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On Mon, 06 Mar 2006 13:12:54 -0500, trousky1@videotron.ca wrote:
Thanks Charles,
I checked the voltages(DC) on all pins on both hybrid power amps and
they are the same. I swapped the input to the hybrid power amps (left
and right channels) and I still have the same power amp getting very
hot. Not sure what to check next.
Without speakers connected,of course?
Yeah, that's the same style of fuse. I just don't know how to testIf it is similar to this model it shouldn't be too difficult to find
out what is wrong with it. Looks pretty basic but I haven't actually
seen one. BTW, if you can't determine whether a fuse is blown or not
then you shouldn't be playing around inside it.
http://it.stlawu.edu/~physics/labs/common/img/labvolt.jpg
I have it. But before I send it to you let me know whats wrong with
this unit and what you have checked on it already. I don`t like to
give schematics out to people that don`t know how to use them. So the
more you tell me that you know then the better it is for you.
Bothindago <elindago@earthlink.net> wrote:
060307 0343 - Luddite posted:
indago <elindago@earthlink.net> wrote:
I have an Amphenol Millivolt Commander Model 870, about 30 years old. It
is
a sensitive, FET unit that uses batteries. Most of the batteries are
general AA 1.5 volt batteries (8), but 2 of the batteries are Duracell
Mercury 1.4 volt batteries (Duracell ZM9). I suppose that these batteries
are a reference voltage. Mercury batteries are no longer in use, so I used
two 1.5 volt batteries in their place.
When I turn the on and select battery test, the meter does not move. It is
supposed to move to above the Battery OK mark. Also, when I select the
positive DC, the meter pegs negative, and when I select the negative DC,
the
meter pegs positive. The batteries are all new batteries, so there is not
a
problem with dead batteries.
Anyone ever worked with one of these meters and can give me some insight
into the problem with it?
Polarity of mercury cells is reversed as I recall,turn the one pair
around if the holder will accept it.
All of the batteries are in their holders in the proper polarity, as shown
on the chart. I did change the two batteries as you had suggested, and
nothing changed with the operation of the meter.
Does the chart show +/- or an outline drawing of the cells?
060307 0343 - Luddite posted:
indago <elindago@earthlink.net> wrote:
I have an Amphenol Millivolt Commander Model 870, about 30 years old. It is
a sensitive, FET unit that uses batteries. Most of the batteries are
general AA 1.5 volt batteries (8), but 2 of the batteries are Duracell
Mercury 1.4 volt batteries (Duracell ZM9). I suppose that these batteries
are a reference voltage. Mercury batteries are no longer in use, so I used
two 1.5 volt batteries in their place.
When I turn the on and select battery test, the meter does not move. It is
supposed to move to above the Battery OK mark. Also, when I select the
positive DC, the meter pegs negative, and when I select the negative DC, the
meter pegs positive. The batteries are all new batteries, so there is not a
problem with dead batteries.
Anyone ever worked with one of these meters and can give me some insight
into the problem with it?
Polarity of mercury cells is reversed as I recall,turn the one pair
around if the holder will accept it.
All of the batteries are in their holders in the proper polarity, as shown
on the chart. I did change the two batteries as you had suggested, and
nothing changed with the operation of the meter.
What do you mean by "that type of fuse". What type is it?Ross Herbert wrote:
If it is similar to this model it shouldn't be too difficult to find
out what is wrong with it. Looks pretty basic but I haven't actually
seen one. BTW, if you can't determine whether a fuse is blown or not
then you shouldn't be playing around inside it.
http://it.stlawu.edu/~physics/labs/common/img/labvolt.jpg
Yeah, that's the same style of fuse. I just don't know how to test
that type of fuse. I am only familiar with repairing PC power supplies
and the glass/filament type fuses that they use.
Speaker connected (switch on or off for them), right channel power amp
still very hot. The sound is good on both speakers but I cant leave it
on for long, I am afraid to fry the power amp ($20.00)
On Mon, 06 Mar 2006 19:37:03 +0100, Damir <nop@nop.hr> wrote:
On Mon, 06 Mar 2006 13:12:54 -0500, trousky1@videotron.ca wrote:
Thanks Charles,
I checked the voltages(DC) on all pins on both hybrid power amps and
they are the same. I swapped the input to the hybrid power amps (left
and right channels) and I still have the same power amp getting very
hot. Not sure what to check next.
If there's one component most influenced by temperature changes it's aThe issues were that the C2 caps Damir suggested appeared to be shorted
- at least to the extent that my meter can test. I replaced that cap
on each of the 4 boards and all were immediately brought back to life.
