This Sony KV-24FV300 powers up for about a second, then shuts down. The front panel l.e.d. shows a blink code of two blinks. According to some older information on the web, the two blinks indicate a B+ over current protection. I cannot find any shorts in the set. Flyback and H.O.T. ring ok. Does anyone know of any common faults with this set?
Thanks for your reply.
-- David Farber David Farber's Service Center L.A., CA
ok.
After further investigation, I've come up with the following observations.
With all plugs and boards attached, the set powers up and about a second later my AC line current measurement spikes to over 2 amps and the set shuts down.
Removal of the deflection yoke plug does not change the situation. Set still shuts down.
With the HOT removed, and everything else plugged in, the set powers up, the
135 volt supply is normal, and it doesn't shut down. The drive signal to the base of the removed HOT is a nice sawtooth, about 6 V p-p. The blink code changes to four blinks which I believe means no vertical deflection.So my question is, can a bad flyback suck a lot of current even though the deflection yoke plug is not attached?
Thanks for your reply.
-- David Farber David Farber's Service Center L.A., CA
Why not?
Leonard
ring
observations.
code
the
With the yoke disconnected, and the HOT installed, doesn't the circuit stop oscillating? If so, wouldn't there have to be a measurable short in the primary windings to ground for the flyback to suck the current? Are there further steps I can take to isolate the flyback as the problem without actually buying a replacement? Keep in mind that the flyback does ring ok with my Dick Smith flyback tester.
Thanks for your reply.
-- David Farber David Farber's Service Center L.A., CA
Disconnecting the yoke, or even removing the HOT, has no effect on the horizontal oscillator. Since there is base drive, you know the horizontal oscillator is working. B+ goes directly to the flyback, so if there was a short to ground it would overload even with the HOT removed. It is possible for a flyback to ring ok and still be bad. Is there any high voltage before it shuts down? Andy Cuffe
snipped-for-privacy@gmail.com
stop
What I meant was there should not be any oscillation on the primary side of the flyback with the yoke plug removed.
My latest test was inserting a 75 watt lamp in series with the 135v supply and reinstalling the HOT. The lamp lit up very brightly and my current meter hooked up to the 135V supply measured 630ma. There is no high voltage and no signal at the collector of the hot.
-- David Farber David Farber's Service Center L.A., CA
stop
What I meant was there should not be any oscillation on the primary side of the flyback with the yoke plug removed.
My latest test was inserting a 75 watt lamp in series with the 135v supply and reinstalling the HOT and deflection yoke plug. The lamp lit up very brightly and my current meter hooked up to the 135V supply measured 630ma. There is no high voltage and no signal at the collector of the hot.
-- David Farber David Farber's Service Center L.A., CA
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.