Finding the cmos battery...

[Cursitor Doom]

On Fri, 8 Jan 2021 10:52:24 -0800 (PST), \"Peter W.\"
<peterwieck33@gmail.com> wrote:

There is a somewhat detailed answer to that question.
a) Do you know what voltage is needed to keep the memory function in operation?
b) Given that a battery is the mother of all capacitors, just a bit slower as a chemical engine, you should be able to do a proof-of-concept.
c) And once you have determined the operating voltage (somewhere between 1.2 and 3.5 VDC at a guess), you will have several choices, including your diode option. BUT:

Caveat: Batteries do not like seeing a dead/partial short. So when diode you install is not in use and the circuit is OFF, the battery is in parallel with whatever device is in place, whether a super-cap or a button cell, or >something else. If that is shorted, so is the battery. OOPS! It really does behoove you to find the OEM source and repair/replace it as designed. You do not want to wake up one morning and find that your installed >battery has spilled its guts all over everything.

I\'m grateful for your observations. I would just point out that it was
never my intention to leave the original power source in situ! I\'m not
quite *that* stupid!

>Remember the Revox B760 tuner? It had two AA cells under the fold-down door on top of the faceplate. Trust the Swiss to take the very simple brute-force approach. ical

I don\'t know that item,I\'m afraid. My experience of electronic repair
is typically 95% vintage boat anchor test equipment, generally at
*least* 25 years old minimum and more likely closer to 40+.

Thanks again.

Peter Wieck
Melrose Park, PA

 

[ohg...@gmail.com]

On Friday, January 8, 2021 at 12:55:24 PM UTC-5, Cursitor Doom wrote:

On Fri, 08 Jan 2021 11:44:55 -0600, Chuck <chu...@dejanews.net
wrote:

On Thu, 07 Jan 2021 23:35:36 +0000, Cursitor Doom <c...@noreply.com
wrote:

On Thu, 07 Jan 2021 13:33:31 -0500, legg <le...@nospam.magma.ca> wrote:

On Wed, 06 Jan 2021 20:51:28 +0000, Cursitor Doom <c...@noreply.com
wrote:

On Wed, 06 Jan 2021 13:44:19 -0600, Chuck <chu...@dejanews.net
wrote:

On Wed, 06 Jan 2021 18:00:32 +0000, Cursitor Doom <c...@noreply.com
wrote:

Hi all,

I have a Roberts Stream 105 internet radio which I bought about 9
years ago. It\'s been fine up until maybe 18 months ago when it could
no longer remember my preferred settings. I\'m guessing it has a little
backup 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. I
asked Roberts for info on where it is but they obfuscated and told me
to return it to them and they\'d fix it for 40 quid! There are no
manuals 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 inside
consists of only 3 boards apart from the display: an audio board (as
it describes itself) the wireless card (I deduce from the fact that
although it\'s fully screened it\'s got a MAC address label on it) and
controller board interfacing to the user controls.
The only place this battery could be hiding is within a screened
enclosure on the \"audio board\". Now, I should have done this sooner
obviously, but time shortages and whatnot, I\'ve probed the underside
of the screened area and found a persistent 0.3V above ground on some
of the joints. Does that sound like the sort of voltage a backup cell
would fall back to after 9 years? This 0.3V is with all external power
removed and after shorting out any capacitances.
Look for a 1/2 to1 farad electrolytic capacitor. Probably near the
upc.

At that value it would be a supercapacitor I\'d imagine. Were they
installing those in new equipment 10 years ago?

They were showing up as surplus 20 years ago.

RL


Well I can\'t understand in that case why there are so few of them
listed on Ebay currently. I may have to imrovise here and go back to
my initial idea of using a lithium button cell in series with a diode
to prevent it being charged.

Anyone see any issues with that approach?
Here is one that is genuine and exactly like the ones I used to use as
a replacement.
https://www.newark.com/kemet/ft0h474zf/supercapacitor-0-47f-5-5v-radial/dp/78AC5690
Thanks, but you guys have avoided answering the question about
replacing the supercap with a cell of whatever capacity in series with
a low reverse-leakage diode. Anyone know what the likely voltage that
cell would need to be?

