1T-TBC-GL has died?

[Augusto Duarte]

Hello!

I have bought a 1T-TBC-GL from here, at the start of the year, and started using it literally only yesterday. It was working well paired w my 1980p, but then I started using it today and it started giving me a grayscale image, which I could see in my jvc 10in monitor through composite.

A few minutes later, it died and wasn't giving me any more pictures; it wasn't powered on even for like 20min. The lights still turn on and I can cycle through the options. The auto mode seems to be stuck at N4 though. But then again, no image

I found an old thread talking about the possible slow death of the AVT-8710, starting with the grayscaling itself. Eventually the user was able to power cycle his AVT-8710 back to full life after a few tries.

I haven't been so lucky, unfortunately; I tried waiting and retrying checking the image after unplugging it for several minutes, but nothing.

One thing to note is that I tested both a 12v 0.5a and a 12v 2v (included when I bought it here), and the same error persists.

It was stored this whole time in a dry place, without receiving direct sunlight, if that serves for anything.

I don't think I can handle this... this was one of my most expensive buys in my life so far. I live in Brazil and.. converting the dollars to brazilian reais is pretty sad, and makes things literally 5x more expensive for us.

I will wait for the night and see if it miraculously comes back to life tomorrow morning but I don't have high expectations.

[lordsmurf]

When you say that you used another power adapter, did you verify CENTER POSTIVE NEGATIVE on it? Or if center positive, did you use a polarity reversal cable? If you give a device wrong polarity, bad things happen. Sometimes it gets fried, sometimes it simply fails to function (but undamaged).

The 1T-TBC-GL -- at least the rare "green" version, and NOT the common "black" version -- rarely suffers the same "attitude problem > slow failure" fate as the actual AVT-8710s. With these 1T-TBC, you can usually cycle the input/output, from NTSC back to NTSC (or PAL back to PAL). That almost always corrects it. It's not actually a fault, but failure to fully pickup and sync the incoming signal at initial power on. It's similar to how every time you turn on a computer, you're actually causing it to experience a power surge, and sometimes hardware fails to boot.

Being stuck on N4 may be power related. You already tested external, so internal caps may need attention.

Unfortunately, being stored properly isn't the sole consideration for electronics. These devices need to be powered on, and used, from time to time. I've been somewhat neglectful of my own gear in recent years (especially after all the sad events of '22). I recently pulled out my AG-1970, only to learn that it no longer powers on at all.

I also wonder if the power grid has damaged it. Remember, TBCs have zero protections, as these devices were expected to be placed behind UPS. So if you plugged it into a wall, even minor power fluctuations may nuke it. Not necessarily permanent (though possible), but enough to cause various issues.

Leave it alone for some hours, as you plan. Sometimes internal power components need to be "jump started", but the first power on attempt fails. You need to take breaks between attempts -- but not too long, nor too short.

[Augusto Duarte]

Hello! Sorry for the late reply.

Quote:

Originally Posted by lordsmurf

When you say that you used another power adapter, did you verify CENTER NEGATIVE on it? Or if center positive, did you use a polarity reversal cable? If you give a device wrong polarity, bad things happen. Sometimes it gets fried, sometimes it simply fails to function (but undamaged).

Both PSUs I used (including the included one in the purchase) were center positive, but the TBC itself also expects a center positive signal (at least from the symbol in it).

Quote:

Originally Posted by lordsmurf

Being stuck on N4 may be power related. You already tested external, so internal caps may need attention.

I assume there is no service manual for this; how can I get this serviced professionally?

Quote:

Originally Posted by lordsmurf

Unfortunately, being stored properly isn't the sole consideration for electronics. These devices need to be powered on, and used, from time to time. I've been somewhat neglectful of my own gear in recent years (especially after all the sad events of '22). I recently pulled out my AG-1970, only to learn that it no longer powers on at all.

Oof

Quote:

Originally Posted by lordsmurf

I also wonder if the power grid has damaged it. Remember, TBCs have zero protections, as these devices were expected to be placed behind UPS. So if you plugged it into a wall, even minor power fluctuations may nuke it. Not necessarily permanent (though possible), but enough to cause various issues.

I took your previous advice on UPS pretty seriously and used it with a sinusoidal UPS. I don't remember how many VAs it has but I doubt I was reaching anywhere close to it's limit.

Quote:

Originally Posted by lordsmurf

Leave it alone for some hours, as you plan. Sometimes internal power components need to be "jump started", but the first power on attempt fails. You need to take breaks between attempts -- but not too long, nor too short.

Unfortunately it still seems dead and no tests I do give any different result

[lordsmurf]

You're right, 12V 2A positive. Tired, rushed, don't know why I wrote that.

No, no service manual.
I know a few people that could look at it for you, but this is the wrong time of year for it.

[timtape]

I'm an electronics service technician. Probably it's capacitor failure. They eventually dry out. The replacement parts are inexpensive and easily available. I suggest having a technician test the capacitors.

[lordsmurf]

Quote:

Originally Posted by timtape

I'm an electronics service technician. Probably it's capacitor failure. They eventually dry out. The replacement parts are inexpensive and easily available. I suggest having a technician test the capacitors.

With this exact model, capacitors are actually less likely. Wear tends to happen at i/o and power input, as well as some chip issues. But caps certainly possible, just not the 1st troubleshooting stop. I'd need to make sure the OP hasn't make a handling mistake, or that it didn't get some sort of invisible transit damage a year ago. Now, that said, this does seem like power related, once others are easily/quickly elimated. Testing caps is a good idea here.

[timtape]

Sure, I'm not familiar with that TBC. It'd be interesting to know to know whether the electrolytics are the older lead types or the later Surface Mount, the latter being the more failure prone generally.