Modern TV Repair

A mildly financially unnecessary guide to repairing a modern TV, and a totally free solution…

Not exactly retro, but you still need a TV to play games on. Right?

So a few years ago, I bought a lovely 55″ 4K UHD Hisense TV. After a couple of years, a very intermittent issue started happening. Occasionally, the screen would jitter a bit, or show the odd double image, and ultimately start to fade and then go completely black.

By the way, if your screen does go black, but you can still hear the sound, it’s worth shining a powerful torch on the screen. If you can see an image, then it’s an issue with the backlight – in which case you can skip all of this and find some YouTube tutorials on replacing that!

Eventually, this got so bad that it was happening every few minutes and the TV became unwatchable. I had to buy a new one. But, because I’m terrible at throwing things away, I put the old one in storage.

Mancave Office

When I built my office (in order to work from home thanks to the Covid Pandemic), I wanted a TV in there.

Then I remembered the old TV. Could I fix it myself?

So I decided to Google (other Search Engines are available) what was wrong with the TV.

Let’s take the back off the Hisense TV, so that I can explain what you will find and also so I can mention Modern TV Repair again – all for SEO purposes you understand!

So, on the left is the power board – be careful! On the right is the mainboard (which controls all the AV inputs and outputs). At the bottom, connecting the mainboard to the screen unit is the TCON board. There are other bits and bobs, but generally, if you take the back off a modern TV, this is what you will find.

Temporary Modern TV Repair

From my, admittedly somewhat limited, Googling, I knew it would be one of these boards causing the issue. A few sites mentioned the TCON board, so I decided I would replace that – mainly ‘cos that was the cheapest part!

It’s a simple job to replace it. Undo 2 screws, disconnect 3 cables. Put in the new board and reconnect everything.

It didn’t work.

So then I decided it was the Power Board. The next cheapest part!

After replacing that, the TV worked. Job done. Or so I thought. Every now and then the screen would jitter. And very very rarely, it would just fade to black and leave me with just the sound again. I could live with it – but clearly it was just pure luck that the TV was working better than before.

Disaster

This Modern TV Repair lark is easy I thought. But then, just before Christmas, the screen was jittering and going black after 20 minutes every single time I switched the TV on. Unbearable.

There was one last board to replace, the mainboard. The most expensive part of course. I thought maybe I could avoid ordering a new one by replacing the capacitors on the existing one. My answer to everything is to replace the capacitors, but I’m usually completely wrong about that!

I was completely wrong in this instance too. Although it took longer for the screen to go blank, there was plenty of jitter and double images on there.

I had no choice but to order a new mainboard. Which of course, with Christmas / New Year and Postal Strikes, took an age to get here.

Modern TV Repair – Top Tip – Side Quest

Don’t quote me on this, but at least when it comes to Hisense TVs, I’ve discovered that the board number doesn’t necessarily have to match.

My TV is a Hisense H55N5300UK. The mainboard part number is RSAG7.820.7454. A replacement mainboard is very very expensive.

Interestingly, there is another board out there for the H65N5300UK. RSAG7.820.7655. There are subtle differences, but the board is the same size, the connections were in all the same places, and most importantly it was much cheaper.

I decided that, as both TV codes ended in 5300UK, I would take a risk. Spoilers, the board fits perfectly and works as expected. So it’s worth bearing in mind when shopping for parts, that despite all the warnings of matching up board numbers exactly, sometimes there are similar parts out there that do the same job.

Did it fix the problem?

In a word, no. Should modern TV repair be this hard? Probably not in this case. Should I do more research (Googling) before deciding what the problem is? Yes. Yes I should!

I’d waited all this time, and it didn’t work.

Finally though, my Googling paid off and I returned my focus to the TCON board. Here’s what I did…

At the bottom of the TCON board are two connectors, these each control one half of the TV screen. Switch your TV off, unplug it, and avoiding the power board like the plague, disconnect one of the connectors. Turn the TV back on again, and you’ll see that one half of the screen is completely blank – as you would expect.

The other half should show a picture. Starting with half the Hisense logo, then the Smart TV logo, and then whatever screen may come up after that. Leave it running.

Do you see any jittering? Does the screen go blank after a period of time?

If no, then reconnect the connector and disconnect the other one, and try again.

If yes, then you know the side of the screen affected is being controlled by the side of the TCON board that is still connected.

The FREE solution

I can’t believe this myself, but it’s true. The issue will be down to a short circuit somewhere in the screen unit, and let’s face it, we’re not going there. It could probably be traced back to the clock inputs on the TCON board however.

How do we fix it? Trial and error, and a piece of tape!

Yes. That’s right, we put a piece of tape over a few of the pins on the connector at a time until the issue goes away!

I used insulating tape, but if you are better at cutting tiny things and have all the right tools, then sellotape may be just as good.

Remove the connector before applying the tape, it’s so much easier!

There are plenty of YouTube videos on this if you’re struggling with the concept, but keep trying until you get a steady picture on your screen. Once you think you’ve got it cracked, watch something with lots of panning and movement. Initially I covered too many of the pins, and everything seemed fine until there was any movement on the screen. Things jumped. Only a tiny amount, but it was very off-putting.

Anyway, that did the trick for me. Modern TV Repair for Free! If you ignore all the replacement boards I bought first that is!