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Loewe TV won't switch on (keeps going back to standby)

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Adam Nielsen

Jan 1, 1970
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Hi all,

I've got a Loewe Planus 4672-Z (Q2400) that's been going fine for years,
but now over the last few months it's been progressively getting worse
when attempting to switch it on. I was hoping someone here may have
seen this problem before and might be able to give some pointers about
what to try next.

Sometimes switching on (via the remote) starts the TV, but then it
'gives up' and switches back to standby. The green LED on the front of
the TV will come on, but where the red LED usually goes off after a
second, both LEDs stay on for a few seconds longer than usual and then
the TV goes back to standby (the green LED goes out.)

When it starts exhibiting this behaviour lifting the back board slightly
(the one with the firmware EEPROM on it and some signal processing
chips) enough to make the main/lower board flex a little, will then
allow you to switch the set on again via the remote. Every time the set
switches on after this the language is in German (so it appears to have
lost its settings) however sometimes the channel presets remain intact,
while other times the channels are lost (so no channels are tuned in.)
Switching the set off and on again via the remote is usually enough to
regain the channel presets, however the language still has to be set
back to English manually.

When the set switches on you can normally hear the degaussing circuit
activate at power up, however if the set is not going to switch on the
degaussing circuit never activates (however the CRT must be powered up
as you can hear the quiet crackling noise when the CRT loses power
again.) Also sometimes lifting the rear circuit board while the TV is
switched on (in the same way as was done to get the TV to switch on in
the first place) will often cause it to switch off instantly.

It looks to me like the TV is 'booting up' when switched on, but one of
the tests that the firmware runs is failing, and it's switching itself
off again. I'm not aware of any diagnostics you can perform to see what
is causing the firmware to shut down, so I'm hoping someone here may
have seen a similar problem before and might have some advice.

Any help would be greatly appreciated!

Kind regards,
Adam.
 
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