Capacitors Question?


Mlynch001
 

We all know the horror stories about the leaky capacitors in TEK Scopes. This may have been answered, however, I cannot find this in a search. I am thinking that the first Surface mounted caps were used in the late 80's and early 90's and these were the ones that had serious electrolyte leakage issues. My question is, about WHEN was this issue solved so that these types of caps were no longer a serious problem? I have a TDS460A that has an inspection date on the CRT of mid 1998 and the caps on the main board look beautiful. Solder joints are clean and bright, there is no apparent leakage or corrosion present. The scope works fine, so I do not want to mess with it unless it begins to exhibit problems.

Michael Lynch

mlynch002@gmail.com

TEK 2440A
TEK TDS360
TEK TDS460A


Chuck Harris <cfharris@...>
 

The problem will never really be completely solved, as
long as manufacture involves putting a plastic/rubber
sealed, liquid filled, component into an oven heated to
soldering temperatures as a means soldering its leads
to the board. You are heating up a lot of things that
don't want to be heated up, just to solder a couple of
tiny little tabs to the board. Heat them a little too
hot, or a little too long (same thing), and the seal will
be damaged, and won't keep the electrolyte inside of the
capacitor.

However, you can be pretty confident that if the capacitor
didn't start leaking electrolyte soon after it left
the factory, it probably won't. The damage to the
capacitors, if it is going to happen, starts right in
the factory, not on your bench.

If your solder is shiny, and I do mean shiny, it is good.

-Chuck Harris

Mlynch001 wrote:

We all know the horror stories about the leaky capacitors in TEK Scopes. This may have been answered, however, I cannot find this in a search. I am thinking that the first Surface mounted caps were used in the late 80's and early 90's and these were the ones that had serious electrolyte leakage issues. My question is, about WHEN was this issue solved so that these types of caps were no longer a serious problem? I have a TDS460A that has an inspection date on the CRT of mid 1998 and the caps on the main board look beautiful. Solder joints are clean and bright, there is no apparent leakage or corrosion present. The scope works fine, so I do not want to mess with it unless it begins to exhibit problems.

Michael Lynch


 

Hi Michael,

Don't do anything until you read this article which explains the problem in detail:
https://en.wikipedia.org/wiki/Capacitor_plague

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Chuck Harris
Sent: Tuesday, March 06, 2018 11:26 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Capacitors Question?

The problem will never really be completely solved, as long as manufacture involves putting a plastic/rubber sealed, liquid filled, component into an oven heated to soldering temperatures as a means soldering its leads to the board. You are heating up a lot of things that don't want to be heated up, just to solder a couple of tiny little tabs to the board. Heat them a little too hot, or a little too long (same thing), and the seal will be damaged, and won't keep the electrolyte inside of the capacitor.

However, you can be pretty confident that if the capacitor didn't start leaking electrolyte soon after it left the factory, it probably won't. The damage to the capacitors, if it is going to happen, starts right in the factory, not on your bench.

If your solder is shiny, and I do mean shiny, it is good.

-Chuck Harris

Mlynch001 wrote:
We all know the horror stories about the leaky capacitors in TEK Scopes. This may have been answered, however, I cannot find this in a search. I am thinking that the first Surface mounted caps were used in the late 80's and early 90's and these were the ones that had serious electrolyte leakage issues. My question is, about WHEN was this issue solved so that these types of caps were no longer a serious problem? I have a TDS460A that has an inspection date on the CRT of mid 1998 and the caps on the main board look beautiful. Solder joints are clean and bright, there is no apparent leakage or corrosion present. The scope works fine, so I do not want to mess with it unless it begins to exhibit problems.

Michael Lynch




--
Dennis Tillman W7PF
TekScopes Moderator


Chuck Harris <cfharris@...>
 

Not to put too fine a point on my nitpicking, but
AFAIK, the capacitor plague applied only to radial
leaded, low ESR electrolytic capacitors, not to
SMD electrolytic capacitors.

