sci.electronics.repair - 25 new messages in 13 topics - digest

sci.electronics.repair
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Today's topics:

==============================================================================
TOPIC: Midiverb ii issues?
http://groups.google.com/group/sci.electronics.repair/t/aaedd7aef36420d1?hl=en
==============================================================================

== 1 of 1 ==
Date: Sun, Jul 25 2010 5:37 pm
From: "Arfa Daily"

"Gareth Magennis" <sound.service@btconnect.com> wrote in message
news:y1%2o.220782$U%7.143992@hurricane...
>
>
> "Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
> news:Efj2o.333105$NW.10213@hurricane...
>>
>>
>> "El Grillo" <nradina@gmail.com> wrote in message
>> news:0b3f8d3e-ce83-4a8d-a032-59a743522db2@k19g2000yqc.googlegroups.com...
>>> Hello,
>>>
>>> I'm an new electronic technician TRYING to grasp a hold of my
>>> troubleshooting skills.
>>> I have two Midiverb 2's on my bench currently.
>>>
>>> One I was able to repair by replaceing some bad Filter caps, but the
>>> other is still giving me all the indicator diodes are lit and the 2
>>> digit screen is dead.
>>>
>>> I tested all caps with an ESR meter and all is good.
>>> Noticed one small decoupling cap looked funky and replaced, but no
>>> luck.
>>> (I'm also a bit unsure if I replaced with the right cap. I had a few
>>> 104 film caps in the shop).
>>>
>>> SO...I'm asking for a bit of help from you all, if willing.
>>>
>>> Any idea where I should be looking?
>>>
>>> Thanks in advice for any help you can send my way.
>>>
>>> nicholas
>>
>> Supply rails all correct voltages and clean (check with digital voltmeter
>> and 'scope) ? Processor chip receiving correct reset ? Processor clock
>> running ? No user control jammed in 'operating' position ? Such things
>> can cause a processor to 'loop forever' if it executes a bit of code
>> during boot up, to check for button presses that are part of a diagnostic
>> entry sequence, and the button that's being 'pressed' is not one that is
>> being expected.
>>
>> Arfa
>
>
> You might pay particular attention to Arfa's suggestion of the uP
> receiving the correct reset.
>
> The first thing I used to do with these old style microprocessor things,
> after checking the power supplies, was to force a warm boot by taking the
> reset line low or high - whatever is appropriate to force a reset. (get
> the datasheet for the processor to find what is required and where) It
> was surprising how many then suddenly burst into life.
>
>
>
> Gareth.

Yes, good advice. A forced reset is a good test. However, the OP's
experience of dealing with this sort of problem appears limited, so if I
were he, I think I would definitely be looking for some schematics, as
without them, it's going to be difficult for him to troubleshoot this ...

Arfa

==============================================================================
TOPIC: Question for the Brits here, what do you call aBelling-Leeconnector?
http://groups.google.com/group/sci.electronics.repair/t/b63d999facac6197?hl=en
==============================================================================

== 1 of 4 ==
Date: Mon, Jul 26 2010 1:09 am
From: "Arfa Daily"

"N_Cook" <diverse@tcp.co.uk> wrote in message
news:i2jeec$6i6$1@news.eternal-september.org...
> Geoffrey S. Mendelson <gsm@mendelson.com> wrote in message
> news:slrni4pb59.d6h.gsm@cable.mendelson.com...
>> N_Cook wrote:
>> > How about TV coax connector (in the UK that is)
>>
>> Great, thanks.
>>
>> > http://www.dastv.co.uk/images/pht/th_s/3407_DAS0982.jpg
>> > What do Americans call the one shown in the above pic?
>> > and I will add to my
>> > http://www.divdev.fsnet.co.uk/tool_terms.htm
>> > UK / USA Tool Terminology Translator
>>
>> 99% of people in the US would not call them anything, they have not, and
>> will never see them.
>>
>> The few people that have are usually SWL's (some Grundig radios used
> them),
>> people who bought or sold PAL TV sets and VCRs (which is how they got
>> the
> name
>> "PAL connectors".)
>>
>> RadioShack calls the adapter a "European TV adapter", but says it
>> connects
>> an F connector to a PAL-type antenna jack.
>>
>> Universal Radio calls them "PAL", as in PAL M (male) or PAL F. to F
>> female adaptor.
>>
>> Geoff.
>> --
>> Geoffrey S. Mendelson N3OWJ/4X1GM
>> To help restaurants, as part of the "stimulus package", everyone must
> order
>> dessert. As part of the socialized health plan, you are forbidden to eat
> it. :-)
>
>
> a masterclass on them
> http://www.megalithia.com/elect/bellinglee/index.html
>
>