Generally speaking, I\'ve found that supercaps used as memory devices are generally 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 value/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 direct value of a cell you want to add, you may have to add more than one diode to drop the voltage to or even a bit below the memory voltage.

 

[Cursitor Doom]

On Fri, 8 Jan 2021 13:54:04 -0800 (PST), \"ohg...@gmail.com\"
<ohger1s@gmail.com> wrote:

>Generally speaking, I\'ve found that supercaps used as memory devices are generally 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 value/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 direct value of a cell you want to add, you may have to add more than one diode 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.

 

[legg]

On Thu, 07 Jan 2021 23:35:36 +0000, Cursitor Doom <cd@noreply.com>
wrote:

On Thu, 07 Jan 2021 13:33:31 -0500, legg <legg@nospam.magma.ca> wrote:

On Wed, 06 Jan 2021 20:51:28 +0000, Cursitor Doom <cd@noreply.com
wrote:

On Wed, 06 Jan 2021 13:44:19 -0600, Chuck <chuck23@dejanews.net
wrote:

On Wed, 06 Jan 2021 18:00:32 +0000, Cursitor Doom <cd@noreply.com
wrote:

Hi all,

I have a Roberts Stream 105 internet radio which I bought about 9
years ago. It\'s been fine up until maybe 18 months ago when it could
no longer remember my preferred settings. I\'m guessing it has a little
backup 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. I
asked Roberts for info on where it is but they obfuscated and told me
to return it to them and they\'d fix it for 40 quid! There are no
manuals 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 inside
consists of only 3 boards apart from the display: an audio board (as
it describes itself) the wireless card (I deduce from the fact that
although it\'s fully screened it\'s got a MAC address label on it) and
controller board interfacing to the user controls.
The only place this battery could be hiding is within a screened
enclosure on the \"audio board\". Now, I should have done this sooner
obviously, but time shortages and whatnot, I\'ve probed the underside
of the screened area and found a persistent 0.3V above ground on some
of the joints. Does that sound like the sort of voltage a backup cell
would fall back to after 9 years? This 0.3V is with all external power
removed and after shorting out any capacitances.
Look for a 1/2 to1 farad electrolytic capacitor. Probably near the
upc.

At that value it would be a supercapacitor I\'d imagine. Were they
installing those in new equipment 10 years ago?

They were showing up as surplus 20 years ago.

RL


Well I can\'t understand in that case why there are so few of them
listed on Ebay currently. I may have to imrovise here and go back to
my initial idea of using a lithium button cell in series with a diode
to prevent it being charged.

Anyone see any issues with that approach?

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

 

[Fox\'s Mercantile]

On 1/9/21 8:23 AM, legg wrote:

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

 

[Cursitor Doom]

On Sat, 09 Jan 2021 09:23:26 -0500, legg <legg@nospam.magma.ca> wrote:

On Thu, 07 Jan 2021 23:35:36 +0000, Cursitor Doom <cd@noreply.com
wrote:

On Thu, 07 Jan 2021 13:33:31 -0500, legg <legg@nospam.magma.ca> wrote:

On Wed, 06 Jan 2021 20:51:28 +0000, Cursitor Doom <cd@noreply.com
wrote:

On Wed, 06 Jan 2021 13:44:19 -0600, Chuck <chuck23@dejanews.net
wrote:

On Wed, 06 Jan 2021 18:00:32 +0000, Cursitor Doom <cd@noreply.com
wrote:

Hi all,

I have a Roberts Stream 105 internet radio which I bought about 9
years ago. It\'s been fine up until maybe 18 months ago when it could
no longer remember my preferred settings. I\'m guessing it has a little
backup 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. I
asked Roberts for info on where it is but they obfuscated and told me
to return it to them and they\'d fix it for 40 quid! There are no
manuals 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 inside
consists of only 3 boards apart from the display: an audio board (as
it describes itself) the wireless card (I deduce from the fact that
although it\'s fully screened it\'s got a MAC address label on it) and
controller board interfacing to the user controls.
The only place this battery could be hiding is within a screened
enclosure on the \"audio board\". Now, I should have done this sooner
obviously, but time shortages and whatnot, I\'ve probed the underside
of the screened area and found a persistent 0.3V above ground on some
of the joints. Does that sound like the sort of voltage a backup cell
would fall back to after 9 years? This 0.3V is with all external power
removed and after shorting out any capacitances.
Look for a 1/2 to1 farad electrolytic capacitor. Probably near the
upc.

