sci.electronics.repair - 24 new messages in 12 topics - digest

sci.electronics.repair
http://groups.google.com/group/sci.electronics.repair?hl=en

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Today's topics:

==============================================================================
TOPIC: Thermal Imaging Camera
http://groups.google.com/group/sci.electronics.repair/t/1041c79652cb2ae5?hl=en
==============================================================================

== 1 of 1 ==
Date: Sat, May 21 2011 11:15 pm
From: vjp2.at@at.BioStrategist.dot.dot.com

Very cool for leak detection and finding gaps in insulation
but way overpriced.. the bulk of the value is in the software.

Ditto doppler flow meters - same hardware as a sonic studfinder, the work is
in the software..

- = -
Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
http://www.panix.com/~vjp2/vasos.htm
---{Nothing herein constitutes advice. Everything fully disclaimed.}---
[Homeland Security means private firearms not lazy obstructive guards]
[Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]

==============================================================================
TOPIC: Tempest / BatterySpec AGM batteries?
http://groups.google.com/group/sci.electronics.repair/t/9ab59c9b0f69f30d?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, May 22 2011 2:46 am
From: The Ghost In The Machine

On May 19, 12:39 am, notme <no...@notme.org> wrote:
> > rest assured that's some no-name chinese battery and quality wasn't a
> > design concern, at all.
>
> > Stick with panasonic or yuasa if you care about quality. Some of those are
> > from china now, but are less bogus than the rest of the stuff out there.
>
> [CL]
>
> A statement full of prejudice and innuendo.
>
> Facts?

ALL HE DOES IS TALK PREJUDICIAL CRAP....HE'S A FOOL TO RETUFN AS CYNDY
THE CHEER LEADER WITH HIS TRACK RECORD AS A CRYING COMPLAINING USENET
TROLL...BUT WATCH OUT, HES CONNECTED BY THE ASS TO SOME BIGWIG ISP
TIPHOIDS...HES A FUCKING WHINING DEMORALIZING ENVIOUS CREEP...WITH
HOOKS ON SOME EVEN BIGGER FOOLS.

TGITM

==============================================================================
TOPIC: ISLAM IN FAIR WESTERN EYES 1 !!!!!!!!!!!!
http://groups.google.com/group/sci.electronics.repair/t/b50c5796d338b092?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, May 22 2011 3:30 am
From: bv

