sci.electronics.repair - 25 new messages in 9 topics - digest

sci.electronics.repair
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Today's topics:

==============================================================================
TOPIC: UPS battery life
http://groups.google.com/group/sci.electronics.repair/t/b73fd839ce17fb50?hl=en
==============================================================================

== 1 of 9 ==
Date: Mon, Jan 3 2011 8:19 am
From: "Michael A. Terrell"

Jeffrey Angus wrote:
>
> On 1/3/2011 8:22 AM, (PeteCresswell) wrote:
> > Per PeterD:
> >> Automotive batteries are not well suited to long, continous drains
> >> that the UPS would require. Using a deep cycle battery (such as a
> >> trolling battery, or an RV battery, would work, but not optimal.)
> >
> > Is that to say with the first power outage and running the
> > battery to near-exhaustion (assuming there is a means to control
> > how far down it goes) that the battery would be damaged?
>
> In a word, possibly.
>
> The construction of the plates in automotive vs marine (RV)
> batteries are different. The Automotive battery is designed
> to deliver large amount so f current for short periods of
> time.
>
> The marine batteries are designed to for a long term steady
> and considerably lower) current draw.

The 12V batteries made for CATV UPS duty are made for high current
and deep cycle loads.

--
For the last time: I am not a mad scientist, I'm just a very ticked off
scientist!!!

== 2 of 9 ==
Date: Mon, Jan 3 2011 12:30 pm
From: news@jecarter.us

On Sun, 2 Jan 2011 10:01:46 -0600, Andrew Rossmann
<andysnewsreply@no_junk.comcast.net> wrote:

>I have a battery I bought for an APC UPS about 4 years ago. I bought 2,
>and used one immediately. I kept the other on the side as I have several
>UPS's that use basically the same battery. Of course, over time, it has
>discharged itself. I measured about 4.3V instead of the normal 12-13V. I
>put it in a spare UPS, which immedialy complains if I try to turn it on.
>Luckily, the UPS charges even when it is off, but slowly. I measured
>about 15mA initially, and after about 36 hours, about 7.5mA. It is
>currently up to about 10.7V.
>
>How much damage do you think was done to the battery? I know it will
>lose some capacity.

A charged but unused SLA should retain its charge for months. The
battery powered cars the grandkids love (got them on freecycle, not
new at $300 each) have 12 volt 10AH SLA batteries and typically get
charged twice a year (when the grandkids are here). I use a Black &
Decker charger that does 1 or2 amp charging (switch selected) and the
1 amp charge works well. The B&D charger is "smarter" than the
original charger which comes with a "do not charge more than X hours"
warning. Many UPS chargers are in the same category - they do a fast
charge to quickly replenish the battery after use, but there is no
"smart" monitoring. I've seen several different brands of small UPS
(300 watts or so) kill batteries in a year or less - even if unused.
The charging circuit simply cooks the battery.

Forget about using a UPS to charge a battery. Instead, buy a real
charger which won't destroy a bettery even if it's left on charge all
the time. For most UPS batteries, I would recommend the Black &
Decker Smart Battery Maintainer. It uses a switch mode power supply
and has LEDs for "charging" and "charge complete". The charger is $22
at amazon.com
http://www.amazon.com/Black-Decker-BM2B-Automatic-Maintainer/dp/B000AMOEPA
and I've seen it for about $20 at Target and Walmart. If you can find
the older version with the 1amp/2amp charge level switch, it's even
better on the smaller batteries.

Keep an SLA battery properly charged and it will last a very long
time. The electric cars are typically driven until they no longer
move, so the batteries get a full discharge at relatively high current
(5 amps on level driveway; 15 amps uphill - more if two kids in one
car). These batteries have been in service two years and seem to have
close to their original capacity.

John

== 3 of 9 ==
Date: Mon, Jan 3 2011 1:01 pm
From: "Wild_Bill"

I think the reason for the long battery life in this case, is more likely
due to the quality of the batteries you're using.
What is the brand name and model number of the batteries?

