Sony Trinitron kv-28wf1d LED blinks twice

Two flashes isn't very helpful, as it's just 'trip anytime', so gives no specific information.

There's a protection line, labelled 'PROT' on socket CN902 pin 9, this goes high if the hardware protection circuits are triggered, so check the voltage on that point for a start, see if it's going high.

Other than that, protection is also triggered via the I2C bus, if the processor doesn't receive the correct replies over the bus, then it goes into protect mode, and (hopefully) gives a more helpful flashing sequence.

Although as it checks the IC's on the I2C bus in sequence, any direct fault on the bus (such as a data or clock line short) will fail on the first IC it checks, which may not (and usually isn't) the issue.

I wouldn't expect adjusting the vertical position to cause the set to trip out - but if the PROT line is going high?, then check the cathode of D505 (vertical protection), see if that's going high - if it is, then it should be 3.6V or so higher than the PROT line.

Nigel Goodwin said:

Two flashes isn't very helpful, as it's just 'trip anytime', so gives no specific information.

There's a protection line, labelled 'PROT' on socket CN902 pin 9, this goes high if the hardware protection circuits are triggered, so check the voltage on that point for a start, see if it's going high.

Other than that, protection is also triggered via the I2C bus, if the processor doesn't receive the correct replies over the bus, then it goes into protect mode, and (hopefully) gives a more helpful flashing sequence.

Although as it checks the IC's on the I2C bus in sequence, any direct fault on the bus (such as a data or clock line short) will fail on the first IC it checks, which may not (and usually isn't) the issue.

I wouldn't expect adjusting the vertical position to cause the set to trip out - but if the PROT line is going high?, then check the cathode of D505 (vertical protection), see if that's going high - if it is, then it should be 3.6V or so higher than the PROT line.

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I could use a little bit of guidance, I have no experience at all with CRTs. Are there any safety steps I gotta do (like discharging)? There isn't even a proper electrical ground in the house I'm in so that could pose an issue.

kintama said:

I could use a little bit of guidance, I have no experience at all with CRTs. Are there any safety steps I gotta do (like discharging)? There isn't even a proper electrical ground in the house I'm in so that could pose an issue.

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You don't need an earth, and there's nothing inherently safe about having an earth anyway - all it does is shift the danger to a different 'place'. But almost all TV's aren't earthed anyway, they are class-II devices - although over the years there have been a VERY few class-I (earthed) devices, but they are rare (and I've never figured out the reason for them?).

Danger wise, the primary side of the power supply is live to the mains, so keep away from that - the secondary side is isolated from the mains, but if your house isn't earthed that won't make much difference anyway.

The CRT has about 27,000V on the final anode, and the CRT can hold that charge for a long time - so keep away from the CRT.

The PROT line I mentioned is only low voltage, and on the isolated (safer) side of the power supply - so is inherently low risk.

However, if you've no experience of working on live/isolated equipment, perhaps you should give it a miss.

Nigel Goodwin said:

You don't need an earth, and there's nothing inherently safe about having an earth anyway - all it does is shift the danger to a different 'place'. But almost all TV's aren't earthed anyway, they are class-II devices - although over the years there have been a VERY few class-I (earthed) devices, but they are rare (and I've never figured out the reason for them?).

Danger wise, the primary side of the power supply is live to the mains, so keep away from that - the secondary side is isolated from the mains, but if your house isn't earthed that won't make much difference anyway.

The CRT has about 27,000V on the final anode, and the CRT can hold that charge for a long time - so keep away from the CRT.

The PROT line I mentioned is only low voltage, and on the isolated (safer) side of the power supply - so is inherently low risk.

However, if you've no experience of working on live/isolated equipment, perhaps you should give it a miss.

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A relative of mine brought the TV to a technician he knows and he, apparently, said something burned through. I don't know what exactly, because the relative of mine isn't very technical. Also he said that the failure indeed had to do with me fiddling around in the factory settings. I'll be seing the technician soon for more details, it would be great if you can do something with the current info.

kintama said:

A relative of mine brought the TV to a technician he knows and he, apparently, said something burned through. I don't know what exactly, because the relative of mine isn't very technical. Also he said that the failure indeed had to do with me fiddling around in the factory settings. I'll be seing the technician soon for more details, it would be great if you can do something with the current info.

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Not without knowing what 'burned through', 'fiddling' with factory settings can certainly kill a TV, but vertical shift probably shouldn't.

You must really love that old Trinitron to spend so much time and effort (and possibly technician labor costs) to fix it.

crutschow said:

You must really love that old Trinitron to spend so much time and effort (and possibly technician labor costs) to fix it.

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Most of them just went for scrap, when flat screens came out they were completely worthless - we had quite a few Sony 28's and 32's out on rental, and normally they would come back in after 2 years, and be sold as ex-rental sets. Once the flat screens came out, they came back after two years and were sent for recycling

Nigel Goodwin said:

Once the flat screens came out, they came back after two years and were sent for recycling

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Rather sad.
That's the downside of technical advances.
The Trinitron was once the cat's meow of TV's, when suddenly it became obsolete and destined for the trash.
And the sophisticated plant that made those huge, amazing tubes was suddenly out of business.
I wonder if it was converted to make flat screens(?).

crutschow said:

Rather sad.

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It was really, and particularly so for the company I used to work for - as when you rent a TV out for two years you essentially just about recover the cost price of the TV, so any profit you hope to make depends on selling the set as ex-rental when it comes back.

crutschow said:

That's the downside of technical advances.
The Trinitron was once the cat's meow of TV's, when suddenly it became obsolete and destined for the trash.
And the sophisticated plant that made those huge, amazing tubes was suddenly out of business.

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All the CRT plants went that way, many even before flat-screens came out - Philips-LG for example had millions of pounds from the UK government (tax payers!!) to build a CRT factory in Wales. They only ran it for a relatively short time (producing absolutely crap and unreliable CRT's), and then closed it - there were rumours about legal action against Philips and LG.

crutschow said:

I wonder if it was converted to make flat screens(?).

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Sony never made flat screen panels, the closest they came was S-LCD, which was a 'collaboration' with Samsung - basically Sony put money in to a Samsung plant manufacturing LCD's, the technology was entirely Samsung, Sony just provided money. Due to this Samsung owned 51%, and Sony owned 49%, of the company. The panels were labelled Samsung for Samsung sets (and anyone else they sold them to) and labelled S-LCD for Sony sets. The labels were identical though, with just one word changed

It all turned bad though, when demand out-stripped manufacturing capacity, and Samsung started keeping more of the production for themselves, leaving Sony in the cold - this resulted in Sony selling their 49% back to Samsung, and sourcing their LCD panels elsewhere - possibly from multiple sources, as they did before the S-LCD deal.

Interestingly, S-LCD must have manufactured different qualities of panels, because you could put a Samsung and a Sony set on side by side, and the Sony was a far better picture. This was obviously partly due to better design and construction of the Sony set (their scalers were the best), but also the viewing angle was far superior, something that is only down to panel design.