TIP: When replacing capacitors in a video monitor...

[Tim O]

I don't know your service experience, but you gave a simple example of
why professional service people warn people who don't have the proper
training and experience to give their service work out to qualified
services to have their repairs done.

I know of cases where people have had injury from a terrible electric
shock, of cases where people had fires, and who were injured from
exploding parts that have not been correctly replaced.

But... For some reason many people think they can do the work
themselves, thinking that they will save a few dollars.


Jerry G.
======

Thats my brother in laws attitude, and he gets screwed on everything.
From basic house maintenance, working on cars, right down to paying
someone to fix his computer problems.

He doesn't have to worry about fixing games because he can't afford
them after paying everyone else.

 

[Dave Plowman (News)]

Anyone who's ever built a kit of any complexity can see the value of
doing all the unsoldering and cleaning at once, followed by doing all
the parts insertion and clipping at once, followed by doing all the
soldering at once.

That's a prime way to miss out soldering things. It may be the way a
factory makes things but no use for home construction. Start with the
things least effected by heat - resistors etc - and end with the
semiconductors.

Perhaps your method clarifies why you talk about unsoldering when building
a kit. ;-)

 

[Mickey Johnson]

Anyone who's ever built a kit of any complexity can see the value of
I sure would like to know what the value in the above plan is. That is
absolutely the worst way to approach a monitor cap kit. Do the job one cap
at a time and the values on the caps and silkscreening will all make sense
and it will be apparent if there is an error with either the silkscreening
or value of the item being replaced.

 

[gamefixer]

That's a prime way to miss out soldering things. It may be the way a
factory makes things but no use for home construction. Start with the
things least effected by heat - resistors etc - and end with the
semiconductors.

Perhaps your method clarifies why you talk about unsoldering when building
a kit. ;-)

--
*One tequila, two tequila, three tequila, floor.

Dave Plowman [email protected] London SW
To e-mail, change noise into sound.

I dunno about that. From the way Ken describes his work he and I do
cap kits in pretty close the same way. I change one cap at a time but
solder them all at the same time. Have yet to miss one in 20+
years....

Matt

 

[Scott Caldwell]

Matt, I absolutely agree with you. Anyone whom has done any repairs
at all has made mistakes. Live, learn, move on and above all, respect
electricity!

Scott C.

 

[clifto]

That's a prime way to miss out soldering things. It may be the way a
factory makes things but no use for home construction. Start with the
things least effected by heat - resistors etc - and end with the
semiconductors.

Parts count X 2 = number of joints for the job described. Sanity check
afterwards: parts count X 2 = number of joints to deflux.

Perhaps your method clarifies why you talk about unsoldering when building
a kit. ;-)

Preparation, you big silly. With a kit I always check the boards, use steel
wool or whatever as necessary, check for obvious damage (hold it up to a
light to look for cracks), etc.

 

[James Sweet]

There's usually a big difference in size between a 50 and 250 working
voltage one. And if replacing the lot it should have been obvious by the
size difference between all the new ones?

We're talking about 25-30 year old monitors, I fix a lot of these, the new
caps are usually far smaller physically than the old ones, plenty of modern
250V caps are smaller even than the old 50V caps.

 

[James Sweet]

I disagree, that example can happen to ANYONE, professionals and amateurs
alike. I wouldn't doubt it happens to professionals more often because of
pure cockiness. An amateur is more likely to take necessary precautions and
check the work over and over.

I for one, if I have the tools or equipment to do so will do anything
myself rather than have a professional do it. (not without doing a little
research first of course) Diagnosing a problem is a different story.

Not to point any fingers, but there's a few "professionals" around here who
seem to have forgotten that everyone started out as an amatuer at one point
or another. I wasn't born knowing anything about electronics, and I've never
been formally taught, I've picked it all up on my own through doing it.

 

[James Sweet]

It would help if there was a standard, some mark + , some mark - and some
mark with arrows consisting of a line of negative signs leading to the
other
side

There are on a lot of things. The really fun one is the G07 chassis, they
made zillions of them, one of the caps has the polarity silkscreen wrong on
one side of the board, thankfully it's right on the other side, but then how
do you know which one is right? Pays to make a mental note when you pull the
part out.

 

[James Sweet]

I sure would like to know what the value in the above plan is. That is
absolutely the worst way to approach a monitor cap kit. Do the job one
cap at a time and the values on the caps and silkscreening will all make
sense and it will be apparent if there is an error with either the
silkscreening or value of the item being replaced.

You must have a lot of free time, or not so many monitors. When you've got
half a dozen monitor chassis' stacked on the bench, any tricks to speed up
the process are worthwhile. I tend to go for an assembly line approach, and
change groups of 4 or 5 caps at a time on each board. Pull them all, put in
all the new ones, solder them all, clip, then repeat with the next group and
mark off the checklist as I go.

 

[Vaxx]

All it proves is he is human like the rest of us. As long as you don't make
the same mistake, you have learnt something/

 

[Meat Plow]

Not to point any fingers, but there's a few "professionals" around here who
seem to have forgotten that everyone started out as an amatuer at one point
or another. I wasn't born knowing anything about electronics, and I've never
been formally taught, I've picked it all up on my own through doing it.

What little formal training in electronics I had was in HVAC school.
Otherwise I like you, am self taught. I started out at the age of 14
when I noticed the barber my mom took me to had a little repair shop in a
back room as a hobby. He taught me how to solder and some fundamental
things. At 15 I borrowed a book from the school library, Howard H.
Gerrish's Electricity and Electronics 1968 edition.I dropped out of
school at 16 because I didn't want to cut my hair to conform to their
dress code and got a job at a hotel restaurant. Back then you could do
that at that age. I did keep the Gerrish book though and still have it to
this day. That book now is 40 years old, geesh!. But it taught me about
ohms law and such. And there were some transistor projects. I have to
laugh at a picture in the book of a "marvel of modern technology" an IC
chip made by Western Electric that rests atop the eye of a needle and has
a whopping 18 transsistors on it LOL!!!!!

