***BANG!***

[Fox's Mercantile]

On 11/11/19 4:01 PM, tabbypurr@gmail.com wrote:

On Monday, 11 November 2019 21:10:58 UTC, Fox's Mercantile wrote:
On 11/11/19 2:18 PM, tabbypurr wrote:
On Sunday, 10 November 2019 16:54:24 UTC, Cursitor Doom wrote:
On Sun, 10 Nov 2019 08:14:36 -0800, Michael Terrell wrote:

What's life, without a challenge?

A challenge has to be, by definition, ultimately achievable. Removing
this cap is *not* achievable. I would have to destroy the entire VNA to
get it out. What a rotten design.

Just snip it then, it's not needed.


NT


Spoken like a true hack.

are you being childish again?

In your dreams kid.
I take pride in my service and repairs.
If it's "difficult" it gets done anyway.

If it's buried, I remove what has to be removed to get access to it.
And the old leads get removed, the terminal gets cleaned and new
part gets soldered in just like "factory original;."
Then the removed parts get put back in place.

It's not that complicated to understand "doing it right."


--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[Phil Allison]

Fox's Mercantile wrote:

---------------------------

Capacitors across the power line, when they fail, they fail
spectacularly. And usually fast enough that they don't always
take out the line fuse.

This is why they make X caps. When they fail they, in addition
to failing short, they don't explode with a vengeance or set
fire to themselves or the surrounding bits.

** Fraid X caps do fail spectacularly.

With tons of smoke and bits flying a well.

On two occasions, I have been in the same room at the time and had it filled with acrid smoke.

Wima X2 types both times, but others are really no better.

Hot environments make it happen sooner, IME.

X2 caps are "double wound" effectively two is series to avoid internal corona that occurs across microscopic internal air gaps.

Y caps are often ceramic or wound "in vacuo" to avoids the issue.


..... Phil

 

[John-Del]

On Monday, November 11, 2019 at 11:25:42 AM UTC-5, Cursitor Doom wrote:

On Mon, 11 Nov 2019 04:48:42 -0800, John-Del wrote:

Back in the mid to late 60s, RCA used a .1uf cap right across the AC
interlock. They would let go on occasion and fail, well, spectacularly.
They would blast bits of metal and tons of carbon under the whole
chassis.

Hmmm. Amazing a little .1uF cap could make that much noise! I freely
admit I've never been in the same room when a cap let-go, so have only
ever heard them from some way off. I really should blow some up on
purpose so I know for myself; that's an essential part of my education
that's been missing all these years.
Is the violence you get commensurate with the capacity? Say for example I
blow up a 10,000uF electrolytic on purpose, is it a *much* bigger deal
than say a 25uF one? What does the noise approximate to - as much as a
pistol shot?

Let me clarify that these RCA line caps were film caps and did not go off like a gunshot like shorted electros do. I would say the sound they made was over several seconds or even minutes and would likely have sounded more like a piece of metal shoved into a bench grinder.

I mentioned a story I might relate earlier in the thread, and here it is: I was doing a house call back in the early 70s with my dad. It was a low end metal cabinet Sylvania hybrid (tube/transistor) that had a tripped breaker.

The breaker was old and creaky and wouldn't reset, so my dad gave it a couple of whacks with the back the nutdriver he used to remove the back. The breaker went in and the TV lit up, but it was dark, shrunk on the sides, rippling, and making a loud hum. Just as my dad was explaining to the customer that it would need a filter (multi segment chassis mounted can electro) we heard a loud hiss for a couple of seconds and before we could pull the cord out, the can electro blew the aluminum cylinder off with the sound of a gunshot. The room was immediately filled with an acrid gray smoke and the people bailed out of the house in a hurry.

The can let go with such force that it actually left a clean circle imprinted upwards in the metal cabinet. Given that the filter housing was lightweight aluminum and given how far it indented the heavy steel cabinet, it must have been launched with impressive speed.

The customer did not want the TV even though it only needed a filter and breaker, and we brought them a new Zenith the next day.

 

[Cursitor Doom]

On Mon, 11 Nov 2019 16:32:39 -0600, Fox's Mercantile wrote:

If it's buried, I remove what has to be removed to get access to it.
And the old leads get removed, the terminal gets cleaned and new part
gets soldered in just like "factory original;."
Then the removed parts get put back in place.