The problem mostly appeared on computer motherboards,
and on graphics cards. The electrolyte would etch
through the factory applied anodize coating, which
was the capacitor's dielectric. When this dielectric
layer was thin enough, the leakage current the capacitor
drew would climb, and the capacitor would get hot.

The heat made the electrolyte boil, and the cap would
blow out its bottom rubber plug, leaving the cap all
akimbo, or it would "dome up" the the explosion relief
on the top, or sides, of the capacitor.

-Chuck Harris

Dennis Tillman W7PF wrote:

Hi Michael,

Don't do anything until you read this article which explains the problem in detail:
https://en.wikipedia.org/wiki/Capacitor_plague

Dennis Tillman W7PF


-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Chuck Harris
Sent: Tuesday, March 06, 2018 11:26 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Capacitors Question?

The problem will never really be completely solved, as long as manufacture involves putting a plastic/rubber sealed, liquid filled, component into an oven heated to soldering temperatures as a means soldering its leads to the board. You are heating up a lot of things that don't want to be heated up, just to solder a couple of tiny little tabs to the board. Heat them a little too hot, or a little too long (same thing), and the seal will be damaged, and won't keep the electrolyte inside of the capacitor.


Dave Casey
 

What about the many SMD electrolytics which are just radial electrolytics
anchored in a base with their leads bent over and cut really short?

Dave Casey

On Tue, Mar 6, 2018 at 3:25 PM, Chuck Harris <cfharris@erols.com> wrote:

Not to put too fine a point on my nitpicking, but
AFAIK, the capacitor plague applied only to radial
leaded, low ESR electrolytic capacitors, not to
SMD electrolytic capacitors.

The problem mostly appeared on computer motherboards,
and on graphics cards. The electrolyte would etch
through the factory applied anodize coating, which
was the capacitor's dielectric. When this dielectric
layer was thin enough, the leakage current the capacitor
drew would climb, and the capacitor would get hot.

The heat made the electrolyte boil, and the cap would
blow out its bottom rubber plug, leaving the cap all
akimbo, or it would "dome up" the the explosion relief
on the top, or sides, of the capacitor.

-Chuck Harris

Dennis Tillman W7PF wrote:
Hi Michael,

Don't do anything until you read this article which explains the problem
in detail:
https://en.wikipedia.org/wiki/Capacitor_plague

Dennis Tillman W7PF


-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
Chuck Harris
Sent: Tuesday, March 06, 2018 11:26 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Capacitors Question?

The problem will never really be completely solved, as long as
manufacture involves putting a plastic/rubber sealed, liquid filled,
component into an oven heated to soldering temperatures as a means
soldering its leads to the board. You are heating up a lot of things that
don't want to be heated up, just to solder a couple of tiny little tabs to
the board. Heat them a little too hot, or a little too long (same thing),
and the seal will be damaged, and won't keep the electrolyte inside of the
capacitor.




Mlynch001
 

Chuck,
As I understand the issue, it is ALL capacitors in almost all equipment manufactured in late 80's to early 90's, I have seen video of destroyed boards in various types of equipment, including TEKTRONIX Scopes, with leaky SMD electrolytic caps. I was concerned enough that I took my machine apart and gave it a good going over. Regardless, the boards look great and solder joints in my machine are shiny, like chrome. They are really nice, with no sign of even the slightest corrosion. I looked them over with a Magnifying glass and a good strong light. This made me feel really good about the machine. Also the fact that this is a fairly late version of the TDS460A series, probably cannot hurt. I appreciate all the advice and guidance.


Mlynch001
 

Thank You Dennis!


Glenn Little
 

When it starts to show problems, there will probably already be board damage.
That scope is 20 years old, well past the design life of the capacitors which was probably 2000 hours.

At the first sign of trouble with a Panasonic DVC pro tape deck, all board capacitors were changed.
The cost of the repair was far better than trying to find a functional replacement board.

