sci.electronics.repair@googlegroups.com

Today's topics:

* Tektronix 7603 - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/efb86f5dc14fc24b?hl=en
* Why do some manufacturers wrap the electrolytic capacitor that gets the
hottest in a switching power supply in shrink wrap? - 6 messages, 4 authors
http://groups.google.com/group/sci.electronics.repair/t/2a675f3c64fd62cc?hl=en
* Contactor coil: 50 Hz vs. 60 Hz - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/0d1a06068779ce43?hl=en
* Yellow Glue strikes again - 13 messages, 3 authors
http://groups.google.com/group/sci.electronics.repair/t/9d8bded3db582b06?hl=en
* Tek 465 - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/b9f473fde6856891?hl=en
* Motor start/stop switch with integrated mini contactor? - 2 messages, 2
authors
http://groups.google.com/group/sci.electronics.repair/t/13b233689d902984?hl=en

==============================================================================
TOPIC: Tektronix 7603
http://groups.google.com/group/sci.electronics.repair/t/efb86f5dc14fc24b?hl=en
==============================================================================

== 1 of 2 ==
Date: Tues, Aug 30 2011 3:12 pm
From: "Michael A. Terrell"

Jeff Urban wrote:
>
> I do not care to join any more groups. This is sci.electronics.repair
> correct ? This is an electronic instrument I wish to repair.
>
> I need another internet ID like a hole in the head, and let me tell
> you when I was in my twenties I got shot in the face, so I can assure
> you I don't need any more holes in my head. What is Usenet dead ? I
> know I am posting through Google but that's the only way I have right
> now. I was here a long time ago and if I could I would retrieve my old
> ID, but I can't.
>
> S.E.R. is dead ? I have to go to yahoo ?
>
> Sorry, I'll just sell the Tek. Fuck it.

This is the reason so many have left the group for greener pastures.
They got tired of whiny jerks like you.

All you need is a Yahoo Email address to join any Yahoo group that
will take you, but they aren't interested in pissing and moaning.

You aren't related to Bill Turner, by any chance? You bitch and
whine just like he used to.

--
You can't have a sense of humor, if you have no sense.

== 2 of 2 ==
Date: Tues, Aug 30 2011 10:18 pm
From: Jeff Urban

"This is the reason so many have left the group for greener pastures.
They got tired of whiny jerks like you. "

You know a hell of alot about me out of one post. I am a whiney
jerk ?

Interesting assessment. You know what, I don't need that or any other
Tektroniks, or any other type of bullshit equipment like that. Gimme
my P2P, PC and good soundcard. I'll throw the fucking Tektronix out on
the treelawn after a treatment with the hammer. No problem.

Was that your goal ? Hope so, so you can be proud of yourself. And,
this little self help group here, help your self. Yuo DON'T want me to
lift a finger, now.

Tell Jim Yanik I am sorry, I'll see him at the NRA meeting. The rest
of you, go fuck yourselves.

Fukt if I have to sign this, you knopw who the fuck I am.

==============================================================================
TOPIC: Why do some manufacturers wrap the electrolytic capacitor that gets the
hottest in a switching power supply in shrink wrap?
http://groups.google.com/group/sci.electronics.repair/t/2a675f3c64fd62cc?hl=en
==============================================================================

== 1 of 6 ==
Date: Tues, Aug 30 2011 3:31 pm
From: dplatt@radagast.org (Dave Platt)

In article <3giq5793mdtgi0f6ssmf2pp79bn9ukbeuv@4ax.com>,
Chuck <chuckh@deja.net> wrote:

>Extron has been doing this for years and of course it is the first
>part to fail in their units. Smart Technologies Sympodium power
>supplies, that they have contract built in China, fail in a year or so
>for the same reason. Technicians and electronic engineers at my work
>place can't think of a rational reason why these manufacturers do
>this. This is pro gear where reliability is a great concern so it
>doesn't seem to be planned failure mode. Thanks. Chuck

I've heard it said:

"When the question is `Why is company X doing seemingly irrational
thing Y in their product design?', the answer is most commonly
`Money',"

Electrolytic capacitors are normally shipped, by their manufacturers,
in a plastic insulating jacket. It's the common method used to
insulate the cases against accidental shorts, and to allow convenient
marking (no separate marking process is required during manufacture,
since the markings are manufactured into the plastic).

Almost all "commodity" 'lytics are of this sort. If you want caps
with another sort of jacketing (even "none at all") you'd probably
have to special-order them, there would be far fewer possible sources,
and the cost per piece would end up being significantly higher.

There's immense price-pressure and competition in the electronics
manufacturing business, even for "pro gear". A matter of a few cents
per power supply can make the difference between a contract
manufacturer getting, or losing the bid. The manufacturers thus have
a *very* strong incentive to use standard parts... and, in fact, the
cheapest and lowest-rated ones which will allow the final supply to
pass its paper requirements (which may not include long-life survival
tests).