ISLAM IN FAIR WESTERN EYES 1

Islam in Fair Western Eyes Dr. Abdulmutti Al-Dalaty In this article I
continue what I have began in ''The Holy Quraan In Fair Western
Eyes'', and I ask the respectful reader to review the introduction of
that article. Sarugen Naido says:" Islam was existing while prayer
time, in the mosque, and in the battle field while Muslims were
fighting side by side. While the prince and the poor were bowing and
kneeling shoulder by shoulder, the justice of islam was laid 5 times a
day. I was attracted several times by the unity of Islam that never
divide and that make a man a brother of the other man…"(1) And Prince
Charles says:" Islam can teach us a way of living and understanding in
the world, the thing that the Christianity have lost, Islam refuses
division between the man and nature, religion and science and between
mind and material"(2) The German Orientalist Zegrid Honkeh" there is
no compulsion in religion, that what quraan orders, Arab never force
the defeated nations to convert in Islam, So with out any force to
enter Islam the believers of Christianity increasingly disappeared as
the disappearing of the ice , as when the sun rise it worms it ! as
the flower trends .towards light searching for more life , that's way
humans trends., even those who remains on their religion, to the
Conqueror "(3) : Jostaf Lopond says in the Islamic modernization All
what in Islam calls to goodness and reforms, Goodness is the
believer's song, and that what I call the Christians for" The
Orientalist Paul de Rakla : "Islam is proud enough by denying the rule
that states "no peace outside the church" that many people are
boasting by these days, Islam is the only religion that established,
by its high virtues, many obstacles against nations leanings towards
bawdry and immorality."(4) Islam is the religion of tolerance: Brthmly
saint Hillar : "the call for monotheism that held by Islam , abided
humanity from the former ages paganism "(5) Counte herry de castry: "
I'v learned the Christians history in the Islamic world, and I
realized very brightly that the Muslim treatment towards Christians is
a proof of their kind companionship ,and that feeling never effect
Muslims ,we never see Islamic religious assembly or preachers walks
behind the fighting armies forcing nations to believe"(6) Gotha shows
the countenance of that forgiveness in his book Muslims Virtues :" for
truth I say : that the Muslim's forgiveness is not out of weakness,
but the Muslim forgives with his proud of his religion , and holding
of his faith" Hanutue confirms his admiration to the greatness of the
Islamic forgiveness by saying:'' we owe to Muslims ,justice, peace,
religious simplicity, and our duty is to learn that religion and work
hard to understand it. And we should take( there is no compulsion in
religion).as our motto"(7) Lean Paul the orientlist says :" at the
time the religious segregation reaches its highest levels Islam came
to say" you have your own religion and we have our own" that was the
real surprise to the human community that has never known the
religious freedom, and maybe never know it till today" (8) Islam the
Humans refuge Arthur Hamelton says:'' If man be a seeker of truth
surly they will believe that Islam is the only solution to humanity
problems"(9) The Law professor Marcille Buazar confirms that meaning
by saying:" the entrance of Islam to the international field , and
putting things in its right places by practicing the asked parlaying,
is not only an active participation , but also a rescue for the
