Fuse Blown After Transporting CRT Monitor

I have a Miro C2085 20" CRT monitor that was working until I gave it to
my brother and he took it away. Now the fuse is blown within the power
supply. When I replaced the fuse and turned on the monitor, the new
fuse lit up instantly like a flash bulb as it also blew.

There is definitely a short-circuit somewhere. The only way I can
imagine that it came about was that monitor may have taken a hard
bounce when my brother transported it in the back of his minivan. Yet I
see no obvious damage to the surrounding external casing. Other than
this, I have no explanation for why the monitor was once working but is
no longer doing so.

I don't remember what kind of CRT this was but the power supply board
is a Sony part.

Any and all advice will be welcomed.

Thanks in advance.

On 31 Jan 2006 21:56:29 -0800, (E-Mail Removed) wrote:

>I have a Miro C2085 20" CRT monitor that was working until I gave it to
>my brother and he took it away. Now the fuse is blown within the power
>supply. When I replaced the fuse and turned on the monitor, the new
>fuse lit up instantly like a flash bulb as it also blew.
>
>There is definitely a short-circuit somewhere. The only way I can
>imagine that it came about was that monitor may have taken a hard
>bounce when my brother transported it in the back of his minivan. Yet I
>see no obvious damage to the surrounding external casing. Other than
>this, I have no explanation for why the monitor was once working but is
>no longer doing so.

Where does your brother keep his coins ?
Any chance that your brother's premises are wired to a different
voltage ?

--
Kind regards,
Gerard Bok

My brother's house uses the same voltage as mine 120v. I'm in NewYork
while he's in New Jersey but both are in the U.S. with the same line
voltage.

Anyway, he returned the monitor to me where I replaced the fuse only to
see it blow again, so that's not at issue here.

I did find a loose screw inside that I did remove. There was one
missing for mounting the metal shielding just inside the plastic shell
so that accounts for this. I had hoped that this would explain the
short-circuit but I ended up blowing yet another fuse anyway.

This monitor is much too large to be able to be shaken with ease so as
to listen for any loose items rattling. I DID stand it up on different
ends to see if this MIGHT happen but no. This thing is built pretty
solid.

BTW, the monitor uses a Sony Trinitron tube

Gerard Bok wrote:
> On 31 Jan 2006 21:56:29 -0800, (E-Mail Removed) wrote:
>
> >I have a Miro C2085 20" CRT monitor that was working until I gave it to
> >my brother and he took it away. Now the fuse is blown within the power
> >supply. When I replaced the fuse and turned on the monitor, the new
> >fuse lit up instantly like a flash bulb as it also blew.
> >
> >There is definitely a short-circuit somewhere. The only way I can
> >imagine that it came about was that monitor may have taken a hard
> >bounce when my brother transported it in the back of his minivan. Yet I
> >see no obvious damage to the surrounding external casing. Other than
> >this, I have no explanation for why the monitor was once working but is
> >no longer doing so.
>
> Where does your brother keep his coins ?
> Any chance that your brother's premises are wired to a different
> voltage ?
>
> --
> Kind regards,
> Gerard Bok

(E-Mail Removed) wrote:
> I have a Miro C2085 20" CRT monitor that was working until I gave it to
> my brother and he took it away. Now the fuse is blown within the power
> supply. When I replaced the fuse and turned on the monitor, the new
> fuse lit up instantly like a flash bulb as it also blew.
>
> There is definitely a short-circuit somewhere. The only way I can
> imagine that it came about was that monitor may have taken a hard
> bounce when my brother transported it in the back of his minivan. Yet I
> see no obvious damage to the surrounding external casing. Other than
> this, I have no explanation for why the monitor was once working but is
> no longer doing so.
>
> I don't remember what kind of CRT this was but the power supply board
> is a Sony part.
>
> Any and all advice will be welcomed.
>
> Thanks in advance.

if the unit was taken from a cold van into room temperature and
switched on, condensation may have formed and shorted the power supply
rectifier or HOT.
you'll need to see the repair faq for trouleshoting this one:

www.repairfaq.org.

READ and observe the vital safety info as there are lethal voltages in
these sets even after the plug has been pulled.
-B.

(E-Mail Removed) wrote:
> My brother's house uses the same voltage as mine 120v. I'm in NewYork
> while he's in New Jersey but both are in the U.S. with the same line
> voltage.
>
> Anyway, he returned the monitor to me where I replaced the fuse only to
> see it blow again, so that's not at issue here.
>
> I did find a loose screw inside that I did remove. There was one
> missing for mounting the metal shielding just inside the plastic shell
> so that accounts for this. I had hoped that this would explain the
> short-circuit but I ended up blowing yet another fuse anyway.
>
> This monitor is much too large to be able to be shaken with ease so as
> to listen for any loose items rattling. I DID stand it up on different
> ends to see if this MIGHT happen but no. This thing is built pretty
> solid.
>
> BTW, the monitor uses a Sony Trinitron tube
>
> Gerard Bok wrote:
>
>>On 31 Jan 2006 21:56:29 -0800, (E-Mail Removed) wrote:
>>
>>
>>>I have a Miro C2085 20" CRT monitor that was working until I gave it to
>>>my brother and he took it away. Now the fuse is blown within the power
>>>supply. When I replaced the fuse and turned on the monitor, the new
>>>fuse lit up instantly like a flash bulb as it also blew.
>>>
>>>There is definitely a short-circuit somewhere. The only way I can
>>>imagine that it came about was that monitor may have taken a hard
>>>bounce when my brother transported it in the back of his minivan. Yet I
>>>see no obvious damage to the surrounding external casing. Other than
>>>this, I have no explanation for why the monitor was once working but is
>>>no longer doing so.
>>


The screw probably shorted something and blew a part in the power
supply. If the fuse blows immediately I'd start by checking the rectifier.