I've heard that it's quite common for overseas contract manufacturers
to covertly "down-rate" parts, after they win a bid... that is, the
specific caps and resistors and etc. that they stuff into the
production lots, may not be the same as the ones they stuffed into the
samples that they submitted. Unless you stand over 'em with a club,
and do a strict verification of what you receive, you may get
lower-quality subsystems than you had been originally offered. You
might even get counterfeit parts (e.g. cheap 85-degree-C caps, which
have been falsely labeled as 105-degree-C, or generic caps falsely
marked to indicate low-ESR, high-ripple-current ruggedness).

If the final system survives to the end of its warranty period, many
companies seem to feel that this is Plenty Good Enough, and brings in
additional revenue for repairs and replacements.

--
Dave Platt <dplatt@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

== 2 of 6 ==
Date: Tues, Aug 30 2011 3:41 pm
From: stratus46@yahoo.com

On Aug 30, 2:48 pm, Jim Yanik <jya...@abuse.gov> wrote:
> Chuck <chu...@deja.net> wrote innews:
3giq5793mdtgi0f6ssmf2pp79bn9ukbeuv@4ax.com:
>
> > Extron has been doing this for years and of course it is the
first
> > part to fail in their units.  Smart Technologies Sympodium power
> > supplies, that they have contract built in China, fail in a year
or so
> > for the same reason.  Technicians and electronic engineers at my
work
> > place can't think of a rational reason why these manufacturers do
> > this.  This is pro gear where reliability is a great concern so
it
> > doesn't seem to be planned failure mode.  Thanks.  Chuck
>
> IMO,in a proper design,the caps should not be getting hot.
> Caps should be sized and rated properly,with a fair amount of
excess
> capacity,not sized/rated right at the margins.
> We have inexpensive thermal imaging available that can identify hot
spots
> so that they can be corrected before the design is finalized.
>
> --
> Jim Yanik
> jyanik
> at
> localnet
> dot com

The caps may not be getting hot on their own but get damaged from
nearby hot items. We had 16 Samsung digital tuners at work that had 1
cap that fails next to a diode on a heatsink. We replaced it with a
very good grade cap but extended the leads just enough to lay the cap
on its side away from the heatsink. Luckily room to do that existed.

G²

== 3 of 6 ==
Date: Tues, Aug 30 2011 5:41 pm
From: "Phil Allison"

"Chuck"
>
> Extron has been doing this for years and of course it is the first
> part to fail in their units. Smart Technologies Sympodium power
> supplies, that they have contract built in China, fail in a year or so
> for the same reason.

** What a load of bullshit !!

Putting a shrink wrap sleeve around an electro will not make it fail early.

I bet the sleeve is there for a totally non electronic reason - like being
able to put markings on it with a pen.

.... Phil

== 4 of 6 ==
Date: Tues, Aug 30 2011 6:01 pm
From: Jeff Liebermann

On Tue, 30 Aug 2011 15:47:21 -0500, Chuck <chuckh@deja.net> wrote:

>Extron has been doing this for years and of course it is the first
>part to fail in their units. Smart Technologies Sympodium power
>supplies, that they have contract built in China, fail in a year or so
>for the same reason. Technicians and electronic engineers at my work
>place can't think of a rational reason why these manufacturers do
>this. This is pro gear where reliability is a great concern so it
>doesn't seem to be planned failure mode. Thanks. Chuck

Probably to keep you from touching the can, which is probably
electrically hot. The life you save may be your own.

Electrolytic caps do not normally get hot. There is a temperature
rise equal to the ripple current times the square of the ESR
(equivlent series resistance). If the ESR is too high, usually due to
underspecifying the voltage rating or capacitor type, it will get
warm. There are derating curves for capacitors at various
temperatures. There are also lifetime prediction calculators which
include the operating temperature.

If you're shopping for a conspiracy theory, I guess the capacitors are
badly specified or picking up heat from adjacent heat dissipating
devices. A nearby resistor or heat sunk xsistor will heat up a cap
quite nicely. The shrink tube will have little effect on the cap
temperature. Black absorbs more heat, so it might be slightly warmer
from nearby radiation. At best, maybe a degree or two.

Pro audio is the same as consumer audio, except for the price tag and
the hype.

--
# 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

== 5 of 6 ==
Date: Tues, Aug 30 2011 6:14 pm
From: "Phil Allison"

"Jeff Liebermann"
>
> Electrolytic caps do not normally get hot. There is a temperature
> rise equal to the ripple current times the square of the ESR
> (equivlent series resistance).

** Wanna try that again ??

> Pro audio is the same as consumer audio, except for the price tag and
> the hype.

