Strayed thinking
 

Yesterday I came across an example where thinking went astray.
My Runco three large CRT projector failed and I traced it to the first
power
supply of all things. There were four square power resisters, two in
series
but what hit me in the head was that the draftsman had put these
resisters in a tight touching square Now you must know that you
add a fudge factor to the power level but you never cancel it by
removing circulation. They didn't have the apearance of damage
but I took them out anyway. True enough two in parallel had blown
and the engineer probably asked for them to be in parallel to provide
the required surface area. I replaced them with tubular hollow wre
wounds
with separation. To many it is only obvious after the fact or shall I
call
them monday morning quarter backs.
I will see the superbowl in my home theatre with a grin on my face
Art

Strayed thinking
 

art wrote:
Yesterday I came across an example where thinking went astray.
My Runco three large CRT projector failed and I traced it to the first
power
supply of all things. There were four square power resisters, two in
series
but what hit me in the head was that the draftsman had put these
resisters in a tight touching square Now you must know that you
add a fudge factor to the power level but you never cancel it by
removing circulation. They didn't have the apearance of damage
but I took them out anyway. True enough two in parallel had blown
and the engineer probably asked for them to be in parallel to provide
the required surface area. I replaced them with tubular hollow wre
wounds
with separation. To many it is only obvious after the fact or shall I
call
them monday morning quarter backs.
I will see the superbowl in my home theatre with a grin on my face
Art


How many hours did you have on this projector at failure? Part of
engineering a design is lifetime expectancy, judging by the projectors
I've seen over the past few years a three CRT projector has exceeded
it's expected lifetime.

Strayed thinking
 

"gwatts" wrote in message
...
art wrote:
Yesterday I came across an example where thinking went astray.
My Runco three large CRT projector failed and I traced it to the first
power
supply of all things. There were four square power resisters, two in
series
but what hit me in the head was that the draftsman had put these
resisters in a tight touching square Now you must know that you
add a fudge factor to the power level but you never cancel it by
removing circulation. They didn't have the apearance of damage
but I took them out anyway. True enough two in parallel had blown
and the engineer probably asked for them to be in parallel to provide
the required surface area. I replaced them with tubular hollow wre
wounds
with separation. To many it is only obvious after the fact or shall I
call
them monday morning quarter backs.
I will see the superbowl in my home theatre with a grin on my face Art


How many hours did you have on this projector at failure? Part of
engineering a design is lifetime expectancy, judging by the projectors
I've seen over the past few years a three CRT projector has exceeded it's
expected lifetime.

Yes these are begining to show up in Goodwill stores.

Strayed thinking
 

I agree, my 8 inch CRTs have very little hours on them tho I am always
looking for spare tubes. I mentioned it to Curt who fixes them and he
stated it is not the first time he has seen power resisters blow in the
supply.
Manufacturers don't want to add a lot of fans because of the noise.
Similar things happen with the Hitachi rear projection t.v.s maybe
that's why so many are failing. The idea of using two power resisters
in parallel instead of just one of a lower value is purely to take
advantage of the increased surface area, in this case the problem
excabated because the resistors were of the square form so the
draftsman probably placed the four in a tight touching square for
neatness which retarded circulation.i The hollow ohmites that I put in
should solve that oversight. The 8 inch crt forms were made by an
unknown company in Japan for Zenith who then supplied them to G.E., nec
and Runco for relabeling so it may well be a one type set thing
..Have a single lamp projector of Runco but liquid spilt on the power
supply and burnt the traces as well. Do you have the schematic? By the
way the 8 inch crt are underdriven which is a huge advantage in terms
of life. The early forms were over driven which forced designers to go
back to the 7 inch forms and below in the case of rear projection to
accomplish better life.
By the way on single lamp incandescent projector forms I replace the
inside bulb when they fail and use a wire clip to hold it in, much
cheaper than paying a few hundred dollars to replace. I would expect
that the new rear projection lights on the new tvs would benefit from
the same treatment.. I do have a lot of fun playing around with things
to retard the oncomming old age.
Art

gwatts wrote:
art wrote:
Yesterday I came across an example where thinking went astray.
My Runco three large CRT projector failed and I traced it to the first
power
supply of all things. There were four square power resisters, two in
series
but what hit me in the head was that the draftsman had put these
resisters in a tight touching square Now you must know that you
add a fudge factor to the power level but you never cancel it by
removing circulation. They didn't have the apearance of damage
but I took them out anyway. True enough two in parallel had blown
and the engineer probably asked for them to be in parallel to provide
the required surface area. I replaced them with tubular hollow wre
wounds
with separation. To many it is only obvious after the fact or shall I
call
them monday morning quarter backs.
I will see the superbowl in my home theatre with a grin on my face
Art


