variac/dc power supply repair

[Smitty Two]

I know the difference between a fuse and a fuse holder in terms of
their function. However, I have not seen every fuse holder nor every
fuse. I jumped to a conclusion at the very beginning when I thought I
was looking at some strange, obsolete type of *fuse* when I was looking
at a *holder* of type which is apparently common and well known in test
equipment. How should I know? That's why I asked. (You know, the
holder says "Slo Blo" on it too.)

To reply to the GP, with this knowledge of what is a fuse and what is a
holder straightened out several posts ago, I concluded that it was
given to me without a fuse. Isn't it a reasonable presumption then
that it previously blew a fuse? What other reason would one have for
removing a fuse? No, there are no obvious short circuits in that there
are no loose wires. Since the presumption was that a fuse blew, that
was the first thing to check. But I can't tell whether it will blow
another fuse without putting another fuse in and powering it up, can I?

I don't see what has been so difficult to understand about what I have
posted. The largest part of the problem is that respondents would
rather jump to conclusions about my mettle than ask for clarification
if what I have posted is ambiguous or seems wrong. I try to anticipate
replies when I post, but it is inescapable that descriptions will be
lacking at times. Furthermore, I have visited this project
approximately three times; since it is at home and I work all day my
opportunities are limited.

My experience is limited to consumer electronics component-swapping
(including fuses). That's why I haven't seen this type of holder
before - fuse holders in consumer equipment are almost invariably the
flex metal type. I can take the appropriate precautions vs becoming a
crispy critter when working on a monitor, a PC power supply, or a
microwave, so why do I feel like I need a disclaimer at the end of
every post I make about this power supply?

I realize you get what you pay for in terms of soliciting advice, but I
recall this group being a lot less hostile 5 years ago.

We're all busy. If you've got time to write long posts complaining about
the treatment you perceive yourself to be receiving here, you've got
time to go buy a fuse and stick it in there. So go do it.

 

[Ross Herbert]

I know the difference between a fuse and a fuse holder in terms of
their function. However, I have not seen every fuse holder nor every
fuse. I jumped to a conclusion at the very beginning when I thought I
was looking at some strange, obsolete type of *fuse* when I was looking
at a *holder* of type which is apparently common and well known in test
equipment. How should I know? That's why I asked. (You know, the
holder says "Slo Blo" on it too.)

You came across something which was obviously a fuse or fuseholder
which you hadn't seen before. You knew the item you were asking about
on the unit was a fuse because it was marked so, and even had the
value and slo-blo written alongside it. The thing has a screw cap
which you removed so if this didn't give the clue that "duh, some type
of fuse must go in here". then no wonder other people are frustrated
at your posts.

So, before getting on the NG and posting did it occur to you to do
some research on the web, even if it was only to protect yourself from
ridicule because of your ignorance on the matter? By typing two words
"fuse fuseholder" (without the quotes) into Google would reveal in the
second picture a 3AG fuseholder similar to the one you had in front of
you.
http://www.allelectronics.com/cgi-bin/category.cgi?category=250

Clicking More Info on this item takes you to
http://www.allelectronics.com/cgi-bin/item/FHPM-31/250/3AG_PANEL_MOUNT_FUSE_HOLDER_.html
and it says "screw style cap" and "suits 3AG and MDL style". Now that
writing 3.2A SLO-BLO on your unit must refer to the fuse which goes in
it.

Browse by Category menu on the right would have revealed there were
separate categories for "Fuses" and "Fuseholders", so have a look at
Fuses. http://www.allelectronics.com/cgi-bin/category/245/Fuses.html

Here we find a sub-category "MDL (Slow-Blow)" so that takes us to
http://www.allelectronics.com/cgi-bin/category/245300/MDL_Slow-Blow.html

Item 5 is the closest you will get at 3A so now you know all you
needed to before getting on the NG and posting.

Look first, and when you have done your research ask questions from a
basis of at least having done something yourself.