Going back to my OP, I still don't know why the chip would work when I
warmed it up and fail at room temp when the board had the bad cap.
Maybe a warm chip was slightly less sensitive to input voltage
fluctuation with the bad cap?
Corey
It sounds to me like the fuse is missing.I am fully aware of how to test a fuse, given that I can find the
terminals of the fuse, which is not usually an unreasonable assumption.
If you look at the picture, it is a type of fuse that screws in. It
is not like the "edison" type screw-in fuses. There is kind of a
"rivet" in the end of it that, when removed, retains a metal cylinder
that hangs loosely over the rivet. I can't figure out how the fuse is
supposed to work, because when I've removed it, it physically becomes
one big short because of the loose cylindrical part.
When someone asks how to test a fuse, it is no wonder that people areI am fully aware of the hazards, but from the replies, you'd think I
was prodding around in it with a kitchen knife while plugged in. All I
am trying to do is test this fuse, and if disassembly is required, I
have no plans to do that with it plugged into the wall or with an
energized filter cap.
060307 1444 - Luddite posted:
indago <elindago@earthlink.net> wrote:
060307 0343 - Luddite posted:
indago <elindago@earthlink.net> wrote:
I have an Amphenol Millivolt Commander Model 870, about 30 years old. It
is
a sensitive, FET unit that uses batteries. Most of the batteries are
general AA 1.5 volt batteries (8), but 2 of the batteries are Duracell
Mercury 1.4 volt batteries (Duracell ZM9). I suppose that these batteries
are a reference voltage. Mercury batteries are no longer in use, so I used
two 1.5 volt batteries in their place.
When I turn the on and select battery test, the meter does not move. It is
supposed to move to above the Battery OK mark. Also, when I select the
positive DC, the meter pegs negative, and when I select the negative DC,
the
meter pegs positive. The batteries are all new batteries, so there is not
a
problem with dead batteries.
Anyone ever worked with one of these meters and can give me some insight
into the problem with it?
Polarity of mercury cells is reversed as I recall,turn the one pair
around if the holder will accept it.
All of the batteries are in their holders in the proper polarity, as shown
on the chart. I did change the two batteries as you had suggested, and
nothing changed with the operation of the meter.
Does the chart show +/- or an outline drawing of the cells?
Both
solution--you refer to high-frequency oscillation.trousky1@videotron.ca> wrote in message
news:u84p02553f8n84bsgfl8rfle6f5s7j26rf@4ax.com...
Speaker connected (switch on or off for them), right channel power amp
still very hot. The sound is good on both speakers but I cant leave it
on for long, I am afraid to fry the power amp ($20.00)
On Mon, 06 Mar 2006 19:37:03 +0100, Damir <nop@nop.hr> wrote:
On Mon, 06 Mar 2006 13:12:54 -0500, trousky1@videotron.ca wrote:
Thanks Charles,
I checked the voltages(DC) on all pins on both hybrid power amps and
they are the same. I swapped the input to the hybrid power amps (left
and right channels) and I still have the same power amp getting very
hot. Not sure what to check next.
If the sound is good, but the hybrid is frying, then I would suggest that it
is hooting, maybe as high as RF. You need to get a 'scope on the output to
check for this. There may be a Zobel network ( R & C in series ) on the
output that was damaged by the previously faulty hybrid. Alternatively,
there may be a defective decoupling cap on one of the bypass pins of the
hybrid, or an open or high ESR supply decoupling cap, and this is allowing
it to hoot, which may be what caused the demise of the original hybrid, and
would ultimately do the same to the replacement, if left.
Arfa
'Hooting', you say. I suppose by that--and your description of the
"Bill Simpson" <plusnetfiles@comcast.net.com> wrote in message
news:aj9o02dm6d2n47hu4qlusena3qnlvf3o1d@4ax.com...
On Mon, 06 Mar 2006 09:03:42 GMT, "Arfa Daily"
arfa.daily@ntlworld.com> wrote:
I see that my reply did get double posted. Thanks for the very
precise information. With my rather low level of technical knowledge,
do you think it more advisable that I just replace the power supply?
The power supply that I currently have is
Sunny
Input :100-240 - 1.6A Max, 50-60Hz, 70-80VA
Output: +12V - 4.0A
I contacted the manufacturer of the monitor and they want $75 for a
replacement power supply (More on that later). I've found some others,
more reasonably priced online. One is a 12V 5A (60W) and the other is
a 12V 4.16A (50W). Am I correct in assuming that both should work?
