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Today's topics:

* Supercaps and ESR - 5 messages, 5 authors
http://groups.google.com/group/sci.electronics.repair/t/2ca41182f5f15ef4?hl=en
* Fender Blues deluxe, PR246 - 2 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/06865a0707061c2e?hl=en
* Update - 24V Lead Acid Battery Charger Control Module PCB Recommendations -
2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/79ff67912b0400b9?hl=en
* 2 Digit LED counter design help needed - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/4802b4acf12f92f4?hl=en
* Discount VERSACE bags Wholesale (http://www.24hour-buy.com/)paypal payment -
1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/ba7d92539d3923b1?hl=en
* EARN 10000 DOLLARS PER DAY - FOREX TRADING ONLINE TODAY - 1 messages, 1
author
http://groups.google.com/group/sci.electronics.repair/t/73c3e41ab37dd53a?hl=en

==============================================================================
TOPIC: Supercaps and ESR
http://groups.google.com/group/sci.electronics.repair/t/2ca41182f5f15ef4?hl=en
==============================================================================

== 1 of 5 ==
Date: Tues, Feb 22 2011 1:07 pm
From: Baron

Meat Plow Inscribed thus:

> On Tue, 22 Feb 2011 12:21:55 -0800, DaveC wrote:
>
>> Trying to find a replacement for a 1F/2.5V supercap.
>>
>> Original:
>>
>> <http://www.newark.com/cooper-bussmann/b0810-2r5105-r/capacitor-
> super-1f-2-5v-
>> 0-4ohm/dp/78K7800?Ntt=B0810-2R5105-R>
>>
>> I can find local replacements rated 1F/5V but the ESR is ~30 ohms
>> instead of 0.4.
>>
>> I presume that supercaps aren't applied to filter applications --
>> their specialty being an alternative to batteries to power memory or
>> such -- so ripple current shouldn't be an issue.
>>
>> My question: what's the impact of replacing a supercap with one with
>> a higher ESR?
>>
>> Thanks,
>> Dave
>
> Logic would dictate it would discharge quicker but my logic is usually
> flawed.
>

I would have thought that the cap, same value, wouldn't be able to
provide the same peak current because of the higher ESR. Other than
that, physical size might be an issue !

--
Best Regards:
Baron.

== 2 of 5 ==
Date: Tues, Feb 22 2011 2:12 pm
From: Meat Plow

On Tue, 22 Feb 2011 21:07:04 +0000, Baron wrote:

> Meat Plow Inscribed thus:
>
>> On Tue, 22 Feb 2011 12:21:55 -0800, DaveC wrote:
>>
>>> Trying to find a replacement for a 1F/2.5V supercap.
>>>
>>> Original:
>>>
>>> <http://www.newark.com/cooper-bussmann/b0810-2r5105-r/capacitor-
>> super-1f-2-5v-
>>> 0-4ohm/dp/78K7800?Ntt=B0810-2R5105-R>
>>>
>>> I can find local replacements rated 1F/5V but the ESR is ~30 ohms
>>> instead of 0.4.
>>>
>>> I presume that supercaps aren't applied to filter applications --
>>> their specialty being an alternative to batteries to power memory or
>>> such -- so ripple current shouldn't be an issue.
>>>
>>> My question: what's the impact of replacing a supercap with one with a
>>> higher ESR?
>>>
>>> Thanks,
>>> Dave
>>
>> Logic would dictate it would discharge quicker but my logic is usually
>> flawed.
>>
>>
> I would have thought that the cap, same value, wouldn't be able to
> provide the same peak current because of the higher ESR. Other than
> that, physical size might be an issue !

I don't think peak current is an issue however size might be. In such a
device I would look for a taper off of charge as long as possible in
order to sustain programmed memory until the bitter end. Otherwise with
proper charge the device is pretty much transparent.