This mains inlet module requires some special service tool to be able to
withdraw it from rear. THEN you get full, unobstructed access to the
capacitor in question. Unfortunately, I don't possess that tool.




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protocols constitutes acceptance of this condition.

 

[Cursitor Doom]

On Mon, 11 Nov 2019 12:15:53 -0800, tabbypurr wrote:

> 240v is 330v peak, so no headroom at all.

Well, quite. So I'm wondering if those caps have a different convention
to others in their voltage ratings. Perhaps in the case of x-caps, that
"250V" essentially means:

"This cap is designed to cope with European voltage levels and is safe to
use across UK mains of the range 220-250V and brief transients vastly in
excess of this limit can also be accommodated."

Just my 2p worth.....




--
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
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[Michael Terrell]

On Monday, November 11, 2019 at 7:15:49 PM UTC-5, Cursitor Doom wrote:

On Mon, 11 Nov 2019 16:32:39 -0600, Fox's Mercantile wrote:

If it's buried, I remove what has to be removed to get access to it.
And the old leads get removed, the terminal gets cleaned and new part
gets soldered in just like "factory original;."
Then the removed parts get put back in place.

This mains inlet module requires some special service tool to be able to
withdraw it from rear. THEN you get full, unobstructed access to the
capacitor in question. Unfortunately, I don't possess that tool.

A special tool? if it is a snap in type, all you need are a couple screwdrivers. One to depress the tabs, an another to push against the body. Work one end then the other until it pops free. I've removed hundreds of them, that way from scrapped computer terminals.

 

On Monday, 11 November 2019 22:15:22 UTC, pf...@aol.com wrote:

The bean counters would never let an unnecessary part into any design. Therefore, leaving a part out of a design is "hack".

That is, unless one is Mad Man Muntz.

Peter Wieck
Melrose Park, PA

Damn, where have you been hiding for half a century? I recently watched a small populated PCB snipped out of a hoover, ran perfectly afterwards. Years ago I removed nearly all of an entire PCB from a Sony TV, it worked afterwards. A big complex psu pcb. A huge proportion of e-stuff has bits in it doesn't need. There's an assortment of reasons why. I don't see how you could design stuff without knowing that.


NT

 

On Tuesday, 12 November 2019 00:13:04 UTC, John-Del wrote:

On Monday, November 11, 2019 at 11:25:42 AM UTC-5, Cursitor Doom wrote:
On Mon, 11 Nov 2019 04:48:42 -0800, John-Del wrote:

Back in the mid to late 60s, RCA used a .1uf cap right across the AC
interlock. They would let go on occasion and fail, well, spectacularly.
They would blast bits of metal and tons of carbon under the whole
chassis.

Hmmm. Amazing a little .1uF cap could make that much noise! I freely
admit I've never been in the same room when a cap let-go, so have only
ever heard them from some way off. I really should blow some up on
purpose so I know for myself; that's an essential part of my education
that's been missing all these years.
Is the violence you get commensurate with the capacity? Say for example I
blow up a 10,000uF electrolytic on purpose, is it a *much* bigger deal
than say a 25uF one? What does the noise approximate to - as much as a
pistol shot?



Let me clarify that these RCA line caps were film caps and did not go off like a gunshot like shorted electros do. I would say the sound they made was over several seconds or even minutes and would likely have sounded more like a piece of metal shoved into a bench grinder.

I mentioned a story I might relate earlier in the thread, and here it is: I was doing a house call back in the early 70s with my dad. It was a low end metal cabinet Sylvania hybrid (tube/transistor) that had a tripped breaker.

The breaker was old and creaky and wouldn't reset, so my dad gave it a couple of whacks with the back the nutdriver he used to remove the back. The breaker went in and the TV lit up, but it was dark, shrunk on the sides, rippling, and making a loud hum. Just as my dad was explaining to the customer that it would need a filter (multi segment chassis mounted can electro) we heard a loud hiss for a couple of seconds and before we could pull the cord out, the can electro blew the aluminum cylinder off with the sound of a gunshot. The room was immediately filled with an acrid gray smoke and the people bailed out of the house in a hurry.