** Only true of most Chinese made stuff.

.... Phil

== 6 of 6 ==
Date: Tues, Aug 30 2011 6:26 pm
From: Jeff Liebermann

On Wed, 31 Aug 2011 11:14:07 +1000, "Phil Allison" <phil_a@tpg.com.au>
wrote:

>"Jeff Liebermann"
>>
>> Electrolytic caps do not normally get hot. There is a temperature
>> rise equal to the ripple current times the square of the ESR
>> (equivlent series resistance).
>
>
>** Wanna try that again ??

Oops.
Powah = Ripple Current squared times ESR.
Thanks (grumble)...

>> Pro audio is the same as consumer audio, except for the price tag and
>> the hype.
>
>** Only true of most Chinese made stuff.

I didn't know that anything was made outside of China these days. If
the boards and boxes aren't built in China, the components probably
are made in China.
<http://www.made-in-china.com/products-search/hot-china-products/Pro_Audio.html>
<http://www.made-in-china.com/Consumer-Electronics-Catalog/Professional-Audio-Lighting.html>
<http://www.diytrade.com/china/4/products-list/0-k-c-1/pro_audio.html>
<http://www.alibaba.com/countrysearch/CN/pro_audio.html>

--
# 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

==============================================================================
TOPIC: Contactor coil: 50 Hz vs. 60 Hz
http://groups.google.com/group/sci.electronics.repair/t/0d1a06068779ce43?hl=en
==============================================================================

== 1 of 1 ==
Date: Tues, Aug 30 2011 5:36 pm
From: John Fields

On Tue, 30 Aug 2011 05:11:20 -0700 (PDT), NT <meow2222@care2.com>
wrote:

>On Aug 30, 12:39 pm, John Fields <jfie...@austininstruments.com>
>wrote:
>> On Mon, 29 Aug 2011 07:25:23 -0700 (PDT), NT <meow2...@care2.com>
>> wrote:
>>
>> >IME relays pull in at in the region of half rated voltage, and dc
>> >ratings are typically about half the voltage of the ac rating, which
>> >gives an idea of how much current is determined by L and how much by
>> >R.
>>
>> ---
>> IME, most relays (with either AC or DC coils) are guaranteed to pull
>> in at about 80% of their rated coil voltage, so I'm at a loss trying
>> to understand what you meant by: "dc ratings are typically about half
>> of the ac rating."
>>
>> Can you elaborate, please?
>
>When relays have dual ratings for ac and dc, its normal for the dc
>voltage rating to be half the ac voltage rating.
>
>
>> >Running your relay on 220v 60Hz it will work fine.
>>
>> Knowing nothing about the contactor, other than that it's specified to
>> energize when 240V 50Hz is placed across the coil, your imprimatur is
>> premature.
>
>I really dont agree. I do know the basics about relays, and one
>normally finds that pull-in occurs at around 50% rated voltage. The OP
>is welcome to test theirs to see if it behaves the usual way.
>
>
>> >Contact closing speed will be slightly slower. Margin will be reduced,
>> >but its only being reduced from enormous to slightly less enormous,
>> >so its a non-issue except in very unusual situations.
>>
>> It seems you've forgotten that when the armature makes, and the
>> magnetic circuit is closed, the inductance of the coil will rise.
>
>I dont know why you think I've forgotten it. What's relevant here is
>inductance in the closed position.

---
I disagree.

Since the relay is open when power is applied to the coil, it's the
open inductance (and the resistance, of course) which will determine
how much current will flow through the coil, that current being what
generates the magnetic field to start the armature on its way.

Then when the relay closes, the closed inductance comes into play and
holds the armature in place until the current through the coil is
reduced to a point where the armature's return spring overcomes the
weakened magnetic field, allowing the armature to open.
---

>> Such being the case, the current in it will diminish,
>
>true with all relays under all ac conditions. Theyre designed to work
>that way.
>
>> reducing the
>> hold on the armature and making the contacts more likely to chatter.
>
>No, its exactly how theyre designed to operate.
>
>
>> >The vibration tolerance of
>> >the contacts will be little affected in practice; if your environment
>> >is harsh enough to shake the relay contact open, then you've got
>> >bigger worries than contacts crackling.
>> >If instead you meant you would use it on 110v 60Hz, then dont. But you
>> >could use diodes to get a higher dc voltage and use that.
>>
>> Interesting conjecture.
>
>Where's the conjecture? I get the feeling you could do with bringing
>your skills up to speed on relays.

---
Perhaps.
---

>> Something like this?
>>
>>         +-----+
>> 120AC>--|~   +|----+
>>         |     |    |  
>>         |     |  [COIL]
>>         |     |    |
>> 120AC>--|~   -|----+
>>         +-----+
>
>That would work.

