Here is a cut and paste of my saved messages regarding these Sony power supply problems. Some of these may be slightly different than your set, I don't know. Hope it helps. Gary McCartney McCartney Electronics 7134 Fife Rd, RR 7 Guelph Ontario Canada N1H 6J4 Fax: (519)821-1530 email: gary (at) number63.ca ========================================================================================= Complaint: Power Supply Transistors keep blowing (Q601 and Q602) 1. Resolder all pin connections on the Standby transformer T805 (which I have yet to find on the models I have repaired). 2. Replace VDR601 # 1-807-288-11, and VDR602 & 603 # 1-810-973-21 3. Replace C609/610/611/612 in the Base circuit of Q601/602. (part# 1-136-169-00) 4. Check all components in the secondary of T604 (diodes and capacitors) and ensure that there is no excessive loading. 5. Resolder all connections to the Horizontal Drive Transformer T502. (Bad connections here will make the HOT to fail). 6. Change the value of R644 from 6.8-ohm-1/4w to 4.7 - ohm - 1/2w. (I changed to 6.8 to 1/2w). but the part # for 4.7 is 57-980-4.7-ohms 1/2wx. 7. Check that the waveforms at the junction of Q601/602 are symmetrical. You should be able to read a resistance with an ohm meter between the Base and emitter of the HOT but from the collector to Base and the collector to emitter you should be able to test it like you would test a diode. Hope that helps C D Routson Dave's TV Cleburne, Tx 76033 817-641-8465 ----------------------------------------------------------------------------------- >The set started to show signs of shrinking or closing on the right hand side, >it would blink once in a while. One morning I just heard the relay click >and that was it. I have replaced two transistors and one resistor but I >have not tried to turn it on. >I am not sure if the horizontal output transistor is bad or not, it seems >like it measures 10 ohms from either lead. >I could not find specs on this transistor C4927. >I appreciate any help I can get. > >Thanks, > >Gabriel "Sony KV-27V55 // KV-32TS46 // KV-32V15 // and similar models. Stock # 14513. KV-27TS29 Complaint:Power Supply Transistors keeps blowing (Q601 and Q602). 1. Resolder all pin connections on the Stanby Transformer T805 2. Replace VDR601/602/603. 3. Replace C609/610/611/612 in the Base circuit of Q601/602. 4. Check all components in the secondary of T604 (diodes and Capacitors) and ensure that there is no excessive loading. 5. Resolder all connections to the Horizontal Drive Transformer T502. 6. Change the value of R644 from 6.8-ohms-1/4w to 4.7-ohms-1/2w. (part no#57-980-4.7-ohms1/2wx). 7. Check that the wavesform at the junction of Q601/602 is symmetrical. Hope that his will help...Yvon Roy ---------------------------------------------------------------------------------- From: Thomas Lander <tommydatek@xxxxxxxx> Subject: RE: kv32s15 sony To prevent repeated failures of Q601 and 602 You should check the following VDR's 601, 602, 603, preferably out of circuit, they should read no resistance in either direction, if any resistance detected replace it. Diodes D603, D605 may be leaky and R607, R644, R611, and R612 may be open. C609 can cause delayed failure of Q601 and 602 and should be replaced for good measure. The trick to not annihilating Q601 and 602 on power up is to use a variac, bring it up to 30 volts and read the voltage on the emitters 602 should be twice the volts of 601. Regards, Tom ---------------------------------------------------------------------------------- I put this together to help others. It is somewhat generic in it's treatment of power supplies. I believe yours only has a degaussing relay and turns the scan on and off to turn the set on and off but the information about checking the DC and wave form will be good. 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 HiFi Buys a Tweeters Etc. Company Atlanta, GA 30331 dmundy@xxxxxxxxxxxxx mailto:dmundy@xxxxxxxxxxxxx 404 699-3830 X5856 Efax (240)352-7717 -------------------------------------------------------------------------------- Hello Everyone. Tom: I always replace the 2SC4834 for 2SC4664 (they are of more wattage and run cooler). Replace T605 (1-423-581-11) Replace C609,C610,C611 and C612.(EVEN IF CHECK GOOD) Check R652.(if open replace VDR603). Check R651.