I replaced the bad 220Pf 2kv Cap and the IRF620 series Switch and now the LED is no longer flashing but there is still no picture or sound. I can hear a chirping noise I think is coming from the power supply section. Before I replaced the IRF620 I was getting HV for a couple of seconds, Now there is no HV just chirping. Any ideas where to look next. Thanks
simon hanlon wrote in , on
19/07/2005, H. Arseen
I forgot to mention that some versions are not insulated, sorry for that and...congratulations ;-)
-- Alain (Albé) Reply-to is valid (only 4 days !) http://home.tiscali.be/a.beguin
You must be a Jedi! So using the force can you tell me why my KV-28WS2U SONY takes so long to switch the picture on, its not always but sometimes it takes a good minute. You can hear the sound but no picture. usually switching off then back on sorts it. It has always taken some seconds for the picture but not that long.
simon hanlon wrote in , on
19/07/2005, H. Arseen
Not at all, only a retired service technician with /some/ experience with European Philips ;-)
Sorry, I can't, because I have *no* experience with Sony
I'm sure someone here will help you!
Bye, Simon.
Alain (Albé)
-- Alain (Albé) Reply-to is valid (only 4 days !) http://home.tiscali.be/a.beguin
Check the voltage on the heater pins of the picture tube. The electrolytic capacitor in the heater circuit is probably weak and needs replacing. You should have about 6.3 volts. John
There's a chance the heater voltage might be less. I know many of their more recent computer monitors used a 4 or 5 volt heater. I'm not sure if they did the same thing to their TV CRTs. Andy Cuffe
snipped-for-privacy@psu.edu
Alain, There I was, having one of these PHILIPS contruptions labelled
28PW9503/12 and showing identical diagnostics as mentioned in this user group thread. I.e RED LED and Flashing GREEN at power ON.A visual learned that cap 220PF 2KV at the LOPT area was exploded and really showed an Ohmic short of about 200 Ohms. Easy does it, get the motherboard out and Rand R the faulty cap by a 3KV type. Checked the LOPT and it measured OK. Get all the connectors back in place and reapplied main power.......Guess what ..it still did not work ....!!!
I had the chassis shoved under the bench for a few days until I learned about the message from Alain Beguin the retired Philips Service Engineer that the FET IRF620 will be the culprit. Not understanding the reasoning behind it I took the shotgun approach and RandR-ed the FET by an IRF830 giving the machine something to burn out if another short was still present.(Yes I did insert an ceramic insulator between the FET casing and the heatsink...
Powered the machine on and watched from a safe distance....PRESTO there was light and sound...
Alain, people like you should be coddled by the sci.electronics.repair user group members. This wealth of PHILIPS experience from retired engineers saves the occasional and theoretical trouble shooters many hours (and money).
Thanks again and keep on doing the good work on those PHILIPS machines repair suggestions. (Any knowledge on Grundig CUC 7880 or 7890 as well ?, BTW In my previous life I used to built aircraft, how does that match your hobbies ? )
TIA Bram Stolk (NL)
"Alain Beguin" schreef in bericht news: snipped-for-privacy@usenet4all.org...
Bram Stolk wrote in , on
20/07/2005, H. Margareta van Antiochië
I flew them...
Thanks for this nice message and I replyed already by mail.
*Not* much experience with Grundig for the last 12 years :-)-- Alain (Albé) Reply-to is valid (only 4 days !) http://home.tiscali.be/a.beguin
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