Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default Finding the cmos battery

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.
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Default Finding the cmos battery

My guess is that it is a 2032 button cell - which have been popular for that function for a long time. Are you able to apply about 3V at the appropriate polarity and see if the memory comes back? Or even 1.5V as proof-of-concept?

After which comes the question of whether it is rechargeable (LIR2032) or not (CR2032).

Peter Wieck
Melrose Park, PA
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On Wed, 6 Jan 2021 10:40:30 -0800 (PST), "Peter W."
wrote:

My guess is that it is a 2032 button cell - which have been popular for that function for a long time. Are you able to apply about 3V at the appropriate polarity and see if the memory comes back? Or even 1.5V as proof-of-concept?

After which comes the question of whether it is rechargeable (LIR2032) or not (CR2032).


I was thinking *if* it is rechargeable, I *could* (could I not?)
replace with an equivalent non-rechargeable in series with a diode to
prevent it from taking a charge it's not designed for?
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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 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.
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Default Finding the cmos battery

On Wed, 06 Jan 2021 12:56:07 -0700, KenW
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 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.


Caps were used to retain voltage to a circuit. Some telephone systems
I worked on used them.


What? Are you guys saying there may be no actual battery at all? And
they've used an electro in place of one?


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Default Finding the cmos battery

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 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?

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On Wednesday, January 6, 2021 at 3:49:00 PM UTC-5, Cursitor Doom wrote:
On Wed, 06 Jan 2021 12:56:07 -0700, KenW
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 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.


Caps were used to retain voltage to a circuit. Some telephone systems
I worked on used them.


What? Are you guys saying there may be no actual battery at all? And
they've used an electro in place of one?


I remember several consumer electronic items using a "supercap", something like 0.47F. They did go bad certainly.




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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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On Wed, 6 Jan 2021 21:40:39 -0600 (CST), Chuck
wrote:

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


I'm suitably amazed. Mind you I've never had much to do with them.

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On 06/01/2021 21:51, Cursitor Doom wrote:
At that value it would be a supercapacitor I'd imagine. Were they
installing those in new equipment 10 years ago?

Sure for memory function but for any active function,like RTC,
batteries are still mostly used.


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On Thu, 07 Jan 2021 14:26:06 +0000, Cursitor Doom
wrote:

On Wed, 6 Jan 2021 21:40:39 -0600 (CST), Chuck
wrote:

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


I'm suitably amazed. Mind you I've never had much to do with them.

Come to think of it, a Denon tuner that I bought in 1988 has a super
capacitor for memory.
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On Wed, 06 Jan 2021 20:51:28 +0000, Cursitor Doom
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 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
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On Thu, 07 Jan 2021 13:33:31 -0500, legg wrote:

On Wed, 06 Jan 2021 20:51:28 +0000, Cursitor Doom
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 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?
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On Thu, 07 Jan 2021 12:25:54 -0600, Chuck
wrote:

On Thu, 07 Jan 2021 14:26:06 +0000, Cursitor Doom
wrote:

On Wed, 6 Jan 2021 21:40:39 -0600 (CST), Chuck
wrote:

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


I'm suitably amazed. Mind you I've never had much to do with them.

Come to think of it, a Denon tuner that I bought in 1988 has a super
capacitor for memory.


Hmmm. I think clearly the older one gets, the harder it is keeping up
to date with new innovations if you're not fully immersed in the field
as a career (I'm not!)

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Anyone see any issues with that approach?

Yes. Purchasing anything of that nature from eBay is an issue. Given that a counterfeit - not unknown from that source - could destroy your unit.

Peter Wieck
Melrose Park, PA


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On Thu, 07 Jan 2021 23:35:36 +0000, Cursitor Doom
wrote:

On Thu, 07 Jan 2021 13:33:31 -0500, legg wrote:

On Wed, 06 Jan 2021 20:51:28 +0000, Cursitor Doom
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 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/ft0h474...al/dp/78AC5690
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On Fri, 08 Jan 2021 11:44:55 -0600, Chuck
wrote:

On Thu, 07 Jan 2021 23:35:36 +0000, Cursitor Doom
wrote:

On Thu, 07 Jan 2021 13:33:31 -0500, legg wrote:

On Wed, 06 Jan 2021 20:51:28 +0000, Cursitor Doom
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 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/ft0h474...al/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?

NB: when I say "whatever capacity" I refer to A, AA, AAA, C, D etc.
cells.
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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.

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.

Peter Wieck
Melrose Park, PA
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On Fri, 8 Jan 2021 10:52:24 -0800 (PST), "Peter W."
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


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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
wrote:

On Thu, 07 Jan 2021 23:35:36 +0000, Cursitor Doom
wrote:

On Thu, 07 Jan 2021 13:33:31 -0500, legg wrote:

On Wed, 06 Jan 2021 20:51:28 +0000, Cursitor Doom
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 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/ft0h474...al/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.


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On Fri, 8 Jan 2021 13:54:04 -0800 (PST), "
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.
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On Thu, 07 Jan 2021 23:35:36 +0000, Cursitor Doom
wrote:

On Thu, 07 Jan 2021 13:33:31 -0500, legg wrote:

On Wed, 06 Jan 2021 20:51:28 +0000, Cursitor Doom
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 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
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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
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On Sat, 09 Jan 2021 09:23:26 -0500, legg wrote:

On Thu, 07 Jan 2021 23:35:36 +0000, Cursitor Doom
wrote:

On Thu, 07 Jan 2021 13:33:31 -0500, legg wrote:

On Wed, 06 Jan 2021 20:51:28 +0000, Cursitor Doom
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 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....
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Here's some photos of the insides:

https://yandex.com/collections/user/...M0MzZmMw%3D%3D


Any suggestions?