That's pretty much how I was taught to do them by the 'old boy' that every
workshop used to have back then. Sid, ours was called ...

When not soldering the centre pin on those sorts of jobs where you just
wanted to be out of the house before the fleas bit you to death or you
caught something, we used to either bend the centre conductor, as the guy in
that tutorial says, but a double 'S' shaped bend rather than a single, or
else we used to 'crimp' the pin to the centre conductor where it emerged
from the nylon bit, using a blunt pair of sidecutters.

Arfa

== 2 of 4 ==
Date: Mon, Jul 26 2010 1:31 am
From: "N_Cook"

Arfa Daily <arfa.daily@ntlworld.com> wrote in message
news:8pb3o.205411$9c1.129137@hurricane...
>
>
> "N_Cook" <diverse@tcp.co.uk> wrote in message
> news:i2jeec$6i6$1@news.eternal-september.org...
> > Geoffrey S. Mendelson <gsm@mendelson.com> wrote in message
> > news:slrni4pb59.d6h.gsm@cable.mendelson.com...

> That's pretty much how I was taught to do them by the 'old boy' that every
> workshop used to have back then. Sid, ours was called ...
>
> When not soldering the centre pin on those sorts of jobs where you just
> wanted to be out of the house before the fleas bit you to death or you
> caught something, we used to either bend the centre conductor, as the guy
in
> that tutorial says, but a double 'S' shaped bend rather than a single, or
> else we used to 'crimp' the pin to the centre conductor where it emerged
> from the nylon bit, using a blunt pair of sidecutters.
>
> Arfa

I assume RS cannot use a "trade name" for generic (Hoover for vacuum cleaner
etc) even if defunct company name

Now all I need is a masterclass on fitting BNC connectors

== 3 of 4 ==
Date: Mon, Jul 26 2010 2:39 am
From: "Geoffrey S. Mendelson"

N_Cook wrote:

> I assume RS cannot use a "trade name" for generic (Hoover for vacuum cleaner
> etc) even if defunct company name

Not defunct:

http://www.belling-lee.com/

Maybe not the same company, but not defunct.

Geoff.

--
Geoffrey S. Mendelson N3OWJ/4X1GM
To help restaurants, as part of the "stimulus package", everyone must order
dessert. As part of the socialized health plan, you are forbidden to eat it. :-)

== 4 of 4 ==
Date: Mon, Jul 26 2010 2:44 am
From: "Geoffrey S. Mendelson"

Geoffrey S. Mendelson wrote:

> Not defunct:
>
> http://www.belling-lee.com/
>
> Maybe not the same company, but not defunct.

After I posted this I looked. If you follow their products down to coaxial
connectors you get to http://www.blpcomp.com/products/viewprod.php?id=218.

That's the standard Belling-Lee connector, although you have to download
the PDF file to see it.

Geoff.

