Sylvania RNH613CH01 problem

[MK1234Tfan]

Hello everyone! I have a nice Sylvania TV sitting here that I've been trying to fix for some time now. The reason I really want to get this working is because it has awesome sound and the CRT tests great on all guns. Anyways on to the problem.
Once I turn the TV on the picture has some weird wavy horizontal lines all over the picture that seem to jump around like some sort of interference. I've replaced some of the capacitors that seemed a little weak. I still have some of the very small electrolytics to check as well. I'm not quite sure where to even look as I have already looked over the whole board and touched up and re-flowed solder in some suspicious spots. I have also tested the large resistors near the flyback as well as some of the smaller ones. I really don't want to check every single resistor and pretty much want to narrow down the problem so I can get this thing fixed and start using it right away! It also has some weird pincushion on the top of the screen as well.

I will make a video if I have to but my video camera is charging right now and it won't be until at least tomorrow until I get a video.

PS. I am ruling out the tuner since when I turn the TV on without anything hooked up I can see the wavy lines in the numbers of the channel.

Thanks in advance!

[MK1234Tfan]

Can't believe I didn't notice it before but on my flyback that thick piece of metal that goes from the bottom of the flyback to the top is missing. I've never seen one without that metal bar there and obviously there is a slot for it. Does anyone think this might be causing my problems? Not sure what it's purpose even is.

[jstout66]

From the sympton you describe, it's one of the large can filter caps.
If the set worked before without the metal bar, I wouldn't worry about it. It could have been a factory mod or something.

[MK1234Tfan]

Thanks for the tip. There is 1 very large capacitor that has a plastic top to it unlike the rest. There are a few 3300uf caps that I can't accurately test with my EDS-88A cap analyzer since the highest it goes is 2200uf. I may end up having to order replacements for all of the 3300uf caps to see if it clears up. I'm going to gather up some other parts I need as well so I can make 1 order. When I change them out I'll be back with a conclusion. Thanks a lot!

[radiotvnut]

What's the chassis number? If it was made prior to the mid '80's, it should be Exx-xx. If it was made from the mid '80's to the '90's, it should be something like 25C5xx, 25P1, etc.

[MK1234Tfan]

Here ya go. The chassis # is 26C9-04 AA built in Nov 1987. Thank you! Just looked at the chassis and realized the biggest cap next to the flyback is only a 330 uf 250v so I'll be able to test that and see if it's ok. But there is 1 3300 250v caps also next to the flyback as well as some 47uf high voltage caps that check good and a couple smaller ones I need to test. The 3300uf cap and the smaller ones are next to the vertical size adjust pot as well as what looks like the vertical IC. So looks like only 1 large cap I have to replace unless any are bad.

[radiotvnut]

I'm not too familiar with that chassis; but, if the problem clears up after the set gets warm, you need to get a can of freeze spray and start hitting components with a cold blast. If you hit a component that causes the problem to come back; then, that part is likely to be bad.

If the set has A/V input jacks, try running a signal through the A/V input jacks to see how it performs. If it works OK through the jacks, that will isolate the problem to the tuner, IF, or AGC circuits.

From what you say, it sounds like a bad cap; but, finding the cap could be a chore. If you have an oscilloscope, it would be advisable to scope all power supply sources to make sure they are clean.

[MK1234Tfan]

Just wanted to say I like your videos and wanted to post info on the TV.

But, as for the tuner I ruled it out in my first post since I have nothing plugged in at all and I can see the weird interference in the channel number.

As for caps there aren't too too many so I might as well check all the ones I can and will report back if I find any bad. I have a kit with many different kinds of caps on hand but I don't have a new 3300uf cap in the kit. 2200uf is the highest one in the kit. However, I did find one on a part board I may try to swap it out and see what happens.

And I'm sorry but I don't have a oscilloscope. =(

I'll report back after I'm doing all of the stuff mentioned.

Thanks!

EDIT: I've come across something that is a little weird and sorta out of my ballpark but I'm going to do my best anyway. When testing caps I came across a cap that said low DSR. I then kept dropping my meter lower and lower until it stopped a little above 50ohms. I then took the cap out and it tested fine so I did a little more checking at the components that is in line with this cap. I found a resistor that tested fine and something called a triode thyristor. I noticed as well that it's part of a high voltage shutdown and is in line with 1 of the pins on the flyback. I was wondering if there is any way of testing this component? (Found out no..) Here is the NTE cross reference datasheet. http://www.nteinc.com/specs/5400to54...nte5452_58.pdf The part is NTE5456. Thanks!
PS. It looks like the tv was repaired at some point as there is a trace cut and a wire reconnecting the components I guess after the test. Where the cap tested low DSR it's also very close to where the trace was cut. I also reflowed solder where the wire was put and tested continuity fine even though it's not in line with this component.

[MK1234Tfan]

Checked every single cap on the main board and left the sound board alone since the sound works. Every cap came back good. I changed the 330uf 250v cap with another to see if anything would happen and nothing. Only other cap I have to change is that 4700uf puppy. I guess until then this is on hold. =(

[Zenith26kc20]

I can't remember the chassis # but is this the single chassis with a large white flyback on the left rear of the chassis as viewed from the rear?
If memory serves me on that one, we had a number of flyback failures due to internal arcing which sounds like what you have described. Can you post a picture of the chassis?

[MK1234Tfan]

I've added some pictures of the chassis as well as a rough schematic on the inside of the case. I decided to check the B+ to see where it was at. I have the black lead of my dmm on the hot ground and the red lead on D434. I turned the brightness all the way down and try to adjust R452 and the highest it goes is 108V. D434 is the only thing I can find on the board about B+. Not sure what TP4 is but it says 130V. By the way no matter what I have the brightness on D434 stays at 108V. Also TP23 says 200V but it's not even close to 200V and it slowly keeps dropping. I'm new to testing voltages while sets are running. Not sure if this stuff is normal and if not I'm not sure what to do next.

I'm about to give up...

[Bill R]

You should probably use an isolation transformer when making measurements.

[Geoff Bourquin]

I see a large, yellow squared off capacitor in the 5th photo, right next to the flyback. It may be bad, and if it isn't, replace it anyway. I used to see those fail often, and when they did the stink was enough to make your head spin. I could sometimes identify that as the problem while I was still in the customers driveway, just from the smell.

[MK1234Tfan]

Alright so here is the deal. I ended up adjusting TP4 to exactly 130V and TP23 is now staying closer to 200V fluctuating at about 194-197V. As for the large brown 330uf capacitor it is at 161V. And for that square yellow cap there is no smell but I will have to order it if my local radioshack doesn't have them. I gotta try and see what it says first lol. I also want to order the 4700uf cap since I can't test it.

By the way nothing at all has changed on the picture. Still the same dang problem.. I'll get a picture of it after I get the brightness adjusted.

[Electronic M]

I took most of the similar looking guts from a Sylvania console reciently for parts.