Sony KV27S15 - 10 minute delay after power on

[Sean Collins]

I have Sony KV27S15 TV which has worked fine since 1995. It has a
soft-start after power up, which delayed about 5-8 seconds before
lighting up the CRT.

About 6-8 months ago, the delay began to gradually get longer and
longer. The delay is now over 10 minutes from when the TV is first
turned on before a picture comes on. Audio comes on instantly.

Even after the TV has been on for hours, changing channels will cause a
blank screen for anywhere from 15-60 seconds, it varies.

Does anyone have a clue what circuit(s) I should be looking at to find
the problem? I do have the schematics.

Thanks

Sean

 

[James Sweet]

I have Sony KV27S15 TV which has worked fine since 1995. It has a
soft-start after power up, which delayed about 5-8 seconds before
lighting up the CRT.

About 6-8 months ago, the delay began to gradually get longer and
longer. The delay is now over 10 minutes from when the TV is first
turned on before a picture comes on. Audio comes on instantly.

Even after the TV has been on for hours, changing channels will cause a
blank screen for anywhere from 15-60 seconds, it varies.

Does anyone have a clue what circuit(s) I should be looking at to find
the problem? I do have the schematics.

Thanks

Sean

Usually this starts to happen when the CRT is getting weak. You may be able
to squeeze a few more months/years out of it by cranking up the G2 control a
tad.

 

[[email protected]]

Sean Collins:
The schematics you have are not going to help you.
More that likely the CRT is showing it age and lower emissions
causing the internal circuitry to "wait" until the emissions are high
enough before it unblanks the video.
Start looking for a new television.... not worth installing a new CRT.
electricitym

 

[[email protected]]

Troubleshoot the AKB circuit starting at the crt. Odds are very high
that following Sony's procedure for the AKB will reveal a weak and out
of balance gun in the picture tube. The proper fix is a new picture
tube, simply not worth it.

 

[Inty]

Sean Collins:
The schematics you have are not going to help you.
More that likely the CRT is showing it age and lower emissions
causing the internal circuitry to "wait" until the emissions are high
enough before it unblanks the video.
Start looking for a new television.... not worth installing a new CRT.

He can try to crank up the G2 pot, and power the filiment from ca. 8 or 9V !

I.

 

[NSM]

Usually this starts to happen when the CRT is getting weak. You may be able
to squeeze a few more months/years out of it by cranking up the G2 control a
tad.

We had a nasty trick of connecting a wire to the HV lead and flashing it on
a grid to 'boost' the tube a bit. Kind of a cheap version of what some
testers would do.

Was worth a try if the tube was nearly gone. Those were the days, eh? Who
would do that stuff now?

N

 

[Tom MacIntyre]

I have Sony KV27S15 TV which has worked fine since 1995. It has a
soft-start after power up, which delayed about 5-8 seconds before
lighting up the CRT.

About 6-8 months ago, the delay began to gradually get longer and
longer. The delay is now over 10 minutes from when the TV is first
turned on before a picture comes on. Audio comes on instantly.

Even after the TV has been on for hours, changing channels will cause a
blank screen for anywhere from 15-60 seconds, it varies.

Does anyone have a clue what circuit(s) I should be looking at to find
the problem? I do have the schematics.

Thanks

Sean

The CRT is failing. Sometimes getting a CRT restoration done will get
you another 6-8 months out of the set...sometimes a technician can do
a setup adjustment and get the picture back for awhile, but the CRT is
failing, I'm virtually certain.

Tom

 

[Tom MacIntyre]

We had a nasty trick of connecting a wire to the HV lead and flashing it on
a grid to 'boost' the tube a bit. Kind of a cheap version of what some
testers would do.

Was worth a try if the tube was nearly gone. Those were the days, eh? Who
would do that stuff now?

N

I had a couple of tricks to use the HV (through an HV probe) to blow
away focus and G2 shorts. One was quite reliable, and the other was
iffy, but I forget which...I think the G2 one was the iffy one,
though.

Tom

 

[Sean Collins]

Gentlemen:

Thanks very much for your advice. It would seem I'll be shopping for a
new TV. Perhaps time for a nice LCD panel.

However, I'm an obstinate type, so I will try your suggestions to see
what comes of it.

This leads me wonder to about quality and longevity of more recent
electronics appliances. In the past year I have experienced 3 failures
of televisions and computer monitors, all of the most recent vintage.
Yet older TVs & monitors are still working.

1995 Sony KV27S15: CRT dying of old age ?
1999 Sony Trinitron 21" CRT monitor: horizontal deflection failed
2000 NEC/Mitsubishi 19" Diamondtron monitor: vertical deflection failed

Yet I have:

1985 NEC 15" TV: still going strong
1989 NEC 20" TV: still going strong
1989 NEC FG 15" monitor: still going strong
1989 RasterOps 20" Trinitron: Still working good, but dimmer than new
1990 HP 17" Trinitron monitor: still going strong
1991 Magnavox 15" TV: still going strong

Was there a big shift in quality in the early '90s, or are larger
displays more prone to failures?

Thanks again

Sean

 

[Tom MacIntyre]

Gentlemen:

Thanks very much for your advice. It would seem I'll be shopping for a
new TV. Perhaps time for a nice LCD panel.

However, I'm an obstinate type, so I will try your suggestions to see
what comes of it.

This leads me wonder to about quality and longevity of more recent
electronics appliances. In the past year I have experienced 3 failures
of televisions and computer monitors, all of the most recent vintage.
Yet older TVs & monitors are still working.

1995 Sony KV27S15: CRT dying of old age ?
1999 Sony Trinitron 21" CRT monitor: horizontal deflection failed
2000 NEC/Mitsubishi 19" Diamondtron monitor: vertical deflection failed

I think many people at least theorize that it's the battle to satisfy
consumer desires for low prices. It started before 1995, though, and
that Sony CRT thing is very common, and it seems to always be the
green cathode that is the problem.

Tom

 

[NSM]

Was there a big shift in quality in the early '90s, or are larger
displays more prone to failures?

Wal-Mart. When you have low, low prices you usually have low, low quality
(and wages).

N

 

[Inty]

The CRT is failing. Sometimes getting a CRT restoration done will get
you another 6-8 months out of the set...sometimes a technician can do
a setup adjustment and get the picture back for awhile, but the CRT is
failing, I'm virtually certain.

Why discourage he ? ;-) If you power the filiment from 12V and restaurate
the CRT it can last for about two years...

I.

 

[Sean Collins]

Problem is fixed for now!

A slight tweak of the G2 pot, and it's back to 8-9 seconds after power
on, and channel changes are almost instantaneous again.

It's bought me enough time to shop frugally for a new one.

Thanks a million!

Sean

 

[Tom MacIntyre]

Why discourage he ? ;-) If you power the filiment from 12V and restaurate
the CRT it can last for about two years...

I.

Simply telling the truth, based on my experience. The restores I've
done on these CRT's generally bought about 6 months give or take, and
you'd get away with it 3 times at the most. Any hike in filament
voltage, while possibly lengthening the useful life of the CRT, is
shortening the actual life of the filament coating. My experience on
sets that I have performed these procedures on.

Nowhere did I say to not bother trying to keep it going...if it was
mine, I would give it some time and effort.

Tom