destroying situation of humanity" Bernard Shaw the philosopher says:
"Islam is the only religion that we can find the whole goodness of
other religions in it but we can not fine whole goodness in other
religions! Islam always have been in the place of my appreciation,
because it is the only religion that has the gift of digesting
different life stages, and has the ability to attract hearts over the
years(10), Islam proved since its first appearance that it is the
religion of all races , for it combine Solemn the Persian , Belal the
Abyssin and Suhaib the Roman and all milted in one pot"(11) France
poet Lamar tine says:" Islam is the only religion that can fulfill the
needs of the soul and the body at the same time, without exposing
Muslim to conscience reproach ,,,and it is the only religion that it's
worships has no relations with images and pictures, and it is the
highest gift from the creator to humane "(12) 1. Islam idealism by
Sarugene Naido (169). 2. Islam and the West Prince Charles speech in
oxford institution for Islamic studies.1993 3. God's Sun Shines on the
West Zegrid Honkeh (364-366). 4. Mugademat alulum wa almanaheej by
Anwar Al-jendy (8\133). 5. ibid 6. from zealotry and forgiveness
between Islam and Christianity by Mohammed Al-Ghazali.(194-196) 7.
from Islam and Christianity with science and civilization by Mohammed
Abduh ,a valuable book we advice to read it. 8. from Islam by dr,Ahmed
Shalaby(296) 9. Mohammed in the fair international arts by Mohammed
Uhman(62) 10. a call for work 11. from Islam by dr,Ahmed Shalaby (294)
12. Travelling to the Orient By Lamar tine (47).

IF YOU WISH TO KNOW MORE ABOUT ISLAM, WE PREFER TO VISIT THE
FOLLOWING WEBSITES:

http://www.islam-guide.com

http://www.islamhouse.com/s/9661

http://www.thisistruth.org

http://www.quran-m.com/firas/en1

http://kaheel7.com/eng

http://www.knowmuhammad.com

http://www.rasoulallah.net/v2/index.aspx?lang=e

http://imanway1.com/eng

http://www.todayislam.com

http://www.thekeytoislam.com

http://www.islamland.com

http://www.discoverislam.com

http://www.thetruereligion.org

http://www.beconvinced.com

http://islamtomorrow.com

http://www.usc.edu/dept/MSA/quran

http://www.quranforall.org

http://www.quranexplorer.com/quran

http://www.prophetmuhammed.org

http://www.chatislamonline.org/ar

http://www.dar-us-salam.com

http://youtubeislam.com

== 2 of 2 ==
Date: Sun, May 22 2011 7:34 pm
From: Peter

On Sun, 22 May 2011 03:30:54 -0700 (PDT), bv <bv6bv6bv6@gmail.com>
wrote:

>ISLAM IN FAIR WESTERN EYES 1

Apart from this diatribe being spamming in an incorrect news group,
the very basis is utterly repugnant to truth. Islam may puport to
hold ideals, but the truth of the matter is far from that in practice.
Please do not spam here again.
Thank you.

peter

==============================================================================
TOPIC: What happened to my hard drive?
http://groups.google.com/group/sci.electronics.repair/t/5638540b7e458b4e?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, May 22 2011 3:37 am
From: mike

On May 21, 8:52 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:
> mike wrote:
>
> > On May 20, 1:17 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>

> You may have some cracked solder joints on the controller board on
> the drive, or other problems. Some repairs are beyond the average tech,
> because they don't have the right tools available. You need good
> magnification and a steady hand to resolder some ultra fine pitch ICs,
> and most people can't do it even with the right tools.