At that value it would be a supercapacitor I\'d imagine. Were they
installing those in new equipment 10 years ago?

They were showing up as surplus 20 years ago.

RL


Well I can\'t understand in that case why there are so few of them
listed on Ebay currently. I may have to imrovise here and go back to
my initial idea of using a lithium button cell in series with a diode
to prevent it being charged.

Anyone see any issues with that approach


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

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.

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.

IME there\'s *rarely* any such thing!

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

 

[Cursitor Doom]

Here\'s some photos of the insides:

https://yandex.com/collections/user/tqdf2ur1bg7j6vdmbh5t7ne1n8/roberts-internet-radio-stream-105/?share=NWZmYTA4MGUxN2I3NTgyMWQyYjYyMjczXzVjZTFmNThkNTFhYTkwNGFmMTM0MzZmMw%3D%3D


Any suggestions?

 

[legg]

On Sat, 09 Jan 2021 19:49:21 +0000, Cursitor Doom <cd@noreply.com>
wrote:

Here\'s some photos of the insides:

https://yandex.com/collections/user/tqdf2ur1bg7j6vdmbh5t7ne1n8/roberts-internet-radio-stream-105/?share=NWZmYTA4MGUxN2I3NTgyMWQyYjYyMjczXzVjZTFmNThkNTFhYTkwNGFmMTM0MzZmMw%3D%3D


Any suggestions?

Look at the actual board with the memory on it?

RL

 

[Cursitor Doom]

On Sat, 09 Jan 2021 17:12:36 -0500, legg <legg@nospam.magma.ca> wrote:

On Sat, 09 Jan 2021 19:49:21 +0000, Cursitor Doom <cd@noreply.com
wrote:

Here\'s some photos of the insides:

https://yandex.com/collections/user/tqdf2ur1bg7j6vdmbh5t7ne1n8/roberts-internet-radio-stream-105/?share=NWZmYTA4MGUxN2I3NTgyMWQyYjYyMjczXzVjZTFmNThkNTFhYTkwNGFmMTM0MzZmMw%3D%3D


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?

 

[Sjouke Burry]

On 09.01.21 20:49, Cursitor Doom wrote:

Here\'s some photos of the insides:

https://yandex.com/collections/user/tqdf2ur1bg7j6vdmbh5t7ne1n8/roberts-internet-radio-stream-105/?share=NWZmYTA4MGUxN2I3NTgyMWQyYjYyMjczXzVjZTFmNThkNTFhYTkwNGFmMTM0MzZmMw%3D%3D


Any suggestions?

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

 

[legg]

On Sat, 09 Jan 2021 22:26:29 +0000, Cursitor Doom <cd@noreply.com>
wrote:

On Sat, 09 Jan 2021 17:12:36 -0500, legg <legg@nospam.magma.ca> wrote:

On Sat, 09 Jan 2021 19:49:21 +0000, Cursitor Doom <cd@noreply.com
wrote:

Here\'s some photos of the insides:

https://yandex.com/collections/user/tqdf2ur1bg7j6vdmbh5t7ne1n8/roberts-internet-radio-stream-105/?share=NWZmYTA4MGUxN2I3NTgyMWQyYjYyMjczXzVjZTFmNThkNTFhYTkwNGFmMTM0MzZmMw%3D%3D


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?