Glenn

On 3/6/2018 11:50 AM, Mlynch001 wrote:
We all know the horror stories about the leaky capacitors in TEK Scopes. This may have been answered, however, I cannot find this in a search. I am thinking that the first Surface mounted caps were used in the late 80's and early 90's and these were the ones that had serious electrolyte leakage issues. My question is, about WHEN was this issue solved so that these types of caps were no longer a serious problem? I have a TDS460A that has an inspection date on the CRT of mid 1998 and the caps on the main board look beautiful. Solder joints are clean and bright, there is no apparent leakage or corrosion present. The scope works fine, so I do not want to mess with it unless it begins to exhibit problems.

Michael Lynch

mlynch002@gmail.com

TEK 2440A
TEK TDS360
TEK TDS460A


--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@arrl.net AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"


Mlynch001
 

Well, I am going to keep a close watch on this machine. It takes all of 5 minutes to get it out of the case and I can spend an hour or so inspecting the boards and caps every so often and before any performance issues rear their ugly heads. .

Michael Lynch

mlynch002@...

TEK 2440A
TEK TDS360
TEK TDS460A


toby@...
 

On 2018-03-06 4:25 PM, Chuck Harris wrote:
Not to put too fine a point on my nitpicking, but
AFAIK, the capacitor plague applied only to radial
leaded, low ESR electrolytic capacitors, not to
SMD electrolytic capacitors.

The problem mostly appeared on computer motherboards,
and on graphics cards. The electrolyte would etch
through the factory applied anodize coating, which
was the capacitor's dielectric. When this dielectric
layer was thin enough, the leakage current the capacitor
drew would climb, and the capacitor would get hot.

The heat made the electrolyte boil, and the cap would
blow out its bottom rubber plug, leaving the cap all
akimbo, or it would "dome up" the the explosion relief
on the top, or sides, of the capacitor.
I've seen it on dozens of LCD inverter boards. In my unlearned opinion,
though some specific plagues may have occurred, it's a general problem
due to the cheapest electrolytics ("CapXon" brand stands out) being
built into consumer/office products, simply making them disposable after
a couple of years.

My introduction to the whole issue was when an ex-boss put his very nice
twin Samsung LCDs in the dumpster. I took them home and gave them a new
lease of life with $2 of caps. Fixed dozens more after that.
http://badcaps.net is a useful resource.

--T


-Chuck Harris

Dennis Tillman W7PF wrote:
Hi Michael,

Don't do anything until you read this article which explains the problem in detail:
https://en.wikipedia.org/wiki/Capacitor_plague

Dennis Tillman W7PF


-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Chuck Harris
Sent: Tuesday, March 06, 2018 11:26 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Capacitors Question?

The problem will never really be completely solved, as long as manufacture involves putting a plastic/rubber sealed, liquid filled, component into an oven heated to soldering temperatures as a means soldering its leads to the board. You are heating up a lot of things that don't want to be heated up, just to solder a couple of tiny little tabs to the board. Heat them a little too hot, or a little too long (same thing), and the seal will be damaged, and won't keep the electrolyte inside of the capacitor.



 

A large part of my business is TV repair. The modern LCD TV motherboards are just as unreliable as the older 80's - 90's first generation SMD motherboards.
It is the norm that I have to replace ALL the SMD electrolytics on a 2-year-old LCD TV, to get it back to working condition (Other service centers tell the customer "You need a new board").

This high failure rate is due to mainly ONE cause - the SMD baking process.
All SMD components are glued onto the PCB, and then baked in an oven at about 300C to flow the solder onto the joints.
Just imagine what that does to the electrolyte inside the caps.

Maybe Vishay, Nichicon and Panasonic caps are built to withstand that heat and pressure during baking, but when was the last time you saw any of those quality caps inside a consumer-grade TV?

So, as long as baking PCB's is an integral part of production, the problem of short lifetimes of SMD electrolytics is NOT going to go away any time soon.