To reply to the GP, with this knowledge of what is a fuse and what is a
holder straightened out several posts ago, I concluded that it was
given to me without a fuse. Isn't it a reasonable presumption then
that it previously blew a fuse? What other reason would one have for
removing a fuse?

Now hang on a minute... You didn't tell us before now that you were
supplied the unit "without the fuse", so how was anybody supposed to
guess this fact. So, NO, it is not a reasonable assumption for us to
"guess" that it had "previously blown a fuse". Only yourself would
have been able to make that assumption. We aren't psychic you know...

Given the information you provided we had to assume (wrongly it now
seems) that you knew what a fuseholder was and the type of fuse to
use, and that you had powered it up but it didn't work. We assumed you
would have ensured there was a fuse in it since you had all the info
written on the unit. And since you didn't say that fuse blew, we
assumed that your problem related to continuity within the fuse. These
things are so obvious to us that we didn't think to ask "have you
tried a new fuse in the fuseholder?" because we thought you would have
done this already.

No, there are no obvious short circuits in that there
are no loose wires. Since the presumption was that a fuse blew, that
was the first thing to check. But I can't tell whether it will blow
another fuse without putting another fuse in and powering it up, can I?

You are dead right there.... so why didn't you do it?

All right, we NOW know that you weren't aware that this style of fuse
holder used a tubular fuse but we couldn't guess that could we. After
all tubular fuses have been around since about 1930 and panel mount
fuseholders have been around for at least 50 years and anybody who is
even vaguely familiar with electronic equipment will have come across
them. The fact is you knew the object was a fuse because it was there
in white letters. It is obvious you must have unscrewed the cap and
found nothing there so pray tell me why this didn't prompt you to ask
yourself "now how can this fuse thing work when I have this completely
disconnected screw cap in my hand and there is nothing at all in it?"
Bloody hell, if it wasn't immediately obvious there was a bit missing
then your logic is non existent.

I don't see what has been so difficult to understand about what I have
posted. The largest part of the problem is that respondents would
rather jump to conclusions about my mettle than ask for clarification
if what I have posted is ambiguous or seems wrong.

Try to imagine that you are asking for help "by remote control". We
can't see what you have in front of you so you have to describe it in
detail. Heck, if I hadn't dug up that pic of the power supply by
Googling nobody would have had much of an idea of what you were
talking about.

I try to anticipate
replies when I post, but it is inescapable that descriptions will be
lacking at times. Furthermore, I have visited this project
approximately three times; since it is at home and I work all day my
opportunities are limited.

My experience is limited to consumer electronics component-swapping
(including fuses). That's why I haven't seen this type of holder
before - fuse holders in consumer equipment are almost invariably the
flex metal type. I can take the appropriate precautions vs becoming a
crispy critter when working on a monitor, a PC power supply, or a
microwave, so why do I feel like I need a disclaimer at the end of
every post I make about this power supply?

You seemed a candidate for a disclaimer because when it became obvious
you had never come across a panel mount fuseholder in your life. Then
it seemed possible you didn't have any electronics knowledge and you
might put yourself in danger by following suggestions. Anybody who has
dabbled in electronics in the last 50 years or more will have come
across this common type of fuseholder so it would have been highly
improbable that you hadn't seen one before.

What is a "flex metal" type fuse? I've never heard of it. What type of
"consumer electronics" are you talking about? Are you talking
whitegoods such as microwave ovens, washing machines etc? If so, you
are right, they don't have panel mount fuseholders. They don't want
ignorant people replacing the fuses when they don't know what they are
doing.

When whitegoods have a fuse it will usually be concealed inside but in
most cases that I have come across they are still tubular fuses either
ceramic or glass and generally size 3AG and mounted in an open style
fuse clip with a plastic insulating cover of some sort. A microwave
oven is a good example.

I realize you get what you pay for in terms of soliciting advice, but I
recall this group being a lot less hostile 5 years ago.

If you had given all the info to start with, and done some research,
you would have received the correct advice. Given the paucity of info
then you can't blame people for getting up your arse. The "hostility",
as you put it, came about because of frustration due to you not
providing all the info you had, or should have had, before posting.