How many hours did you have on this projector at failure? Part of
engineering a design is lifetime expectancy, judging by the projectors
I've seen over the past few years a three CRT projector has exceeded
it's expected lifetime.

Strayed thinking
 

"art" wrote in message
ups.com...
I agree, my 8 inch CRTs have very little hours on them tho I am always
looking for spare tubes. I mentioned it to Curt who fixes them and he
stated it is not the first time he has seen power resisters blow in the
supply.
Manufacturers don't want to add a lot of fans because of the noise.
Similar things happen with the Hitachi rear projection t.v.s maybe
that's why so many are failing. The idea of using two power resisters
in parallel instead of just one of a lower value is purely to take
advantage of the increased surface area, in this case the problem
excabated because the resistors were of the square form so the
draftsman probably placed the four in a tight touching square for
neatness which retarded circulation.i The hollow ohmites that I put in
should solve that oversight. The 8 inch crt forms were made by an
unknown company in Japan for Zenith who then supplied them to G.E., nec
and Runco for relabeling so it may well be a one type set thing
.Have a single lamp projector of Runco but liquid spilt on the power
supply and burnt the traces as well. Do you have the schematic? By the
way the 8 inch crt are underdriven which is a huge advantage in terms
of life. The early forms were over driven which forced designers to go
back to the 7 inch forms and below in the case of rear projection to
accomplish better life.
By the way on single lamp incandescent projector forms I replace the
inside bulb when they fail and use a wire clip to hold it in, much
cheaper than paying a few hundred dollars to replace. I would expect
that the new rear projection lights on the new tvs would benefit from
the same treatment.. I do have a lot of fun playing around with things
to retard the oncomming old age.
Art

gwatts wrote:
art wrote:
Yesterday I came across an example where thinking went astray.
My Runco three large CRT projector failed and I traced it to the first
power
supply of all things. There were four square power resisters, two in
series
but what hit me in the head was that the draftsman had put these
resisters in a tight touching square Now you must know that you
add a fudge factor to the power level but you never cancel it by
removing circulation. They didn't have the apearance of damage
but I took them out anyway. True enough two in parallel had blown
and the engineer probably asked for them to be in parallel to provide
the required surface area. I replaced them with tubular hollow wre
wounds
with separation. To many it is only obvious after the fact or shall I
call
them monday morning quarter backs.
I will see the superbowl in my home theatre with a grin on my face
Art


How many hours did you have on this projector at failure? Part of
engineering a design is lifetime expectancy, judging by the projectors
I've seen over the past few years a three CRT projector has exceeded
it's expected lifetime.


Doubt if it was a fault in engineering. If the engineers had their way it
would probably be a dale heatsinked to the chassis.Often one engineering
team designs it and another goes through to find out how they can cut
corners.

Strayed thinking
 

On 23 Jan, 14:49, "Jimmie D" wrote:
"art" wrote in oglegroups.com...