(if open replace VDR602). Check R644.(if open replace VDR601). All 3 resistors are 6.8 ohms. Also check Capacitor that goes to the base of hor.driver transistor (I think is C525-50V/.47UF) Also check all pins for cold solders at Flyback. I hope this help. Jorge. ----------------------------------------------------------------------------- Did you jumper the relay 1st before bringing up the variac? You need to do that. You may also have to take it up up 60 v ac to get an unrounded signal , but the duty cycle should be apparent at 30 volts ac. This duty cycle should be 50% so that both the transistors are doing equal work, tolerance is 51-53%, but I don't trust that! 30 volts AC should measure about 42-43 Vdc (30v x 1.4 = peak ac). Run it at 30 vac, but bring it up gently, you should be able to see a balanced waveform before you even get to 30 vac. Now if it looks balanced, then verify at 30, then gently up to 60 to test for minor slope and flat top (minor ringing on leading edge of flat top). If it looks good at 60 Vac then start looking at the horiz circuit or especially look at the AUDIO circuit for shorts, the audio circuit has no shutdown or fusing protection on quite a few models, they just started to fuse those circuits in the last 2 to 3 years. Might be smart to remove the horiz output and audio output (or disable the audio B+) to test the power supply and save those transistors. BTW $9.00 a transistor is rather hi in my opinion, check http://www.mcmelectronics.com or some where else. Damon Brunger damon101@xxxxxxxxxxxxxx Telrad Electronic Services Ft Wayne, IN 46815 --------------------------------------------------------------------------- Do not know why, but there is still a wide missunderstanding about such a typical Sony problem. FIRST : we must know if the power supply died by itself or because a shorted HOT in this case it is fairly obvious that the HOT killed himself first and the power supply post mortem.. SECOND: we already have the reason for the power supply collapse, no use wondering why it dies in such circumstances: it is just destiny, vg. it is a design flaw. THIRD: We must then find out why the HOT died so young. there are two answers: first, C4927 are not such strong transistors, they can be substituted with great advantage by D1881 or BU2508D to mention just two. If you dont believe me, take a look at the data sheets.... and live aside the original parts myth.... FOURTH: The HOT heath sink is so obviously under designed, I sometimes add some mor heath sinking with very good results. Just try it and you will notice the temperature lowers down dramatically.. FIFTH: besides all that, PLEASE follow the HOT base path from the transistor itself to the driving transformer. 99 % you will find one or more cold solder points on the way. C4927 can not resist its base left floating for a while, hence the loud snap :o)) Last but not least: use C4834 even if he originals are C4664s Again, the data sheets will tell you why...... Good luck. Jorge Camboni GY Electronics, Dallas ----------------------------------------------------------------------------- Hello. I just copy and past from an article of Nasda. Common Failures In Sony Direct View TV's All, This is a list of the common failures in the Sony Direct View. Most failures are caused by Vertical or Horizontal problems. Sony Switch Mode Power Supply Rebuild Parts AA-1 Chassis Q601 Q602 VDR601 VDR602 VDR603 R607 R644 2SC4834 2SC4834 Varistor Varistor Varistor Fusible 0.1 ohm Fusible 6.8 ohm Sony Part # 8-729-019-51 8-729-019-51 1-807-288-11 1-810-053-11 1-810-053-11 1-202-933-61 1-212-853-61 AA-2 Chassis Q601 Q602 R607 VDR601 2SC4834 2SC4834 Fusible 0.1 ohm Varistor Sony Part # 8-729-019-51 8-729-019-51 1-202-933-61 1-810-974-11 The above parts should be replaced as a set. Always check HOT circuit before repairing power supply. Resolder horizontal drive transformer and do a good visual check in that area. Check Vertical output IC for shorts or signs of overheating ------------------------------------------------------------------------------ We do dozens of these sets each year with no recalls using generic 2sc4824 from Tritronics for ~$1.89 each as compared to ~$9.00 from sony. Just buy a lot of about 10 pieces and match them yourself with the diode test on your DMM. The matching