The can let go with such force that it actually left a clean circle imprinted upwards in the metal cabinet. Given that the filter housing was lightweight aluminum and given how far it indented the heavy steel cabinet, it must have been launched with impressive speed.

The customer did not want the TV even though it only needed a filter and breaker, and we brought them a new Zenith the next day.

I'd appreciate it if I could email you briefly about this. Is there some way to?


NT

 

On Tuesday, 12 November 2019 00:27:21 UTC, Cursitor Doom wrote:

On Mon, 11 Nov 2019 12:15:53 -0800, tabbypurr wrote:

240v is 330v peak, so no headroom at all.

Well, quite. So I'm wondering if those caps have a different convention
to others in their voltage ratings. Perhaps in the case of x-caps, that
"250V" essentially means:

"This cap is designed to cope with European voltage levels and is safe to
use across UK mains of the range 220-250V and brief transients vastly in
excess of this limit can also be accommodated."

Just my 2p worth.....

Oh, if they're x caps they're normally an ac rating.


NT

 

On Monday, 11 November 2019 22:33:21 UTC, Fox's Mercantile wrote:

On 11/11/19 4:01 PM, tabbypurr wrote:
On Monday, 11 November 2019 21:10:58 UTC, Fox's Mercantile wrote:
On 11/11/19 2:18 PM, tabbypurr wrote:
On Sunday, 10 November 2019 16:54:24 UTC, Cursitor Doom wrote:
On Sun, 10 Nov 2019 08:14:36 -0800, Michael Terrell wrote:

What's life, without a challenge?

A challenge has to be, by definition, ultimately achievable. Removing
this cap is *not* achievable. I would have to destroy the entire VNA to
get it out. What a rotten design.

Just snip it then, it's not needed.


NT


Spoken like a true hack.

are you being childish again?


In your dreams kid.
I take pride in my service and repairs.
If it's "difficult" it gets done anyway.

If it's buried, I remove what has to be removed to get access to it.
And the old leads get removed, the terminal gets cleaned and new
part gets soldered in just like "factory original;."
Then the removed parts get put back in place.

It's not that complicated to understand "doing it right."

That approach is the right one for mil spec kit repairs. It is inappropriate for domestic kit.


NT

 

[Fox's Mercantile]

On 11/12/19 9:46 PM, tabbypurr@gmail.com wrote:

On Monday, 11 November 2019 22:33:21 UTC, Fox's Mercantile wrote:
On 11/11/19 4:01 PM, tabbypurr wrote:
On Monday, 11 November 2019 21:10:58 UTC, Fox's Mercantile wrote:
On 11/11/19 2:18 PM, tabbypurr wrote:
On Sunday, 10 November 2019 16:54:24 UTC, Cursitor Doom wrote:
On Sun, 10 Nov 2019 08:14:36 -0800, Michael Terrell wrote:

What's life, without a challenge?

A challenge has to be, by definition, ultimately achievable. Removing
this cap is *not* achievable. I would have to destroy the entire VNA to
get it out. What a rotten design.

Just snip it then, it's not needed.


NT


Spoken like a true hack.

are you being childish again?


In your dreams kid.
I take pride in my service and repairs.
If it's "difficult" it gets done anyway.

If it's buried, I remove what has to be removed to get access to it.
And the old leads get removed, the terminal gets cleaned and new
part gets soldered in just like "factory original;."
Then the removed parts get put back in place.

It's not that complicated to understand "doing it right."

That approach is the right one for mil spec kit repairs. It is inappropriate for domestic kit.


NT

Like I said, you're a hack.

--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[Cursitor Doom]

On Sun, 10 Nov 2019 18:37:41 -0800, Michael Terrell wrote:

They are designed to burn away the short, so there is no contradiction.
The foil is very thin, so it vaporizes away from the point of failure,
leaving the remaining part of the capacitor, in circuit. If you measure
the capacitance of a damaged X or Y capacitor, it will be lower than
marked.