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

 

[Cursitor Doom]

On Sat, 09 Jan 2021 19:11:53 -0500, legg <legg@nospam.magma.ca> wrote:

On Sat, 09 Jan 2021 22:26:29 +0000, Cursitor Doom <cd@noreply.com
wrote:

On Sat, 09 Jan 2021 17:12:36 -0500, legg <legg@nospam.magma.ca> wrote:

On Sat, 09 Jan 2021 19:49:21 +0000, Cursitor Doom <cd@noreply.com
wrote:

Here\'s some photos of the insides:

https://yandex.com/collections/user/tqdf2ur1bg7j6vdmbh5t7ne1n8/roberts-internet-radio-stream-105/?share=NWZmYTA4MGUxN2I3NTgyMWQyYjYyMjczXzVjZTFmNThkNTFhYTkwNGFmMTM0MzZmMw%3D%3D


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?

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.

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

 

[Bertrand Sindri]

Cursitor Doom <cd@noreply.com> wrote:

Here\'s some photos of the insides:

https://yandex.com/collections/user/tqdf2ur1bg7j6vdmbh5t7ne1n8/roberts-internet-radio-stream-105/?share=NWZmYTA4MGUxN2I3NTgyMWQyYjYyMjczXzVjZTFmNThkNTFhYTkwNGFmMTM0MzZmMw%3D%3D


Any suggestions?

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?

 

[Cursitor Doom]

On Sun, 10 Jan 2021 02:44:28 +0000 (UTC), Bertrand Sindri
<bertrand.sindri@yahoo.com> wrote:

Cursitor Doom <cd@noreply.com> wrote:
Here\'s some photos of the insides:

https://yandex.com/collections/user/tqdf2ur1bg7j6vdmbh5t7ne1n8/roberts-internet-radio-stream-105/?share=NWZmYTA4MGUxN2I3NTgyMWQyYjYyMjczXzVjZTFmNThkNTFhYTkwNGFmMTM0MzZmMw%3D%3D


Any suggestions?

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.
>

 

[Adrian Caspersz]

On 10/01/2021 02:44, Bertrand Sindri wrote:

Cursitor Doom <cd@noreply.com> wrote:
Here\'s some photos of the insides:

https://yandex.com/collections/user/tqdf2ur1bg7j6vdmbh5t7ne1n8/roberts-internet-radio-stream-105/?share=NWZmYTA4MGUxN2I3NTgyMWQyYjYyMjczXzVjZTFmNThkNTFhYTkwNGFmMTM0MzZmMw%3D%3D


Any suggestions?

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?

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

 

[Cursitor Doom]

On Sun, 10 Jan 2021 10:53:35 +0000, Adrian Caspersz
<email@here.invalid> wrote:

On 10/01/2021 02:44, Bertrand Sindri wrote:
Cursitor Doom <cd@noreply.com> wrote:
Here\'s some photos of the insides:

https://yandex.com/collections/user/tqdf2ur1bg7j6vdmbh5t7ne1n8/roberts-internet-radio-stream-105/?share=NWZmYTA4MGUxN2I3NTgyMWQyYjYyMjczXzVjZTFmNThkNTFhYTkwNGFmMTM0MzZmMw%3D%3D


Any suggestions?

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?


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.

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]

> SNIP
I found a manual for a 94i. It said to leave the wall wart plugged in.
Maybe it doesn\'t have internal power !!??


KenW

 

[KenW]

On Sun, 10 Jan 2021 06:30:18 -0700, KenW <ken1943@invalid.net> wrote:

SNIP
I found a manual for a 94i. It said to leave the wall wart plugged in.
Maybe it doesn\'t have internal power !!??


KenW

And preprogrammed freqs. are in a rom.


KenW

 

[Adrian Caspersz]

On 10/01/2021 13:17, Cursitor Doom wrote:

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.

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.

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 ...

https://swling.com/blog/2019/05/frontier-silicon-and-vtuner-aggregation-aggravation-continues/

https://forums.digitalspy.com/discussion/2282513/frontier-silicon-portal-not-working

I\'ve given up using Internet Radio on it.

--
Adrian C

 

[Adrian Caspersz]

On 10/01/2021 13:33, KenW wrote:

On Sun, 10 Jan 2021 06:30:18 -0700, KenW <ken1943@invalid.net> wrote:

SNIP
I found a manual for a 94i. It said to leave the wall wart plugged in.
Maybe it doesn\'t have internal power !!??


KenW

And preprogrammed freqs. are in a rom.

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