Ed Breya
 

I too have seen plenty of bad electrolytic caps in all sorts of gear, especially consumer electronics. The problems haven't necessarily been the same type or cause as the infamous bad SMT caps we find in that era of Tek stuff. In consumer gear, it may be from the plague, or due to maximizing cheapness, with caps that aren't rated sufficiently.

It boils down (so to speak) to three failure types, regardless of component style - leakers, puffers, and just plain bad. Leakers are the worst because of the possible damage done by the electrolyte. Puffers are obviously shot - puffed up from too much internal pressure and possibly with safety vent features opened up. They may also be leakers, but most I've seen had no juices around, just dry and open. Just plain bad ones may happen due to various common and normal failures always associated with caps, and are the hardest to find because they show no obvious physical symptoms. I've also had leakers that did no damage at all, and were easy to find by the wet spots around them that would shine, or gather dust. The damage risk depends on the electrolyte and time.

BTW there is an extreme form of puffer - one that has the can blown off entirely. I've seen that once or twice.

Ed


Michael A. Terrell
 

You've never seen a modern reflow oven in operation. It doesn't 'bake' boards. There is a very minimum of three stages: preheat stage, the reflow stage and the cooling stage. The Heller oven we used at Microdyne had over a dozen stages, and a profile for each board that we produced was stored in the computer that controlled it. The reflow stage was as short as possible, to prevent any damage, but long enough to ensure proper reflow. Otherwise, plastic cased components like relays and trimpots would melt. Here is a link to one of the Heller ovens of that time period:

<http://islandsmt.com/wp-content/uploads/2017/02/1707EXL-Heller-Manual-680441-ver3.8.pdf>

As far as gluing components, the boards we built never used any glue. The surface tension of the paste solder held the components in place. They were double sided, and 16 layer VME based boards were common.

-----Original Message-----
From: M Yachad <yachadm@gmail.com>
Sent: Mar 7, 2018 12:36 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Capacitors Question?

A large part of my business is TV repair. The modern LCD TV motherboards are just as unreliable as the older 80's - 90's first generation SMD motherboards.
It is the norm that I have to replace ALL the SMD electrolytics on a 2-year-old LCD TV, to get it back to working condition (Other service centers tell the customer "You need a new board").

This high failure rate is due to mainly ONE cause - the SMD baking process.
All SMD components are glued onto the PCB, and then baked in an oven at about 300C to flow the solder onto the joints.
Just imagine what that does to the electrolyte inside the caps.

Maybe Vishay, Nichicon and Panasonic caps are built to withstand that heat and pressure during baking, but when was the last time you saw any of those quality caps inside a consumer-grade TV?

So, as long as baking PCB's is an integral part of production, the problem of short lifetimes of SMD electrolytics is NOT going to go away any time soon.



Michael A. Terrell


Chuck Harris <cfharris@...>
 

All SMD aluminum electrolytics are made that way. It keeps
the rubber seal's as far as possible from the oven heat. The
plastic lead forming boots are made from a high temperature
withstanding, thermally insulating plastic material.

They even keep the aluminum cans bare, and mill colored
(white) to take advantage of aluminum's high reflectivity
at IR (heat) wavelengths... they reflect most of the heat
from the oven rather than get hot... Just like you do by
putting aluminum foil strips around a pie crust's edge
to prevent burning...but this only works so well. Keep
the heat on too long, or too hot, and it will cause a
big problem.

What kills most SMD using manufacturers is their desire to
do all of the soldering in the ovens. Even big stuff like
CAT5, USB, DB15's, HDMI, and power connectors.

They get themselves in a bind where if they want the big
stuff to get hot enough to make a good solder joint, they
have to let the little stuff, like SMD electrolytics get
too hot. They get away with it most of the time, but the
parts are damaged, and start to leak during the product's
lifetime.

The proper way to do oven soldering of large parts is to
either do them first, before installing the smaller more
thermally sensitive parts, or do them last, and put an
aluminum heat reflecting cover over the sensitive parts
before you do the oven pass for the big stuff...