But to make a long story even longer I got out of the HVAC business in
1978 and was mentored in the consumer electronics industry by a person who
is a very dear friend now. He had an EE degree and took me under his wing.
As I learned on the job I eventually surpassed his expertise worked for
maybe 15 years at a warranty facility then left that to a better paying
job doing warranty work on pro audio stuff for Yamaha and eventually for
other names like Soundcraftsman, BGW, Carvin, etc.. But still I wasn't
making enough money so in 2000 I left and took a job as an IT tech with a
friend who had worked with me back in the 80's. He showed me the ropes
with NT4 and Novell servers, I had already become very knowledgeable with
Windows 98 and local area networking having had a home lan and the first
cable modem from Time Warner in NE Ohio. Needless to say my income tripled
the first year as with my salary and bonuses for hardware sales I made
nearly 80K the very first year. However health issues caught up with me
in 2004 from a leg injury in a motorcycle accident I had back in 1975 and
I just couldn't do all the walking through office and industrial complexes
so I had to retire from that and take a desk job at a NOC (network
operation center) of a friend who taught me the IT stuff. Not as much
money but still a challenge and something I can do here from home via a
VPN.

Sheesh did I just type all that shit? (Starbuck's powered this morning as
usual

 

[mark krawczuk]

hi, i`ve know properly trained service people in public and THE MILITARY
who have made much worse mistakes than that, mistakes my friends 14 yo son
wouldnt even make.

 

[mark krawczuk]

hi, also , so overnight people become fully trained techs ?? i bet u
$1000 that , they got interested in electronics , and made stuff ups as
USUAL when starting any hobby .
just because u might be a tech , does not mean YOU DO NOT MAKE STUFF UPS.


you learn from experiance .

and people CAN DO THE WORK THEMSELVES and have saved a few dollars.
thats why we have fully trained techs because people start of with
electronics as a hobby and make screw ups..
, and think , hey , what makes this tick , ???if i do,,,,,,,, etc..

 

[mark krawczuk]

i see jerry g hasent replied....

twat.

 

[Don Bowey]

i see jerry g hasent replied....

twat.

There wasn't anything meaningful to which he might have "replied."

Besides seeming rude, you are a top-posting twat, which can be overlooked
only if one is not a rude twat.

 

[Clams Canino]

The other good reason they warn them is to stay in business.

Fact is that anyone can make a stupid mistake, or in the case of the OP a
very legitimate error. In my 30 year involvement with Ham Radio I know
personally of a few guys that became instantly deceased by coming across the
B+ supply of a final amplifier circuit that they designed, built, and used
for years and years before they screwed up. Many of the tube type amps run
4-8kv at 1-2 amps DC. Even forgetting to discharge the filter caps can kill
you deader than dead. IMHO anyone working on this stuff needs to remain
paranoid of safety errors. In the case of the OP, a good schematic would
have shown the 250v cap and avoided the error.

-W

 

[Grauwulf]

I firmly believe that if you don't make mistakes, you never actually
learn anything.

I'm not a pro, just an experienced amateur, and how I approach a cap
kit depends on the chassis. For G07's and K4900 and K7000, I generally
change the caps in groups because I've done so many of them. Most
other monitors I just do one at a time to make sure I don't miss
anything.

James

 

[Pat D.]

I have worked on chassis that have had the incorrect value of caps
installed. (Which is why they weren't working in the first place).
Honest to God, they must have had something like a 220 uf @ 160v cap in
place where a 22uf@50v belonged. The person that worked on it before
must have just stuck whatever cap they had sitting on the bench in
whatever spot was open.

So, moral of the story...always use a cap list. Many times these have
been updated with new values anyway to fix issues with particular types
of chassis. The jamma fix for the G07 comes to mind. FWIW, I desolder
a cap, stick a new one in and move on. Then I solder all the legs and
clip all the legs. Then I look at the complete bottom of the chassis
with a magnifying lamp to look for suspect soldering from previous
repairs or solder splotches.

Yes, Matt knows what he is doing. I would like to repeat one of my
rules I have posted before. Never do a cap kit when drunk. You're just
going to have to do it again.

Pat D.

 

[boardjunkie]

Fact is that anyone can make a stupid mistake, or in the case of the OP a
very legitimate error. In my 30 year involvement with Ham Radio I know
personally of a few guys that became instantly deceased by coming across the
B+ supply of a final amplifier circuit that they designed, built, and used
for years and years before they screwed up. Many of the tube type amps run
4-8kv at 1-2 amps DC. Even forgetting to discharge the filter caps can kill
you deader than dead.  

That ain't no shit.....serious current at that voltage. Actually I'd
think it to be a little more current for large x-mitter tubes. I pay
the bills working on music equipment and a lot of that is tube guitar
amps. A 500v electrolytic installed reverse polarity makes a serious
racket and a huge mess (along with a rank stench) when they vent. My
general rule is check polarity after replacement, then again before
power up. I've never put one in backwards, but I've had 'em go postal
on the bench due to excessive leakage current.....should've been
monitoring the temp since they were 20+ yr old caps. I did have an amp
come in once with someone else's cap job already done and a bias
filter cap in backwards. How that didn't go ka-blooey I'll never know.

IMHO anyone working on this stuff needs to remain
paranoid of safety errors.  In the case of the OP, a good schematic would
have shown the 250v cap and avoided the error.

Actually he should have pulled off the glue-gunk to verify what came
out. Going by a list and checking them off as they were replaced
should've raised a red flag.