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

<news@jecarter.us> wrote in message
news:koa4i6luqv4j60hmt390ca322qbbpedpda@4ax.com...
>
> A charged but unused SLA should retain its charge for months. The
> battery powered cars the grandkids love (got them on freecycle, not
> new at $300 each) have 12 volt 10AH SLA batteries and typically get
> charged twice a year (when the grandkids are here). I use a Black &
> Decker charger that does 1 or2 amp charging (switch selected) and the
> 1 amp charge works well. The B&D charger is "smarter" than the
> original charger which comes with a "do not charge more than X hours"
> warning. Many UPS chargers are in the same category - they do a fast
> charge to quickly replenish the battery after use, but there is no
> "smart" monitoring. I've seen several different brands of small UPS
> (300 watts or so) kill batteries in a year or less - even if unused.
> The charging circuit simply cooks the battery.
>
> Forget about using a UPS to charge a battery. Instead, buy a real
> charger which won't destroy a bettery even if it's left on charge all
> the time. For most UPS batteries, I would recommend the Black &
> Decker Smart Battery Maintainer. It uses a switch mode power supply
> and has LEDs for "charging" and "charge complete". The charger is $22
> at amazon.com
> http://www.amazon.com/Black-Decker-BM2B-Automatic-Maintainer/dp/B000AMOEPA
> and I've seen it for about $20 at Target and Walmart. If you can find
> the older version with the 1amp/2amp charge level switch, it's even
> better on the smaller batteries.
>
> Keep an SLA battery properly charged and it will last a very long
> time. The electric cars are typically driven until they no longer
> move, so the batteries get a full discharge at relatively high current
> (5 amps on level driveway; 15 amps uphill - more if two kids in one
> car). These batteries have been in service two years and seem to have
> close to their original capacity.
>
> John
>

== 4 of 9 ==
Date: Mon, Jan 3 2011 3:14 pm
From: Andrew Rossmann

In article <npc1i61udidtlunkc67qqahu0s4t0u5gjj@4ax.com>,
jeffl@cruzio.com says...
>
> On Sun, 2 Jan 2011 10:01:46 -0600, Andrew Rossmann
> <andysnewsreply@no_junk.comcast.net> wrote:
>
> >I have a battery I bought for an APC UPS about 4 years ago. I bought 2,
> >and used one immediately.
>
> Model number please? I'm curious.

The battery I'm trying to recover is a PowerSonic PS1270. The UPS I want
to put it in (the current battery lasted about 5 minutes) is a Back UPS
ES 725. I'm trying to use an unused ES 350 to charge it for now. It was
up to about 11.1V this morning. I may try the shake thing another poster
mentioned, as a last resort.

Problem is, I buy these things, but then completely forget about them
until I need them!! It's not too big of a deal, as it's just a
convenience to try and keep the Comcast DVR powered up as it can take a
day or two for the program guide to fully reload.

--
If there is a no_junk in my address, please REMOVE it before replying!
All junk mail senders will be prosecuted to the fullest extent of the
law!!
http://home.comcast.net/~andyross

== 5 of 9 ==
Date: Mon, Jan 3 2011 3:48 pm
From: "David"

I have been following this thread for awhile. Many have talked
about sulfated cells and you initially said the charging current
was less than 10 mA. Given the low battery terminal voltage, I
doubt the problem is a sulfated battery since sulfation leads to
a high impedance battery and high terminal voltage while
charging. I would suspect a problem with the charging circuitry
in the 'spare' UPS you are using for charging. The current should
be closer to 1A until the voltage rises some more. At ~13.6 volts
the current should drop off markedly.

David

"Andrew Rossmann" wrote in message
news:MPG.278c1457729021cd98976e@news.eternal-september.org...

In article <npc1i61udidtlunkc67qqahu0s4t0u5gjj@4ax.com>,
jeffl@cruzio.com says...
>
> On Sun, 2 Jan 2011 10:01:46 -0600, Andrew Rossmann
> <andysnewsreply@no_junk.comcast.net> wrote:
>
> >I have a battery I bought for an APC UPS about 4 years ago. I
> >bought 2,
> >and used one immediately.
>
> Model number please? I'm curious.