But, this amounts to extra hand work, and extra passes
through the oven, and they want things to be cheap.

In my experience, the corrosive electrolyte formulations
do not end up in SMD electrolytic capacitors. Because of
all of the extra steps required to add the plastic cup
and lead forming hardware, it just isn't worth it to
shave a few microcents off by using fake electrolyte.
Even the small size of the aluminum cans puts them out
of reach of the scam artists...

The same is not true of radial leaded electrolytic caps.
They can be built on manufacturing machines that were made
in the 1960's. There is a lot of cheap surplus component
manufacturing equipment out there to enable cheating in
radial leaded capacitor manufacture.

The companies that get fooled are buying parts that are
odd name brands, and much, much cheaper than the usual
name brands. They know, they just don't care.

-Chuck Harris

Dave Casey wrote:
What about the many SMD electrolytics which are just radial electrolytics
anchored in a base with their leads bent over and cut really short?

Dave Casey

On Tue, Mar 6, 2018 at 3:25 PM, Chuck Harris <cfharris@erols.com> wrote:

Not to put too fine a point on my nitpicking, but
AFAIK, the capacitor plague applied only to radial
leaded, low ESR electrolytic capacitors, not to
SMD electrolytic capacitors.
...


 

Terrell

I don't know you, and you don't know me.
It is astoundingly arrogant and disrespectful of you to lecture me, with overwhelming self-presumptuousness that you are correct.
"You've never seen a modern reflow oven in operation."

Instead of making presumptuous statements, how about asking me that question, with a little respect?
If you had, you would have got the answer that I HAVE seen and monitored reflow MANY times, AND understand the 3 stages, AND used the word "bake", as a generic term, to not get into irrelevant specifics for the purpose of my posting.

On this forum, people ask questions to clarify, and don't assume.
AFAIAC, assumptions have no place in engineering environments.

Your company may do things correctly and perfectly, however, if you've ever been in a Chinese PCB factory (have you?), you would likely be astounded at how corners are cut and sloppy workmanship is the norm. I was astounded.
Little or no preheat at all, workers drinking coffee and joking during the reflow and not paying attention to the clock or temperature rise, and doing away with the controlled cooling, to save time.
That's the norm.
Does the consumer know about all that? Forget about it.

Is it any wonder that these PCB's don't last?

Yachad


Mlynch001
 

Yachad,

I have never been to a Chinese PCB factory, however, I have dealt intimately with other forms of their so called "Manufacturing" processes; specifically motorcycle engine and transmission manufacturing. The lack of quality control; and even a basic understanding of dimensional tolerances and process controls is astounding. So when you speak of the horrors of these PCB factories, I can verify that this is indeed how they work, at least in their consumer goods manufacturing. it is all about "cheaper and faster", with no regard for the end result. It took me 5 years of work to make a Chinese engineer understand that he had to heat treat gears to a certain surface hardness or they would not hold up, regardless of their dimensional accuracy. There is no way to compare top quality manufacturing to what happens in these Chinese factories, these are direct opposites.


Michael A. Terrell
 

Early Japanese electronics was no better. Their circuit boards were either hand dipped, or run through a wave solder machine. The end result was a dull gray solder that looked like they rarely skimmed the dross. I have seen bad assembly work in electronics back to WW II. That includes Aircraft radios that left the factory with some wires not being soldered to the lugs they went through. Not bad solder work, they had never been soldered and they made it through multiple inspections before they were shipped.

Some of the boards we built ended up on the ISS, and others at NOAA, NASA and the ESA. We had base models of our products that were customized to the customer's needs, and NASA had some in use that hadn't been powered down for over 30 years. I gave up on Consumer Electronics, in the late '80s. After that, ZI went back to Broadcast Engineering, and then to manufacturing when I could no longer climb to the roof of the transmitter buildings or the towers.