--
Geoffrey S. Mendelson N3OWJ/4X1GM
To help restaurants, as part of the "stimulus package", everyone must order
dessert. As part of the socialized health plan, you are forbidden to eat it. :-)

==============================================================================
TOPIC: hissing sound coming from behind woofer on one side AR11
http://groups.google.com/group/sci.electronics.repair/t/3a9cce9766f809ce?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jul 26 2010 1:11 am
From: "Arfa Daily"

"Amanda Ripanykhazov" <dmanzaluni@googlemail.com> wrote in message
news:8f36b444-2b05-4f98-85e1-d79583ce9c63@g19g2000yqc.googlegroups.com...
> On Jul 24, 7:21 am, bz <WQAHBGMXS...@spammotel.com> wrote:
>> Amanda Ripanykhazov wrote:
>> > Anyone know what this means? This hissing sound isnt constant, it is
>> > irregular: It isnt related to the music or any movement of the cone
>> > or any signal put through it, though it doesnt happen when no sound is
>> > put through the speaker.
>>
>> > Frankly it sounds more mechancial than electronic (as if there is
>> > something behind there!) but as I say, it isnt related to whatever is
>> > coming through the speaker though it does increase and decrease with
>> > adjustment of the volume control. Andit is louder than most signals
>> > put through the woofer itself??
>>
>> > Is it indicative of some pot in the crossover needing cleaning or is
>> > there something else going on please? (I have seen reference to people
>> > improving the sound of AR11s by bypassing the tone controls in the
>> > speaker completely). This speaker is quite elderly and I would
>> > imagine that if it does use mechanical pots, they must be fairly dirty
>> > by now
>>
>> I know it is a silly question, but are you SURE that the hiss isn't
>> coming out of your amplifier?
>> (have you put a scope on the speaker lines or substituted either speaker
>> or amp?)
>>
>> From your description, it isn't clear to me that you have eliminated the
>> 'more obvious' possibility that your amplifier is putting out white
>> noise, perhaps intermittently varying in amplitude.- Hide quoted text -
>>
>> - Show quoted text -
>
> Yeah, switching one speaker pretty much solved that one.

What, solved it as in proved that the amplifier *was* the cause, or solved
it as in it wasn't ?

Arfa

==============================================================================
TOPIC: Video projector lamps
http://groups.google.com/group/sci.electronics.repair/t/de8bc2f235a2c38c?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jul 26 2010 1:28 am
From: "N_Cook"

The inkjet printer syndrome. Why pay for a new set of inks when a whole new
printer costs only a little more than that. Another thrown out video
projector, all that clever technology , just because a replacement bulb is
near enough the cost of a whole new projector. Anyone know of a supply of
generic basic discharge lamps, intended for fanned operation?
This one, from the manual, was 210 watt NSH lamp, NSH = ??? = something
metalic nickel? (N ?) Sodium Halide ?
I have a few 150W "Power Star" discharge lamps that will physically just
about fit in the available space. Used in floodlights they don't need fans,
projector versions , as fan cooled , are physically smaller.
In a luminaire these 150W lamps take 0.55 to 0.6 amp at 240 V mains , in
use. Tried one on the projector with a 12V 50W filament halogen lamp in
series as a bit of a dropper.
With ammeter in mains supply , overall current (including SMPS and fans etc)
was 0.8 amp for 10 seconds or so and then jumped to 1.2 amp to full
brightness. I chickened out then and switched off. Where to go next ? Next
time I will dig out an old analogue ammeter (concerned about the presumed 4
or 5 KV starter/igniter) and place in series with the lamps.
No mention in the manual of this initial power step but it is the same with
my other projector so presumably generically normal. 6 wires connect to the
ballast/choke so presumably there is active switching of parts of the choke
which maybe selectively disableable and not monitored by the controller. I
can live with reduced light output, my other one has a preset option and is
set for half power maximum on normal user brightness control.
Any other ideas ?