The battery I'm trying to recover is a PowerSonic PS1270. The UPS
I want
to put it in (the current battery lasted about 5 minutes) is a
Back UPS
ES 725. I'm trying to use an unused ES 350 to charge it for now.
It was
up to about 11.1V this morning. I may try the shake thing another
poster
mentioned, as a last resort.

Problem is, I buy these things, but then completely forget about
them
until I need them!! It's not too big of a deal, as it's just a
convenience to try and keep the Comcast DVR powered up as it can
take a
day or two for the program guide to fully reload.

--
If there is a no_junk in my address, please REMOVE it before
replying!
All junk mail senders will be prosecuted to the fullest extent of
the
law!!
http://home.comcast.net/~andyross

== 6 of 9 ==
Date: Mon, Jan 3 2011 7:04 pm
From: Jeff Liebermann

On Mon, 3 Jan 2011 17:14:32 -0600, Andrew Rossmann
<andysnewsreply@no_junk.comcast.net> wrote:

>In article <npc1i61udidtlunkc67qqahu0s4t0u5gjj@4ax.com>,
>jeffl@cruzio.com says...
>>
>> On Sun, 2 Jan 2011 10:01:46 -0600, Andrew Rossmann
>> <andysnewsreply@no_junk.comcast.net> wrote:
>>
>> >I have a battery I bought for an APC UPS about 4 years ago. I bought 2,
>> >and used one immediately.
>>
>> Model number please? I'm curious.
>
>The battery I'm trying to recover is a PowerSonic PS1270.

That's the very common 12v 7.0A gel cell found in many UPS's. $15 to
$20 almost everywhere.

>The UPS I want
>to put it in (the current battery lasted about 5 minutes) is a Back UPS
>ES 725.

<http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=BE725bb>
I have one of those running my home system. It eats a battery every 3
years. What seems to be killing it is that if it operates when I'm
not at home, it runs until the battery is discharged. Do that a few
times, and the battery is dead. Nothing like waking up in the middle
of the night just to turn off the bleeping UPS.

The PowerSonic PS1270 is a good replacement for the stock battery.

>I'm trying to use an unused ES 350 to charge it for now. It was
>up to about 11.1V this morning.

<http://www.apc.com/resource/include/techspec_index.cfm?base_sku=BE350U>
Very similar UPS. It should work.

>I may try the shake thing another poster
>mentioned, as a last resort.

That was me. It's not very reliable way of removing sulfation, but
has supplied a few miraculous revivals.

>Problem is, I buy these things, but then completely forget about them
>until I need them!!

Easy. Don't buy them until you need them or invent some scheme to
keep the inventory charged.

>It's not too big of a deal, as it's just a
>convenience to try and keep the Comcast DVR powered up as it can take a
>day or two for the program guide to fully reload.

Switch to Satellite TV. My DirecTV DVR boots and loads in about 5
minutes.

You may want to power cycle your DVR anyway:
<http://en.wikibooks.org/wiki/How_to_use_a_Motorola_DVR/Bugs#Bugs>
It is advisable to cold-reboot the DCT once a month, by simply
unplugging the box for 30 seconds. After power is restored,
be patient as the program guide and other features reload
(approx. 20 minutes, 24 hours for the guide to fully populate).
Minor odd DVR behaviors are usually cleared up, and more serious
ones prevented by this procedure. However, sometimes a bug is
still just a bug.

I just made a quick check of my battery collection on the shelf. Last
time I charged them was about 3 months ago. Out of about 8 batteries,
2 of them are showing very low terminal voltage, which is a good
indication that they're dead or dying. So much for charging every 6
months. Most were used when I bought them for $5/ea at a ham radio
swap meet, so I can't really complain.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com jeffl@cruzio.com
# http://www.LearnByDestroying.com AE6KS