--
Live Fast, Die Young and Leave a Pretty Corpse

== 3 of 5 ==
Date: Tues, Feb 22 2011 2:18 pm
From: "petrus bitbyter"

"DaveC" <invalid@invalid.net> schreef in bericht
news:0001HW.C9895AE3005BC238B042E9BF@news.eternal-september.org...
> Trying to find a replacement for a 1F/2.5V supercap.
>
> Original:
>
> <http://www.newark.com/cooper-bussmann/b0810-2r5105-r/capacitor-super-1f-2-5v-
> 0-4ohm/dp/78K7800?Ntt=B0810-2R5105-R>
>
> I can find local replacements rated 1F/5V but the ESR is ~30 ohms instead
> of
> 0.4.
>
> I presume that supercaps aren't applied to filter applications -- their
> specialty being an alternative to batteries to power memory or such -- so
> ripple current shouldn't be an issue.
>
> My question: what's the impact of replacing a supercap with one with a
> higher
> ESR?
>
> Thanks,
> Dave
>

Well,

As its says itself it's a Equivalent Series Resistor so it can be considered
a resistor in series with the capacitor. As such it dissipates some energy
during charging and charging takes some more time. On discharging the
resistor will also dissipate some of the energy and lowers the on the cap
available voltage by the voltage drop over the resistor. So a high ESR gives
a less power efficiency and will earlier be "empty".

petrus bitbyter

== 4 of 5 ==
Date: Tues, Feb 22 2011 2:16 pm
From: asdf

On Tue, 22 Feb 2011 12:21:55 -0800, DaveC wrote:

> Trying to find a replacement for a 1F/2.5V supercap.
>
> Original:
>
> <http://www.newark.com/cooper-bussmann/b0810-2r5105-r/capacitor-
super-1f-2-5v-
> 0-4ohm/dp/78K7800?Ntt=B0810-2R5105-R>
>
> I can find local replacements rated 1F/5V but the ESR is ~30 ohms
> instead of 0.4.
>
> I presume that supercaps aren't applied to filter applications -- their
> specialty being an alternative to batteries to power memory or such --
> so ripple current shouldn't be an issue.
>
> My question: what's the impact of replacing a supercap with one with a
> higher ESR?
>
> Thanks,
> Dave

Supercaps are also used as batteries in those quick charging micro rc
cars where they supply current for about a minute to a small motor and
the steering servo. Those models could probably have a lower internal
resistance.

== 5 of 5 ==
Date: Tues, Feb 22 2011 6:12 pm
From: Rich Grise

asdf wrote:
>
> Supercaps are also used as batteries in those quick charging micro rc
> cars where they supply current for about a minute to a small motor and
> the steering servo. Those models could probably have a lower internal
> resistance.

I once bought two of those little toy RC cars for about two bucks apiece
from the clearance bin. It was fun, for a little while, but frustrating
because there was no throttle or proportional steering. It was either
stop or go-as-fast-as-you-can, and straight or lock left or lock right,
so it was almost impossible to actually steer it, especially over anything
but a totally bare hard smooth floor. The tires were about 1/4" diameter.

Some months later, they hired some new kid in the shop, and he bought one
of them for ten bucks. >:->

Cheers!
Rich

==============================================================================
TOPIC: Fender Blues deluxe, PR246
http://groups.google.com/group/sci.electronics.repair/t/06865a0707061c2e?hl=en
==============================================================================

== 1 of 2 ==
Date: Tues, Feb 22 2011 2:13 pm
From: "Phil Allison"

"N_Cook" <
>
> Instead of the original 3x 12AX7 it now has 2 and 2x 12AT7 and a 5AR4
> rectifier
>

** You need to find a schem of the Bandmaster-Reverb Amp AA768.

Shame all the ones Google turns up are illegible.

.... Phil

== 2 of 2 ==
Date: Tues, Feb 22 2011 3:07 pm
From: "Phil Allison"

"Phil Allison"
>
> ** You need to find a schem of the Bandmaster-Reverb Amp AA768.
>
> Shame all the ones Google turns up are illegible.
>

** This is probably close enough:

http://www.thevintagesound.com/ffg/schem/pro_reverb_aa165_schem.gif

Ignore the Vibrato circuit.