==============================================================================
TOPIC: TO92 marked F422 = BF422 ?
http://groups.google.com/group/sci.electronics.repair/t/fb98b9d2f1919287?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jul 26 2010 6:09 am
From: "N_Cook"

ian field <gangprobing.alien@ntlworld.com> wrote in message
news:8i13o.319199$k15.160568@hurricane...
>
> "N_Cook" <diverse@tcp.co.uk> wrote in message
> news:i2e3d6$hlp$1@news.eternal-september.org...
> > I'm aware that in some situations TO92 transistors marked C556 mean
BC556
> > (not 2SC556), can the same be for BF...?
> > I have a board with dozens of BF422, HV transistors on. These agree with
> > the
> > schematic but someone has previously replaced 2 with a pair marked F422
> > and
> > one of them has failed B-C-E short. Diode testing (Vb-c < Vb-e) the
> > remaining one shows correct pinout for BF422
>
>
> That marking style is fairly common.
>
>

I don't remember coming across it before for BF... , a few times I've seen
it with Philips TO92 BC... types

==============================================================================
TOPIC: Paralleled Amplifier Wiring
http://groups.google.com/group/sci.electronics.repair/t/d586ede5490acff1?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Jul 26 2010 6:27 am
From: zekfrivo@zekfrivolous.com (GregS)

In article <i2dq9k$co1$1@news-01.bur.connect.com.au>, "Phil Allison" <phil_a@tpg.com.au> wrote:
>
>"Greg Shithead"
>
>> You forgot to give the power.
>
>
>** It in the very first line of the original post.
>
> You pathetic imbecile.
>
>
>
>.... Phil

Reading.........

I have a small stereo amplifier which came with two tiny 4ohm 3watt speakers

Still reading.........................................

How tiny?

What color ??

greg

== 2 of 2 ==
Date: Mon, Jul 26 2010 6:35 am
From: "Phil Allison"

"Greg the trolling Shithead"
>>
>>>>> You forgot to give the power.
>>
>>
>>** It in the very first line of the original post.
>>
>> You pathetic imbecile.
>>

>
> I have a small stereo amplifier which came with two tiny 4ohm 3watt
> speakers

** Wot a pathetic moron....

... Phil

==============================================================================
TOPIC: I GOT $2,000 FROM ' PAYPAL'
http://groups.google.com/group/sci.electronics.repair/t/233acd72ed97b3e2?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jul 26 2010 6:46 am
From: paypal

I GOT $2,000 FROM ' PAYPAL' At http://veryhotguru.co.cc

i have hidden the PayPal Form link in an image.
in that website On Top Side Above search box , click on image
and enter your PayPal id And Your name.

==============================================================================
TOPIC: Zenith 25CC25 horizontal sweep problem
http://groups.google.com/group/sci.electronics.repair/t/f0f84fb8db596265?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Jul 26 2010 7:01 am
From: Chuck

On Sat, 24 Jul 2010 13:50:38 +0100, "Arfa Daily"
<arfa.daily@ntlworld.com> wrote:

>
>
>"Mike WB2MEP" <michael.w.appenzeller@lmco.com> wrote in message
>news:d7e2b8d5-52eb-49ff-acba-60225081f059@5g2000yqz.googlegroups.com...
>> On Jul 23, 12:59 pm, "Arfa Daily" <arfa.da...@ntlworld.com> wrote:
>>> > Another Zenith had one in the HV regulator circuit that went open and
>>> > lost regulation. The HV was running around 30 kV on a 19" set. A
>>> > regular resistor did't work on that set and I had to get the correct
>>> > part.
>>>
>>> > It looks likewww.moyerelectronics.comhas a 63-5440 sub. in stock.
>>>
>>> > Mike WB2MEP
>>>
>>> Good grief ! Did you not have x-ray protection circuits on the sets your
>>> side of the pond ?
>>>
>>> Arfa
>>
>> Not on tube sets, and early solid-state ones. X-ray protection came
>> into widespread use when they started running the horiz. sweep from a
>> regulated B+ supply and did away with regulation of the HV itself.
>>
>> Mike
>
>That surprises me. It's of course been a very long time ago, but I'm sure
>that the early tube sets that I worked on, which employed a type PD500 shunt
>stabilizer for the HV. had at least some crude form of x-ray protection, in
>the form of sensing the beam current and using the result to back-bias the
>H-out tube into cutoff. At 30kV on a 19" CRT, the average beam current must
>have been well over the top, and fairly easily sensed as a fault condition ?
>Perhaps they were just a bit more 'picky' about such things this side of the
>pond ? :-)
>
>Arfa