I agree, my 8 inch CRTs have very little hours on them tho I am always
looking for spare tubes. I mentioned it to Curt who fixes them and he
stated it is not the first time he has seen power resisters blow in the
supply.
Manufacturers don't want to add a lot of fans because of the noise.
Similar things happen with the Hitachi rear projection t.v.s maybe
that's why so many are failing. The idea of using two power resisters
in parallel instead of just one of a lower value is purely to take
advantage of the increased surface area, in this case the problem
excabated because the resistors were of the square form so the
draftsman probably placed the four in a tight touching square for
neatness which retarded circulation.i The hollow ohmites that I put in
should solve that oversight. The 8 inch crt forms were made by an
unknown company in Japan for Zenith who then supplied them to G.E., nec
and Runco for relabeling so it may well be a one type set thing
.Have a single lamp projector of Runco but liquid spilt on the power
supply and burnt the traces as well. Do you have the schematic? By the
way the 8 inch crt are underdriven which is a huge advantage in terms
of life. The early forms were over driven which forced designers to go
back to the 7 inch forms and below in the case of rear projection to
accomplish better life.
By the way on single lamp incandescent projector forms I replace the
inside bulb when they fail and use a wire clip to hold it in, much
cheaper than paying a few hundred dollars to replace. I would expect
that the new rear projection lights on the new tvs would benefit from
the same treatment.. I do have a lot of fun playing around with things
to retard the oncomming old age.
Art

gwatts wrote:
art wrote:
Yesterday I came across an example where thinking went astray.
My Runco three large CRT projector failed and I traced it to the first
power
supply of all things. There were four square power resisters, two in
series
but what hit me in the head was that the draftsman had put these
resisters in a tight touching square Now you must know that you
add a fudge factor to the power level but you never cancel it by
removing circulation. They didn't have the apearance of damage
but I took them out anyway. True enough two in parallel had blown
and the engineer probably asked for them to be in parallel to provide
the required surface area. I replaced them with tubular hollow wre
wounds
with separation. To many it is only obvious after the fact or shall I
call
them monday morning quarter backs.
I will see the superbowl in my home theatre with a grin on my face
Art

How many hours did you have on this projector at failure? Part of
engineering a design is lifetime expectancy, judging by the projectors
I've seen over the past few years a three CRT projector has exceeded
it's expected lifetime.Doubt if it was a fault in engineering. If the engineers had their way it
would probably be a dale heatsinked to the chassis.Often one engineering
team designs it and another goes through to find out how they can cut
corners.- Hide quoted text -- Show quoted text -

Strayed thinking
 

On 23 Jan, 14:49, "Jimmie D" wrote:
"art" wrote in oglegroups.com...




snipurs did you have on this projector at failure? Part of
engineering a design is lifetime expectancy, judging by the projectors
I've seen over the past few years a three CRT projector has exceeded
it's expected lifetime.Doubt if it was a fault in engineering. If the engineers had their way it
would probably be a dale heatsinked to the chassis.Often one engineering
team designs it and another goes through to find out how they can cut
corners.- Hide quoted text -- Show quoted text -

Jimmy it is rare to use two resisters instead of one because a board
becomes bigger
and introduces cost. When you get to power resisters it is not unusual
to place two
in parallel and accept the cost. In this case a cost improver would
try to make the case
for one single resister instead of four since a Dale with heatsink
would be
comparitively prohibative. The engineers calculation for wattage may
well have
been correct without being side blinded by the fact of some square
form resisters.
Art

Strayed thinking
 

"art" wrote in message
oups.com...


On 23 Jan, 14:49, "Jimmie D" wrote:
"art" wrote in
oglegroups.com...




snipurs did you have on this projector at failure? Part of
engineering a design is lifetime expectancy, judging by the projectors
I've seen over the past few years a three CRT projector has exceeded
it's expected lifetime.Doubt if it was a fault in engineering. If the
engineers had their way it
would probably be a dale heatsinked to the chassis.Often one engineering
team designs it and another goes through to find out how they can cut
corners.- Hide quoted text -- Show quoted text -

Jimmy it is rare to use two resisters instead of one because a board
becomes bigger
and introduces cost. When you get to power resisters it is not unusual
to place two
in parallel and accept the cost. In this case a cost improver would
try to make the case
for one single resister instead of four since a Dale with heatsink
would be
comparitively prohibative. The engineers calculation for wattage may
well have
been correct without being side blinded by the fact of some square
form resisters.
Art


Depends on the cost of the resistors. Prices seem to increase somewhat
expotentially with wattage so the two smaller ones may have been cheaper
than one larger. In this case the cost improver would have went for the
multiple resistors.

Strayed thinking
 

art wrote:

On 23 Jan, 14:49, "Jimmie D" wrote:
"art" wrote in oglegroups.com...