If the connector is different in these power supplies, would cutting
and soldering the original connector to the new power supply be
acceptable rather than the more complicated and dangerous course that
professionals with your expertise would take? I know it's a crude
solution, but it's something I would feel comfortable with.
The rest if off topic, but if you have some time, I would like your
opinion. I had mentioned earlier that I contacted the manufacturer
about a new power supply. I went to their home page and read the FAQ
ahead of time. I found this in the FAQ:
"My screen comes on for a second and then goes black. How do I resolve
this issue?
1. Please contact Customer Service for further assistance at
323-346-0888. There is a possible short in the ac adapter. "
It seems that the manufacturer knew about this problem for some time.
I had registered my monitor and asked the representative when I called
why they hadn't notified me of the problem (As the warranty on the
montitor had just run out). I also asked if this wasn't a potential
fire hazard. I got a typical rebuff. My question is: Could a short
in the power supply cause a fire? I this a dangerous situation or
would normal internal safeguards kept anything hazardous from
happening?
Thanks again for all of the expert help. You all went above and
beyond what I expected.
Bill
If you don't feel qualified to go inside the supply, then I would not be
comfortable advising you to do so. The fault almost certainly will be one of
the things I suggested, but it's not worth risking injury to try to repair
it, if you're not absolutely confident of what you're doing.
Either of the two power supplies should be ok rating-wise. Any power supply
with a rating of 4 amps, will be a switch mode type, so by very nature will
be regulated to its declared 12v output.
Cutting and joining on the output lead is fine, BUT make absolutely sure
that you get the polarity the same as original. The monitor will not like
having reverse polarity DC shoved up it ...
If ever I join wires in this way, I always use heatshrink sleeving, which
you could probably get from your local Radio Shack. It shrinks easily with a
small paint stripper gun on 'low', and does a nice neat job of re-insulating
the cable, and reinforcing the join.
As far as the manufacturer's statement about a " short in the power supply "
goes, it's probably a bit of generic techno-babble that means nothing more
than ' a faulty power supply '. Joe public can equate with a " short ". It
sounds just technical enough to be describing something real, but is
basically meaningless in this context. It is unlikely that any fire would
ensue from any of the typical ( and much more likely ) faults that the power
supply would really be suffering from. It's probably just a typical switch
mode power supply design issue, where whover laid out the board, decided, as
they always seem to, to place an important cap right next to a resistor that
gets hot. It probably just happens that the fallout from this has been
particularly bad for this manufacturer, using this ( almost certainly
bought-in ) power supply on his particular product.
Arfa
FUCK TUBE TVS GET A SONY LCD HDTV.I see from ads online that I could get a brand new tube TV for under
$200, so I guess it would have to be REALLY inexpensive to warrant
repair.
GODDAMN I LOVE FOOTBALLHi. The tape cassete will not move onto the reels. I've checked the belts,
gears but no visible damage. If I move the gearing by hand, it works , could
it be electronic? Any help would be appreciated. Mark.
Arfa Daily wrote:
trousky1@videotron.ca> wrote in message
news:u84p02553f8n84bsgfl8rfle6f5s7j26rf@4ax.com...
Speaker connected (switch on or off for them), right channel power amp
still very hot. The sound is good on both speakers but I cant leave it
on for long, I am afraid to fry the power amp ($20.00)
On Mon, 06 Mar 2006 19:37:03 +0100, Damir <nop@nop.hr> wrote:
On Mon, 06 Mar 2006 13:12:54 -0500, trousky1@videotron.ca wrote:
Thanks Charles,
I checked the voltages(DC) on all pins on both hybrid power amps and
they are the same. I swapped the input to the hybrid power amps (left
and right channels) and I still have the same power amp getting very
hot. Not sure what to check next.
If the sound is good, but the hybrid is frying, then I would suggest that it
is hooting, maybe as high as RF. You need to get a 'scope on the output to
check for this. There may be a Zobel network ( R & C in series ) on the
output that was damaged by the previously faulty hybrid. Alternatively,
there may be a defective decoupling cap on one of the bypass pins of the
hybrid, or an open or high ESR supply decoupling cap, and this is allowing
it to hoot, which may be what caused the demise of the original hybrid, and
would ultimately do the same to the replacement, if left.
Arfa
'Hooting', you say. I suppose by that--and your description of the
solution--you refer to high-frequency oscillation.
Hooting...that's a new one on me; but I like it.
jak