== 7 of 9 ==
Date: Mon, Jan 3 2011 8:26 pm
From: Mysterious Traveler

On 01/03/2011 05:14 PM, Andrew Rossmann wrote:
> In article<npc1i61udidtlunkc67qqahu0s4t0u5gjj@4ax.com>,
> jeffl@cruzio.com says...
>>
>> On Sun, 2 Jan 2011 10:01:46 -0600, Andrew Rossmann
>> <andysnewsreply@no_junk.comcast.net> wrote:
>>
>>> I have a battery I bought for an APC UPS about 4 years ago. I bought 2,
>>> and used one immediately.
>>
>> Model number please? I'm curious.
>
> The battery I'm trying to recover is a PowerSonic PS1270. The UPS I want
> to put it in (the current battery lasted about 5 minutes) is a Back UPS
> ES 725. I'm trying to use an unused ES 350 to charge it for now. It was
> up to about 11.1V this morning. I may try the shake thing another poster
> mentioned, as a last resort.
>
> Problem is, I buy these things, but then completely forget about them
> until I need them!! It's not too big of a deal, as it's just a
> convenience to try and keep the Comcast DVR powered up as it can take a
> day or two for the program guide to fully reload.
>
I zapped one of those batteries with a 110 volt welder at 40 amps and
brought it back to life for a short while by hooking it to the correct
poles like jump starting a car.

== 8 of 9 ==
Date: Mon, Jan 3 2011 8:43 pm
From: "Jerry G."

On Jan 2, 11:01 am, Andrew Rossmann
<andysnewsreply@no_junk.comcast.net> wrote:
> I have a battery I bought for an APC UPS about 4 years ago. I bought 2,
> and used one immediately. I kept the other on the side as I have several
The UPS batteries are lead acid jell types. This type of battery if
discharged for any length of time will become sulfide damaged.

Under normal use these lead acid jell batteries have a usable lifespan
of about 3 to 4 years. Sometimes I only got about 2 to 3 years out of
the batteries.

Here in our facility we have many UPS's. I keep logs on their
maintenance. I am changing the batteries on an average of about 3
years. If l leave a UPS discharged for more than about a week, I have
to replace the battery. I found they become damaged very fast.

When the UPS is powered off and the battery is left connected inside
it can hold the charge for maybe a week or two. If I disconnect the
battery it will hold enough charge for about a month or maybe two.

Jerry G.

> UPS's that use basically the same battery. Of course, over time, it has
> discharged itself. I measured about 4.3V instead of the normal 12-13V. I
> put it in a spare UPS, which immedialy complains if I try to turn it on.
> Luckily, the UPS charges even when it is off, but slowly. I measured
> about 15mA initially, and after about 36 hours, about 7.5mA. It is
> currently up to about 10.7V.
>
> How much damage do you think was done to the battery? I know it will
> lose some capacity.
>
> --
> If there is a no_junk in my address, please REMOVE it before replying!
> All junk mail senders will be prosecuted to the fullest extent of the
> law!!http://home.comcast.net/~andyross

== 9 of 9 ==
Date: Mon, Jan 3 2011 10:54 pm
From: Jeff Liebermann

On Mon, 3 Jan 2011 17:48:13 -0600, "David" <someone@somewhere.com>
wrote:

>I have been following this thread for awhile. Many have talked
>about sulfated cells and you initially said the charging current
>was less than 10 mA. Given the low battery terminal voltage, I
>doubt the problem is a sulfated battery since sulfation leads to
>a high impedance battery and high terminal voltage while
>charging. I would suspect a problem with the charging circuitry
>in the 'spare' UPS you are using for charging. The current should
>be closer to 1A until the voltage rises some more. At ~13.6 volts
>the current should drop off markedly.

<http://www.bulldog-battery.com/PDF%20Files/sulphated%20batteries.pdf>
Most cases of sulphation are caused by:
- UNDER CHARGING OR NEGLECT OF EQUALIZING CHARGE
- STANDING IN A PARTIALLY OR COMPLETELY DISCHARGED CONDITION
- LOW ELECTROLYTE
- ADDING ACID
- HIGH SPECIFIC GRAVITY

Note that undercharging is a common cause of sulfation.
10ma qualifies as undercharging.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

==============================================================================
TOPIC: Where to find (affordable) Oven Set Control G.E.
http://groups.google.com/group/sci.electronics.repair/t/1cb36c021a0afb59?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Jan 3 2011 8:54 am
From: Vacillator

Arfa,

Thanks for the informative reply. I have yet to
disassemble anything. I was hoping it would fix itself, or that I
would be able to figure out how to use the oven by tweaking the dials
in a certain way, but it is just getting worse, actually, so I will be
opening it up soon.
The switch on my oven in a bit different, of course, but, like
yours, it is a rotary mechanical, so possibly can be cleaned, of
course. I don't know if it is attached with screws, or rivets.
I will need to walk the oven out from the wall, get the front
panel off, then see what's there. It will be a weekend project, I
think.

