sci.electronics.repair@googlegroups.com

Today's topics:

* Need help with switching power supply repair - 4 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/efc81d21dede85df?hl=en
* OT Re: CFLs - retrofitting low ESR capacitors - 3 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/4b33f31f667954a0?hl=en
* splice fail - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/cae74cda683b83fa?hl=en
* CRT TV repair, power supply defect. - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/d4c2d93f9d169dcb?hl=en
* why Dc Adapter get faulty on UPS? - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/879da62c8528b4d8?hl=en
* TL064 in PV 212 Deuce, VT Series, 1980 - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/335a27fd0c57212f?hl=en

==============================================================================
TOPIC: Need help with switching power supply repair
http://groups.google.com/group/sci.electronics.repair/t/efc81d21dede85df?hl=en
==============================================================================

== 1 of 4 ==
Date: Wed, Sep 21 2011 6:14 pm
From: Sjouke Burry

senator richards wrote:
> I am trying to troubleshoot a small SMPS that came from an A/V
> switcher. Input is 120vac and it is supposed to output + and - 15vdc
> at .8A. Currently it is outputting +17 on one output and somewhere
> between +22 and +30 on the other output. My experience with SMPS has
> usually been shorted rectifiers or bad output filter caps so the first
> thing I did was check all the diodes and replace the output caps.
> Obviously that didn't fix the problem. The high voltage is about
> 170vdc. The supply to the pwm chip is fluctuating between 7-15v, so
> i'm thinking this might be the problem, but maybe its something else.
> In case its not obvious, i'm fairly new to tinkering with these
> things. Thanks in advance for any help.
>
> Randy
Try to load both sides with about .1amp, low load on a switcher
can confuse the hardware sometimes.

== 2 of 4 ==
Date: Wed, Sep 21 2011 7:55 pm
From: Franc Zabkar

On Wed, 21 Sep 2011 13:31:46 -0700 (PDT), senator richards
<rnewman36@gmail.com> put finger to keyboard and composed:

>I am trying to troubleshoot a small SMPS that came from an A/V
>switcher. Input is 120vac and it is supposed to output + and - 15vdc
>at .8A. Currently it is outputting +17 on one output and somewhere
>between +22 and +30 on the other output. My experience with SMPS has
>usually been shorted rectifiers or bad output filter caps so the first
>thing I did was check all the diodes and replace the output caps.
>Obviously that didn't fix the problem. The high voltage is about
>170vdc. The supply to the pwm chip is fluctuating between 7-15v, so
>i'm thinking this might be the problem ...

Just to add to what Arfa said, the supply to the PWM chip often starts
with a simple resistor feed from the +170V rectfied mains voltage, and
is then augmented by a regenerated supply from a tap on the switchmode
transformer. If this is the case, then there will be a small
electrolytic filter capacitor (~10uF) that often develops high ESR.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

== 3 of 4 ==
Date: Wed, Sep 21 2011 8:41 pm
From: "Phil Allison"

"senator richards"

> Thanks in advance for any help.

** FFS - get yourself an ESR meter.

.... Phil

== 4 of 4 ==
Date: Wed, Sep 21 2011 11:58 pm
From: Kripton

On 2011-09-21 22:31:46 +0200, senator richards <rnewman36@gmail.com> said:

> I am trying to troubleshoot a small SMPS that came from an A/V
> switcher. Input is 120vac and it is supposed to output + and - 15vdc
> at .8A. Currently it is outputting +17 on one output and somewhere
> between +22 and +30 on the other output. My experience with SMPS has
> usually been shorted rectifiers or bad output filter caps so the first
> thing I did was check all the diodes and replace the output caps.
> Obviously that didn't fix the problem. The high voltage is about
> 170vdc. The supply to the pwm chip is fluctuating between 7-15v, so
> i'm thinking this might be the problem, but maybe its something else.
> In case its not obvious, i'm fairly new to tinkering with these
> things. Thanks in advance for any help.
>
> Randy

try to check the main capacitor with an esr meter, or change it !
build yourself easy an esr meter grab any you want on my web site below
regards,
--
----------
Kripton

the ESR Repository @ http://kripton2035.free.fr/esr-repository.html
the Geiger Repository @ http://kripton2035.free.fr/geiger-repositor.html

==============================================================================
TOPIC: OT Re: CFLs - retrofitting low ESR capacitors
http://groups.google.com/group/sci.electronics.repair/t/4b33f31f667954a0?hl=en
==============================================================================

== 1 of 3 ==
Date: Wed, Sep 21 2011 6:51 pm
From: "Trevor Wilson"

Arfa Daily wrote:
>> BTW: The discussion also involves LEDs. IMO, CFLs are an interim
>> step. They have far too many drawbacks to be a long term solution.
>> Incandescents are, of course, no solution at all.
>>
>>
>> --
>> Trevor Wilson
>> www.rageaudio.com.au
>>
>
> But actually, what exactly is the problem that we're trying to find a
> solution to ?

**Let see. Incandescents are:

* Around 5% efficient. At best.
* Have a short life-span.
* Suffer poor colour rendition.

