Toshiba MW27F51
 

If you find or own one of these demons and it has no vertical sweep, replace the LA78041, the two zener diodes connected to the IC and replace the 100uf/35 volt cap on pin three of the IC. Forget to replace any of these and the new chip is toast! Hard set to work on! Bring your magnifier and a good flashlight!

Is that one of the newer Orion built sets? If so, I've already found out - the hard way! The cap failed, which then shorted the IC and the diodes. I just fixed an Orion built Insignia with the bad 100 uf cap. Fortunately, I caught it before it fried the chip. In the process of working on it, I knocked off a surface mounted resistor. Like you said, not the easiest to work on.

I've worked on a lot of newer sets where the 100 uf (sometimes 220 uf) cap would fail in the vertical circuit, causing lines at the top of the screen. Usually, the owners continue to watch the set until the IC blows up, often taking out more parts.

Yes, it is one of the wonderful Orion built TVCRDVD combos. I see a lot of the sets with foldovers but this set seems way more prone to having that IC fail. Such a fun repair!

I've got a 2007 27" flat tube Toshiba TV/VCR/DVD combo with built in DTV tuner that's supposed to be dead (courtesy of the TV shop). Haven't even looked at it yet. He said he'd probably have 2 or 3 more identical models for me before long. It will probably be the last thing out of the pile that I open, as I hate any kind of TV/VCR and/or DVD combo.

I have found the ultra-fast diodes on the output of the switch mode supply short. This usually knocks out the chopper and some resistors on the primary of that supply. Check the zeners on the output lines (some have them, some don't). They clamp on plug in to prevent damage. The factory uses a 1/2 watt and they don't last long. I replace them with 5 watt and it seems to keep them from failing prematurely.
Give me a good tube set (love the older Motorola's) anyday!

Might be the same model I had given to me earlier this year. After I eliminated solder joints and small caps I decided not to dump any money into it and gave it to a local repair shop-I'm pretty sure he junked it. I was baffled that the woman who had it wasn't willing to put any money into having it fixed.

I'm not surprised that she didn't want to spend any money on it. Ever since I've been fooling with TV's, I've had people give me nice, often later model TVs that they didn't want to spend any money on. I think it was just an excuse to buy the latest TV. That activity has been on the rise since flatscreens came out. I was recently given a 32" Insignia TV w/ digital tuner because the owner bought an LCD set and didn't want to put any money in the old one. I replaced some caps in the vertical circuit and it worked fine.

OTOH, I've had people approve and pay good money to fix junk that, IMHO, wasn't worth the time of day.

I opened up two more sets that I got from the TV shop and thought about the vertical circuit repair that you did on the Orion.

First set was a 4 or 5 year old 27" Orion with no vertical deflection. I could tell that he changed the vertical IC (LA78041), a cap, and a diode. Who knows if he used the right parts. I put it back together and said I'd tackle it another day.

The second set was a 27" Sylvania (Funai) that was dead with a squealing P/S. Unsoldered the LA78041 and it came up with no vertical deflection. Also found a bad cap. I went through my junk looking for an LA78041 and found everything but what I needed. I'll check the local parts place to see if they have anything. If not, I'll have to order the part, which will tick me off. It's getting so I have to order more and more of what I need because the local parts house does not stock many TV repair parts anymore. The owner told me that TV/radio repair parts were his "bread & butter" 40+ years ago. Now, he said the schools and other commercial interest are the only things keeping him going.

I probably need to order several of these LA78041's as well as some of the other common vertical IC's. Over the past several months, I've fixed many of these "junk brand" TV's and many of them had vertical deflection failures, usually caused by the cheap low grade electrolytic caps used.

Scary.

My daily watcher is a Sylvania 6427GFF. Still working fine after 4 years heavy use, and I want to keep it running (beautiful color gamut, three inputs plus dual mode tuner, uses little electricity).

Should I consider replacing any electrolytics to avoid future failure?

And who do I choose a quality replacement electrolytic?

I'd change the caps around the vertical IC. Would probably be a good idea to change any caps in the power supply. Others may chime in on this; but, the Nichicon brand caps seem to be OK. The caps I usually find in these sets are a mix of off brands that I've never heard of.