It's quite possible this screw may have shorted something out within
the power supply but I think that it is unlikely. The power supply has
it's own metal cage and, when I disconnect all of the cables, can be
completely removed from the monitor. Also, its PC board is positioned
in a vertical orientation when mounted within the monitor while this is
normally standing. The screw wasn't likely touching inside there. The
scarier possibility is that it shorted out something near the flyback
transformer.

Now that I think about it, disconnecting the cables will isolate the
power supply from the rest of the monitor. This should allow me to see
if the power supply is still working properly by itself. Or at least
not blow another fuse.

What risk would I take for creating further damage to the monitor if I
were to play with this?

There are four connectors to the power supply. Five, if you include the
AC power cord. Two are for ribbon cables which are most likely for
low-voltage stuff such as logic chips. The other two are for heavier
guage wiring obviously for high-voltage stuff. Of these, one is a
two-pin connector while the other is a four-pin.

One of these have to be for the monitor on/off switch. Which of these
two? I'm not sure. My first guess would be the two-pin connector but
the on/off switch could be a double-pole switch used to completely
isolate the monitor electrically while turned off.

James Sweet wrote:
> (E-Mail Removed) wrote:
> > My brother's house uses the same voltage as mine 120v. I'm in NewYork
> > while he's in New Jersey but both are in the U.S. with the same line
> > voltage.
> >
> > Anyway, he returned the monitor to me where I replaced the fuse only to
> > see it blow again, so that's not at issue here.
> >
> > I did find a loose screw inside that I did remove. There was one
> > missing for mounting the metal shielding just inside the plastic shell
> > so that accounts for this. I had hoped that this would explain the
> > short-circuit but I ended up blowing yet another fuse anyway.
> >
> > This monitor is much too large to be able to be shaken with ease so as
> > to listen for any loose items rattling. I DID stand it up on different
> > ends to see if this MIGHT happen but no. This thing is built pretty
> > solid.
> >
> > BTW, the monitor uses a Sony Trinitron tube
> >
> > Gerard Bok wrote:
> >
> >>On 31 Jan 2006 21:56:29 -0800, (E-Mail Removed) wrote:
> >>
> >>
> >>>I have a Miro C2085 20" CRT monitor that was working until I gave it to
> >>>my brother and he took it away. Now the fuse is blown within the power
> >>>supply. When I replaced the fuse and turned on the monitor, the new
> >>>fuse lit up instantly like a flash bulb as it also blew.
> >>>
> >>>There is definitely a short-circuit somewhere. The only way I can
> >>>imagine that it came about was that monitor may have taken a hard
> >>>bounce when my brother transported it in the back of his minivan. Yet I
> >>>see no obvious damage to the surrounding external casing. Other than
> >>>this, I have no explanation for why the monitor was once working but is
> >>>no longer doing so.
> >>
>
>
> The screw probably shorted something and blew a part in the power
> supply. If the fuse blows immediately I'd start by checking the rectifier.

(E-Mail Removed) wrote:
> It's quite possible this screw may have shorted something out within
> the power supply but I think that it is unlikely. The power supply has
> it's own metal cage and, when I disconnect all of the cables, can be
> completely removed from the monitor. Also, its PC board is positioned
> in a vertical orientation when mounted within the monitor while this is
> normally standing. The screw wasn't likely touching inside there. The
> scarier possibility is that it shorted out something near the flyback
> transformer.
>
> Now that I think about it, disconnecting the cables will isolate the
> power supply from the rest of the monitor. This should allow me to see
> if the power supply is still working properly by itself. Or at least
> not blow another fuse.
>
> What risk would I take for creating further damage to the monitor if I
> were to play with this?
>
> There are four connectors to the power supply. Five, if you include the
> AC power cord. Two are for ribbon cables which are most likely for
> low-voltage stuff such as logic chips. The other two are for heavier
> guage wiring obviously for high-voltage stuff. Of these, one is a
> two-pin connector while the other is a four-pin.
>
> One of these have to be for the monitor on/off switch. Which of these
> two? I'm not sure. My first guess would be the two-pin connector but
> the on/off switch could be a double-pole switch used to completely
> isolate the monitor electrically while turned off.

you need a load on the power supply . don't try to connect it without
one or it'll probably die !
replace any obviously shorted components, put it back in the set and
power up with the 60w light bulb in place of the fuse as per the FAQ.
Beyond this there's little you can do if you aren't expèrienced in
this work. May be easier to get another monitor as there are planty of
cheap used CRTS around these days for peanuts.
-B