== 2 of 2 ==
Date: Mon, Jan 3 2011 9:23 am
From: "Arfa Daily"

"Vacillator" <user132384@aol.com> wrote in message
news:24c892bb-712e-4dea-a74b-975ff4684a96@r40g2000prh.googlegroups.com...
> Arfa,
>
> Thanks for the informative reply. I have yet to
> disassemble anything. I was hoping it would fix itself, or that I
> would be able to figure out how to use the oven by tweaking the dials
> in a certain way, but it is just getting worse, actually, so I will be
> opening it up soon.
> The switch on my oven in a bit different, of course, but, like
> yours, it is a rotary mechanical, so possibly can be cleaned, of
> course. I don't know if it is attached with screws, or rivets.
> I will need to walk the oven out from the wall, get the front
> panel off, then see what's there. It will be a weekend project, I
> think.
>

Mine was actually exceptionally easy to get at. It's a 'range style' cooker.
One small oven with grill, one large oven with grill, and five gas burners
on top. The entire top actually hinged up from the back, after undoing a few
very obvious screws, and a couple of less obvious ones, concealed under the
burners, which of course just lift off for cleaning. I understand from a
friend who does this stuff for a living, that this is a common arrangement -
at least on UK cookers. Once the top was hinged up, a 'sub-deck' was
revealed, to which was fixed all the gas pipework and electrical wiring. The
front panel gas valves for the burners, and rotary switches for oven and
grill control, were completely exposed, fixed to the front panel. Once the
knobs were removed, and a couple more screws removed, the decorative front
panel just lifted away, exposing the fixings for the controls. The whole
dismantling procedure took just a few minutes. The actual switch that was
dodgy, was an open frame type, so easy to see the contacts. The shaft was
easy to remove. A spigot on the far end engaged with a hole in the switch
back-plate, and further forward, a half-round 'cap' secured by two screws,
held it to the main body. Think car crankshaft main bearing cap to get an
idea.

When mine first started giving trouble, it could be 'fixed' for a day or two
at a time, by careful rotation to the desired position, in one direction,
rather than the other. Don't really know why that should have been, but
perhaps the previous position to the one needed, lifted the contacts a bit
higher or something, so 'slammed' them back together a bit harder, or caused
them to 'wipe' a bit, maybe ??

Arfa

==============================================================================
TOPIC: Heathkit ETI-7040 Manual Wanted Universal Counter 175 MHz
http://groups.google.com/group/sci.electronics.repair/t/68f783e836097763?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Jan 3 2011 9:31 am
From: "Wild_Bill"

Thanks again, Neil. You're correct that the datasheet shows all the details
of the operation of the counter/display IC.. and going thru the complete set
of I/O signals will likely show if the IC is functional.

I'd still like to have a manual and schematic to see what the recommended
uses or limitations of the counter are, and to confirm that the correct
parts are present.

BTW, the unit was factory built, manufactured in Japan, so the so the design
and features could be nearly identical or similar to counters of other brand
names.

The 80s were around the time when a lot of U.S. domestic test equipment
manufacturers started selling imported models.. Leader, BK Precision etc.
Browsing catalogs back then, it was common to see numerous brand models that
were nearly identical except for cosmetic differences.. front panel, knob
styles etc.

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

"nesesu" <neil_sutcliffe@telus.net> wrote in message
news:f425f984-210a-470f-a2b8-dd42899c4893@q8g2000prm.googlegroups.com...

This data sheet looks like it gives enough information to trace
through the operating parameters of the chip in your application.
Heath was known to utilize the 'typical application' circuits of the
manufacturers, so I would not be surprised to find the data sheet
fairly close to the circuit you have. This also explains the various
functions of the controls.
http://www.electroniccircuits.gr/files/ICM7226.pdf

Neil S.