Yeah, I guess it would. Anyway, after hacking a hole in the bottom of the
motherboard I was able to removed the cap in question from underneath and
it looks far worse now I can see it properly. It definitely let go in a
big way and now I'm pretty confident it was the source of the loud bang I
heard. I've also carefully examined all the other sub-boards and the PCB
underneath them and they're all fine. Shards of broken cap were scattered
about the area of the explosion. Shame I had to butcher the board to get
it out, but there was no other way open to me. I follow what you said
about removing that j6 power connector but I just don't have the
dexterity I'm afraid. So it was a case of Dremmel to the rescue!

 

On Wednesday, 13 November 2019 09:18:14 UTC, Fox's Mercantile wrote:

On 11/12/19 9:46 PM, tabbypurr wrote:
On Monday, 11 November 2019 22:33:21 UTC, Fox's Mercantile wrote:
On 11/11/19 4:01 PM, tabbypurr wrote:
On Monday, 11 November 2019 21:10:58 UTC, Fox's Mercantile wrote:
On 11/11/19 2:18 PM, tabbypurr wrote:
On Sunday, 10 November 2019 16:54:24 UTC, Cursitor Doom wrote:
On Sun, 10 Nov 2019 08:14:36 -0800, Michael Terrell wrote:

What's life, without a challenge?

A challenge has to be, by definition, ultimately achievable. Removing
this cap is *not* achievable. I would have to destroy the entire VNA to
get it out. What a rotten design.

Just snip it then, it's not needed.


NT


Spoken like a true hack.

are you being childish again?


In your dreams kid.
I take pride in my service and repairs.
If it's "difficult" it gets done anyway.

If it's buried, I remove what has to be removed to get access to it.
And the old leads get removed, the terminal gets cleaned and new
part gets soldered in just like "factory original;."
Then the removed parts get put back in place.

It's not that complicated to understand "doing it right."

That approach is the right one for mil spec kit repairs. It is inappropriate for domestic kit.


NT


Like I said, you're a hack.

like I said you're childish.

 

[Fox's Mercantile]

On 11/21/19 1:00 PM, tabbypurr@gmail.com wrote:

On Wednesday, 13 November 2019 09:18:14 UTC, Fox's Mercantile wrote:
On 11/12/19 9:46 PM, tabbypurr wrote:
On Monday, 11 November 2019 22:33:21 UTC, Fox's Mercantile wrote:
On 11/11/19 4:01 PM, tabbypurr wrote:
On Monday, 11 November 2019 21:10:58 UTC, Fox's Mercantile wrote:
On 11/11/19 2:18 PM, tabbypurr wrote:
On Sunday, 10 November 2019 16:54:24 UTC, Cursitor Doom wrote:
On Sun, 10 Nov 2019 08:14:36 -0800, Michael Terrell wrote:

What's life, without a challenge?

A challenge has to be, by definition, ultimately achievable. Removing
this cap is *not* achievable. I would have to destroy the entire VNA to
get it out. What a rotten design.

Just snip it then, it's not needed.


NT


Spoken like a true hack.

are you being childish again?


In your dreams kid.
I take pride in my service and repairs.
If it's "difficult" it gets done anyway.

If it's buried, I remove what has to be removed to get access to it.
And the old leads get removed, the terminal gets cleaned and new
part gets soldered in just like "factory original;."
Then the removed parts get put back in place.

It's not that complicated to understand "doing it right."

That approach is the right one for mil spec kit repairs. It is inappropriate for domestic kit.


NT


Like I said, you're a hack.

like I said you're childish.

That's your opinion.
My opinion is that you're hack.


--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

[Cursitor Doom]

On Thu, 21 Nov 2019 15:49:38 -0600, Fox's Mercantile wrote:

> My opinion is that you're hack.

My opinion is you're Phil Alison and ICTFP.



--
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.

 

[Fox's Mercantile]

On 11/22/19 3:22 AM, Cursitor Doom wrote:

On Thu, 21 Nov 2019 15:49:38 -0600, Fox's Mercantile wrote:

My opinion is that you're hack.

My opinion is you're Phil Alison and ICTFP.

Oh look, the hacks are circling the wagons.