...Part of
engineering a design is lifetime expectancy...
...Doubt if it was a fault in engineering. If the engineers had their way it
would probably be a dale heatsinked to the chassis.Often one engineering
team designs it and another goes through to find out how they can cut
corners.

Jimmy it is rare to use two resisters instead of one because a board
becomes bigger
and introduces cost.

If they used one resistor in another place or places it's could have
been easier to use multiples in series/parallel where they could rather
than purchase and stock another value at the factory. I worked at a
place where we used 5532 op amps in many audio circuits and in one place
as a flip flop so we wouldn't have to stock a 74xx or 40xx just for that
one use. It was easier on the assemblers to have one bin of chips,
better quantity pricing, no sweating running out of one part kept in
smaller quantity, (insert more bean counter stuff...)

Strayed thinking
 

On 23 Jan, 18:14, gwatts wrote:
art wrote:

On 23 Jan, 14:49, "Jimmie D" wrote:
"art" wrote in oglegroups.com...

...Part of
snip where we used 5532 op amps in many audio circuits and in one place
as a flip flop so we wouldn't have to stock a 74xx or 40xx just for that
one use. It was easier on the assemblers to have one bin of chips,
better quantity pricing, no sweating running out of one part kept in
smaller quantity, (insert more bean counter stuff...)

Very interesting if you are refering to power resisters used in a
non switching power supply. In my case I have had no experience
of seeing power supplies with excess resisters or with the use of dale
prescision resisters or resisters mounted on a heat sink which
is fortunate for me otherwise I would never have resolved my
particular problem It would appear that I retired just in time
before engineering studies became out of fashion
Happy trails
Art

Strayed thinking
 

art wrote:

On 23 Jan, 18:14, gwatts wrote:

art wrote:


On 23 Jan, 14:49, "Jimmie D" wrote:

"art" wrote in oglegroups.com...

...Part of

snip where we used 5532 op amps in many audio circuits and in one place

as a flip flop so we wouldn't have to stock a 74xx or 40xx just for that
one use. It was easier on the assemblers to have one bin of chips,
better quantity pricing, no sweating running out of one part kept in
smaller quantity, (insert more bean counter stuff...)


Very interesting if you are refering to power resisters used in a
non switching power supply.

Your particular case sounds like they designed for one resistor and
designed very close to the function/failure edge, then rushed to
production only to discover the single resistor was too far over that
edge. Their solution was to quickly change the board design for four in
series-parallel but put them in the same space, since they already had
umpteen thousand resistors ordered or even in stock. It worked in test,
worked for a week or so running continuously... ship it!

... It would appear that I retired just in time
before engineering studies became out of fashion

Engineering studies aren't out of fashion, in fact they're more
intensive, involve a lot more computer modeling and help push the design
closer to the function/failure edge. Not out of fashion but a smaller
piece of the pie, now the design involves a lot more
design-for-manufacture including pick-and-place instead of a human
assembler, all SMT (see previous reason), least component count
possible, limited lifetime so you have to buy a new unit in a few years,
less 'robust design' and more 'economical,' higher profit and lower quality.

Don't blame the engineers, unless they went on to get an MBA after the
EE, ME, etc. I got out of private industry ten years ago for these
reasons, I was tired of design reviews where management pushed the 'you
can cut this out, it won't be so bad' line. Designs aren't for the
benefit of the customer, they are for the benefit of the stockholder and
the board of directors. What was 'The quality goes in before the name
goes on,' is now 'the profit is determined before the unit is produced.'
I'm not saying that profit isn't a good thing, just that it shouldn't
be the overwhelming thing.

73,
W8LNA

Strayed thinking
 

On Wed, 24 Jan 2007 12:40:32 GMT, gwatts
wrote:

I was tired of design reviews where management pushed the 'you
can cut this out, it won't be so bad' line.

Hi OM,

My very first EE professor (also an engineer at the HP division in
Colorado Springs) taught us the merits of designs meeting the
expectations of Mad Man Muntz.

