Picked up (not by myself) a Sony KV35S42 - Videokarma.org TV - Video

radiotvnut · #1 12-22-2008, 10:55 PM

Picked up this Sony KV35S42 off of the front porch of the local TV shop. It had been sitting there for 3-4 weeks and the owner said I could have it. This was made in 2001 and appears to be suffering from the same problem it's older '90's relatives suffered from: blown power supply due to shorted HOT due to (hopefully) loose solder connections in the horizontal circuit. The only difference I see in this set and the '90's models is that this one uses an MX0841 IC (actually two transistors in a single package) instead of two individual transistors in the regulator circuit. The HOT is a 2SC5148. And, there is a .1 ohm 1/2 watt fusible resistor that is open. Some mail order places sell the parts as a kit for around $10; but, I'm afraid these may be Chinese knock off parts that will not hold up. I think I'll spend a little extra and order the original parts. Hopefully, the flyback is not bad.

As far as the looks of this set, it's just a big black box that looks very similar to the '90's models. BTW, I did check the CRT and it is good (emission wise, anyway). The guy at the shop told me that he suspected that this set had the usual blown HOT/PS transistors. He didn't want to mess with it because the customer didn't want to spend any money on it and he didn't feel like putting the heavy thing on his bench.

Findm-Keepm · #2 12-22-2008, 11:44 PM

Quote:

Originally Posted by radiotvnut

Some mail order places sell the parts as a kit for around $10; but, I'm afraid these may be Chinese knock off parts that will not hold up. I think I'll spend a little extra and order the original parts.

Very smart move - went through varying quality with some distributor MX0841's - Sony originals hold up better. They are getting scarce -last I ordered, they were backordered and the distributor had a limit as to how many they could order from Sony national parts.

Best of luck! PM me if you need a service manual, I may have one in PDF format.

Cheers,

radiotvnut · #3 03-09-2009, 07:34 PM

Well, I'm pissed. Finally got around to ordering the HOT, power supply IC, and the fusible resistor. I resoldered everything in the horizontal circuit, installed the parts, and turned it on. I have good sound; but, no HV. I have not checked anything else because I'm so irritated at the moment, I might break something. I remember another similar Sony that had no HV. I used an o'scope to trace the horizontal drive signal up to the base of the HOT. The HOT checked fine; but, I changed it anyway and got HV back. On another 27" Sony similar to this, the sound would come up for about 5 seconds, then the set would shut down and the blinking light indicated horiz. circuit shutdown. That one had a bad flyback. I hope mine turns out to be something stupid.

Have also been working on a 2002 27" Panasonic TV/DVD/VCR combo for the Salvation Army (yeah, I let them talk me into it). It has about a 3" picture in the middle of the screen. Looks liky typical bad caps in the vertical circuit. This TV has a stand up board soldered to the main chassis that contains the vertical circuit. You would have thought that they would have made the board PLUG-IN for easier service; but, HELL NO! I checked all the caps and found a 100uf that checked 80uf and a 220 uf that checked 208 uf. I also replaced a 1 uf and a 2.2 uf that looked like they had been hot, even though they checked fine. All of the other caps checked right on. Changed all the caps, resoldered the vertical IC for good measure, soldered the vertical module back in, sat the main board back in it's holder and plugged everything up, turned it on and STILL the same symptom. I think I'll replace the LA7837 vertical IC and if that doesn't do it; I'm done!

I don't know why it happens this way; but, it's always the nice, big, later model TV's that I could get semi decent money for that turn out to be dogs. Let me bring home some POS '82 19" Emerson knob tuner set with cigarette burns all over the case that I would have to pay someone to haul off and I'll have it fixed in 5 minutes. And, I'm not saying all knob tuner TV's are a POS; but, I think you get my meaning.

I'll get back on the Sony sometime; but, I've got to cool down first. If anyone has any information that might be useful, I'd appreciate it.

radiotvnut · #4 03-09-2009, 08:51 PM

OK, I calmed down and checked my work again and found that one of the HOT leads was not soldered good; but, the problems did not end there. I resoldered the HOT, powered up the set and the damm thing blew all of the new parts. And, I ordered "real" parts. I didn't use cheap knockoff parts. Now, I guess I'm looking at a bad flyback. I'm probably going to end up trashing this set. I've already got around $25 in parts blown to hell as it is. A flyback will probably cost who knows what plus the other parts. It's really not worth it, is it? If I knew a flyback and those other parts would fix it, I might go for it; but, I'm tired of blowing money on parts just to watch them go up in smoke or discover problems in other areas of the TV.

I remember several years ago that a friend who had a shop had thousands of $ worth of Sencore TV test equipment. Among that equipment was a device that place a load test on the entire horizontal sweep circuit of a TV. If I had something like that, I could probably avoid a lot of this crap of blowing parts. The closest thing I have is a flyback ringer built into an old Sencore analyst; but, the flyback has to be removed from the circuit for a test.

radiotvnut · #5 03-09-2009, 09:14 PM

Just checked tritronics and they say that the flyback is NLA. According to the model, the flyback P/N is x-4560-159-1. I swear that one day I'm going to learn not to bring this heavy black plastic shit home! Now, this is something else that I'm going to have to throw out; and, I could have spend that $25 on something that was actually worth a damn!

radiotvnut · #6 03-09-2009, 09:50 PM

OK, pulled the flyback and it rings good on the tester. The actual number on the transformer is 8-598-809-00. I know a flyback can ring good but still not work. The only other indication that I'm getting that may indicate that it's bad is a slight odor from under the flyback. It smells like it may have arced.

holmesuser01 · #7 03-12-2009, 06:53 PM

You say you had sound? Sounds like the diodes on the HV side of the windings may be open. Have you tried MAT Electronics, or Asti Magnetics? Both are in New Jersey. They carry flybacks.

radiotvnut · #8 03-12-2009, 07:13 PM

Actually, I just sent this set to it's grave. I had sound only before I discovered a bad solder connection (made by me) on the new HOT. After I resoldered the HOT and powered it up, the new parts went up in smoke. I checked some more things and couldn't find a definite problem so I then decided that I wasn't going to burn any more money on this set. I saved the chassis for parts and shoved the rest off of the cart. The plastic case busted when it hit the ground; but, the CRT did not break.