Have you ever seen early GE consumer PC boards? Single sided phenolic through hole that was dipped in a solder pot before the leads were trimmed. Then a large rotary cutter trimmed them while leaving razor sharp edges, and globs of solder on the remaining leads.

How about the soft pink plastic that Philco used in the '70s? Repairs were almost impossible without burning holes in the plastic. They also had no idea how to install TO-220 transistors. They replaced a TO-3 transistor with the TO-220 package. Rathr than redesign the circuit board, they made a daughterboard. Then thye bent the two outside leads about 45% to the sides right at the body. They were failing like crazy, nd Philco insisted tthat irt wasn't a design flaw. The ECG, RCA SK, GE and other universal replacement transistors were all shipped with a warning not to do it that way.

I worked at a Defense contractor in the '70s, on the PRC77 in QA, but I had to show production how to solder some transformer housings to PC boards at the rework stations as the Union Steward glared at me.

I learned to solder 58 years ago, and I quickly learned how crappy most tools and brands of solder really were. I bought my first desoldering iron in 1966. It was made by ENDECO, and it was over $45 wholesale. A good soldering iron was only $5 at that time.

As far as the process that he described, it is closer to the hobbyist using an old toaster oven than a reflow oven.

-----Original Message-----
From: Mlynch001 <mlynch002@gmail.com>
Sent: Mar 8, 2018 2:00 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Capacitors Question?

Yachad,

I have never been to a Chinese PCB factory, however, I have dealt intimately with other forms of their so called "Manufacturing" processes; specifically motorcycle engine and transmission manufacturing. The lack of quality control; and even a basic understanding of dimensional tolerances and process controls is astounding. So when you speak of the horrors of these PCB factories, I can verify that this is indeed how they work, at least in their consumer goods manufacturing. it is all about "cheaper and faster", with no regard for the end result. It took me 5 years of work to make a Chinese engineer understand that he had to heat treat gears to a certain surface hardness or they would not hold up, regardless of their dimensional accuracy. There is no way to compare top quality manufacturing to what happens in these Chinese factories, these are direct opposites.



Michael A. Terrell


Richard Knoppow
 

I was immediately reminded of John Ruskin :
"There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are this man's lawful prey."

I have enountered non-soldered joints in old General Radio and Drake Radio equipment. Not many but some. Wrapped but unsoldered joints can work fine for decades.

The quality of Chinese goods seems to depend on how the factories are supervised. When run by the Chinese the quality is simply not there. Along Ruskin's line, as long as someone is willing to accept something based on its being cheap regardless of other qualities, we will continue to have this kind of thing.
Its obvious that its not just the Chinese. I also remember when the Japanese got a reputation for making junk right after WW-2. They soon learned and began to make products of outstanding quality and design. I think the Chinese are a lot further to go.

On 3/8/2018 11:37 AM, Michael A. Terrell wrote:
Early Japanese electronics was no better. Their circuit boards were either hand dipped, or run through a wave solder machine. The end result was a dull gray solder that looked like they rarely skimmed the dross. I have seen bad assembly work in electronics back to WW II. That includes Aircraft radios that left the factory with some wires not being soldered to the lugs they went through. Not bad solder work, they had never been soldered and they made it through multiple inspections before they were shipped.
Some of the boards we built ended up on the ISS, and others at NOAA, NASA and the ESA. We had base models of our products that were customized to the customer's needs, and NASA had some in use that hadn't been powered down for over 30 years. I gave up on Consumer Electronics, in the late '80s. After that, ZI went back to Broadcast Engineering, and then to manufacturing when I could no longer climb to the roof of the transmitter buildings or the towers.
Have you ever seen early GE consumer PC boards? Single sided phenolic through hole that was dipped in a solder pot before the leads were trimmed. Then a large rotary cutter trimmed them while leaving razor sharp edges, and globs of solder on the remaining leads.
How about the soft pink plastic that Philco used in the '70s? Repairs were almost impossible without burning holes in the plastic. They also had no idea how to install TO-220 transistors. They replaced a TO-3 transistor with the TO-220 package. Rathr than redesign the circuit board, they made a daughterboard. Then thye bent the two outside leads about 45% to the sides right at the body. They were failing like crazy, nd Philco insisted tthat irt wasn't a design flaw. The ECG, RCA SK, GE and other universal replacement transistors were all shipped with a warning not to do it that way.
I worked at a Defense contractor in the '70s, on the PRC77 in QA, but I had to show production how to solder some transformer housings to PC boards at the rework stations as the Union Steward glared at me.
I learned to solder 58 years ago, and I quickly learned how crappy most tools and brands of solder really were. I bought my first desoldering iron in 1966. It was made by ENDECO, and it was over $45 wholesale. A good soldering iron was only $5 at that time.
As far as the process that he described, it is closer to the hobbyist using an old toaster oven than a reflow oven.
-----Original Message-----
From: Mlynch001 <mlynch002@gmail.com>
Sent: Mar 8, 2018 2:00 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Capacitors Question?