 

[Arfa Daily]

You came across something which was obviously a fuse or fuseholder
which you hadn't seen before. You knew the item you were asking about
on the unit was a fuse because it was marked so, and even had the
value and slo-blo written alongside it. The thing has a screw cap
which you removed so if this didn't give the clue that "duh, some type
of fuse must go in here". then no wonder other people are frustrated
at your posts.

So, before getting on the NG and posting did it occur to you to do
some research on the web, even if it was only to protect yourself from
ridicule because of your ignorance on the matter? By typing two words
"fuse fuseholder" (without the quotes) into Google would reveal in the
second picture a 3AG fuseholder similar to the one you had in front of
you.
http://www.allelectronics.com/cgi-bin/category.cgi?category=250

Clicking More Info on this item takes you to
http://www.allelectronics.com/cgi-bin/item/FHPM-31/250/3AG_PANEL_MOUNT_FUSE_HOLDER_.html
and it says "screw style cap" and "suits 3AG and MDL style". Now that
writing 3.2A SLO-BLO on your unit must refer to the fuse which goes in
it.

Browse by Category menu on the right would have revealed there were
separate categories for "Fuses" and "Fuseholders", so have a look at
Fuses. http://www.allelectronics.com/cgi-bin/category/245/Fuses.html

Here we find a sub-category "MDL (Slow-Blow)" so that takes us to
http://www.allelectronics.com/cgi-bin/category/245300/MDL_Slow-Blow.html

Item 5 is the closest you will get at 3A so now you know all you
needed to before getting on the NG and posting.

Look first, and when you have done your research ask questions from a
basis of at least having done something yourself.


Now hang on a minute... You didn't tell us before now that you were
supplied the unit "without the fuse", so how was anybody supposed to
guess this fact. So, NO, it is not a reasonable assumption for us to
"guess" that it had "previously blown a fuse". Only yourself would
have been able to make that assumption. We aren't psychic you know...

Given the information you provided we had to assume (wrongly it now
seems) that you knew what a fuseholder was and the type of fuse to
use, and that you had powered it up but it didn't work. We assumed you
would have ensured there was a fuse in it since you had all the info
written on the unit. And since you didn't say that fuse blew, we
assumed that your problem related to continuity within the fuse. These
things are so obvious to us that we didn't think to ask "have you
tried a new fuse in the fuseholder?" because we thought you would have
done this already.


You are dead right there.... so why didn't you do it?

All right, we NOW know that you weren't aware that this style of fuse
holder used a tubular fuse but we couldn't guess that could we. After
all tubular fuses have been around since about 1930 and panel mount
fuseholders have been around for at least 50 years and anybody who is
even vaguely familiar with electronic equipment will have come across
them. The fact is you knew the object was a fuse because it was there
in white letters. It is obvious you must have unscrewed the cap and
found nothing there so pray tell me why this didn't prompt you to ask
yourself "now how can this fuse thing work when I have this completely
disconnected screw cap in my hand and there is nothing at all in it?"
Bloody hell, if it wasn't immediately obvious there was a bit missing
then your logic is non existent.


Try to imagine that you are asking for help "by remote control". We
can't see what you have in front of you so you have to describe it in
detail. Heck, if I hadn't dug up that pic of the power supply by
Googling nobody would have had much of an idea of what you were
talking about.


You seemed a candidate for a disclaimer because when it became obvious
you had never come across a panel mount fuseholder in your life. Then
it seemed possible you didn't have any electronics knowledge and you
might put yourself in danger by following suggestions. Anybody who has
dabbled in electronics in the last 50 years or more will have come
across this common type of fuseholder so it would have been highly
improbable that you hadn't seen one before.

What is a "flex metal" type fuse? I've never heard of it. What type of
"consumer electronics" are you talking about? Are you talking
whitegoods such as microwave ovens, washing machines etc? If so, you
are right, they don't have panel mount fuseholders. They don't want
ignorant people replacing the fuses when they don't know what they are
doing.

