I just wanted to pass on my experience with a Magnavox projection TV I
recently fixed. Now, I do want to stress that unless you have an
understanding of electronics and know how dangerous working around
high voltage is, then please don't try to repair a TV yourself. You
may cause more harm to the circuits, and possibly yourself.
My father-in-law had me look at this TV, it was his main set, about 10
years old. I'm not a TV repairman, but I do have a 2 year electronics
degree and I am employed in the semiconductor industry repairing
lithography equipment. So automatically I'm the one in the family that
gets called went the TV/radio/computer stops working.
I took a quick look at it, will not power on, was working fine the
night before. My father-in-law mentioned that the night before, a text
message came on the screen "BATTERY LOW". Wow, he thought, that is one
smart TV to know when the batteries in the remote are low! So I do the
normal checks, fuse was good, power to the outlet was good, no
thunderstorms to knock out the circuits.
He mentioned that he did call a repair service and they quoted $250
plus time to replace the main board, they didn't even look at it, just
a shotgun approach. I inquired about purchasing the board directly
from the manufacturer, $600, because they will not take the old board
back from individuals, only certified repair shops.

So when I started looking at power supplies, etc., that Battery Low
message kept me wondering. I did find a quarter sized watch battery
SOLDERED to the main board, UNDER metal shields, on BOTH sides of the
circiut board.

After carefully removing the shields to access the battery, I
unsoldered it and placed a 3V, AA battery pack from Radio Shack in its
place. Would you believe the TV powered on! This set would have been
thrown out for a $3 battery. Now this unit is over 10 years old, and I
am surprized that the battery lasted this long. And here is the
kicker, eventhough the battery was low and I removed it from the
circuit, it still retained the channel programming memory. Then what
the hell is it's purpose! I do have the full schematics from Magnavox
(Philips), it doesn't even go to the memory chip (EPROM), it does go
to a clock/ram chip.

So the moral of the story is, heed all messages the TV gives you. If
you have a TV that will not power on and the fuses are good, ask the
repairman about the battery on the board.

Does anyone else know of this 'problem' on other sets? I can't believe
that this would be designed into the circuit like this. A battery has
a known life, in use and a shelf life. This should have been
accessable and in a holder, not soldered. But I guess it's better
profits when a new set is purchased as compared to a new battery.

Regards..
Mike...

These are serviced by board replacement only. The manufacture will usually
take the old board back from the service rep for rebuilding, and reselling
with a basic warranty. The manufacture will not release schematics or sell
service parts to anyone outside. You are stuck to have it serviced by the
rep.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Mike" wrote in message
om...
I just wanted to pass on my experience with a Magnavox projection TV I
recently fixed. Now, I do want to stress that unless you have an
understanding of electronics and know how dangerous working around
high voltage is, then please don't try to repair a TV yourself. You
may cause more harm to the circuits, and possibly yourself.
My father-in-law had me look at this TV, it was his main set, about 10
years old. I'm not a TV repairman, but I do have a 2 year electronics
degree and I am employed in the semiconductor industry repairing
lithography equipment. So automatically I'm the one in the family that
gets called went the TV/radio/computer stops working.
I took a quick look at it, will not power on, was working fine the
night before. My father-in-law mentioned that the night before, a text
message came on the screen "BATTERY LOW". Wow, he thought, that is one
smart TV to know when the batteries in the remote are low! So I do the
normal checks, fuse was good, power to the outlet was good, no
thunderstorms to knock out the circuits.
He mentioned that he did call a repair service and they quoted $250
plus time to replace the main board, they didn't even look at it, just
a shotgun approach. I inquired about purchasing the board directly
from the manufacturer, $600, because they will not take the old board
back from individuals, only certified repair shops.

So when I started looking at power supplies, etc., that Battery Low
message kept me wondering. I did find a quarter sized watch battery
SOLDERED to the main board, UNDER metal shields, on BOTH sides of the
circiut board.

After carefully removing the shields to access the battery, I
unsoldered it and placed a 3V, AA battery pack from Radio Shack in its
place. Would you believe the TV powered on! This set would have been
thrown out for a $3 battery. Now this unit is over 10 years old, and I
am surprized that the battery lasted this long. And here is the
kicker, eventhough the battery was low and I removed it from the
circuit, it still retained the channel programming memory. Then what
the hell is it's purpose! I do have the full schematics from Magnavox
(Philips), it doesn't even go to the memory chip (EPROM), it does go
to a clock/ram chip.