Early Zenith solid state sets had a horizontal tuning cap that would
open, then the high voltage would skyrocket until the neck would fall
off of the crt. RCA sets with SCR sweep had a failure mode where the
high voltage would go over 60 KV. The vertical deflection was
designed to collapse, when the hv rose, which was supposed to signal
the customer that they should shut off the set. However, many people
would leave the set on and just listen to the sound. I always
wondered why RCA didn't just kill the horizontal drive. Chuck

== 2 of 2 ==
Date: Mon, Jul 26 2010 8:19 am
From: Jim Adney

On Jul 21, 11:22 pm, Jim Adney <jad...@vwtype3.org> wrote:

> Finally, I checked the DC bias on the HOT. The Zenith manual says it
> should be -80 V, so I was expecting it to be lower. It's actually -65
> V. So there must be something else wrong in that circuit.

In comparing my Sams & Zenith manuals, I find that Zenith says the HOT
control grid bias should be -80 V but Sams says -48 V. I now have -65
V. I'm going to guess that Sams is right and I need something closer
to -50 V, which should turn things up a bit more and get me to the 26
kV that I should have for the HV. I also checked the tube data sheets
for the 20LF6 and 26LF6 and found that typical control grid bias
values are -10 and -20 V. So I can afford to boost that voltage quite
a bit higher (more positive) than the -65 V where it's at now.

The set is put back together now, but I'll pull it apart again once
our houseguests (arriving tomorrow) are gone. In the meantime, it
looks like I should try to buy one of those odd 63-5440s. AFAIK that's
the one remaining part in there that might be the problem, but I'll
check around the circuit, too, to make sure I haven't missed
something.

As an aside: Was it common for the Sams to be more accurate than the
Zenith manual? Or, to put it differently: Did the Zenith manuals have
a poor reputation?

thanks,

==============================================================================
TOPIC: Sony Wega KD-36XS955
http://groups.google.com/group/sci.electronics.repair/t/d41634951796c588?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Jul 26 2010 8:22 am
From: Dani

Firstly, be carefull if you are not familiar with electronics, it's
dangerous to work on this stuff! What led code do you have? A constant
flash while in "startup mode" is normal, but at failure you will get
an led flash like one blink, a pause, then a five blink...code 15. Or
six blinks over & over...meaning code six. Best way to repair, is to
replace all three MCZ3001DB IC's with original, although, only one or
two MAY be bad. High failure rate, using the MCZ3001 without the DB in
the end, will LIKELY end in failure. Flyback transformers are common
in Sony too. The code helps narrow it down greatly. Hope this is
helpfull.

==============================================================================
TOPIC: Fender Concert amp
http://groups.google.com/group/sci.electronics.repair/t/618084923bc57a44?hl=en
==============================================================================

== 1 of 4 ==
Date: Mon, Jul 26 2010 8:39 am
From: "N_Cook"

Bad splitter-driver plate/anode 100K resistor, what goes bad with them?
Causing rustle noise in output. Partial crack? or something chemical. I may
as well replace the 82K while I'm at it , but is there any point to
pre-emptively replacing all the HV droppers ?
Anyone happen to know the datecode structure for Mallory electrolytics of
the 1980s?
say 4uF, 450VDC
marked
012022
235
8346B

1982 and 35/52 from 235 or 1983 and 46/52 from the last number?