== 2 of 2 ==
Date: Mon, Jan 3 2011 9:57 am
From: "Wild_Bill"

Thanks John.. as that seemed to be my only option, I made the purchase.. so
I may have the manual by the end of the week.

BTW, they send manuals by USPS ($5 for this purchase), which I prefer, and
they also accept PayPal so it's a fairly easy checkout, and the checkout
system accepted "not published" for the phone number entry.
FWIW, using PayPal may be preferrable for some folks, so one isn't giving
credit card info to various online sellers.

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

"John Robertson" <spam@flippers.com> wrote in message
news:X9udnVjqcPdVXoLQnZ2dnUVZ_jSdnZ2d@giganews.com...
>
> These folks claim to have a copy for sale @ $22USD (not bad if original):
>
> http://www.vintagemanuals.com/manual.php?manufacturer=Heathkit&model=ETI-7040
>
> However these folks don't have a download schematic (pity) although they
> do have a lot of older Heathkit info:
>
> http://www.vintage-radio.info/heathkit/
>
> John :-#)#
>
> --
> (Please post followups or tech enquiries to the newsgroup)
> John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
> Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
> www.flippers.com
> "Old pinballers never die, they just flip out."

==============================================================================
TOPIC: Adjusting scanner focus
http://groups.google.com/group/sci.electronics.repair/t/46e902abed9b7a3f?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Jan 3 2011 1:03 pm
From: Ron

On Jan 3, 2:15 am, David Nebenzahl <nob...@but.us.chickens> wrote:
> Anyone here ever attempted (or better yet, succeeded at) adjusting the
> focus on an ordinary tabletop scanner?
>
> I've got a cheapie (Microtek V6USL), now more than 10 years old, still
> works, still as noisy as ever. It works, but it's certainly not a great
> scanner, and perhaps is doing the best it ever will do. But I'm not sure
> it's in focus. Having stripped down scrapped scanners, I know there's a
> focus adjustment, done at the factory and invariably set with some kind
> of paint or glue.
>
> Just wondering if it would be worthwhile trying to adjust mine. I
> suppose marking the current setting for return in case of problems, and
> trial and error could work.
>
> The other annoying thing about the scanner is that it has to be "warmed
> up"; the first scan or two are always way too light and washed out. Is
> this typical of CCDs of this vintage? I remember seeing this same
> behavior with some low-res cameras my company used to use on a CD
> printing system we made, to take snapshots of CDs in the printer tray;
> our software took two or three shots, threw them away and then took one
> for real.
>
> --
> Comment on quaint Usenet customs, from Usenet:
>
> To me, the *plonk...* reminds me of the old man at the public hearing
> who stands to make his point, then removes his hearing aid as a sign
> that he is not going to hear any rebuttals.

I'm still trying to figure out why all of the scanners (four) I have
ever bought have permanently broken down within 2 or 3 days after I
buy them. Oy.

Ron

== 2 of 2 ==
Date: Mon, Jan 3 2011 1:45 pm
From: David Nebenzahl

On 1/3/2011 3:14 AM N_Cook spake thus:

> David Nebenzahl <nobody@but.us.chickens> wrote in message
> news:4d21a1b8$0$30399$822641b3@news.adtechcomputers.com...
>
>> Anyone here ever attempted (or better yet, succeeded at) adjusting
>> the focus on an ordinary tabletop scanner?
>>
>> I've got a cheapie (Microtek V6USL), now more than 10 years old,
>> still works, still as noisy as ever. It works, but it's certainly
>> not a great scanner, and perhaps is doing the best it ever will do.
>> But I'm not sure it's in focus. Having stripped down scrapped
>> scanners, I know there's a focus adjustment, done at the factory
>> and invariably set with some kind of paint or glue.
>>
>> Just wondering if it would be worthwhile trying to adjust mine. I
>> suppose marking the current setting for return in case of problems,
>> and trial and error could work.
>
> I would firstly try 3 test scans with a piece of paper, as normal, stuck
> under the doc glass and placed over a piece of glass over the doc glass, to
> see if there is a focussing difference

Why bother doing that? Of course there'll be a focusing difference: the
lens is wide-open, and therefore has a small depth of field, so moving
the subject by the thickness of a piece of glass will make a visible
difference.