Well, that's a thought, I've not spent any time looking over the
circuit board
under the magnifying light - but, I have no confidence in being able
to do
solder joint touch ups to a board with surface-mount components.
I was kind of transitioning out of electronics about the same time
surface
mount stuff started being used in everything,so I've never even seen
any
of the specialized tools up close.

> I keep dead
> drives on hand to swap boards and sometimes repair a controller board,
> but I worked in electronics manufacturing where it was part of my job to
> do that level of work. Just keep studying electronics and you may be
> surprised at what you can learn. :)

Oh, yeah, gotta keep the ole synapses properly exercised, so why
not...:)
>
> --
> It's easy to think outside the box, when you have a cutting torch.

== 2 of 2 ==
Date: Sun, May 22 2011 3:56 am
From: "Michael A. Terrell"

mike wrote:
>
> On May 21, 8:52 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
> wrote:
> > mike wrote:
> >
> > > On May 20, 1:17 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
>
> > You may have some cracked solder joints on the controller board on
> > the drive, or other problems. Some repairs are beyond the average tech,
> > because they don't have the right tools available. You need good
> > magnification and a steady hand to resolder some ultra fine pitch ICs,
> > and most people can't do it even with the right tools.
>
> Well, that's a thought, I've not spent any time looking over the
> circuit board
> under the magnifying light - but, I have no confidence in being able
> to do
> solder joint touch ups to a board with surface-mount components.
> I was kind of transitioning out of electronics about the same time
> surface
> mount stuff started being used in everything,so I've never even seen
> any
> of the specialized tools up close.
>
> > I keep dead
> > drives on hand to swap boards and sometimes repair a controller board,
> > but I worked in electronics manufacturing where it was part of my job to
> > do that level of work. Just keep studying electronics and you may be
> > surprised at what you can learn. :)
>
> Oh, yeah, gotta keep the ole synapses properly exercised, so why
> not...:)

I was hand soldering leads spaced .015" center to center under a
stereo microscope just before I ended up on 100% disability. I miss
being able to do that kind of wotk, and the ~ $500,000 worth of test
equipment I had on my benches at work.

--
It's easy to think outside the box, when you have a cutting torch.

==============================================================================
TOPIC: Fixing a bent usb
http://groups.google.com/group/sci.electronics.repair/t/9f38e546d86013dd?hl=en
==============================================================================

== 1 of 3 ==
Date: Sun, May 22 2011 6:46 am
From: Allodoxaphobia

On Sun, 22 May 2011 02:59:17 +0000 (UTC), vjp2.at@at.BioStrategist.dot.dot.com wrote:
> Too many times I've thrown out a bent USB..

A "bent USB" *WHAT*?

== 2 of 3 ==
Date: Sun, May 22 2011 8:02 am
From: Evan Platt

On Sun, 22 May 2011 02:59:17 +0000 (UTC),
vjp2.at@at.BioStrategist.dot.dot.com wrote:

>Too many times I've thrown out a bent USB..
>what if I really needed it? how likely would I be to repair it?
>Any kits?
>
>Usually happens with memory, but I just dropped and messed up a modem

If you're breaking USB devices that frequently, it's time to look at
the root cause of why you're dropping / breaking them so frequently.
--
To reply via e-mail, remove The Obvious and .invalid from my e-mail address.

== 3 of 3 ==
Date: Sun, May 22 2011 8:17 am
From: chrisj.doran%proemail.co.uk@gtempaccount.com

On May 22, 3:59 am, vjp2...@at.BioStrategist.dot.dot.com wrote:
> Too many times I've thrown out a bent USB..
> what if I really needed it? how likely would I be to repair it?
> Any kits?
>
> Usually happens with memory, but I just dropped and messed up a modem
>
> - = -
> Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist
> http://www.panix.com/~vjp2/vasos.htm
> ---{Nothing herein constitutes advice. Everything fully disclaimed.}---
> [Homeland Security means private firearms not lazy obstructive guards]
> [Urb sprawl confounds terror] [Phooey on GUI: Windows for subprime Bimbos]

Since you mention it, I have an SD card reader that's fallen apart and
will no longer recognise the card, although the computer recognises it
as a disk drive with no disk. For a while, I could get it to find the
card if I squeezed it between my fingers, but that doesn't work any
more. No sweat, I got a replacement for guess what in a 99p shop. But
just out of curiosity, is there anything I could use it for, e.g.
could the computer waggle any of the card contacts up and down somehow
to control something?