is a factor but there is nothing magic about it. Just look at the duty cycle and verify it at 50% +/- a couple of percent. Also, we replace the HOT, 2sc4927 with 2sd1881 which runs more efficiently and cleaner. Just look at the collector waveform and you can see that the timing is right on and the waveform is cleaner than with the original. Leonard G. Caillouet Service Manager Electronics World Gainesville, FL 352-332-5608 352-332-5668 (fax) ---------------------------------------------------------------------------- Check and replace the following: PART ID PART# C609,C610,C611 & C612 113616900 R607 120293361 R644 121285300 VDR602 & VDR603 181097321 VDR601 180728811 Q601 & Q602 872901949 R610 & R609 121636900 The above parts are common on the Power Supply. Hope it helps' Panday ------------------------------------------------------------------------ Sony 35" Fixed then Dead Again replace the small cap tied to the HDT I believe its a .22 uf 50v Jeff Farnsworth Lyles TV and Appliance 17 S Washington St Elkhorn, Wi. 53121 -------------------------------------------------------------------------- In addition to what you replaced, few other parts goes defective on this unit: a. C608 b. C611 and C612 c. T603 d. R622, if damaged VDR601 is defective. I troubleshoot this power supply as a stand alone unit. Using a 40w light bulb on the B+ line and power up with variable transformer slowly from zero VAC. At 36VAC, the supply should be 135 B+ , which remain stable as you turn the AC up to 120VAC on the Transformer. Look at the waveform at the emitter of Q601 (53KHz) for any noise or ripples. I had a defective T603 once that created your similar symptom. Check for cold solder joints on the actual pin where the wire from the transformer solder on to the pins. At one time the PCB was cheaper to replace than repair in Canada. Panday ph 262-723-3477 fax 262-723-3658 ================================================================================ tech@xxxxxxxxxxx Scott wrote: > > Hello everyone, > > I am working on a Sony KV32XBR35 and I am having some difficulties with the > power supply. (G Board) The set was dead with F602 open. I replaced Q601, > 602 (shorted), VDR602, and R623 (almost open). I resoldered as needed, (like > IC651) and when I would try to power it up, I would shut down. (relay click) > Found D1409 shorted on the A board going to the audio B+. After replacing > the diode, the set powered up for about 10 seconds before Q601 and 602 > shorted again. Does anyone have some insight to this power supply, I'm not > very familiar with it. Thanx for your help. > > Scott Beebe > Ohm Electronics Inc. > 609 W. Clinton St. > Ithaca NY 14850 > Voice: (607) 273-8406 > Fax: (607) 273-8743 > www.ohmelectronicsinc.com > Gary McCartney McCartney Electronics Guelph Ontario Canada Est. 1984 email: gary (at) number63.ca Paul wrote: > This is the chassis that has Q 601,Q602,Q591 shorted and R 607 open. I have > seen tips that mention C909,910,911&912 as needing to be changed. Do any of > you do this when making this repair. Also the vdrs for shorts is mentioned. > Is there anything else that should be checked or replaced beside the flyback > and solder joints in the drive circuit. Reason for the question, it wiped out > all those components again, but I was using an aftermarket kit. I have since > replace with all oem's but don't want to wipe them out again. > Paul > > Paul ,B > Central TV&Video > 911W Grand Ave > Grover Beach Ca. > (805)481-8084 > > ----------------------------------------------------------------------------- > This Email List is accessible to the general public through search engines. > Remove: http://www.tech-assist.org/remove.htm > Set Vacation mailto:ecartis@xxxxxxxxxxxxx?subject=set%20techassist%20vacation > Lost Password: http://www.tech-assist.org and select "Login Problems?". > Email Archives: //www.freelists.org/archives/techassist/ > ----------------------------------------------------------------------------- This Email List is accessible to the general public through search engines. Remove: http://www.tech-assist.org/remove.htm Set Vacation mailto:ecartis@xxxxxxxxxxxxx?subject=set%20techassist%20vacation Lost Password: http://www.tech-assist.org and select "Login Problems?". Email Archives: //www.freelists.org/archives/techassist/