When whitegoods have a fuse it will usually be concealed inside but in
most cases that I have come across they are still tubular fuses either
ceramic or glass and generally size 3AG and mounted in an open style
fuse clip with a plastic insulating cover of some sort. A microwave
oven is a good example.


If you had given all the info to start with, and done some research,
you would have received the correct advice. Given the paucity of info
then you can't blame people for getting up your arse. The "hostility",
as you put it, came about because of frustration due to you not
providing all the info you had, or should have had, before posting.

I can only add to all that Ross has said. Most of us who take the trouble to
try to help posters on here, are professional engineers in one field of
electronics, or another, and it would be grossly irresponsible of us to help
an inexperienced poster to his death, by recommending that he start work on
something that he did not understand. That is why you have suffered the type
of replies that you have from some respondents.

For what it's worth, I think that I probably understood where you were
coming from on this, in your earlier posts, but unfortunately, some of the
observations that you then went on to make, didn't help your case one little
bit, and the " abuse ( ?? ) " started. All I can ask is that you don't get
too offended by this, and stop coming to the group. Whilst the nature of the
posters has changed over the last five years, and probably the way that the
group is used now, there are still many good people on here, ready and
willing to help.

Please take Ross's good advice on board. It will help you in the future.
Also, please remember that Newsgroups are international, and whilst the
primary language in use is English, there are a number of different
variants - as in English English, American English, Australian English and
so on. What may seem like a clear statement to you, in whatever your variety
of English is, might appear to be utter nonsense to someone else who speaks
a different variety. Also, bear in mind that what might seem like an
offensive reply to you, might just be harmless banter from the respondents
point of view. I've seen many people get upset over this one.

Take a deep breath, calm down, and put your new fuse in. If it works, come
back and tell us. If it doesn't work, or blows, again, come back and tell
us, clearly, what does happen, and I'm sure we'll all just start again, and
offer you what help we can.

Arfa

 

[Ross Herbert]

I can only add to all that Ross has said. Most of us who take the trouble to
try to help posters on here, are professional engineers in one field of
electronics, or another, and it would be grossly irresponsible of us to help
an inexperienced poster to his death, by recommending that he start work on
something that he did not understand. That is why you have suffered the type
of replies that you have from some respondents.

For what it's worth, I think that I probably understood where you were
coming from on this, in your earlier posts, but unfortunately, some of the
observations that you then went on to make, didn't help your case one little
bit, and the " abuse ( ?? ) " started. All I can ask is that you don't get
too offended by this, and stop coming to the group. Whilst the nature of the
posters has changed over the last five years, and probably the way that the
group is used now, there are still many good people on here, ready and
willing to help.

Please take Ross's good advice on board. It will help you in the future.
Also, please remember that Newsgroups are international, and whilst the
primary language in use is English, there are a number of different
variants - as in English English, American English, Australian English and
so on. What may seem like a clear statement to you, in whatever your variety
of English is, might appear to be utter nonsense to someone else who speaks
a different variety. Also, bear in mind that what might seem like an
offensive reply to you, might just be harmless banter from the respondents
point of view. I've seen many people get upset over this one.

Take a deep breath, calm down, and put your new fuse in. If it works, come
back and tell us. If it doesn't work, or blows, again, come back and tell
us, clearly, what does happen, and I'm sure we'll all just start again, and
offer you what help we can.

Arfa

Nicely encapsulated Arfa

Yes Ryan, we will sincerely try to help once you have established some
facts as to what is happening. Without concise info we are just making
wild guesses.

 

[[email protected]]

I don't want to interrupt your outburst (heck we all have to let it out
at times), but let me point out several things:

1) Another poster posted a picture of a similar supply, which I
confirmed had the same type of fuse, and which I assumed everyone had
access to refer to. It was pointed out to me that not everyone has a
news reader configured to display inline images.

2) Why on earth would I have mistaken the holder for the fuse if there
were a fuse in it to begin with?

3) I can't buy the correct fuse locally. I either waste several
dollars on shipping for a single order, or I wait until I have a batch
of parts for several projects that I need to order.