---
Not in all cases, certainly.
---
>
>
>> Since the coil has an impedance of about 6600 ohms at 50Hz, then the
>> current through it will be:
>>
>>           E      240V
>>      I = --- = ------- = 0.036A = 36mA
>>           Z     6600R
>>
>> Then, since the coil has a resistance of 4800 ohms, the DC voltage
>> across it required to force 36mA through it would be:
>>
>>      E = IR = 0.036A * 4800R ~ 174V.
>
>You're not saying where you got those figures from.

---
The P&B MR5A I talked about in an earlier post, which has a 240V
50/60Hz coil, a coil resistance of 4800 ohms, an impedance of ~ 6600
ohms at 50 Hz, an open inductance of 14.5 henrys, and a closed
inductance of 16 henrys
---

>Typically dc rating is half ac rating.

---
But I don't think "typical" is what we're after since we want
something that will _always_ work.

Since current is what's doing the work, my real-world example shows
that 240V 50 Hz RMS impressed across a load with an impedance of 6600
ohms will force 36mA RMS of current through the load.

Then, since it's current that's doing the work, 36mA of DC through the
coil should accomplish the same thing.
---

>> The peak voltage out of the bridge would be:
>>
>>      E = RMS * sqrt(2) = 120 * 1.414 ~ 170V.
>>
>> Pretty close, but at 120Hz, the reactance of the coil would increase,
>> limiting the current to something less than the 36mA needed to close
>> the armature.
>
>The effect of the relay's inductance, when run off a BR, is simply to
>smooth the current flow somewhat.

---
Yeah, I know, said so earlier, and posted a simulation showing the
ripple.
---

>Mean current remains much the same.
>So we're looking for 120v rms, which is what the BR would deliver.

---
But, what it won't deliver is the worst-case voltage required over the
interval required to guarantee the armature will close.
---

>> However, the reactance of the coil will smooth the current and the
>> addition of a capacitor in parallel with the coil will remove some of
>> the ripple and allow the coil to see more nearly pure DC.
>
>and overheat the relay by increasing its rms dc voltage to above 120v.

---
There's no such thing as "rms dc voltage", and if the relay is
designed to operate on AC with a certain RMS current in its coil, how
can it possibly overheat if that current is DC?
---

>> Here's a simulation showing both ways:
>>
>> Version 4
>> SHEET 1 880 680
>> WIRE -144 16 -304 16
>> WIRE 112 16 -144 16
>> WIRE 448 16 288 16
>> WIRE 704 16 448 16
>> WIRE -304 80 -304 16
>> WIRE 288 80 288 16
>> WIRE 448 80 448 64
>> WIRE 480 80 448 80
>> WIRE 592 80 560 80
>> WIRE 704 80 704 64
>> WIRE 704 80 672 80
>> WIRE -144 112 -144 80
>> WIRE -112 112 -144 112
>> WIRE 0 112 -32 112
>> WIRE 112 112 112 80
>> WIRE 112 112 80 112
>> WIRE -144 160 -144 112
>> WIRE 112 160 112 112
>> WIRE 448 160 448 80
>> WIRE 544 160 448 160
>> WIRE 704 160 704 80
>> WIRE 704 160 608 160
>> WIRE -304 224 -304 160
>> WIRE -144 224 -304 224
>> WIRE 112 224 -144 224
>> WIRE 288 224 288 160
>> WIRE 448 224 288 224
>> WIRE 704 224 448 224
>> WIRE -304 272 -304 224
>> WIRE 288 272 288 224
>> FLAG -304 272 0
>> FLAG 288 272 0
>> SYMBOL ind -128 128 R270
>> WINDOW 0 32 56 VTop 0
>> WINDOW 3 5 56 VBottom 0
>> SYMATTR InstName L1
>> SYMATTR Value 15
>> SYMBOL voltage -304 64 R0
>> WINDOW 3 24 104 Invisible 0
>> WINDOW 123 0 0 Left 0
>> WINDOW 39 0 0 Left 0
>> SYMATTR InstName V1
>> SYMATTR Value SINE(0 170 60)
>> SYMBOL diode -160 16 R0
>> WINDOW 0 4 -52 Left 0
>> WINDOW 3 -28 -24 Left 0
>> SYMATTR InstName D1
>> SYMATTR Value MUR460
>> SYMBOL diode 128 80 R180
>> WINDOW 0 1 119 Left 0
>> WINDOW 3 -33 84 Left 0
>> SYMATTR InstName D2
>> SYMATTR Value MUR460
>> SYMBOL diode 96 160 R0
>> WINDOW 0 3 89 Left 0
>> WINDOW 3 -27 118 Left 0
>> SYMATTR InstName D3
>> SYMATTR Value MUR460
>> SYMBOL diode -128 224 R180
>> WINDOW 0 2 -28 Left 0
>> WINDOW 3 -31 -57 Left 0
>> SYMATTR InstName D4
>> SYMATTR Value MUR460
>> SYMBOL res -16 128 R270
>> WINDOW 0 32 56 VTop 0
>> WINDOW 3 0 56 VBottom 0
>> SYMATTR InstName R1
>> SYMATTR Value 4800
>> SYMBOL ind 464 96 R270
>> WINDOW 0 32 56 VTop 0
>> WINDOW 3 5 56 VBottom 0
>> SYMATTR InstName L2
>> SYMATTR Value 15
>> SYMBOL voltage 288 64 R0
>> WINDOW 3 24 104 Invisible 0
>> WINDOW 123 0 0 Left 0
>> WINDOW 39 0 0 Left 0
>> SYMATTR InstName V2
>> SYMATTR Value SINE(0 170 60)
>> SYMBOL diode 432 16 R0
>> WINDOW 0 4 -52 Left 0
>> WINDOW 3 -28 -24 Left 0
>> SYMATTR InstName D5
>> SYMATTR Value MUR460
>> SYMBOL diode 720 80 R180
>> WINDOW 0 1 119 Left 0
>> WINDOW 3 -33 84 Left 0
>> SYMATTR InstName D6
>> SYMATTR Value MUR460
>> SYMBOL diode 688 160 R0
>> WINDOW 0 3 89 Left 0
>> WINDOW 3 -27 118 Left 0
>> SYMATTR InstName D7
>> SYMATTR Value MUR460
>> SYMBOL diode 464 224 R180
>> WINDOW 0 2 -28 Left 0
>> WINDOW 3 -31 -57 Left 0
>> SYMATTR InstName D8
>> SYMATTR Value MUR460
>> SYMBOL res 576 96 R270
>> WINDOW 0 32 56 VTop 0
>> WINDOW 3 0 56 VBottom 0
>> SYMATTR InstName R2
>> SYMATTR Value 4800
>> SYMBOL cap 608 144 R90
>> WINDOW 0 0 32 VBottom 0
>> WINDOW 3 32 32 VTop 0
>> SYMATTR InstName C1
>> SYMATTR Value 10µ
>> TEXT -298 246 Left 0 !.tran .05
>>
>> If the relay is spec'ed as "must make" at 80% of rated current through
>> the coil (~29mA), then note that with a 10µF cap in parallel with the
>> coil the relay will _always_ make using full-wave rectified 120V 60Hz
>> mains.  