Chris

==============================================================================
TOPIC: AM/FM radio troubleshooting
http://groups.google.com/group/sci.electronics.repair/t/9e2ca200c549afdd?hl=en
==============================================================================

== 1 of 8 ==
Date: Sun, May 22 2011 7:16 am
From: klem kedidelhopper

On May 22, 12:38 am, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:
> klem kedidelhopper wrote:
>
> > On May 21, 8:58 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
> > wrote:
> > > klem kedidelhopper wrote:
>
> > > > On May 21, 10:05 am, "N_Cook" <dive...@tcp.co.uk> wrote:
> > > > > klem kedidelhopper <captainvideo462...@gmail.com> wrote in message
>
> > > > >news:d384fa64-4fcf-42c3-b061-1c0a786f3c15@p23g2000vbl.googlegroups.com...
>
> > > > > > I have a Grundig "Transistor 305" portable radio. It uses germanium
> > > > > > transistors. I've had this thing for over forty years and although I
> > > > > > don't use it often it has been a nice radio. In 1971 I replaced the
> > > > > > transistor in the FM detector circuit and I have had no problems with
> > > > > > it until just recently. Last month I spent three days in the hospital
> > > > > > and I brought the Grundig with me. I noticed that after it was on for
> > > > > > about a half hour it would start to cut out. I turned it off and then
> > > > > > later turned it on again, and after a period of time it happened
> > > > > > again. After several similar episodes I stopped using it. I wondered
> > > > > > about some type of interference from the hospital but that was wishful
> > > > > > thinking. In any case being in no position to test it I decided to
> > > > > > just put it away. Yesterday I put it on the bench and took a look at
> > > > > > it. Sure enough after a brief time it cut out again. I injected a
> > > > > > signal, (my finger on a small screwdriver) onto the wiper of the
> > > > > > volume control and ascertained that there is nothing wrong up to the
> > > > > > speaker. So now I need to get into the IF's and detector. My problem
> > > > > > is my old signal generators are not working and all I can come up with
> > > > > > for 10.7MHZ. is a CW signal out of my MFJ249 SWR meter. The MFJ puts
> > > > > > out a clean signal however it is CW, and it's amplitude is not
> > > > > > adjustable. I don't think that an unmodulated signal would be a
> > > > > > problem in this application but I don't know what the amplitude of the
> > > > > > MFJ is and I would hate to blow up an otherwise good IF amplifier with
> > > > > > an excessive signal. I''m admittedly a bit rusty having not trouble
> > > > > > shot an IF amplifier/detector circuit in many years so does anyone
> > > > > > have a feel for how I might signal trace this radio with what I have
> > > > > > on hand? Thanks very much for any advice. Lenny
>
> > > > > Any 4 pin Ge transistors in there? if there is then the usual simple fudge
> > > > > is worth a try
>
> > > > Well the AM is not working either when this set fails. And since the
> > > > set uses the same transistors but different coils for each stage that
> > > > doesn't really help me to track this down. I could look at the CW
> > > > signal from the 249 with my 50MHZ. scope or my spectrum analyzer but I
> > > > still don't know what a safe signal amplitude would be. Does anyone
> > > > know what the proper typical amplitude of an IF signal would be so
> > > > that I would be able to simulate this and inject this signal into the
> > > > IF amplifiers and detector stage? BTW except for the outputs, they're
> > > > all 4 pin GE transistors. What do you mean by the "simple fudge"?
> > > > Thanks, Lenny
>
> > > Check the collector voltages on the IF and mixer stage. Use at least
> > > a 1 meg resistor between the probe and the transistor to keep from
> > > disturbing the circuit. I saw a lot of this in old germanium transistor
> > > car radios. Noise induced into the circuit would momentarily restore
> > > the transistor enough to work for a while, but of there was zero
> > > collector voltage, one of the IF transformers was open. If it was high,
> > > the transistor was bad. I troubleshot those radios and repaired most of
> > > them in under five minutes with that simple method. :)
>
> > The IF's are AF124,and 126. And to answer a previous question I did
> > use cold spray on everything but the detector, which is inside a can.
>
> I may still have a couple new ECG160 in stock. I'll try to get into
> the old shop and check, if I can climb through some of the junk that's
> piled up to be hauled off.
>
> http://www.nteinc.com/specs/100to199/pdf/nte160.pdfis the datasheet
> for the NTE version.
>
> I only used freeze mist as a last resort. On early transistor
> equipment it seemed to cause more failures. Thermal expansion & cooling
> inside the transistor case caused metal fatigue.
>
> > It didn't seem to have any effect. I plan to open the can and hit the
> > detector too.
>
> AM or FM? A bad diode shouldn't affect both bands.
>
> > The "whiskering" as well as the method to remove it are
> > both kind of interesting, sort of like what happens to nicads it
> > seems. Well the transistors seem to have lasted forty some odd years
> > so I can't complain much. The NTE 160 is a germanium and it seems to
> > replace all of these however it does not have a fourth can lead.
>
> A short between the shel & the collector was a common failure.
>
> > I don't know if that could make much of a difference. To check one of
> > these for whiskering, would you simply look for leakage between any
> > junction and the can? I never thought of this.
>
> Using an analog meter would caue open juctions to start working
> again, for a short time. All this did was make you waste time, since
> they invariably quit again. You probably have a crack weld inside the
> can, or a fractured bonding wire. That is why I monitored the collector
> voltages, with added isolation and used a VTVM, and later, a FETVM.
>
> > On another note, considering the bias issues, I really would not want
> > to use a silicon transistor if I don't have to.
>
> It's not that difficult to change. If it uses the typical two
> resisotor bias, you need to raise the E_B voltage to get .6 volts
> instead of .1 volts. Since the silicon parts have less leakage
> currents, raise the value of the bottom resistor in the string. Tack a
> trimpot or use a resistors sub box to find the new value, and solder it
> in.
>
> --
> It's easy to think outside the box, when you have a cutting torch.