.... Phil

==============================================================================
TOPIC: Update - 24V Lead Acid Battery Charger Control Module PCB
Recommendations
http://groups.google.com/group/sci.electronics.repair/t/79ff67912b0400b9?hl=en
==============================================================================

== 1 of 2 ==
Date: Tues, Feb 22 2011 3:01 pm
From: "Wild_Bill"

The solution of using a daily, short duration timer cycle would likely be a
very good maintenance solution for many common batteries.

The forklift battery in this instance is more than a half-cubic yard in
size, weighing about a half-ton, and somewhere in the neighborhood of about
800 Ah capacity.. subjected to outdoor temperatures here in the northest
U.S.

The history of the battery is unknown, but has been able to meet the demand
of occassional lifting, but has recently been subjected to some neglect by
the owner.
As I mentioned previously, the forklift is used only occassionally as a
lift, not for moving heavy loads around with the traction drive.

If the charge can't be automatically/routinely refreshed, it may just become
a scrap battery, which would then need to be replaced with a bank/stack of
automotive or marine batteries, as one possible fairly economical solution.

The heavy duty charger is indoors, and moving the charger to the forklift is
complicated/troublesome, which is why the owner has been neglectful at
keeping the battery charged on a regular schedule.
Once the battery has been charged, a small automatic charger might be able
to prevent further decline of the battery's health from sitting idle without
proper attention.

--
Cheers,
WB
.............

<hrhofmann@att.net> wrote in message
news:bad47249-5072-4532-bc5b-9cb209a5c5bd@n11g2000vbm.googlegroups.com...

Get a regular 24 hour mechanical clock timer and use it to power a
relay whose contact is in parallel with the push-on start contact on
the power supply. Set the timer for the minimum possible on time,
usually 15 minutes per day. That will start the power supply once
each day and that should kep the batteries charged just fine. Simple
solutions for simple problems!!!

== 2 of 2 ==
Date: Tues, Feb 22 2011 4:31 pm
From: "Michael A. Terrell"

Wild_Bill wrote:
>
> If the charge can't be automatically/routinely refreshed, it may just become
> a scrap battery, which would then need to be replaced with a bank/stack of
> automotive or marine batteries, as one possible fairly economical solution.

Good luck with that. I've seen people try it, and all they did was
ruin a bank of truck batteries.

--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.

==============================================================================
TOPIC: 2 Digit LED counter design help needed
http://groups.google.com/group/sci.electronics.repair/t/4802b4acf12f92f4?hl=en
==============================================================================

== 1 of 1 ==
Date: Tues, Feb 22 2011 3:27 pm
From: whit3rd

On Feb 22, 8:05 am, Harlan <hpga...@charter.net> wrote:

> Well a customer (business) would like [take-a-number display] where the
> employee can
> increase or decrease the displayed value (max of two digits) with the
> push of an
> up or down button . A clear or reset button would also be helpful.
>
> Another feature desired would be to "light up" another indicator,

> Also it would be desirable to have a smaller LED display at the
> operator's desk

These systems are available pre-built, of course. For the displays,
just buy a big bag of LEDs and connect series to make seven-segment
displays of any size you want (it's relatively easy to find drivers
for such
things). For the 'other indicator' just pull more LEDs from the big
bag.
Prebuilt displays aren't anything more complex than that, just molded
into a plastic block.

And if a desk doesn't have easy view of the main display, consider the
truck-mirror-addon convex mirrors at the local auto-parts store; hang
a few
in appropriate locations, and anyone's desk can have line-of-sight to
the
big numbers (though, mirror-reversed).

If you want to get elaborate, you could put a CCTV camera on the main
display and plop a few repeater screens around the office (or even in
the
restrooms and other places patrons might wander).

==============================================================================
TOPIC: Discount VERSACE bags Wholesale (http://www.24hour-buy.com/)paypal
payment
http://groups.google.com/group/sci.electronics.repair/t/ba7d92539d3923b1?hl=en
==============================================================================

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==============================================================================
TOPIC: EARN 10000 DOLLARS PER DAY - FOREX TRADING ONLINE TODAY
http://groups.google.com/group/sci.electronics.repair/t/73c3e41ab37dd53a?hl=en
==============================================================================

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