Yachad,

I have never been to a Chinese PCB factory, however, I have dealt intimately with other forms of their so called "Manufacturing" processes; specifically motorcycle engine and transmission manufacturing. The lack of quality control; and even a basic understanding of dimensional tolerances and process controls is astounding. So when you speak of the horrors of these PCB factories, I can verify that this is indeed how they work, at least in their consumer goods manufacturing. it is all about "cheaper and faster", with no regard for the end result. It took me 5 years of work to make a Chinese engineer understand that he had to heat treat gears to a certain surface hardness or they would not hold up, regardless of their dimensional accuracy. There is no way to compare top quality manufacturing to what happens in these Chinese factories, these are direct opposites.


Michael A. Terrell
--
Richard Knoppow
dickburk@ix.netcom.com
WB6KBL


Michael A. Terrell
 

Japan still built some real crap, into the mid '70s and replacement parts took months or years to arrive f you weren't the company's only authorized service center. The documentation wasn't much better. A service manual for one of Panasonic's top of the line home cassette decks bragged about the 'RERAY' logic used to control the motors and solenoids. The rest of the translations in that manual weren't much better.

-----Original Message-----
From: Richard Knoppow <dickburk@ix.netcom.com>
Sent: Mar 8, 2018 3:02 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Capacitors Question?

I was immediately reminded of John Ruskin :
"There is hardly anything in the world that some man cannot make
a little worse and sell a little cheaper, and the people who
consider price only are this man's lawful prey."

I have enountered non-soldered joints in old General Radio
and Drake Radio equipment. Not many but some. Wrapped but
unsoldered joints can work fine for decades.

The quality of Chinese goods seems to depend on how the
factories are supervised. When run by the Chinese the quality is
simply not there. Along Ruskin's line, as long as someone is
willing to accept something based on its being cheap regardless
of other qualities, we will continue to have this kind of thing.
Its obvious that its not just the Chinese. I also remember
when the Japanese got a reputation for making junk right after
WW-2. They soon learned and began to make products of outstanding
quality and design. I think the Chinese are a lot further to go.

On 3/8/2018 11:37 AM, Michael A. Terrell wrote:
Early Japanese electronics was no better. Their circuit boards were either hand dipped, or run through a wave solder machine. The end result was a dull gray solder that looked like they rarely skimmed the dross. I have seen bad assembly work in electronics back to WW II. That includes Aircraft radios that left the factory with some wires not being soldered to the lugs they went through. Not bad solder work, they had never been soldered and they made it through multiple inspections before they were shipped.

Some of the boards we built ended up on the ISS, and others at NOAA, NASA and the ESA. We had base models of our products that were customized to the customer's needs, and NASA had some in use that hadn't been powered down for over 30 years. I gave up on Consumer Electronics, in the late '80s. After that, ZI went back to Broadcast Engineering, and then to manufacturing when I could no longer climb to the roof of the transmitter buildings or the towers.

