Al, thanks for taking all that time to answer my post, but the XBR55 uses a different chassis, doesn`t have Q601 & Q602 in the power supply, but I do appreciate your attempt, Larry E al wrote: > Below is a procedure for which you guys can thank the author. al > > Al Leatherman > alleathe@xxxxxxxxxxxxx > 973-361-5796 > Mine Hill, NJ. 07803 > http://WWW.ALS-TV.NET > > Here is Dan's article: > HTH > > This is a fast check for Sony power supplies. The important thing to > remember about these supplies is that it is a push pull amplifier. > The load > across the 2 transistors must be close to equal or it will > self-destruct. > The frequency is the regulating part of the equation. They are > designed to > start at a high frequency out of resonance and be pulled lower by the > regulator toward resonant frequency to achieve proper regulation. The > supply > will oscillate at very low voltages and this is the only way to check > them > out. > After doing the usual repair of transistors and I generally include > the > damper diodes (you can use Sony parts but they are subbing to a > 1N5401). If > you don't know why the supply blew up check the Horizontal output and > look > for rings around the driver transformer. > First pull the relay RY602. This will prevent the set from trying to > power > up during repair and testing. > Monitor the voltage at Q601 collector or R607 is just as good. > Scope Q602 collector for waveform and DC voltage. > > Lower the AC voltage to 20 volts DC. The supply should be > oscillating and > each transistor should be dropping 10 volts. If that looks good run > the DC > up to 40 Volts. > At about 80 volts DC the current drawn by the supply should peek and > start > to decline with further increase in voltage. You should also have a > nice > square wave of equal duty time with no peeks or ringing. Each > transistor > should be dropping 40 volts. > > You may see a slight bounce in the supply frequency at this time. > The > standby is up enough to turn the micro on and the slow start circuit > is > trying to bring the run supplies up to full value. Of course this > won't > happen with the relay still out. > On the latest supplies you must stop and return the set to normal > operation > as they do not like trying to run on reduced voltage above 40VAC. > Older > sets have no problem and I continue to increase the DC stopping at > 150 volts > and 200 volts. These are nice round numbers that are easy to work > with. If > everything is looking OK then run the supply on up to full value. > You > should have 16 volts on D619 reference to cold ground. > > The supply is now running at full voltage. If you have fixed all > problems > on the secondary side you can reinstall the relay and tune for > minimum > smoke. > > Daniel Mundy, CET®/CSM > > > Glenn Larkman > > ----- Original Message ----- > From: "Larry E." <videotech@xxxxxxxxxxxx> > To: <techassist@xxxxxxxxxxxxx> > Sent: Thursday, November 14, 2002 3:00 PM > Subject: [TechAssist] Re: Sony KV32XBR55 dead set > > > >>Leonard, thanks for the reply, replaced Q604, C651, C613, now pin 1 >>of IC651 reads 168 volts regardless if plug F61 is in or out of circuit. >>Pin 9 of IC651 reads zero volts even after replacing Q604, I read a >>short (11 Ohms) on Diode D652, pulled diode and it checks good, short is >>on traces, the print I`m using is useless in this area, is this a >>problem or am I chasing my tail? Thanks for any help you can give, Larry >> >>Larry Eastman >>American TV & Electronics >>Crystal River, Fl. >> >>Leonard G. Caillouet wrote: >> >> >>>Larry, >>> >>>I had one do this a while back. The fix was to replace Q604 2sc3311A >>> > (soft > >>>start driver) at pins 8 & 9 of IC651. >>> >>>Also, always ESR the electrolytics in the circuit and look for leaks, >>>especially C651 2.2uF 160V and C613 100uF 25V. >>> >>>The two SE135 error amps are always suspect as well. >>> >>>I did the same as you, looked to the A board until a tech at sony told >>> > me to > >>>just change Q604, even if it checks good. >>> >>>Leonard G. Caillouet >>>Service Manager >>>Electronics World >>>Gainesville, FL >>>352-332-5608 >>>352-332-5668 (fax) >>> >>>----- Original Message ----- >>>From: "Larry E." <videotech@xxxxxxxxxxxx> >>>To: <techassist@xxxxxxxxxxxxx> >>>Sent: Wednesday, November 13, 2002 1:45 PM >>>Subject: [TechAssist] Sony KV32XBR55 dead set >>> >>> >>> >>> >>>>Hi guys, Sony KV32XBR55 came in dead, replaced IC651, C652,C672,C654 >>>>and C674 as advised, now have 5v & 12v standby but voltage on reg. IC >>>>pin 1 is only 86 volts, If I remove connector/plug F61/A61 pin 1`s >>>>voltage goes up to 160 volts so obviously there is a heavy load >>>>somewhere on the "A" board. I`m using a "similiar" schematic and it`s >>>>close on the F board but not so good on the A board and the schematic >>>>for this set is NLA. HOT is not shorted, all low ohm resistors on A >>>>board are good, any ideas? tia, Larry E. >>>>-- >>>>Larry Eastman >>>>American TV & Electronics >>>>Crystal River, Fl. >>>>http://www.tvjunkyard.com >>>> >>>>------------------------------------------ >>>>To REMOVE your email address, click here: >>>> http://www.tech-assist.org/unsubb.html >>>>To CHANGE your email address, click here: >>>> http://www.techassist.net/forms/change.html >>>>------------------------------------------ >>>>***NEW*** Tips Added Instantly!!!*** >>>>Submit Repair Tips here: >>>>http://www.tech-assist.org/secure/tip/ >>>> >>>> >>> >>>------------------------------------------ >>>To REMOVE your email address, click here: >>> http://www.tech-assist.org/unsubb.html >>>To CHANGE your email address, click here: >>> http://www.techassist.net/forms/change.html >>>------------------------------------------ >>>***NEW*** Tips Added Instantly!!!*** >>>Submit Repair Tips here: >>>http://www.tech-assist.org/secure/tip/ >>> >>> >>> >>> >> >>-- >>Larry Eastman >>American TV & Electronics >>Crystal River, Fl. >>http://www.tvjunkyard.com >> >>------------------------------------------ >>To REMOVE your email address, click here: >> http://www.tech-assist.org/unsubb.html >>To CHANGE your email address, click here: >> http://www.techassist.net/forms/change.html >>------------------------------------------ >>***NEW*** Tips Added Instantly!!!*** >>Submit Repair Tips here: >>http://www.tech-assist.org/secure/tip/ >> >> >> > > > ------------------------------------------ > To REMOVE your email address, click here: > http://www.tech-assist.org/unsubb.html > To CHANGE your email address, click here: > http://www.techassist.net/forms/change.html > ------------------------------------------ > ***NEW*** Tips Added Instantly!!!*** > Submit Repair Tips here: > http://www.tech-assist.org/secure/tip/ > > > -- Larry Eastman American TV & Electronics Crystal River, Fl. http://www.tvjunkyard.com ------------------------------------------ To REMOVE your email address, click here: http://www.tech-assist.org/unsubb.html To CHANGE your email address, click here: http://www.techassist.net/forms/change.html ------------------------------------------ ***NEW*** Tips Added Instantly!!!*** Submit Repair Tips here: http://www.tech-assist.org/secure/tip/