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On Sat, 09 Jan 2021 19:49:21 +0000, Cursitor Doom
wrote:

Here's some photos of the insides:

https://yandex.com/collections/user/...M0MzZmMw%3D%3D


Any suggestions?


Look at the actual board with the memory on it?

RL
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On Sat, 09 Jan 2021 17:12:36 -0500, legg wrote:

On Sat, 09 Jan 2021 19:49:21 +0000, Cursitor Doom
wrote:

Here's some photos of the insides:

https://yandex.com/collections/user/...M0MzZmMw%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?

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On 09.01.21 20:49, Cursitor Doom wrote:
Here's some photos of the insides:

https://yandex.com/collections/user/...M0MzZmMw%3D%3D


Any suggestions?

Yes. Use a valid,working photo website instead of the crap site.
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On Sat, 09 Jan 2021 22:26:29 +0000, Cursitor Doom
wrote:

On Sat, 09 Jan 2021 17:12:36 -0500, legg wrote:

On Sat, 09 Jan 2021 19:49:21 +0000, Cursitor Doom
wrote:

Here's some photos of the insides:

https://yandex.com/collections/user/...M0MzZmMw%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
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On Sat, 09 Jan 2021 19:11:53 -0500, legg wrote:

On Sat, 09 Jan 2021 22:26:29 +0000, Cursitor Doom
wrote:

On Sat, 09 Jan 2021 17:12:36 -0500, legg wrote:

On Sat, 09 Jan 2021 19:49:21 +0000, Cursitor Doom
wrote:

Here's some photos of the insides:

https://yandex.com/collections/user/...M0MzZmMw%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..........


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Cursitor Doom wrote:
Here's some photos of the insides:

https://yandex.com/collections/user/...M0MzZmMw%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?


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On Sun, 10 Jan 2021 02:44:28 +0000 (UTC), Bertrand Sindri
wrote:

Cursitor Doom wrote:
Here's some photos of the insides:

https://yandex.com/collections/user/...M0MzZmMw%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.


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On 10/01/2021 02:44, Bertrand Sindri wrote:
Cursitor Doom wrote:
Here's some photos of the insides:

https://yandex.com/collections/user/...M0MzZmMw%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
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On Sun, 10 Jan 2021 10:53:35 +0000, Adrian Caspersz
wrote:

On 10/01/2021 02:44, Bertrand Sindri wrote:
Cursitor Doom wrote:
Here's some photos of the insides:

https://yandex.com/collections/user/...M0MzZmMw%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.

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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/fron...ion-continues/

https://forums.digitalspy.com/discus...al-not-working

I've given up using Internet Radio on it.

--
Adrian C


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On 10/01/2021 13:33, KenW wrote:
On Sun, 10 Jan 2021 06:30:18 -0700, KenW 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.

--
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On Sun, 10 Jan 2021 13:51:00 +0000, Adrian Caspersz
wrote:

On 10/01/2021 13:33, KenW wrote:
On Sun, 10 Jan 2021 06:30:18 -0700, KenW 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.


Yes, and it remembered my choices perfectly well for many years before
developing dementia, so I think it's fair to assume there's an
internal power supply of some sort.

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Cursitor Doom wrote:

Adrian Caspersz wrote:

Internet only.


Yes, and it remembered my choices perfectly well for many years before
developing dementia, so I think it's fair to assume there's an
internal power supply of some sort.


It might send its unique ID to the cloud, which remembers your
favourites and tells the "radio" every time it boots?

Does it manage to remember your WiFi credentials every time you turn it
on? Try a factory reset if it has one buried in the menus.

Maybe the "favourites" part of the cloud has gone away? Or is
geo-restricted?
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On Sun, 10 Jan 2021 14:31:52 +0000, Andy Burns
wrote:

Cursitor Doom wrote:

Adrian Caspersz wrote:

Internet only.


Yes, and it remembered my choices perfectly well for many years before
developing dementia, so I think it's fair to assume there's an
internal power supply of some sort.


It might send its unique ID to the cloud, which remembers your
favourites and tells the "radio" every time it boots?

Does it manage to remember your WiFi credentials every time you turn it
on? Try a factory reset if it has one buried in the menus.

Maybe the "favourites" part of the cloud has gone away? Or is
geo-restricted?


Well, if they've pulled some sort of stunt like that then it's the
last time I'll ever buy a Roberts radio. It's funny they seemed to
know already what the problem was since they quoted me 40 quid to fix
it I'm just wondering if they don't do anything to the radio but just
renew my subscription or something like that.

I've got the thing apart now and there's nothing amiss visually.
There's no supercaps and no button cells or anything else of that
nature. In fact the only odd thing is that there are several 220uF
caps which are showing as anything between 1000uF and 1200uF on my
Peak ESR70 meter. I've never known caps so far out of tolerance
before. However, I don't think that could explain the issue here
anyway. Sigh...

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On Sun, 10 Jan 2021 14:31:52 +0000, Andy Burns
wrote:

Sorry I forgot to answer your point he

Does it manage to remember your WiFi credentials every time you turn it
on? Try a factory reset if it has one buried in the menus.


Yes, it remembers the password and accesses the router no problem.
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