Good idea about the VTVM. I don't get to use my RCA Senior Voltohmyst
much anymore. I bought it as a kit from the RCA distributor at the
time, Bruno NY in Manhattan and built it when I was 17. It still works
great. I use an Energiser for the ohmmeter but I really do worry about
the battery leaking. I've been meaning to replace the battery with a
little isolated DC supply for a long time but just have never gotten
to it. Lenny

== 2 of 8 ==
Date: Sun, May 22 2011 9:19 am
From: "Ian Field"

"klem kedidelhopper" <captainvideo462009@gmail.com> wrote in message
news:f84e7e90-e7e4-470c-bd7c-cc56751a1013@w36g2000vbi.googlegroups.com...
On May 21, 8:58 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:
> klem kedidelhopper wrote:
>
> > On May 21, 10:05 am, "N_Cook" <dive...@tcp.co.uk> wrote:
> > > klem kedidelhopper <captainvideo462...@gmail.com> wrote in message
>
> > >news:d384fa64-4fcf-42c3-b061-1c0a786f3c15@p23g2000vbl.googlegroups.com...
>
> > > > I have a Grundig "Transistor 305" portable radio. It uses germanium
> > > > transistors. I've had this thing for over forty years and although I
> > > > don't use it often it has been a nice radio. In 1971 I replaced the
> > > > transistor in the FM detector circuit and I have had no problems
> > > > with
> > > > it until just recently. Last month I spent three days in the
> > > > hospital
> > > > and I brought the Grundig with me. I noticed that after it was on
> > > > for
> > > > about a half hour it would start to cut out. I turned it off and
> > > > then
> > > > later turned it on again, and after a period of time it happened
> > > > again. After several similar episodes I stopped using it. I wondered
> > > > about some type of interference from the hospital but that was
> > > > wishful
> > > > thinking. In any case being in no position to test it I decided to
> > > > just put it away. Yesterday I put it on the bench and took a look at
> > > > it. Sure enough after a brief time it cut out again. I injected a
> > > > signal, (my finger on a small screwdriver) onto the wiper of the
> > > > volume control and ascertained that there is nothing wrong up to the
> > > > speaker. So now I need to get into the IF's and detector. My problem
> > > > is my old signal generators are not working and all I can come up
> > > > with
> > > > for 10.7MHZ. is a CW signal out of my MFJ249 SWR meter. The MFJ puts
> > > > out a clean signal however it is CW, and it's amplitude is not
> > > > adjustable. I don't think that an unmodulated signal would be a
> > > > problem in this application but I don't know what the amplitude of
> > > > the
> > > > MFJ is and I would hate to blow up an otherwise good IF amplifier
> > > > with
> > > > an excessive signal. I''m admittedly a bit rusty having not trouble
> > > > shot an IF amplifier/detector circuit in many years so does anyone
> > > > have a feel for how I might signal trace this radio with what I have
> > > > on hand? Thanks very much for any advice. Lenny
>
> > > Any 4 pin Ge transistors in there? if there is then the usual simple
> > > fudge
> > > is worth a try
>
> > Well the AM is not working either when this set fails. And since the
> > set uses the same transistors but different coils for each stage that
> > doesn't really help me to track this down. I could look at the CW
> > signal from the 249 with my 50MHZ. scope or my spectrum analyzer but I
> > still don't know what a safe signal amplitude would be. Does anyone
> > know what the proper typical amplitude of an IF signal would be so
> > that I would be able to simulate this and inject this signal into the
> > IF amplifiers and detector stage? BTW except for the outputs, they're
> > all 4 pin GE transistors. What do you mean by the "simple fudge"?
> > Thanks, Lenny
>
> Check the collector voltages on the IF and mixer stage. Use at least
> a 1 meg resistor between the probe and the transistor to keep from
> disturbing the circuit. I saw a lot of this in old germanium transistor
> car radios. Noise induced into the circuit would momentarily restore
> the transistor enough to work for a while, but of there was zero
> collector voltage, one of the IF transformers was open. If it was high,
> the transistor was bad. I troubleshot those radios and repaired most of
> them in under five minutes with that simple method. :)
>
> --
> It's easy to think outside the box, when you have a cutting torch.

The IF's are AF124,and 126. And to answer a previous question I did
use cold spray on everything but the detector, which is inside a can.
It didn't seem to have any effect. I plan to open the can and hit the
detector too. The "whiskering" as well as the method to remove it are
both kind of interesting,

===========================================

So far I've never heard of whiskering problems with the AF12x series -
that's not to say it never happens though.

As the fault is intermittent, continuity checks may not tell you anything
useful.

Simply remove the solder from the copper pad around the screen lead and make
sure its isolated, if there is whiskering that will cure the symptom.

== 3 of 8 ==
Date: Sun, May 22 2011 5:42 pm
From: "Ron D."

Phil:

I've seen an intermittant 2AG fuse twice, Drove me nuts the first
time. By intermittant, I mean it would open in circuit, but would
test OK with an ohmmeter.

== 4 of 8 ==
Date: Sun, May 22 2011 5:43 pm
From: "Ron D."

On May 22, 8:42 pm, "Ron D." <ron.doz...@gmail.com> wrote:
> Phil:
>
> I've seen an intermittant 2AG fuse twice, Drove me nuts the first
> time. By intermittant, I mean it would open in circuit, but would
> test OK with an ohmmeter.

I mean 3AG fuse.

== 5 of 8 ==
Date: Sun, May 22 2011 5:49 pm
From: "Phil Allison"

"Ron D."
>
> I've seen an intermittant 2AG fuse twice, Drove me nuts the first
> time. By intermittant, I mean it would open in circuit, but would
> test OK with an ohmmeter.

** Yep.

Typically, the fuse wire has come loose at one end - or was never soldered
in the first place.

It looks fine and has continuity due to light pressure contact alone.

When the wire heats under load, it opens and closes.