Have you ever seen early GE consumer PC boards? Single sided phenolic through hole that was dipped in a solder pot before the leads were trimmed. Then a large rotary cutter trimmed them while leaving razor sharp edges, and globs of solder on the remaining leads.

How about the soft pink plastic that Philco used in the '70s? Repairs were almost impossible without burning holes in the plastic. They also had no idea how to install TO-220 transistors. They replaced a TO-3 transistor with the TO-220 package. Rathr than redesign the circuit board, they made a daughterboard. Then thye bent the two outside leads about 45% to the sides right at the body. They were failing like crazy, nd Philco insisted tthat irt wasn't a design flaw. The ECG, RCA SK, GE and other universal replacement transistors were all shipped with a warning not to do it that way.

I worked at a Defense contractor in the '70s, on the PRC77 in QA, but I had to show production how to solder some transformer housings to PC boards at the rework stations as the Union Steward glared at me.

I learned to solder 58 years ago, and I quickly learned how crappy most tools and brands of solder really were. I bought my first desoldering iron in 1966. It was made by ENDECO, and it was over $45 wholesale. A good soldering iron was only $5 at that time.

As far as the process that he described, it is closer to the hobbyist using an old toaster oven than a reflow oven.

-----Original Message-----
From: Mlynch001 <mlynch002@gmail.com>
Sent: Mar 8, 2018 2:00 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Capacitors Question?

Yachad,

I have never been to a Chinese PCB factory, however, I have dealt intimately with other forms of their so called "Manufacturing" processes; specifically motorcycle engine and transmission manufacturing. The lack of quality control; and even a basic understanding of dimensional tolerances and process controls is astounding. So when you speak of the horrors of these PCB factories, I can verify that this is indeed how they work, at least in their consumer goods manufacturing. it is all about "cheaper and faster", with no regard for the end result. It took me 5 years of work to make a Chinese engineer understand that he had to heat treat gears to a certain surface hardness or they would not hold up, regardless of their dimensional accuracy. There is no way to compare top quality manufacturing to what happens in these Chinese factories, these are direct opposites.



Michael A. Terrell



--
Richard Knoppow
dickburk@ix.netcom.com
WB6KBL



Michael A. Terrell


Richard Knoppow
 

Oh, yes. I had to deal with Japlish manuals for broadcast equipment. OTOH, the optical industry was turning out outstanding lenses. Japanese TV was established in the US mostly through product dumping (there was a "Front Line" program about this) but eventually the quality came up. I have an especial bee about Panasonic. Fox bought nearly a thousand of 9" monitors. All had to be seriously modified because the design was incompetent. Long story. We didn't want them to begin with but JVC could not deliver the quantity. I also ran into incompetent design in Sony picture monitors. Boards burning up because whoever did the design did not understand that one can't simply divide the heat load into the overall volume of the cabinet. However, I recognized the problem because I had enountered the same thing at Hewlett-Packard many years before. Several of the VFH/UHF signal generators were redesigned with solid state power supplies. Less heat load etc. Sounds good except boards were burning up, sometimes litterally. The new designer had not calculated the concentrated heat load correctly and left out the cooling blower. All got rebuilt with new, blower equipped, cabinets. All ancient history now.

On 3/8/2018 3:23 PM, Michael A. Terrell wrote:
Japan still built some real crap, into the mid '70s and replacement parts took months or years to arrive f you weren't the company's only authorized service center. The documentation wasn't much better. A service manual for one of Panasonic's top of the line home cassette decks bragged about the 'RERAY' logic used to control the motors and solenoids. The rest of the translations in that manual weren't much better.
-----Original Message-----
From: Richard Knoppow <dickburk@ix.netcom.com>
Sent: Mar 8, 2018 3:02 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Capacitors Question?

I was immediately reminded of John Ruskin :
"There is hardly anything in the world that some man cannot make
a little worse and sell a little cheaper, and the people who
consider price only are this man's lawful prey."
--
Richard Knoppow
dickburk@ix.netcom.com
WB6KBL