4) I have "dabbled" in electronics for at least the past 15 years and
have never run across this type of fuse holder, ergo, at least one
statement regarding my lack of intelligence is false. "Electronics" is
a big and diverse field.

5) Apologies for the image link, but this is the fuse holder I am
talking about that I do in fact see in almost everything I have
repaired. I would be extremely surprised if you have not:
http://www.epn-online.com/images/editorial/33/11/P-11035.JPG

 

[[email protected]]

I'm not offended. It takes a lot to offend me. And I'm certainly not
going to be offended by someone who spends their free time helping
others for something they could charge money for. All I'm saying is
taking an unclear post, and from there jumping to conclusions about the
intelligence of the poster - instead of simply stating that the post
was unclear - is nothing more than noise. Posting nothing at all is
better than posting noise.

I guess I'm not going to get any more replies since I'm in everyone's
kill file by now. But I really didn't feel like the ad hominem attacks
were on target with respect to reaching a conclusion. Not that they
have to be - it's not my time they are wasting - but if the intent is
to convince me that I'm incompetent, I'm not interested, since I can
gauge my own level of competence and act (or not act) accordingly.

 

[Arfa Daily]

I'm not offended. It takes a lot to offend me. And I'm certainly not
going to be offended by someone who spends their free time helping
others for something they could charge money for. All I'm saying is
taking an unclear post, and from there jumping to conclusions about the
intelligence of the poster - instead of simply stating that the post
was unclear - is nothing more than noise. Posting nothing at all is
better than posting noise.

I guess I'm not going to get any more replies since I'm in everyone's
kill file by now. But I really didn't feel like the ad hominem attacks
were on target with respect to reaching a conclusion. Not that they
have to be - it's not my time they are wasting - but if the intent is
to convince me that I'm incompetent, I'm not interested, since I can
gauge my own level of competence and act (or not act) accordingly.

I would doubt that you are in everyone's killfile - yet. But may I
respectfully ask that we just leave it as it is now. I'm sure we all
understand where you're coming from, and none of us wants to question your
intelligence. For the most part, from what I see in the many posts, it was
your expertise and competence to work on line powered equipment with a
degree of personal safety, that was being questioned, and I certainly don't
have a problem with that. I have no desire to help lead you to death or
injury. The reason that posters questioned your ability, was because you
were unable to recognise a type of fuseholder that has been used for many
years on all manner of equipment types - not just test equipment, but if
you've never had cause to work on such equipment, then fine, we will accept
that you were misled by a component that you didn't recognise, and not
question your competence, further.

Now, as I said before, calm down, forget about all the comments that you
considered to be at least unkind to you, if not offensive, put a new fuse
in, and tell us what happens. If it doesn't work, tell us, and we'll do our
best to help you.

Arfa

 

[Sam Goldwasser]

I'm not offended. It takes a lot to offend me. And I'm certainly not
going to be offended by someone who spends their free time helping
others for something they could charge money for. All I'm saying is
taking an unclear post, and from there jumping to conclusions about the
intelligence of the poster - instead of simply stating that the post
was unclear - is nothing more than noise. Posting nothing at all is
better than posting noise.

I guess I'm not going to get any more replies since I'm in everyone's
kill file by now. But I really didn't feel like the ad hominem attacks
were on target with respect to reaching a conclusion. Not that they
have to be - it's not my time they are wasting - but if the intent is
to convince me that I'm incompetent, I'm not interested, since I can
gauge my own level of competence and act (or not act) accordingly.

My only comment is that for someone to never have seen a fuse holder
like that means you have nver had the joy of working on older equipment
or industrial equipment. Those are the style fuse holder found in nearly
every non-consumer electronic equipment. If all you've dealt with are
computers, then perhaps not. But just do any kind of search on eBay,
for example, of "electronic equipment" and that's what you'll find.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

 

[Smitty Two]

I don't want to interrupt your outburst (heck we all have to let it out
at times), but let me point out several things:

1) Another poster posted a picture of a similar supply, which I
confirmed had the same type of fuse, and which I assumed everyone had
access to refer to. It was pointed out to me that not everyone has a
news reader configured to display inline images.