--
JF

==============================================================================
TOPIC: Yellow Glue strikes again
http://groups.google.com/group/sci.electronics.repair/t/9d8bded3db582b06?hl=en
==============================================================================

== 1 of 13 ==
Date: Tues, Aug 30 2011 5:59 pm
From: "Phil Allison"

** I had hoped that the dreaded Yellow Glue peril had gone away - but it is
still with us.

Most of you will have seen it holding parts down to PCBs on Asian made
equipment and many of those will have seen what happens if the parts
involved get hot.

The example on my bench is the SMPS from an Alesis powered monitor ( M1
Active, Chinese made) ) which has blown up big time because of the damn
Yellow Glue used to secure a ferrite toroidal coil. All the glue used had
gone brown or back ( ie carbonised ) on this coil and arced across nearby
tracks taking out the main switching MOSFET, its drive IC and associated
transistors, high speed diodes and even the AC bridge rectifier diodes.

The toroidal coil had to be un-wound, cleaned up and re-wound. The same glue
was attacking parts elsewhere on the board too ( it corrodes copper) and had
to be laboriously scraped off.

Are the dickheads who squirt this horrible goop all over PCBs NEVER going
to wake up ??

..... Phil

== 2 of 13 ==
Date: Tues, Aug 30 2011 6:28 pm
From: Jeff Liebermann

On Wed, 31 Aug 2011 10:59:58 +1000, "Phil Allison" <phil_a@tpg.com.au>
wrote:

>** I had hoped that the dreaded Yellow Glue peril had gone away - but it is
>still with us.
>
>Most of you will have seen it holding parts down to PCBs on Asian made
>equipment and many of those will have seen what happens if the parts
>involved get hot.

Is that hot melt glue or something else?
Hot melt should, umm... melt, not burn.

--
# 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

== 3 of 13 ==
Date: Tues, Aug 30 2011 6:34 pm
From: "Phil Allison"

"Jeff Liebermann"

>
> Is that hot melt glue or something else?

** So you do no repair work at all ?

.... Phil

== 4 of 13 ==
Date: Tues, Aug 30 2011 6:36 pm
From: Jeffrey Angus

On 8/30/2011 8:28 PM, Jeff Liebermann wrote:
> Is that hot melt glue or something else?
> Hot melt should, umm... melt, not burn.

No, this crap looks like 3M weather strip adhesive.
Sometimes it looks like it's applied sparingly, other times
it looks like it was put on with a caulking gun.