--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.

==============================================================================
TOPIC: Canon A420 camera
http://groups.google.com/group/sci.electronics.repair/t/11a9e31849085804?hl=en
==============================================================================

== 1 of 5 ==
Date: Mon, Jan 3 2011 1:06 pm
From: adrian@poppyrecords.invalid.invalid (Adrian Tuddenham)

who where <noone@home.net> wrote:

> On Sun, 2 Jan 2011 22:33:02 +0000, adrian@poppyrecords.invalid.invalid
> (Adrian Tuddenham) wrote:
>
> >John Keiser <john.keiser2@hawaiiantel.net> wrote:
> >
> >> Is this in all modes - Auto, Program, etc?
> >
> >It seems to be.
> >
> >Even using it with the manual exposure at its darkest setting gives
> >over-exposure and a coarse 'raster' effect.
>
> Possibly the sudden freeing up of the mode switch is the clue. It may
> be "detached" and stuck in an inappropriate mode.
>
> Basically with the cost of these device dropping continuously you will
> find - as we have - that repair is not a cost-effective alternative to
> replacement. That said, you have littlle to lose by disassembling it
> (not trivial) and exploring the internals with special attention to
> the mode switch.

I've taken it apart and discovered that the mode switch is a robust
single pole type with nothing to suggest a fault. The click mechanism
is outside the main casing underneath the operating knob and I suspect
that it became stiff when some dirt got into that part of it.

I have put the camera back together and it operate exactly as before.

Next step is to contact the camera repairers in London, when they come
back after the Bank Holiday, and ask for an estimate.

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

== 2 of 5 ==
Date: Mon, Jan 3 2011 3:41 pm
From: "Phil Allison"

"Adrian Tuddenham"

** The advice for your problem is that the shutter is stuck open causing
over exposure on bright subjects.

.... Phil

== 3 of 5 ==
Date: Mon, Jan 3 2011 4:00 pm
From: who where

On Mon, 3 Jan 2011 11:28:40 +0000, adrian@poppyrecords.invalid.invalid
(Adrian Tuddenham) wrote:

>who where <noone@home.net> wrote:
>
>> On Sun, 2 Jan 2011 22:33:02 +0000, adrian@poppyrecords.invalid.invalid
>> (Adrian Tuddenham) wrote:
>>
>> >John Keiser <john.keiser2@hawaiiantel.net> wrote:
>> >
>> >> Is this in all modes - Auto, Program, etc?
>> >
>> >It seems to be.
>> >
>> >Even using it with the manual exposure at its darkest setting gives
>> >over-exposure and a coarse 'raster' effect.
>>
>> Possibly the sudden freeing up of the mode switch is the clue. It may
>> be "detached" and stuck in an inappropriate mode.
>
>It seems to switch between modes normally, so at least one section of
>the switch is working - but I agree it does seem the first place to
>look.
>
>I have found two other references on the Web from people who have
>experienced the same fault - but neither of them appeared to have found
>a solution.
>
>> Basically with the cost of these device dropping continuously you will
>> find - as we have - that repair is not a cost-effective alternative to
>> replacement. That said, you have littlle to lose by disassembling it
>> (not trivial) and exploring the internals with special attention to
>> the mode switch.
>
>That's going to be my first plan of action. I notice there is a camera
>repair shop in London which claims to do economically-priced repairs on
>this model.

Good luck with that (sincerely). You may also be able to locate a
pre-loved A420/430 for the same sort of cost.

>My problem with buying a new camera is that I may not be able to get a
>suitable card reader which works with my current Mac OS 8.6 system - and
>I cannot change the OS because all my business software runs on it.

SD/MMC? Close to standard for very many cameras.

We have a couple of Canons here (A200 and A540), chosen for quick
point-n-shoot duty. They were selected because of key features on my
shopping list - AA batteries, macro, USB interfacing, etc etc - if you
start the hunt for a replacement with a "must-have" feature list
you'll surely have some success. (We don't read the card to retrieve
pics, we use ZB and the USB posts only).

