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Akai CT2870 TV

Nothing except initial attempt at power up shown on a couple of LEDs illuminating for a second. Somewhere, mislaid, I have the schematics for this TV but will have to get another copy. Thought it was the BU508A but then I saw the 1 ohm or so resistor between base and emitter, the LOPT driver tests ok on DVM "diode test" Mains getting to the primary power supply reservoir cap, but not explored any further until I get some schema. Can anyone direct me into a suspect device, meantime.? Also a long term problem was a noisy sound as though off tune but as a VCR tuner used as AV feed into this TV it didn't matter. As the sound IF is in an awkward area anyone any specific knowledge or I will leave that as is, assuming I can resusitate the power supply/ies.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N Cook
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test the horiz out transistor

Reply to
Ken G.

I located the schematics again.

Does anyone know if the primary switch mode power supply is independent of the line output oscillator and LOPT ? so could / should work with just a load but not a feed ?. I imagine not as that would mean 2 HV squarish oscillator frequencies and potential beat problems in audio or something.

Anyone aware of elecronic German to English machine translator/ dictionary ? as a lot of German legends on the overlay etc

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N Cook

I dug out the data sheet for the TEA2164 primary switch mode ps processor and it takes a feed from the line o/p oscillator IC. It has numerous protection trips so I'll have to check for overload. As its desoldered , firstly without the LOPT BU508A in there, and see if there is anything on the LV regulators fed from the primary ps.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N Cook

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is this an ITT nokia chassis? euromono? core 2? have you connected a bulb on the HOT c-e terminals with it removed? any b+? i seem to recall having similar trouble with a core 2 chassis- poor startup- resoldered a series thermistor in the psu and i think there was a mod with a 1uf cap between gnd and a pion off the smps control chip...anway lets not get ahead of ourselves. see if theres any b+

-Ben

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b

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Similar or same as Pioneer SD 21/25/28 AVI

Sounds plausible remedies. Unfortunately other repair work is now taking precedence and it has become a back-burner job.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N Cook

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