Jeff

--
"Everything from Crackers to Coffins"

== 5 of 13 ==
Date: Tues, Aug 30 2011 6:50 pm
From: "Phil Allison"

"Jeffrey Angus"
>
> No, this crap looks like 3M weather strip adhesive.
> Sometimes it looks like it's applied sparingly, other times
> it looks like it was put on with a caulking gun.
>

** I've always wanted to know just WFT it really is !!

At first impression, it looks like ordinary contact adhesive - but it is
quick setting and dries to a hard surface. With time and heat it become tan
coloured and brittle. Then it goes toast brown and becomes corrosive and
conductive.

If coating the pins of an op-amp, the leakage current causes DC offsets and
crackling noises.

If coating small diodes and resistors etc - it will slowly eat the leads
right off.

If coating PCB tracks with hundreds of volts between them, the conduction
heats the glue directly until there is an explosion.

IME , a local ambient temp of about 55C is enough to set it off on its
pathway to hell.

.... Phil

== 6 of 13 ==
Date: Tues, Aug 30 2011 6:51 pm
From: Jeff Liebermann

On Wed, 31 Aug 2011 11:34:43 +1000, "Phil Allison" <phil_a@tpg.com.au>
wrote:

>"Jeff Liebermann"
>>
>> Is that hot melt glue or something else?
>
>** So you do no repair work at all ?

Just answer the question. I've seen plenty of hot melt glue being
used. It comes in clear, yellow, and brown. I've never noticed
anything else. Maybe it's a pro-audio only thing? I don't do any
pro-audio as what little audio repair work I do usually doesn't
involve incinerated parts and carbonized yellow glue.

--
# 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 13 ==
Date: Tues, Aug 30 2011 6:53 pm
From: Jeffrey Angus

On 8/30/2011 8:50 PM, Phil Allison wrote:
> ** I've always wanted to know just WFT it really is !!

It's probably related to that crap rubber they love to use
for drive belts and such that turns to extremely sticky goo
that's next to impossible to clean off of everything it
touches.

Jeff

--
"Everything from Crackers to Coffins"

== 8 of 13 ==
Date: Tues, Aug 30 2011 6:57 pm
From: "Phil Allison"

"Jeff Liebermann"
>>
>>> Is that hot melt glue or something else?
>>
>>** So you do no repair work at all ?
>
> Just answer the question.

** You are not a repair tech, or you would have seen it many times.

Always Asian made gear, from about the 1980s onwards.

TV sets, VCRs, SMPSs anything where the maker felt it was a good idea to
glue things to the PCB.

Do a Google search on this NG under " yellow glue".

..... Phil

== 9 of 13 ==
Date: Tues, Aug 30 2011 6:56 pm
From: Jeff Liebermann

On Wed, 31 Aug 2011 11:50:53 +1000, "Phil Allison" <phil_a@tpg.com.au>
wrote:

>** I've always wanted to know just WFT it really is !!

This description seems to fit:
<http://www.alibaba.com/product-gs/482344777/One_component_solvent_resistant_flame_retardant.html>
"One component solvent resistant flame-retardant waterproof yellow
fixing adhesive glue for electronic components"

Note the photos. Is that it? I'll do some more Googling later. Gotta
seperate my customers from their money.

--
# 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

== 10 of 13 ==
Date: Tues, Aug 30 2011 6:59 pm
From: Jeff Liebermann

On Tue, 30 Aug 2011 18:56:39 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

>On Wed, 31 Aug 2011 11:50:53 +1000, "Phil Allison" <phil_a@tpg.com.au>
>wrote:
>
>>** I've always wanted to know just WFT it really is !!
>
>This description seems to fit:
><http://www.alibaba.com/product-gs/482344777/One_component_solvent_resistant_flame_retardant.html>
>"One component solvent resistant flame-retardant waterproof yellow
>fixing adhesive glue for electronic components"
>
>Note the photos. Is that it? I'll do some more Googling later. Gotta
>seperate my customers from their money.

More:
<http://www.aliexpress.com/store/906248/210638773-439369255/accept-sample-order-wholesale-flame-retardant-yellow-adhesive-free-shipping-for-you.html>
The page says it's an "acrylic".

--
# 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

== 11 of 13 ==
Date: Tues, Aug 30 2011 7:04 pm
From: Jeffrey Angus

On 8/30/2011 8:56 PM, Jeff Liebermann wrote:
> "One component solvent resistant flame-retardant waterproof yellow
> fixing adhesive glue for electronic components"

Odd, I read this: "Usage: Construction, Fiber & Garment, Footwear "

Jeff, but yeah, that sure looks like it.
Some of the stuff looks almost porous.

Jeff

--
"Everything from Crackers to Coffins"

== 12 of 13 ==
Date: Tues, Aug 30 2011 7:15 pm
From: "Phil Allison"

"Jeff Liebermann"
>
>>** I've always wanted to know just WFT it really is !!
>
> This description seems to fit:
>
> <http://www.alibaba.com/product-gs/482344777/One_component_solvent_resistant_flame_retardant.html>
>
> "One component solvent resistant flame-retardant waterproof yellow
> fixing adhesive glue for electronic components"
>
> Note the photos. Is that it?