Muntz was a car salesman who entered the nascent field of TV in the
late 40s and would wander the design lab with a pair of dikes in his
pocket. Looking over the shoulder of any designer he would snip out
components until they lost the picture, it would roll, or the sound
would go dead. Then he would suggest they put back in the last
snipped component.

He discovered his TVs didn't need synchronization circuits because his
market was in urban cities where the signal was so powerful as to
provide enough level to be self-syncing. I know, because I fixed many
of those TVs that eventually found their way into the Burbs, and were
forever rolling unless you found the sweet spot on the horizontal or
vertical adjustment (always in the back).

73's
Richard Clark, KB7QHC

Strayed thinking
 

Richard Clark wrote:
On Wed, 24 Jan 2007 12:40:32 GMT, gwatts
wrote:


I was tired of design reviews where management pushed the 'you
can cut this out, it won't be so bad' line.


Hi OM,

My very first EE professor (also an engineer at the HP division in
Colorado Springs) taught us the merits of designs meeting the
expectations of Mad Man Muntz...he would snip out
components until they lost the picture, it would roll, or the sound
would go dead. Then he would suggest they put back in the last
snipped component.

He discovered his TVs didn't need synchronization circuits because his
market was in urban cities where the signal was so powerful as to
provide enough level to be self-syncing. I know, because I fixed many
of those TVs that eventually found their way into the Burbs, and were
forever rolling unless you found the sweet spot on the horizontal or
vertical adjustment (always in the back).

Yes, I've heard the tales of M. M. Muntz, but apparently so had the head
designer at the audio mfr I worked at. They had a VCA circuit using a
well known VCA chip. The data sheet notes mentioned a small value
capacitor across two pins for stability. The designer discovered his
circuit would work just as well without the cap and thus left it out of
his design, so far out that there weren't even traces or pads to put the
cap in should it become necessary (you can see where this is going,
no?). The VCA vendor outsourced fabrication of the chip and all of a
sudden the noise level of the VCA circuit would jump about 70 dB as the
fader reached the bottom of travel, not desirable in an audio
application. I spent a little time perusing the data sheets and our
schematics, noticed the cap omission, soldered a cap across the pins of
an offending circuit and within the hour we had the assemblers tack
soldering caps we bought at a local electronics shop (not RS) onto
assembled modules. The designer's comment was 'Well, it worked for
quite a while...' Later we found customers with similar noise level
jumps using pre-outsourced VCAs. Yes, they saved a few pennies on each
module but lost about two dozen customers when they figured out what had
been left out of their very expensive audio equipment.

When I started at that place I was told not to make suggestions
regarding modifications of existing designs lest I offend the managing
'engineer'.

Strayed thinking
 

gwatts wrote:

Don't blame the engineers, unless they went on to get an MBA after the
EE, ME, etc. I got out of private industry ten years ago for these
reasons, I was tired of design reviews where management pushed the 'you
can cut this out, it won't be so bad' line. Designs aren't for the
benefit of the customer, they are for the benefit of the stockholder and
the board of directors. What was 'The quality goes in before the name
goes on,' is now 'the profit is determined before the unit is produced.'
I'm not saying that profit isn't a good thing, just that it shouldn't
be the overwhelming thing.

On the other hand, someone has to take the project from the engineers
because if they don't, the engineers won't stop working on it.


- 73 de Mike KB3EIA -

Strayed thinking
 

gwatts wrote:
Richard Clark wrote:
On Wed, 24 Jan 2007 12:40:32 GMT, gwatts
wrote:


I was tired of design reviews where management pushed the 'you can
cut this out, it won't be so bad' line.


Hi OM,

My very first EE professor (also an engineer at the HP division in
Colorado Springs) taught us the merits of designs meeting the
expectations of Mad Man Muntz...he would snip out
components until they lost the picture, it would roll, or the sound
would go dead. Then he would suggest they put back in the last
snipped component.

He discovered his TVs didn't need synchronization circuits because his
market was in urban cities where the signal was so powerful as to
provide enough level to be self-syncing. I know, because I fixed many
of those TVs that eventually found their way into the Burbs, and were
forever rolling unless you found the sweet spot on the horizontal or
vertical adjustment (always in the back).