== 4 of 5 ==
Date: Mon, Jan 3 2011 5:03 pm
From: "Phil Allison"

"Adrian Tuddenham"

>> ** The camera has no memory battery.
>
> This one does, it is a 1220 coin cell in a little plastic clip at the
> opposite end from the main battery door.

** Then the camera was made prior to 2006.

Musta been old stock when you bought it.

... Phil

== 5 of 5 ==
Date: Mon, Jan 3 2011 10:34 pm
From: who where

On Tue, 04 Jan 2011 08:00:03 +0800, who where <noone@home.net> wrote:

(snip)
>(We don't read the card to retrieve
>pics, we use ZB and the USB posts only).

posts -> ports

==============================================================================
TOPIC: I Don't Get It!
http://groups.google.com/group/sci.electronics.repair/t/a367b736ad25687d?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jan 3 2011 1:47 pm
From: David Nebenzahl

On 1/3/2011 6:49 AM William Sommerwerck spake thus:

>>> Canon had problems with some of its sensors.
>>> I don't know if that applied to this model.
>
>> Canon makes a DTV converter?
>
> Duh... I'm getting old. I must have answered the wrong post.

Y'know, William, it would really help if you'd quote the message you're
replying to, or at least a snippet of it ...

--
Comment on quaint Usenet customs, from Usenet:

To me, the *plonk...* reminds me of the old man at the public hearing
who stands to make his point, then removes his hearing aid as a sign
that he is not going to hear any rebuttals.

==============================================================================
TOPIC: Repair of Kaon satellite/terrestrial receiver
http://groups.google.com/group/sci.electronics.repair/t/81d030413198eb43?hl=en
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== 1 of 1 ==
Date: Mon, Jan 3 2011 3:41 pm
From: Jeroni Paul

> Since there is a buffer driver with output enable (OE) capability in
> the main processor to front processor bus I was thinking in a
> workaround to delay the OE activation some seconds at power up with a

I found out the initial burst is used to tell the front processor the
last st-by status, probably stored in EEPROM, so if unplugged while it
was on it will turn on when plugged. This points out these initial
bursts are there by design.

This leaves the 27MHz crystal as suspect or some sort of unidentified
reset circuit it seems to have associated with the oscillator built
around a small 8 pin SMD chip with markings (MUAC A10). I'm scoping
the crystal output and see nothing strange in it.

==============================================================================
TOPIC: Datasheet assist: IC regulator MMC6100
http://groups.google.com/group/sci.electronics.repair/t/5e90a41d1cf13cbb?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jan 3 2011 3:56 pm
From: Stroonz

It's on a T-con board, there is 3.5 volts on the input pin, .8V on the
output tab. Most likely it should be in the 1.8 to 2.5v range. I
can't find a datasheet on this IC which is a surface mount in an
SOT-223 case. Any help appreciated.

Edwin

==============================================================================
TOPIC: SMD 1 percent resistor markings - aide memoire?
http://groups.google.com/group/sci.electronics.repair/t/c52c0c1e4db26587?hl=en
==============================================================================

== 1 of 2 ==
Date: Tues, Jan 4 2011 12:30 am
From: "N_Cook"

N_Cook <diverse@tcp.co.uk> wrote in message
news:ifsnqf$f3i$1@news.eternal-september.org...
> Confronted by resistor marking 75B translates as 5K9, anyone have an
> approximate ie 10 percent conversion technique?
> to avoid table lookup, eg
>
http://talkingelectronics.com/projects/ResistorsMadeEasy/SMD-Resistors-EIA-M
> arkings.html
>
>

add 100 to the 0. ones
100 up to 800 multiply number by 7
add 100 to 8. and 9.
(I always confuse grey and white designations anyway)

A suffix =x1 ..... E= x10000 is straightforward
S for (S)ilver /100
R for o(R) for gold for /10
for the multipliers is the best I could come up with

== 2 of 2 ==
Date: Tues, Jan 4 2011 12:32 am
From: "N_Cook"

for
add 100 to 8. and 9.

read
add 100 to 8. and 9. ones after multiplying by 7

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