2) Why on earth would I have mistaken the holder for the fuse if there
were a fuse in it to begin with?

3) I can't buy the correct fuse locally. I either waste several
dollars on shipping for a single order, or I wait until I have a batch
of parts for several projects that I need to order.

4) I have "dabbled" in electronics for at least the past 15 years and
have never run across this type of fuse holder, ergo, at least one
statement regarding my lack of intelligence is false. "Electronics" is
a big and diverse field.

5) Apologies for the image link, but this is the fuse holder I am
talking about that I do in fact see in almost everything I have
repaired. I would be extremely surprised if you have not:
http://www.epn-online.com/images/editorial/33/11/P-11035.JPG

Intelligence comes in many forms. If you know what a fuse does, that is,
connect two parts of a circuit, then you *should* have been able to tell
that the fuseholder wasn't doing that all by itself. That is a
particular form of intelligence called logic.

Also, if you know what a fuse does, and use logical, rational, problem
solving type of thinking, then you wouldn't jump to the conclusion that
a missing fuse equals a defective piece of equipment, particularly when
we're talking about a device that provides power to other things. It's
equally likely, if not more so, that whatever was last plugged into the
thing blew the fuse. Again, a failure of logic.

It's also possible that the last owner of the thing, uh, borrowed the
fuse for something that he needed more urgently.

I'm going to make you an offer. Delete the first h in my name, and send
me an email with your mailing address, and I'll send you a couple of
fuses at my expense. Then, perhaps, you can get to work doing whatever
you wanted to do with the thing in the first place.

 

[Ross Herbert]

Intelligence comes in many forms. If you know what a fuse does, that is,
connect two parts of a circuit, then you *should* have been able to tell
that the fuseholder wasn't doing that all by itself. That is a
particular form of intelligence called logic.

Also, if you know what a fuse does, and use logical, rational, problem
solving type of thinking, then you wouldn't jump to the conclusion that
a missing fuse equals a defective piece of equipment, particularly when
we're talking about a device that provides power to other things. It's
equally likely, if not more so, that whatever was last plugged into the
thing blew the fuse. Again, a failure of logic.

It's also possible that the last owner of the thing, uh, borrowed the
fuse for something that he needed more urgently.

I'm going to make you an offer. Delete the first h in my name, and send
me an email with your mailing address, and I'll send you a couple of
fuses at my expense. Then, perhaps, you can get to work doing whatever
you wanted to do with the thing in the first place.

Smitty, that's a great offer of help. I would have done the same
except sending fuses from Australia by airmail is many times the cost
of the fuses themselves.

And to Ryan, I very much doubt that anyone has you on their killfile
list. I certainly don't, and anyway, there are a whole heap of very
obnoxious posters well ahead of you for this treatment

Just take the advice of Arfa and Smitty and carry out some more
testing and note what takes place then tell us here. I'm sure that we
will be able to steer you in the right direction. Any schematic
details you can work out by inspection would be handy, but here is
where knowledge of components is vital in order to describe what you
are talking about. Nevertheless, you can only try and see how it goes
from there.

 

[Sam Goldwasser]

Sam, save the flames for someone more deserving, please. I said that I
have never seen THIS TYPE of fuse before, because I mistook what is
apparently a broken fuse holder for the fuse itself. That is not
equivalent to asking "how do I test a fuse?". As for "questioning my
experience", go right ahead, I'm not going to get into a pissing match,
but it is usually less effort to simply answer the question as posed.

I openly admit that I rarely get to deal with nice test equipment. And
I don't see where that means that I should simply accept that it is
broken and not attempt to learn about it - just as I learned about
microwaves, televisions, monitors, amplifiers or any other piece of
electronics that could be dangerous if one does not employ common sense.

Have it your way. You have been doing a great job of pissing off some
of the most helpful people on this newsgroup.

Enough said.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.