Yes, I've heard the tales of M. M. Muntz, but apparently so had the head
designer at the audio mfr I worked at. They had a VCA circuit using a
well known VCA chip. The data sheet notes mentioned a small value
capacitor across two pins for stability. The designer discovered his
circuit would work just as well without the cap and thus left it out of
his design, so far out that there weren't even traces or pads to put the
cap in should it become necessary (you can see where this is going,
no?). The VCA vendor outsourced fabrication of the chip and all of a
sudden the noise level of the VCA circuit would jump about 70 dB as the
fader reached the bottom of travel, not desirable in an audio
application. I spent a little time perusing the data sheets and our
schematics, noticed the cap omission, soldered a cap across the pins of
an offending circuit and within the hour we had the assemblers tack
soldering caps we bought at a local electronics shop (not RS) onto
assembled modules. The designer's comment was 'Well, it worked for
quite a while...' Later we found customers with similar noise level
jumps using pre-outsourced VCAs. Yes, they saved a few pennies on each
module but lost about two dozen customers when they figured out what had
been left out of their very expensive audio equipment.

When I started at that place I was told not to make suggestions
regarding modifications of existing designs lest I offend the managing
'engineer'.


This reminds me of an old story about how you can become a hero in
Detroit. Save 1/2 cent each on 10 million washers. To become a bum in
Detroit, have those washers cause a 10 million car recall.

Dave N

Strayed thinking
 

"Richard Clark" wrote in message
...
On Wed, 24 Jan 2007 12:40:32 GMT, gwatts
wrote:

I was tired of design reviews where management pushed the 'you
can cut this out, it won't be so bad' line.

Hi OM,

My very first EE professor (also an engineer at the HP division in
Colorado Springs) taught us the merits of designs meeting the
expectations of Mad Man Muntz.

Muntz was a car salesman who entered the nascent field of TV in the
late 40s and would wander the design lab with a pair of dikes in his
pocket. Looking over the shoulder of any designer he would snip out
components until they lost the picture, it would roll, or the sound
would go dead. Then he would suggest they put back in the last
snipped component.

He discovered his TVs didn't need synchronization circuits because his
market was in urban cities where the signal was so powerful as to
provide enough level to be self-syncing. I know, because I fixed many
of those TVs that eventually found their way into the Burbs, and were
forever rolling unless you found the sweet spot on the horizontal or
vertical adjustment (always in the back).

73's
Richard Clark, KB7QHC

Oh, you reveal you age. I worked on a bunch of those until I just started
not letting them in the door. Seems a guy bought a bunch(100+) from a
motel(s) that had gotten new TVs and had sold the for about $30 a piece. I
think they had a 1 tube IF if I remember right. They wouldnt work at all in
our area unles you had a really good antenna on a tall tower. The only
places that had this was the shop I worked in and the local motels.

Jimmie

Strayed thinking
 

"Michael Coslo" wrote in message
...
gwatts wrote:

Don't blame the engineers, unless they went on to get an MBA after the
EE, ME, etc. I got out of private industry ten years ago for these
reasons, I was tired of design reviews where management pushed the 'you
can cut this out, it won't be so bad' line. Designs aren't for the
benefit of the customer, they are for the benefit of the stockholder and
the board of directors. What was 'The quality goes in before the name
goes on,' is now 'the profit is determined before the unit is produced.'
I'm not saying that profit isn't a good thing, just that it shouldn't be
the overwhelming thing.

On the other hand, someone has to take the project from the engineers
because if they don't, the engineers won't stop working on it.


- 73 de Mike KB3EIA -

Engineers design it and the techs actually make it work.

Strayed thinking
 

On Wed, 24 Jan 2007 18:20:51 GMT, gwatts
wrote:

When I started at that place I was told not to make suggestions
regarding modifications of existing designs lest I offend the managing
'engineer'.

I feel your pain.

I followed one bum who couldn't figure out the gozinta from the
comesoutta on a linear IC. The design (heart monitor) went all the
way through to production, then testing, and they wondered why the
processor only produced a flat line for any patient. I also came to
the conclusion that the project engineer was brain dead too (design
review an exercise in swinging rubber stamps). I have forever after
examined the equipment of any hospital I had procedures in. There was
one trademark I didn't want to see.