..... Phil

== 6 of 8 ==
Date: Sun, May 22 2011 6:41 pm
From: Meat Plow

On Fri, 20 May 2011 15:21:01 -0700, klem kedidelhopper wrote:

> I have a Grundig "Transistor 305" portable radio. It uses germanium
> transistors. I've had this thing for over forty years and although I
> don't use it often it has been a nice radio. In 1971 I replaced the
> transistor in the FM detector circuit and I have had no problems with it
> until just recently. Last month I spent three days in the hospital and
> I brought the Grundig with me. I noticed that after it was on for about
> a half hour it would start to cut out. I turned it off and then later
> turned it on again, and after a period of time it happened again. After
> several similar episodes I stopped using it. I wondered about some type
> of interference from the hospital but that was wishful thinking. In any
> case being in no position to test it I decided to just put it away.
> Yesterday I put it on the bench and took a look at it. Sure enough after
> a brief time it cut out again. I injected a signal, (my finger on a
> small screwdriver) onto the wiper of the volume control and ascertained
> that there is nothing wrong up to the speaker. So now I need to get into
> the IF's and detector. My problem is my old signal generators are not
> working and all I can come up with for 10.7MHZ. is a CW signal out of my
> MFJ249 SWR meter. The MFJ puts out a clean signal however it is CW, and
> it's amplitude is not adjustable. I don't think that an unmodulated
> signal would be a problem in this application but I don't know what the
> amplitude of the MFJ is and I would hate to blow up an otherwise good IF
> amplifier with an excessive signal. I''m admittedly a bit rusty having
> not trouble shot an IF amplifier/detector circuit in many years so does
> anyone have a feel for how I might signal trace this radio with what I
> have on hand? Thanks very much for any advice. Lenny

Start with the first RF amp. It's probably a superhet so there will be a
455 osc and mixer. After that a couple rf amps and the the detector.

Google a superhetrodyne receiver. This one uses ICs but the basics are the
same

http://www.seekic.com/uploadfile/ic-circuit/20097173226815.gif

Should give you some insight as to where the signal is being lost in the
path.

--
Live Fast Die Young, Leave A Pretty Corpse

== 7 of 8 ==
Date: Sun, May 22 2011 9:53 pm
From: spamtrap1888

On May 22, 6:41 pm, Meat Plow <mhywa...@yahoo.com> wrote:

>
> Start with the first RF amp. It's probably a superhet so there will be a
> 455 osc and mixer. After that a couple rf amps and the the detector.
>
> Google a superhetrodyne receiver. This one uses ICs but the basics are the
> same
>
> http://www.seekic.com/uploadfile/ic-circuit/20097173226815.gif
>
> Should give you some insight as to where the signal is being lost in the
> path.

How do you tune the radio in that schematic?

== 8 of 8 ==
Date: Sun, May 22 2011 11:10 pm
From: "Phil Allison"

"spamtrap1888"
>
> http://www.seekic.com/uploadfile/ic-circuit/20097173226815.gif
>

How do you tune the radio in that schematic?

** Like any receiver that uses a crystal oscillator.

By swapping the crystal.

Ask anyone with a RC model.

..... Phil

==============================================================================
TOPIC: Randall RG100G3 powerFET amp
http://groups.google.com/group/sci.electronics.repair/t/57d83a13c4840b3c?hl=en
==============================================================================

== 1 of 2 ==
Date: Sun, May 22 2011 7:45 am
From: "N_Cook"

I could not read the device number on the only other transistor on the pa
board. Required my PTFE magic trick to read it. Will add a bit of heatsink
to this TO220 .
TR7 on overlay
marked
TRF820
TR 542P
7D
and 83 impressed in the casting vent hole plastic
again no logo or makers name
no data found in wwwland
"passing off " as IRF820 ?
its not a bipolar transistor, the T of TRF is about the only readable letter
without PTFE, so not an I.

== 2 of 2 ==
Date: Sun, May 22 2011 5:06 pm
From: "Phil Allison"

"Nutcase Kook"
>
>I could not read the device number on the only other transistor on the pa
> board. Required my PTFE magic trick to read it. Will add a bit of heatsink
> to this TO220 .
> TR7 on overlay
> marked
> TRF820
> TR 542P
> 7D
> and 83 impressed in the casting vent hole plastic
> again no logo or makers name
> no data found in wwwland
> "passing off " as IRF820 ?
> its not a bipolar transistor, the T of TRF is about the only readable
> letter
> without PTFE, so not an I.

** FFS - the full schematic is easy to find:

http://music-electronics-forum.com/t16660/

Click on the thumb size schem at the bottom of the first post.