So the moral of the story is, heed all messages the TV gives you. If
you have a TV that will not power on and the fuses are good, ask the
repairman about the battery on the board.

Does anyone else know of this 'problem' on other sets? I can't believe
that this would be designed into the circuit like this. A battery has
a known life, in use and a shelf life. This should have been
accessable and in a holder, not soldered. But I guess it's better
profits when a new set is purchased as compared to a new battery.

Regards..
Mike...

(Mike) wrote in message . com...
I just wanted to pass on my experience with a Magnavox projection TV I
recently fixed. Now, I do want to stress that unless you have an
understanding of electronics and know how dangerous working around
high voltage is, then please don't try to repair a TV yourself. You
may cause more harm to the circuits, and possibly yourself.
My father-in-law had me look at this TV, it was his main set, about 10
years old. I'm not a TV repairman, but I do have a 2 year electronics
degree and I am employed in the semiconductor industry repairing
lithography equipment. So automatically I'm the one in the family that
gets called went the TV/radio/computer stops working.
I took a quick look at it, will not power on, was working fine the
night before. My father-in-law mentioned that the night before, a text
message came on the screen "BATTERY LOW". Wow, he thought, that is one
smart TV to know when the batteries in the remote are low! So I do the
normal checks, fuse was good, power to the outlet was good, no
thunderstorms to knock out the circuits.
He mentioned that he did call a repair service and they quoted $250
plus time to replace the main board, they didn't even look at it, just
a shotgun approach. I inquired about purchasing the board directly
from the manufacturer, $600, because they will not take the old board
back from individuals, only certified repair shops.

So when I started looking at power supplies, etc., that Battery Low
message kept me wondering. I did find a quarter sized watch battery
SOLDERED to the main board, UNDER metal shields, on BOTH sides of the
circiut board.

After carefully removing the shields to access the battery, I
unsoldered it and placed a 3V, AA battery pack from Radio Shack in its
place. Would you believe the TV powered on! This set would have been
thrown out for a $3 battery. Now this unit is over 10 years old, and I
am surprized that the battery lasted this long. And here is the
kicker, eventhough the battery was low and I removed it from the
circuit, it still retained the channel programming memory. Then what
the hell is it's purpose! I do have the full schematics from Magnavox
(Philips), it doesn't even go to the memory chip (EPROM), it does go
to a clock/ram chip.

So the moral of the story is, heed all messages the TV gives you. If
you have a TV that will not power on and the fuses are good, ask the
repairman about the battery on the board.

Does anyone else know of this 'problem' on other sets? I can't believe
that this would be designed into the circuit like this. A battery has
a known life, in use and a shelf life. This should have been
accessable and in a holder, not soldered. But I guess it's better
profits when a new set is purchased as compared to a new battery.

Regards..
Mike...


Awesome. I'll have to remember that one. I never pass a dead TV on
the side of the road ;-) Sometimes you get lucky...

Why a dead battery powering a RAM chip would cause a television to
fail powerup is beyond me... bizarre indeed. Sure it wasn't a bad
solder or connection somewhere that you jostled working on it? That,
I have seen many upon many times.

Jerry, did you even read half of what he wrote.

1. He fixed the bloody thing with a $2 battery. No matter what your
party line view is, there has to be something in you that's saying
"well maybe the customer does get ripped off sometimes with board
replacement service policies."

2. He has the complete schematics.

Cheers!

--- sam | Sci.Electronics.Repair FAQ Home Page: 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 Site Info: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: The email address in this message header may no longer work. To
contact me, please use the feedback form on the S.E.R FAQ Web sites.




"Jerry G." writes:

These are serviced by board replacement only. The manufacture will usually
take the old board back from the service rep for rebuilding, and reselling
with a basic warranty. The manufacture will not release schematics or sell
service parts to anyone outside. You are stuck to have it serviced by the
rep.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Mike" wrote in message
om...
I just wanted to pass on my experience with a Magnavox projection TV I
recently fixed. Now, I do want to stress that unless you have an
understanding of electronics and know how dangerous working around
high voltage is, then please don't try to repair a TV yourself. You
may cause more harm to the circuits, and possibly yourself.
My father-in-law had me look at this TV, it was his main set, about 10
years old. I'm not a TV repairman, but I do have a 2 year electronics
degree and I am employed in the semiconductor industry repairing
lithography equipment. So automatically I'm the one in the family that
gets called went the TV/radio/computer stops working.
I took a quick look at it, will not power on, was working fine the
night before. My father-in-law mentioned that the night before, a text
message came on the screen "BATTERY LOW". Wow, he thought, that is one
smart TV to know when the batteries in the remote are low! So I do the
normal checks, fuse was good, power to the outlet was good, no
thunderstorms to knock out the circuits.
He mentioned that he did call a repair service and they quoted $250
plus time to replace the main board, they didn't even look at it, just
a shotgun approach. I inquired about purchasing the board directly
from the manufacturer, $600, because they will not take the old board
back from individuals, only certified repair shops.

So when I started looking at power supplies, etc., that Battery Low
message kept me wondering. I did find a quarter sized watch battery
SOLDERED to the main board, UNDER metal shields, on BOTH sides of the
circiut board.

After carefully removing the shields to access the battery, I
unsoldered it and placed a 3V, AA battery pack from Radio Shack in its
place. Would you believe the TV powered on! This set would have been
thrown out for a $3 battery. Now this unit is over 10 years old, and I
am surprized that the battery lasted this long. And here is the
kicker, eventhough the battery was low and I removed it from the
circuit, it still retained the channel programming memory. Then what
the hell is it's purpose! I do have the full schematics from Magnavox
(Philips), it doesn't even go to the memory chip (EPROM), it does go
to a clock/ram chip.

So the moral of the story is, heed all messages the TV gives you. If
you have a TV that will not power on and the fuses are good, ask the
repairman about the battery on the board.

Does anyone else know of this 'problem' on other sets? I can't believe
that this would be designed into the circuit like this. A battery has
a known life, in use and a shelf life. This should have been
accessable and in a holder, not soldered. But I guess it's better
profits when a new set is purchased as compared to a new battery.

Regards..
Mike...

(Kevin) wrote in message . com...
(Mike) wrote in message . com...
I just wanted to pass on my experience with a Magnavox projection TV I
recently fixed. Now, I do want to stress that unless you have an
SNIP......................

Does anyone else know of this 'problem' on other sets? I can't believe
that this would be designed into the circuit like this. A battery has
a known life, in use and a shelf life. This should have been
accessable and in a holder, not soldered. But I guess it's better
profits when a new set is purchased as compared to a new battery.

Regards..
Mike...


Awesome. I'll have to remember that one. I never pass a dead TV on
the side of the road ;-) Sometimes you get lucky...

Why a dead battery powering a RAM chip would cause a television to
fail powerup is beyond me... bizarre indeed. Sure it wasn't a bad
solder or connection somewhere that you jostled working on it? That,
I have seen many upon many times.


This is acutally the second time this occured to me with this TV set.
I even posted some questions a few years ago in the alt.home.repair
group. That time I actually soldered leads to a 3V lithium and
soldered it to the board. I guess this didn't last as long because I
heated the battery. This time I just used the battery pack. One of the
things I do is look for cold solder joints, although I do error from
time to time, I didn't see any before. Since the same thing happened
again, and when I put the battery pack in it worked, I'm not leaning
to a cold joint.
One of the hints I was told last time was to remove the battery from
the board and it should power on, possibly with out the channel setup.
This did not work at all, my set needs the battery to allow it to
power on... The description on the schematic is Clock/Ram. I haven't
tried to look it up in a reference book.

Thanks for the response..
Mike...........

I've repaired several of these with the low battery warning, and I've never
seen this prevent startup; more likely there are some marginal caps in the
standby power circuit, or a marginal zener in the standby regulator circuit;
these will cause highly intermittant operation, including long periods of
normal operation; sometimes simply unplugging and replugging the power cord
will recharge the circuit enough to get it going. Eventually the standby
circuit will need servicing, if you can find a tech willing to work on it.

"BWL" wrote in message
...
I've repaired several of these with the low battery warning, and I've
never
seen this prevent startup; more likely there are some marginal caps in the
standby power circuit, or a marginal zener in the standby regulator
circuit;
these will cause highly intermittant operation, including long periods of
normal operation; sometimes simply unplugging and replugging the power
cord
will recharge the circuit enough to get it going. Eventually the standby
circuit will need servicing, if you can find a tech willing to work on it.


Sounds like he's capable of working on it so if it acts up again he'll
probably wanna have a look.