Consulting can be a tough life of techno-whoring. Praise the idiots
(or repress the urge to strangle) and clean up their mess.

73's
Richard Clark, KB7QHC

Strayed thinking
 

On Wed, 24 Jan 2007 16:12:24 -0500, "Jimmie D"
wrote:

Oh, you reveal you age.

Hi Jimmie,

I did my apprentice work in TV as a teen in the mid 60s. The real
challenge came when I was in the Navy (1970) and we put out a call to
the Bay area for folks to donate their TVs for charity (Xmas of 1970),
and the ET school would fix them for free for redistribution to the
needy.

My crew took in 100-150 TVs and 200 radios and turned out 60 or 70 TVs
and nearly all the radios. Some TVs were so old as to have vertically
mounted tubes with a mirror to view them. I taught the fellows how to
cannibalize the truly dead to resurrect the lame. This was the gift
of a Navy technical education. At sea, there was no mall to pull
into and go to Radio Shack - you had to make the broken stuff work or
the Captain would keel haul you. This demanded every tech know
electronics, not board swapping. I never had such an enthusiastic
class. These guys learned like sponges, and tackled every problem
like a commando gutting a commie.

One interesting incident came when a student asked me for a set of
rabbit ears to test his work on a tough-dog TV. My budget was like
$20 a week from the Old Man's wallet (and I wasn't going to ask him
for that). I told the student that we had a ground bus-bar that ran
the length around the repair shed (a former laundry) that would work
just as well as it was many wavelengths longs so as to not short the
signal (sitting in the middle of SF bay offered huge amounts of
available RF).

He connected an alligator clip lead to the antenna input, the other to
the bus bar; the lead turned to smoke, the insulation dripped right
off like a length of spaghetti, and then fused open.

The astonished crew quickly learned the hazards of poorly engineered
grounds in commercial equipment, the hazards of using a service cord
to defeat an interlock, and why we in the trade called it a suicide
adapter.

73's
Richard Clark, KB7QHC

Strayed thinking
 

"Richard Clark" wrote in message
...
On Wed, 24 Jan 2007 16:12:24 -0500, "Jimmie D"
wrote:

Oh, you reveal you age.

Hi Jimmie,

I did my apprentice work in TV as a teen in the mid 60s. The real
challenge came when I was in the Navy (1970) and we put out a call to
the Bay area for folks to donate their TVs for charity (Xmas of 1970),
and the ET school would fix them for free for redistribution to the
needy.

My crew took in 100-150 TVs and 200 radios and turned out 60 or 70 TVs
and nearly all the radios. Some TVs were so old as to have vertically
mounted tubes with a mirror to view them. I taught the fellows how to
cannibalize the truly dead to resurrect the lame. This was the gift
of a Navy technical education. At sea, there was no mall to pull
into and go to Radio Shack - you had to make the broken stuff work or
the Captain would keel haul you. This demanded every tech know
electronics, not board swapping. I never had such an enthusiastic
class. These guys learned like sponges, and tackled every problem
like a commando gutting a commie.

One interesting incident came when a student asked me for a set of
rabbit ears to test his work on a tough-dog TV. My budget was like
$20 a week from the Old Man's wallet (and I wasn't going to ask him
for that). I told the student that we had a ground bus-bar that ran
the length around the repair shed (a former laundry) that would work
just as well as it was many wavelengths longs so as to not short the
signal (sitting in the middle of SF bay offered huge amounts of
available RF).

He connected an alligator clip lead to the antenna input, the other to
the bus bar; the lead turned to smoke, the insulation dripped right
off like a length of spaghetti, and then fused open.

The astonished crew quickly learned the hazards of poorly engineered
grounds in commercial equipment, the hazards of using a service cord
to defeat an interlock, and why we in the trade called it a suicide
adapter.

73's
Richard Clark, KB7QHC

I always called them fool killers, especilly the ones that used gator clips
on the end..

Strayed thinking
 

On Thu, 25 Jan 2007 09:24:00 -0500, "Jimmie D"
wrote:

The astonished crew quickly learned the hazards of poorly engineered
grounds in commercial equipment, the hazards of using a service cord
to defeat an interlock, and why we in the trade called it a suicide
adapter.