== 2 of 4 ==
Date: Mon, Jul 26 2010 9:17 am
From: Ron

On 26/07/2010 16:39, N_Cook wrote:
> Bad splitter-driver plate/anode 100K resistor, what goes bad with them?
> Causing rustle noise in output. Partial crack? or something chemical. I may
> as well replace the 82K while I'm at it , but is there any point to
> pre-emptively replacing all the HV droppers ?
> Anyone happen to know the datecode structure for Mallory electrolytics of
> the 1980s?
> say 4uF, 450VDC
> marked
> 012022
> 235
> 8346B
>
> 1982 and 35/52 from 235 or 1983 and 46/52 from the last number?
>
>

Noisy 100k resistors is a common and well known problem with Fender
amps, change em all.

Ron

--
I am using the free version of SPAMfighter.
We are a community of 7 million users fighting spam.
SPAMfighter has removed 1572 of my spam emails to date.
Get the free SPAMfighter here: http://www.spamfighter.com/len

The Professional version does not have this message

== 3 of 4 ==
Date: Mon, Jul 26 2010 9:54 am
From: "Arfa Daily"

"Ron" <ron@lunevalleyaudio.com> wrote in message
news:uoydnVAX4qqSKNDRnZ2dnUVZ7sWdnZ2d@bt.com...
> On 26/07/2010 16:39, N_Cook wrote:
>> Bad splitter-driver plate/anode 100K resistor, what goes bad with them?
>> Causing rustle noise in output. Partial crack? or something chemical. I
>> may
>> as well replace the 82K while I'm at it , but is there any point to
>> pre-emptively replacing all the HV droppers ?
>> Anyone happen to know the datecode structure for Mallory electrolytics of
>> the 1980s?
>> say 4uF, 450VDC
>> marked
>> 012022
>> 235
>> 8346B
>>
>> 1982 and 35/52 from 235 or 1983 and 46/52 from the last number?
>>
>>
>
> Noisy 100k resistors is a common and well known problem with Fender amps,
> change em all.
>
> Ron
>

I reckon that goes for all amps with 12AX7 stages, doesn't it Ron ?

Arfa

== 4 of 4 ==
Date: Mon, Jul 26 2010 10:36 am
From: Meat Plow

On Mon, 26 Jul 2010 17:54:00 +0100, Arfa Daily wrote:

> "Ron" <ron@lunevalleyaudio.com> wrote in message
> news:uoydnVAX4qqSKNDRnZ2dnUVZ7sWdnZ2d@bt.com...
>> On 26/07/2010 16:39, N_Cook wrote:
>>> Bad splitter-driver plate/anode 100K resistor, what goes bad with
>>> them? Causing rustle noise in output. Partial crack? or something
>>> chemical. I may
>>> as well replace the 82K while I'm at it , but is there any point to
>>> pre-emptively replacing all the HV droppers ? Anyone happen to know
>>> the datecode structure for Mallory electrolytics of the 1980s?
>>> say 4uF, 450VDC
>>> marked
>>> 012022
>>> 235
>>> 8346B
>>>
>>> 1982 and 35/52 from 235 or 1983 and 46/52 from the last number?
>>>
>>>
>>>
>> Noisy 100k resistors is a common and well known problem with Fender
>> amps, change em all.
>>
>> Ron
>>
>>
>
> I reckon that goes for all amps with 12AX7 stages, doesn't it Ron ?
>
> Arfa

I repaired an old 50 watt Silvertone a few months ago and found two 100k
plate resistors one in the splitter and one in the reverb driver that had
increased in value by nearly double. The splitter was a 12a-something but
the reverb driver was a 6-something.

==============================================================================
TOPIC: SMPS capacitor test question
http://groups.google.com/group/sci.electronics.repair/t/47a9ad25e4f5e03c?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Jul 26 2010 9:00 am
From: Cydrome Leader

I noticed the lithium battery for my nikon camera was acting as it it had
a bad cell. It would charge, but just not last very long. The battery is
"smart" with a third terminal that the camera talks to. It shows perfect
"health" which is total nonsense after 2 years of use and the fact that it
doesn't work right.

