Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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The real Andy
 
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Default Philips tv, not remembering last channel:no battery and no supercap.

"Jim Lazzaro" wrote in message
om...
If anyone could please advise me about what keeps the memory of the
last channel viewed before switch off.
TV is a Philips 14CN2001/75S, it doesn't have a remote.
I am unable to find any batteries or supercaps.
The problem is when switched on the TV starts on channel 0 (sound is
okai)regardless of what channel it was used on.
Unfortunayely I do not have schematics and also I don't see any eeprom
on PCB.


EEPROM is probably incorporated into the micro that controls the TV. IT
might pay you to track down the service manual from High Country,
hcsd.com.au I think.


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Rudolf Ladyzhenskii
 
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Default Philips tv, not remembering last channel:no battery and no supercap.

Do you switch it on at AC power or from stand by?

It should remember channel when you do from stand by, but it does not have
to when you do at mains.
If yoour PP (sound, brightness, etc...) stay same and channel tune is OK, I
would think memory backup is fine.

Rudolf

"Jim Lazzaro" wrote in message
om...
If anyone could please advise me about what keeps the memory of the
last channel viewed before switch off.
TV is a Philips 14CN2001/75S, it doesn't have a remote.
I am unable to find any batteries or supercaps.
The problem is when switched on the TV starts on channel 0 (sound is
okai)regardless of what channel it was used on.
Unfortunayely I do not have schematics and also I don't see any eeprom
on PCB.
Thanking you in advance.
Jim


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Jerry Greenberg
 
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Default Philips tv, not remembering last channel:no battery and no supercap.

I have not worked on this model, but can be general.

This can get fairly compex for the novice. If you want to fix this
yourself, you would have to invest in the service manual and see how
your particular model does the memory operation. You will have to
understand the schematics, have the proper tools, and follow procedure
to locate the fault.

The problem is most likely associated with the main uPC. There may be
a CMOS ram or an EEPROM involved. Depending on the design, this can
be an integral part of the uPC, or some other IC device. Some sets
also have a cap, or battery for this function. There are a number of
ways that the memory is retained.

I have also seen firmware problems in sets where the uPC, and or the
IC that does the memory control and function be replaced. If this is
the case, the associated IC's had to be replaced. I have also had some
support components for the controler area fail, thus causing memory
problems.

I would suggest you give the set to an authorsed Philips service rep
if you are not able to do this type of service. This is very
specialized work.



Jerry Greenberg

--




(Jim Lazzaro) wrote in message . com...
If anyone could please advise me about what keeps the memory of the
last channel viewed before switch off.
TV is a Philips 14CN2001/75S, it doesn't have a remote.
I am unable to find any batteries or supercaps.
The problem is when switched on the TV starts on channel 0 (sound is
okai)regardless of what channel it was used on.
Unfortunayely I do not have schematics and also I don't see any eeprom
on PCB.
Thanking you in advance.
Jim

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