** Sure as heck looks like the vile stuff.

But the stuff has been in use for decades, firstly with Taiwanese made gear.

The specs quoted do not mention aging or the effects of temperature - so the
marketing is dishonest.

BTW:

the pics show the glue in its liquid state, when dry the surface is quite
dull.

To me, the pics are cringe worthy.

Like looking at pics of child abuse.

.... Phil

== 13 of 13 ==
Date: Tues, Aug 30 2011 7:16 pm
From: Jeff Liebermann

On Tue, 30 Aug 2011 21:04:46 -0500, Jeffrey Angus <grendelair@aim.com>
wrote:

>On 8/30/2011 8:56 PM, Jeff Liebermann wrote:
>> "One component solvent resistant flame-retardant waterproof yellow
>> fixing adhesive glue for electronic components"
>
>Odd, I read this: "Usage: Construction, Fiber & Garment, Footwear "

Sure. Haven't you seen PCB shoes and underwear?
<http://blogs.discovermagazine.com/discoblog/2010/04/07/circuit-board-chic-motherboards-recycled-into-shoes-and-boxers/>
<http://boingboing.net/2010/04/06/circuit-board-shoes.html>
<http://www.zazzle.com/circuit_board_shoes-167287736986690214>
<http://www.xactstudios.com/pcbcreations/>
<http://www.zazzle.com/computer_circuit_board_shoes-167535214684590497>
<https://plus.google.com/103033413691031223989/posts/Kq6qgFDULaj>

>Jeff, but yeah, that sure looks like it.
>Some of the stuff looks almost porous.

Agressive hardener action causing gas bubbles. It's acrylic, but I'm
not familiar with the chemistry. I'll dig it out, later...

--
# 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

==============================================================================
TOPIC: Tek 465
http://groups.google.com/group/sci.electronics.repair/t/b9f473fde6856891?hl=en
==============================================================================

== 1 of 1 ==
Date: Tues, Aug 30 2011 6:04 pm
From: "Mark Zacharias"

"Jim Yanik" <jyanik@abuse.gov> wrote in message
news:Xns9F5170331F672jyaniklocalnetcom@216.168.3.44...
> "Mark Zacharias" <mark_zacharias@labolgcbs.net> wrote in
> news:4e5cb7ec$0$2871$a8266bb1@newsreader.readnews.com:
>
>>> http://www.sphere.bc.ca/test/tek1.html
>>>
>>> --
>>> Cheers,
>>> WB
>>> .............
>>>
>>>
>>> "Mark Zacharias" <mark_zacharias@labolgcbs.net> wrote in message
>>> news:4e58de02$0$2960$a8266bb1@newsreader.readnews.com...
>>>> Just bought a Tek 2246 on the 'Bay. This means the 465 will probably
>>>> need to be sold, assuming the new one is OK and all.
>>>>
>>>> I would entertain serious offers from the good folks who know me
>>>> here on the Group (USA only, please) prior to putting it up on eBay.
>>>>
>>>> Probably about 175.00 plus freight.
>>>>
>>>> Yes, this is the same 'scope Mr. Yanik helped me with recently.
>>>> Replaced a bad bridge rectifier.
>>>>
>>>> Everything works great, bright sharp trace, no burns. Physical
>>>> condition very good, nothing bent or broken, minor scuffs around the
>>>> case but not involving the face. I have several versions of the
>>>> manuals etc on PDF.
>>>>
>>>> Any questions please ask.
>>>>
>>>> Thanks.
>>>>
>>>>
>>>> Mark Z.
>>>>
>>>> --
>>>> "I can't die until the government finds a safe place to bury my
>>>> liver."
>>>
>>
>> "Wild_Bill" <wb_wildbill@XSPAMyahoo.com> wrote in message
>> news:Xf_6q.144751$BZ.132582@en-nntp-03.dc1.easynews.com...
>>> Dunno if the need will arise, but Sphere in Canada has a lot of
>>> online info wrt Tek equipment (and numerous other brands) parts,
>>> parts cross-reference lists, etc.
>>>
>>
>> Yeah - this is where I got that sweep logic IC the last time my 465
>> broke. About 60.00 plus frt. Grrr.
>>
>> Mark Z.
>>
>>
>
> IIRC,that is cheaper than TEK sold it(new stock).
> 155-0049-02,right?

Don't remember the part number...