--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

 

On Thursday, 21 November 2019 21:49:46 UTC, Fox's Mercantile wrote:

On 11/21/19 1:00 PM, tabbypurr wrote:
On Wednesday, 13 November 2019 09:18:14 UTC, Fox's Mercantile wrote:
On 11/12/19 9:46 PM, tabbypurr wrote:
On Monday, 11 November 2019 22:33:21 UTC, Fox's Mercantile wrote:
On 11/11/19 4:01 PM, tabbypurr wrote:
On Monday, 11 November 2019 21:10:58 UTC, Fox's Mercantile wrote:
On 11/11/19 2:18 PM, tabbypurr wrote:
On Sunday, 10 November 2019 16:54:24 UTC, Cursitor Doom wrote:
On Sun, 10 Nov 2019 08:14:36 -0800, Michael Terrell wrote:

What's life, without a challenge?

A challenge has to be, by definition, ultimately achievable. Removing
this cap is *not* achievable. I would have to destroy the entire VNA to
get it out. What a rotten design.

Just snip it then, it's not needed.


NT


Spoken like a true hack.

are you being childish again?


In your dreams kid.
I take pride in my service and repairs.
If it's "difficult" it gets done anyway.

If it's buried, I remove what has to be removed to get access to it.
And the old leads get removed, the terminal gets cleaned and new
part gets soldered in just like "factory original;."
Then the removed parts get put back in place.

It's not that complicated to understand "doing it right."

That approach is the right one for mil spec kit repairs. It is inappropriate for domestic kit.


NT


Like I said, you're a hack.

like I said you're childish.


That's your opinion.
My opinion is that you're hack.

heh. you said that already.

 

[Jeff Liebermann]

On Sun, 10 Nov 2019 13:37:34 -0000 (UTC), Cursitor Doom
<curd@notformail.com> wrote:

No visible signs inside what could have catastrophically
failed, just the unmistakable smell that *something* has. The device
still powers up fine and the screen traces are normal, so wtf else goes
*bang* and smells toxic?

You seem to be floundering:

1. Are you sure that it was the HP VNA that blew a capacitor or
something? When you removed the case, was it lit up?

2. Toxic smells tend to be cause by vaporized electrolye. That
leaves a messy stain which should have been present. If you can't see
the damage, perhaps playing bloodhound and smelling for the damage
might help. Find a vinyl hose, cram it into your nose, and sniff
around the VNA and the shop for the strongest smell. Unless you use
an air freshener (nasal desensitize), you should be able to find the
source many days after it went bang.

3. When you tested the electrolytics, did you use both an ESR meter
and a capacitance meter? If the ESR meter doesn't show a problem, the
capacitance meter might.

4. Do you have a UV LED flashlight? When tracking down bulging
electrolytic problems on computah motherboards, I sometimes (not
always) can seen the electrolyte residue using a UV flashlight.

5. Did you have the AC power switch set for 230VAC or 117VAC?

6. Check if the small is coming from a power strip. The MOV's
sometimes go bang.

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

 

[Cursitor Doom]

On Fri, 22 Nov 2019 07:54:53 -0800, Jeff Liebermann wrote:

1. Are you sure that it was the HP VNA that blew a capacitor or
something? When you removed the case, was it lit up?

Thank you, Jeffrey. Not sure if you were able to read the thread right
through, but it's been established that the blown cap was an X2 rated one
fitted right across the incoming mains power line. It took a while to
confirm this was the actual culprit as it was well buried under a load of
spaghetti. When I finally got it out I was able to see it had literally
exploded which accounts for the report I heard from 30' away.
That cap has now been replaced and the device appears to be working fine
again, although after 10 years of storage there's no doubt some re-
aligning and whatnot to be done.



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This message may be freely reproduced without limit or charge only via
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protocols, whether for profit or not, is conditional upon a charge of
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[Cursitor Doom]

On Fri, 22 Nov 2019 04:22:06 -0600, Fox's Mercantile wrote:

On 11/22/19 3:22 AM, Cursitor Doom wrote:
On Thu, 21 Nov 2019 15:49:38 -0600, Fox's Mercantile wrote:

My opinion is that you're hack.

My opinion is you're Phil Alison and ICTFP.

Oh look, the hacks are circling the wagons.

You can call me a hack as well if you like; I couldn't give a shit TBH.
I'm not very practical. I get the job done but it doesn't look as pretty
as some genius like yourself would leave it. But do I care? Nope! Because
the case goes back on and no one can see it anyway.




--
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.