I always called them fool killers, especilly the ones that used gator clips
on the end..

Our name for them was a "Kills-me-quick."

One of my buddies aboard ship was holding just such a cord, plugged
in, and while he talked, or was telling a joke, we watched him flick
the cord around. Occassionally he would absent mindedly smack it into
his hand to emphasize a point. Absolutely no one was paying attention
to what he was saying. We all followed the arc of those leads
wondering when the big moment would come.

Of course we all knew CPR....

73's
Richard Clark, KB7QHC

Strayed thinking
 

"Richard Clark" wrote in message
...
On Thu, 25 Jan 2007 09:24:00 -0500, "Jimmie D"
wrote:

The astonished crew quickly learned the hazards of poorly engineered
grounds in commercial equipment, the hazards of using a service cord
to defeat an interlock, and why we in the trade called it a suicide
adapter.

I always called them fool killers, especilly the ones that used gator
clips
on the end..

Our name for them was a "Kills-me-quick."

One of my buddies aboard ship was holding just such a cord, plugged
in, and while he talked, or was telling a joke, we watched him flick
the cord around. Occassionally he would absent mindedly smack it into
his hand to emphasize a point. Absolutely no one was paying attention
to what he was saying. We all followed the arc of those leads
wondering when the big moment would come.

Of course we all knew CPR....

73's
Richard Clark, KB7QHC

Ive done this watching a guy play with a charged cap. He had just charged it
up to place on the bench for some unsuspecting sole to grap, started running
his mouth and zapped himself.

Strayed thinking
 

On Thu, 25 Jan 2007 13:39:32 -0500, "Jimmie D"
wrote:

Ive done this watching a guy play with a charged cap. He had just charged it
up to place on the bench for some unsuspecting sole to grap, started running
his mouth and zapped himself.

As Cartman would say
"SWEET!"

Strayed thinking
 

"Jimmie D" wrote in
:


"Michael Coslo" wrote in message
...
gwatts wrote:

Don't blame the engineers, unless they went on to get an MBA after
the EE, ME, etc. I got out of private industry ten years ago for
these reasons, I was tired of design reviews where management pushed
the 'you can cut this out, it won't be so bad' line. Designs aren't
for the benefit of the customer, they are for the benefit of the
stockholder and the board of directors. What was 'The quality goes
in before the name goes on,' is now 'the profit is determined before
the unit is produced.' I'm not saying that profit isn't a good
thing, just that it shouldn't be the overwhelming thing.

On the other hand, someone has to take the project from the engineers
because if they don't, the engineers won't stop working on it.


- 73 de Mike KB3EIA -

Engineers design it and the techs actually make it work.


I suspect that is why the better engineers that I know buy their
Techs pizza every so often! ;^)

- 73 de Mike KB3EIA -

Strayed thinking
 

Richard Clark wrote:
On Thu, 25 Jan 2007 13:39:32 -0500, "Jimmie D"
wrote:

Ive done this watching a guy play with a charged cap. He had just charged it
up to place on the bench for some unsuspecting sole to grap, started running
his mouth and zapped himself.

As Cartman would say
"SWEET!"


In our High School electronics shop, we had an entire Superhet tube
radio demo unit mounted on the wall, with all components pluggable.
Seniors and juniors were mixed in the class, and one of the favorite
rituals for the older guys was to pull one of the p.s. Electrolytics out
very carefully, and toss it to one of the new guys with a "catch it
quick" command.

Of course, I never partook of such tomfoolery.


- 73 de Mike KB3EIA -

Strayed thinking
 

On Thu, 01 Feb 2007 11:17:27 -0500, Michael Coslo
wrote:

Of course, I never partook of such tomfoolery.

Mike, what a lightweight.

I took a cap out of TV Buck-Boost section of the flyback (couple of
hundred pF rated at 20,000V, what is called a doorknob cap) and
charged it with a van-deGraff generator. Unfortunately it was my
Physics teacher that wondered what strange item I had on my desk....

73's
Richard Clark, KB7QHC