of the insides:

Any suggestions?

Look at the actual board with the memory on it?

RL

Good steer. Unfortunately this is the most inaccessible of the lot; sandwiched up against the top display module it's impossible to see what's in there without further disassembly. But now you have suggested it, I think there's no other obvious course of action here.

Am I still looking solely for a supercap?

Yes. Use a valid,working photo website instead of the crap site.

If it, or a battery, is there, it will be obvious and likely mounted on the through-hole side of the board.

Niether are small parts, just low profile.

RL

OK, got it, thanks.I'll investigate further tomorrow..........

Wait, you've only dissasembled maybe a quarter of the unit, and it has not occurred to you yet that what you seek just might be in the three quarters you have not yet disassembled?

Yeah, I know, I know. I'm not a technician so I don't think like a technician; sorry about that.

>

I'd just snip a few wires, dump the guts in the nearest trashcan.

A single board linux computer and an audio amp don't cost much.

--
Adrian C

That is a very fair point! However, I'll properly investigate first (which I'll be doing shortly) and fix the damn thing if I can.

KenW

And preprogrammed freqs. are in a rom.

KenW

If you don't, consider eBay'ing as it is, you might get some interest.

I've got a Roberts Stream 83i.

Great sound quality (the cabinet is a lump of MDF!), and a very sensitive DAB receiver, but the user interface is very poor and Wifi stability hopeless.

And then there is this vtuner mess ...

I've given up using Internet Radio on it.

--
Adrian C

There are no "freqs" on the 105. There is no traditional AM/FM/digital radio tuner in the thing.

Internet only.

Settings beyond WiFi could well be in the cloud.

--
Adrian C