THe charger itself is is little less smart. It charges the battery at 8.4V
and 0.9A or something like that, but using only the + and - terminals
from the battery pack.

I also noticed it got pretty hot, so I opened it and found very few parts
aside from some 20+ pin charging controller and pretty basic switching
power supply. The transformer and filter caps were pretty hot. The older
Kodak/Sony AA NiMH chargers seriously look more complex than this charger.

I guess it's expected that that cap will warm up at whatever crazy
frequencies they use these days in compact power supplies, however while
it would fail my standard for the touch test, it may still be in spec.

Is a capacitor ESR meter of some sort going to be useful for testing the
cap? What frequencies do they test at?

While I could just replace the cap and not worry about it, not being able
to test it is the issue I'm more interested in solving.

== 2 of 2 ==
Date: Mon, Jul 26 2010 9:52 am
From: "Arfa Daily"

"Cydrome Leader" <presence@MUNGEpanix.com> wrote in message
news:i2kbe6$od9$1@reader1.panix.com...
> I noticed the lithium battery for my nikon camera was acting as it it had
> a bad cell. It would charge, but just not last very long. The battery is
> "smart" with a third terminal that the camera talks to. It shows perfect
> "health" which is total nonsense after 2 years of use and the fact that it
> doesn't work right.
>
> THe charger itself is is little less smart. It charges the battery at 8.4V
> and 0.9A or something like that, but using only the + and - terminals
> from the battery pack.
>
> I also noticed it got pretty hot, so I opened it and found very few parts
> aside from some 20+ pin charging controller and pretty basic switching
> power supply. The transformer and filter caps were pretty hot. The older
> Kodak/Sony AA NiMH chargers seriously look more complex than this charger.
>
> I guess it's expected that that cap will warm up at whatever crazy
> frequencies they use these days in compact power supplies, however while
> it would fail my standard for the touch test, it may still be in spec.
>
> Is a capacitor ESR meter of some sort going to be useful for testing the
> cap? What frequencies do they test at?
>
> While I could just replace the cap and not worry about it, not being able
> to test it is the issue I'm more interested in solving.

An ESR meter such as the Bob Parker Blue now available from Anatek Corp,
would tell you the story. It tests at around 100kHz, as I recall. It's not
an expensive instrument, especially if you build it yourself from a kit, and
is certainly endlessly useful in a commercial workshop. For non-commercial
casual use, still cheap enough to be one of those 'nice to have' items ...

Arfa

==============================================================================
TOPIC: Isopropyl Alcohol for Cleaning Flux
http://groups.google.com/group/sci.electronics.repair/t/a7a3663fd81cf5bd?hl=en
==============================================================================

== 1 of 3 ==
Date: Mon, Jul 26 2010 9:57 am
From: "Arfa Daily"

"Joe" <none@given.now> wrote in message
news:none-2507101756580001@dialup-4.231.173.83.dial1.losangeles1.level3.net...
> In one of the posts about solder, somebody mentioned CVS Drug Store for
> 91% isopropyl alcohol.
>
> I just called a CVS, it's $2.79 for 16 ounces and $2.99 for 32 ounces.
> That's 20 cents more for double the 16 ounce size. (This is in southern
> California).
>
>
> A mildly related question: In thinking about other uses for rosin, it
> occurred to me that I haven't seen any pitchers using a rosin bag for
> years.
>
> Maybe it went the way of the vanishing caboose. :)
>
> --- Joe

91% IPA is not usually considered to be 'electronics grade', which should be
99.7% minimum. It's also not the most appropriate stuff for cleaning a lot
of flux, which requires a proper defluxing agent such as Electrolube Deflux
160

Arfa

== 2 of 3 ==
Date: Mon, Jul 26 2010 10:30 am
From: Meat Plow

On Mon, 26 Jul 2010 17:57:25 +0100, Arfa Daily wrote:

> "Joe" <none@given.now> wrote in message
>
news:none-2507101756580001@dialup-4.231.173.83.dial1.losangeles1.level3.net...
>> In one of the posts about solder, somebody mentioned CVS Drug Store for
>> 91% isopropyl alcohol.
>>
>> I just called a CVS, it's $2.79 for 16 ounces and $2.99 for 32 ounces.
>> That's 20 cents more for double the 16 ounce size. (This is in southern
>> California).
>>
>>
>> A mildly related question: In thinking about other uses for rosin, it
>> occurred to me that I haven't seen any pitchers using a rosin bag for
>> years.
>>
>> Maybe it went the way of the vanishing caboose. :)
>>
>> --- Joe
>
> 91% IPA is not usually considered to be 'electronics grade', which
> should be 99.7% minimum. It's also not the most appropriate stuff for
> cleaning a lot of flux, which requires a proper defluxing agent such as
> Electrolube Deflux 160
>
> Arfa

91 leaves a bit of residue in certain cases. After reading the
ingredients on a can of Flux-Off spray flux stripper I thought why not
just use 91 isoprop. It usually does work in conjunction with a
toothbrush. But like I said can leave a residue.

== 3 of 3 ==
Date: Mon, Jul 26 2010 10:43 am
From: David Nebenzahl

On 7/26/2010 10:30 AM Meat Plow spake thus:

> On Mon, 26 Jul 2010 17:57:25 +0100, Arfa Daily wrote:
>
>> "Joe" <none@given.now> wrote in message
>> news:none-2507101756580001@dialup-4.231.173.83.dial1.losangeles1.level3.net...
>>
>>> In one of the posts about solder, somebody mentioned CVS Drug Store for
>>> 91% isopropyl alcohol.
>>>
>>> I just called a CVS, it's $2.79 for 16 ounces and $2.99 for 32 ounces.
>>> That's 20 cents more for double the 16 ounce size. (This is in southern
>>> California).
>>
>> 91% IPA is not usually considered to be 'electronics grade', which
>> should be 99.7% minimum. It's also not the most appropriate stuff for
>> cleaning a lot of flux, which requires a proper defluxing agent such as
>> Electrolube Deflux 160
>
> 91 leaves a bit of residue in certain cases. After reading the
> ingredients on a can of Flux-Off spray flux stripper I thought why not
> just use 91 isoprop. It usually does work in conjunction with a
> toothbrush. But like I said can leave a residue.

Why mess around with isopropyl alcohol at all, since all of it contains
*some* water? Use denatured alcohol (methanol) instead, in a
tightly-capped container to guard against absorbing moisture.

--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.

- Comment from an article on Antiwar.com (http://antiwar.com)

==============================================================================
TOPIC: Using the proper technical terms ... :-)
http://groups.google.com/group/sci.electronics.repair/t/70f4a28084d10b2c?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Jul 26 2010 10:11 am
From: "Arfa Daily"

Just in. A combo, the job ticket on which says "Low volume. Sounds like
shit."

There's hope for the lads behind the counter, yet. How nice to get one with
a perfect owner's description of the problem, rather than some wild guess
that the person who's booked it in has made, based on what the owner said. I
can just see some hairy guitarist lugging it in and saying to whoever booked
it in "Go on lad ! Just write it down, Low volume. Sounds like shit !"

:-)

Arfa

== 2 of 2 ==
Date: Mon, Jul 26 2010 10:39 am
From: Meat Plow

On Mon, 26 Jul 2010 18:11:36 +0100, Arfa Daily wrote:

> Just in. A combo, the job ticket on which says "Low volume. Sounds like
> shit."
>
> There's hope for the lads behind the counter, yet. How nice to get one
> with a perfect owner's description of the problem, rather than some wild
> guess that the person who's booked it in has made, based on what the
> owner said. I can just see some hairy guitarist lugging it in and saying
> to whoever booked it in "Go on lad ! Just write it down, Low volume.
> Sounds like shit !"
>
> :-)
>
> Arfa

LOL!

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