>
> What I wonder is where all the stock TEK had on hand went to when they
> made
> the 400 series obsolete? TEK's Recycling store?
>
> I know some small part of it went to an employee instead of the trash
> where
> it was supposed to go. TEK throws out a lot of old parts(instead of
> "close-out" batch-selling them to 3rd parties),and takes a tax writeoff on
> them.
> But I knew one guy who instead had it all boxed up and took it home,after
> one Service Center bench stock purge.
> If I had tried that,I'd have been fired.

Or arrested...

>
> --
> Jim Yanik
> jyanik
> at
> localnet
> dot com

Just a quick note to thank you for your help and interesting comments,
history, etc.

Mark Z.

==============================================================================
TOPIC: Motor start/stop switch with integrated mini contactor?
http://groups.google.com/group/sci.electronics.repair/t/13b233689d902984?hl=en
==============================================================================

== 1 of 2 ==
Date: Tues, Aug 30 2011 6:18 pm
From: The Ghost In The Machine

On Aug 30, 4:03 pm, "k...@att.bizzzzzzzzzzzz"
<k...@att.bizzzzzzzzzzzz> wrote:
> On Tue, 30 Aug 2011 12:18:02 -0700, DaveC <inva...@invalid.net> wrote:
> >The only Telemecanique products I've been able to find are full-size magnetic
> >starters (contactors).
>
> Ignore the troll.
>
> >I'm looking for a manual start/stop switch with 2-pole contactor built-in.
> >Pressing the start button manually closes the contacts and energizes a coil,
> >which holds the contacts closed. Power fail opens the contacts.
>
> >Small (micro!) is what I'm looking for. No larger than the size of a
> >start/stop switch without contactor.
>
> These are sometimes called "magnetic start switches" and are commonly found on
> larger woodworking tools. I don't know if they're small enough for you but:http://www.grizzly.com/search/search.aspx?q=power%20switch

........SHUT UP ASS DROOL.......I OWED YOU THAT!
AS FOR A P/N DAVE I DO NOT WORK FOR THEM...CONTACT THE CO's I
PROVIDED...THEY COME HIGHLY RECOMMENED FOR SWITCHES ETC.
WHATS NEXT?
COME OVER & INSTALL IT? BOOWAHAHAHAHA, NO WAY JOSÈ!
I AM A GHOST AND DO NOT DO MANUAL LABOR, BUT MAYBE KRAWFISHRW IS
WILLING TO COMPLETE THE JOB FOR YOU.
ASK HIS SQUALID ASS TO HELP YOU GET IT & HELP US KEEP THE INTERNET
FOOL FREE, ITS A GOOD COMBO.
ANYTIME OF THE VIRTUAL NIGHT OR DAY.
++BEST WISHES++
PATECUM
TGITM

== 2 of 2 ==
Date: Tues, Aug 30 2011 6:26 pm
From: "krw@att.bizzzzzzzzzzzz"

On Tue, 30 Aug 2011 18:18:28 -0700 (PDT), The Ghost In The Machine
<proteusiiv@gmail.com> wrote:

>On Aug 30, 4:03 pm, "k...@att.bizzzzzzzzzzzz"
><k...@att.bizzzzzzzzzzzz> wrote:
>> On Tue, 30 Aug 2011 12:18:02 -0700, DaveC <inva...@invalid.net> wrote:
>> >The only Telemecanique products I've been able to find are full-size magnetic
>> >starters (contactors).
>>
>> Ignore the troll.
>>
>> >I'm looking for a manual start/stop switch with 2-pole contactor built-in.
>> >Pressing the start button manually closes the contacts and energizes a coil,
>> >which holds the contacts closed. Power fail opens the contacts.
>>
>> >Small (micro!) is what I'm looking for. No larger than the size of a
>> >start/stop switch without contactor.
>>
>> These are sometimes called "magnetic start switches" and are commonly found on
>> larger woodworking tools. I don't know if they're small enough for you but:http://www.grizzly.com/search/search.aspx?q=power%20switch
>
>........SHUT UP ASS DROOL.......I OWED YOU THAT!
>AS FOR A P/N DAVE I DO NOT WORK FOR THEM...CONTACT THE CO's I
>PROVIDED...THEY COME HIGHLY RECOMMENED FOR SWITCHES ETC.
>WHATS NEXT?
> COME OVER & INSTALL IT? BOOWAHAHAHAHA, NO WAY JOSÈ!
>I AM A GHOST AND DO NOT DO MANUAL LABOR, BUT MAYBE KRAWFISHRW IS
>WILLING TO COMPLETE THE JOB FOR YOU.
> ASK HIS SQUALID ASS TO HELP YOU GET IT & HELP US KEEP THE INTERNET
>FOOL FREE, ITS A GOOD COMBO.
>ANYTIME OF THE VIRTUAL NIGHT OR DAY.
>++BEST WISHES++

At least DaveC now knows what you are.

>PATECUM

Still eating that stuff Queerjano.

>TGITM

I told you a long time ago, Queerjano, penicillin will do wonders for that.

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