If those problems can be solved, then thast would be a good thing.

I saw some figures a few weeks ago that said that if
> every single light bulb in the UK was changed to a CFL, the total
> saving in energy would amount to the output of one small power
> station.

**I'll take your word for it. That does not tell the entire story though.
For every 100 Watts of incandescent light that can be eliminated, a
significant amount of air conditioning costs can be eliminated. There's a
very good bunch of reasons why fluoros and other types of discharge lamps
are used in every office building, shopping centre and many other places in
most nations. They're efficient and they reduce demands on air conditioning.
And, consequently, on energy suppliers. Every Watt not dissipated, is a Watt
that does not need to be countered with an air conditioner. It adds up.

Having said all that, here in Australia, lighting is far less important than
heating, cooling and pool filtering in terms of total energy consumption. Do
a Google Earth on Sydney of Brisbane and count the number of pools. Each one
uses around 8kWhr of energy every day. Lighting, by comparison is no where
near as significant. Mostly. I just came back from a service call at a
neighbour's home. Every single part of the home was lit by halogen
downlights. These are an incredibly wasteful way to light a home, yet they
are very popular. The kitchen, alone had 6 X 50 Watt downlights.

I suppose that you could argue that any saving is worth
> having, but I sometimes think that this religion of 'green' has
> completely overtaken common sense, and in some cases, the
> disadvantages of a substitute technology such as CFLs, needs to be
> weighed against the perceived disadvantages of what it's trying to
> replace.

**Fair enough, but we have not seen any real data yet. I don't have the
data, do you? The idiot who keeps claiming that CFLs are less reliable than
incadescents has yet to supply any data.

The problem with green technology is that its advocators are
> often zealots, who seek to portray the alternatives that they are
> pedaling as the only solution to a problem which often, only they
> see. They never tell the full story behind these technologies, being
> selective in the extreme. CFLs are a good example of this, where the
> *only* aspects that have been promoted, are the fact that they
> consume less energy for the same amount of light output as an
> 'equivalent' incandescent - and therein lies a can of worms before we
> start - and that they are supposedly longer lived.

**IME, they are certainly MUCH longer lived. By a dramatic amount. My sample
size is:

19 CFLs.
1 incandescent
12 halogen incandescents

* In six years, none of the CFLs have failed. Several CFLs were transferred
from a previous residence and are at least 8 years old. One is operated at
least 4 hours per day. Most others see around 1 ~ 1.5 hours per day.
* My non-halogen incandescent has failed twice in 6 years. It's use is
severely restricted to less than 1 hour per week.
* The halogen downlights are used around 2 hours per week. I've replaced at
least a dozen halogens in the last 6 years.

The huge amounts
> of manufacturing processes, and shipping energy for all the component
> parts, and all the other hidden energy inputs, are politely ignored.

**Are they? I'm pretty certain that shipping costs are taken into account.

> Not to mention the true disposal costs, if this is done properly. No
> one really understands the real manufacturing costs either, because
> governments are making sure that the true price is subsidised by
> collecting additional 'green' taxes via the energy companies, from
> the likes of you and I.

**Not me. Here in Australia, there are no subsidies or special treatment for
low energy lamps. Yet. CFLs have been cheap for quite a few years. I pay
around 5 Bucks for high quality, 23 Watt, Philips branded lamps. There are
MUCH cheaper lamps available, but I don't buy them (anymore). Once bitten,
twice shy. If you examine my analysis of the running costs of incandescent
vs. CFLs, you'll see why CFLs are a MUCH better choice.

If ever these subsidies are removed, CFLs
> will become a major expense to a household, unless they use really
> crappy quality Chinese imports that give poor light quality and poor
> starting characteristics, and are much shorter lived than people are
> currently being persuaded is the case.

**Bollocks. There are no subsidies in Australia and qualility CFLs can be
purchased for around 5 Bucks. Given the exceptionally long life and low
operating costs, there is simply no comparison.

--
Trevor Wilson
www.rageaudio.com.au

== 2 of 3 ==
Date: Wed, Sep 21 2011 7:15 pm
From: "Phil Allison"

"Arfa Daily"

** Stop trying to reason with TW.

The guy is one of the biggest all round lunatics and charlatans in
Australia.

He never listens and he never changes his views, no matter how wrong he is.

He is utterly autistic.

... Phil

== 3 of 3 ==
Date: Wed, Sep 21 2011 8:08 pm
From: "Trevor Wilson"

Michael A. Terrell wrote:
> Trevor Wilson wrote:
>>
>> Michael A. Terrell wrote:
>>> Trevor Wilson wrote:
>>>>
>>>> **I do. I keep track of the life of my lamps. Incandescents don't
>>>> last long.
>>>
>>>
>>> There are some in the US that have been on 24/7 for decades, and
>>> still work. Some are over 100 years old.
>>
>> **Indeed. The ways to get incandescents to last a long time are well
>> known. They are simply under-run massively. IOW: Use a 280VAC rated
>> lamp at 240VAC and the thing will last MUCH longer. Of course,
>> colour temperature edges much closer towards the red and efficiency
>> is absolute crap.
>>
>> Cheap bulbs don't last,
>>> and neither do those that are used improperly.
>>
>> **Not so different to CFLs and LEDs. Funny about that.
>
>
> Still doesn't prove your lame assed claim that incandescents don't
> last.