.... Phil

==============================================================================
TOPIC: Follow-up on IR-remote-remote
http://groups.google.com/group/sci.electronics.repair/t/1dff87c6199dfd18?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, May 22 2011 7:46 am
From: etpm@whidbey.com

On Thu, 12 May 2011 01:25:30 -0400, mm <NOPSAMmm2005@bigfoot.com>
wrote:

>On Thu, 12 May 2011 00:06:08 -0400, mm <NOPSAMmm2005@bigfoot.com>
>wrote:
>
>>Follow-up on IR remote remote
>>
>>I figured that just like light fills the whole room when you turn on a
>>light, so did IR!
>>
>>But no, I noticed that if I held my hand between the CFL ceiling light
>>and the Powermid pyramid, the red light on the pyramid went off.
>
>I ran the power cord across the sink, though I didn't want to do that,
>and moved the powermid to almost 3 feet from tv, so the tv doesn't
>cause the red light to go on anymore.
>
>But I'd still like to know why the IR doesn't bounce off the white
>walls and fixtures and fill the room, like the visible light does.
>
If the IR doesn't bounce off of the tiles it is because the tiles are
absorbing the IR. Many substances that are opaque to visible light let
IR shine through. This is why law enforcement agencies sometimes use
IR cameras to look for pot growing operations by flying above homes.
>
>
>>So rather than change the bulb, I was going to make a little paper
>>awning that would keep the IR from the light away from the pyramid.
>>
>>But I noticed again that turning on the tv also lights the red light,
>>and that no place I put a paper shield made any difference.
>>
>>So I'll do more testing, with a pyramid and mostly with other
>>televisions. Or moving the pyramid. I may have to install another
>>outlet -- the room only has one.
>>
>>I have five of these in operation, but only the bathroom gives me a
>>problem, maybe because that ceiling light is only a foot in front of
>>the pyramid and because only there does the pyramid sit right on the
>>tv.
>>
>>Thanks again for all the advice.

==============================================================================
TOPIC: Part Needed for APC Smart-UPS SUA1500
http://groups.google.com/group/sci.electronics.repair/t/2266384d6b8f97e4?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, May 22 2011 12:03 pm
From: "Chris F."

Does anyone have one of these laying around for parts? I need the little
transformer on the mainboard, mine got broken off while reinstalling the
battery. This is the later black version BTW.

==============================================================================
TOPIC: another puzzler
http://groups.google.com/group/sci.electronics.repair/t/b80657d8be4c22cd?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, May 22 2011 2:43 pm
From: "Bill Graham"

Smitty Two wrote:
> In article <ir8997$2gd3$2@pyrite.mv.net>, PeterD <peter2@hipson.net>
> wrote:
>
>> On 5/20/2011 8:49 PM, Bill Graham wrote:
>>
>>> Suppose for the moment that there are two contestants. One picks
>>> door two, and the other picks door one. Then the moderator opens
>>> door three and shows everyone that there is a donkey behind that
>>> door. Now, will it make any difference if the other two switch
>>> their initial picks or not? And, if they do swap doors, with they
>>> both enjoy a 2/3 chance of winning?
>>
>> This is called the Monty Hall problem. And yes, switching does change
>> the probabilities of winning, and this can be proved with a simple
>> computer program. I use this in both my math classes when we cover
>> probabilities, and in my programming classes.
>
> Did you just wake up from a long winter's nap?

No, but I must have been napping when they mentioned Monty Hall. I never
heard of him or his math problems, and I have a BS in Math. (Santa Clara,
1974)

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http://groups.google.com/group/sci.electronics.repair/t/7c3916928ab3b357?hl=en
==============================================================================

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==============================================================================
TOPIC: Old garage light fixture with no sign of existing switch
http://groups.google.com/group/sci.electronics.repair/t/dbc8e5862471cfc7?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, May 23 2011 12:45 am
From: Jim

[Original thread posted 7/2/10 under same subject line.]

Here's a long term follow-up for anyone who recalls this old
thread or might stumble onto it trying to fix a similar
problem.

It turned out that the single inside garage wall switch DID
indeed control the outside and inside garage lights
simultaneously. Kind of an odd setup, but it can be mitigated
with a separate switch inside if you don't want both lights on
at once.

It seems to have been an unlucky coincidence of a test bulb
burning out right after being screwed in (outside), giving the
false impression that the switch was unrelated. That, combined
with being told it hadn't worked in decades!

We just got around to checking it again (became a high
priority) and the lesson is to double-check a test bulb, even
if it worked minutes before. Never assume, in other words!

Jim

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