**I don't need to prove it. It has been well documented:

http://www.megavolt.co.il/Tips_and_info/bulbs_at_glance.html

http://en.wikipedia.org/wiki/Compact_fluorescent_lamp#Lifespan

http://www.designrecycleinc.com/led%20comp%20chart.html

http://www.gelighting.com/eu/resources/firstlight/module04/08.html

http://en.wikipedia.org/wiki/Lamp_rerating

This is an interesting primer on the topic:

http://donklipstein.com/bulb1.html

--
Trevor Wilson
www.rageaudio.com.au

==============================================================================
TOPIC: splice fail
http://groups.google.com/group/sci.electronics.repair/t/cae74cda683b83fa?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Sep 21 2011 8:03 pm
From: newb

I just read the wiki and some other bits about tinsel wire. Yep, that sounds like the stuff I'm dealing with. And yep, non-trivial. I suppose I'll just buy a new pair of headphones and crank up some Jade Warrior. Thanks Dave!

==============================================================================
TOPIC: CRT TV repair, power supply defect.
http://groups.google.com/group/sci.electronics.repair/t/d4c2d93f9d169dcb?hl=en
==============================================================================

== 1 of 2 ==
Date: Wed, Sep 21 2011 9:00 pm
From: Vernon Paul

An update on my repair situation. I decided to follow all the
instruction gathered here and some from Sam, beginning with the
easiest first. This is what I got. By reducing the G2 and brightness
all the way down the TV works fine, no shutdown. Even with a decent
brightness and G2 cranked up and decent picture available, it does not
shutdown. However when there is some bright scene there is signs of
tendency to shutdown. When the the brightness and G2 is cranked up too
much it shutdowns. The voltages from the power supply seems to be
stable during the shutdown, not sure about the currents though.

Is the problem more likely in the power supply or deflection side?

== 2 of 2 ==
Date: Thurs, Sep 22 2011 12:36 am
From: Franc Zabkar

On Wed, 21 Sep 2011 21:00:20 -0700 (PDT), Vernon Paul
<vernondopaul@gmail.com> put finger to keyboard and composed:

>An update on my repair situation. I decided to follow all the
>instruction gathered here and some from Sam, beginning with the
>easiest first. This is what I got. By reducing the G2 and brightness
>all the way down the TV works fine, no shutdown. Even with a decent
>brightness and G2 cranked up and decent picture available, it does not
>shutdown. However when there is some bright scene there is signs of
>tendency to shutdown. When the the brightness and G2 is cranked up too
>much it shutdowns. The voltages from the power supply seems to be
>stable during the shutdown, not sure about the currents though.
>
> Is the problem more likely in the power supply or deflection side?

Is there an ABL (automatic beam limiter) circuit? I have seen ABL
failures that have caused shutdown.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

==============================================================================
TOPIC: why Dc Adapter get faulty on UPS?
http://groups.google.com/group/sci.electronics.repair/t/879da62c8528b4d8?hl=en
==============================================================================

== 1 of 1 ==
Date: Wed, Sep 21 2011 9:35 pm
From: Jeff Urban

Two possibilities.

One is if it uses a standard power transformer. If the UPS puts out
square waves or "sine" waves that are full of harmonics it may cause
enough inefficiency in the transformer to overheat it.

Two, if it uses a switchmode convertor, it might not like square
waves. If a 120 V square wave is input you get 120V DC rectified. If
it's a sine wave it would be 160 V DC. If it only has 120 V DC it's
the same as only feeding it 85 V AC sine wave. It might not like less
than 90 V AC (effectively) because to remain in regulation the peak
current will be higher in the chopper output device(s).

UPSes are only supposed to be used for a short time. In fact at one
time I was thinking of connecting some big big truck batteries to one
and having a longer use time but thought about it for a minute and
decided it would be a bad idea. Not only do I think the UPS itself may
burn up, there is also the issue of what is plugged into it. If you
want to stay off the grid for a long time either get a generator
or...........

It converts to DC right ? Well just cut the cord, get a battery of the
proper voltage and set it up with a charging ballast resistor and a
diode to feed the thing when the power goes out. I have seriously been
considering doing this to cordless phones.

J

==============================================================================
TOPIC: TL064 in PV 212 Deuce, VT Series, 1980
http://groups.google.com/group/sci.electronics.repair/t/335a27fd0c57212f?hl=en
==============================================================================

== 1 of 1 ==
Date: Thurs, Sep 22 2011 12:17 am
From: "N_Cook"

Wild_Bill <wb_wildbill@XSPAMyahoo.com> wrote in message
news:Igpeq.225430$IH7.52377@en-nntp-09.dc1.easynews.com...

I have a few dozen 211 radily at hand and PV proven workaround and plenty of
headroom available

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