Prev: IFR-2398 Spectrum analyzer HELP
Next: How to convert old NuTone Intercom IM-4006 cassette to iPod
From: Sylvia Else on 29 Dec 2009 00:00
hr(bob) hofmann(a)att.net wrote:
> On Dec 28, 8:36 pm, Sylvia Else <syl...(a)not.at.this.address> wrote:
>> Franc Zabkar wrote:
>>> On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) hofm...(a)att.net"
>>> <hrhofm...(a)att.net> put finger to keyboard and composed:
>>>> Just had a Sony Model KV-1380R given to me a couple of days ago. Only
>>>> problem is simultaneous but intermittent horizontal and vertical
>>>> shrinkage of about 20%, on a random basis.
>>> It sounds like the EHT is increasing substantially. Does the set have
>>> separate horizontal deflection and EHT generation circuits? Is there a
>>> H-stat?
>>> http://www.repairfaq.org/samnew/tvfaq/tvsonyhstat.htm
>>> http://www.repairfaq.org/samnew/tvfaq/tvmohstat.htm
>>> - Franc Zabkar
>> Would also make the image brighter, wouldn't it?
>>
>> Sylvia.- Hide quoted text -
>>
>> - Show quoted text -
>
> Sylvia:
>
> It might, it is hard to tell if the image gets brighter since I have
> never actually seen it make the transition from normal to shrunk.

Perhaps get a video camera and recorder on it? Would also tell you
whether the change is abrupt, or somewhat gradual, which you presumably
also don't yet know.

Sylvia.
From: Franc Zabkar on 29 Dec 2009 01:39
On Tue, 29 Dec 2009 13:36:17 +1100, Sylvia Else
<sylvia(a)not.at.this.address> put finger to keyboard and composed:

>Franc Zabkar wrote:
>> On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) hofmann(a)att.net"
>> <hrhofmann(a)att.net> put finger to keyboard and composed:
>>
>>> Just had a Sony Model KV-1380R given to me a couple of days ago. Only
>>> problem is simultaneous but intermittent horizontal and vertical
>>> shrinkage of about 20%, on a random basis.
>>
>> It sounds like the EHT is increasing substantially. Does the set have
>> separate horizontal deflection and EHT generation circuits? Is there a
>> H-stat?
>>
>> http://www.repairfaq.org/samnew/tvfaq/tvsonyhstat.htm
>>
>> http://www.repairfaq.org/samnew/tvfaq/tvmohstat.htm
>>
>> - Franc Zabkar
>
>Would also make the image brighter, wouldn't it?
>
>Sylvia.

Yes, I would think so.

As for the effects on H & V size, if the set generates the EHT from
the line stage, then I'm finding it difficult to comprehend how the
size varies proportionately in both directions.

If the B+ were to increase, then the horizontal deflection current
would also tend to increase. However the vertical deflection current
should remain unchanged because there is a low ohm, current sensing,
feedback resistor in the yoke circuit. At the same time, the EHT would
increase and the raster would shrink.

AFAICs, the width should be far less affected than the height.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
From: Sylvia Else on 29 Dec 2009 07:07
Franc Zabkar wrote:
> On Tue, 29 Dec 2009 13:36:17 +1100, Sylvia Else
> <sylvia(a)not.at.this.address> put finger to keyboard and composed:
>
>> Franc Zabkar wrote:
>>> On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) hofmann(a)att.net"
>>> <hrhofmann(a)att.net> put finger to keyboard and composed:
>>>
>>>> Just had a Sony Model KV-1380R given to me a couple of days ago. Only
>>>> problem is simultaneous but intermittent horizontal and vertical
>>>> shrinkage of about 20%, on a random basis.
>>> It sounds like the EHT is increasing substantially. Does the set have
>>> separate horizontal deflection and EHT generation circuits? Is there a
>>> H-stat?
>>>
>>> http://www.repairfaq.org/samnew/tvfaq/tvsonyhstat.htm
>>>
>>> http://www.repairfaq.org/samnew/tvfaq/tvmohstat.htm
>>>
>>> - Franc Zabkar
>> Would also make the image brighter, wouldn't it?
>>
>> Sylvia.
>
> Yes, I would think so.
>
> As for the effects on H & V size, if the set generates the EHT from
> the line stage, then I'm finding it difficult to comprehend how the
> size varies proportionately in both directions.
>
> If the B+ were to increase, then the horizontal deflection current
> would also tend to increase. However the vertical deflection current
> should remain unchanged because there is a low ohm, current sensing,
> feedback resistor in the yoke circuit. At the same time, the EHT would
> increase and the raster would shrink.
>
> AFAICs, the width should be far less affected than the height.
>
> - Franc Zabkar

What I had in mind when I asked the question I'm finding it difficult to
express properly. If people will allow me some lattitude in terminology
then, it seemed to me that some TVs, at least, contain a digital
processor which, amongst other things, allows control of the picture
size from a maintenance menu. If that processor was getting confused
about how big the picture should be - e.g. a digital bit has gone flaky
- then it could be adjusting the image size accordingly, but also
adjusting the beam current to maintain constant brightness.

Thus it seems to me that whether the brightness changes is an important
symptom.

Sylvia.
From: Andy Cuffe on 29 Dec 2009 11:40
On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) hofmann(a)att.net"
<hrhofmann(a)att.net> wrote:

>Just had a Sony Model KV-1380R given to me a couple of days ago. Only
>problem is simultaneous but intermittent horizontal and vertical
>shrinkage of about 20%, on a random basis. Removed the set back,
>problem is still intermittent, but appears to be less frequent. Tried
>beating on anything related to power supply, both in normal and
>trouble modes, no effects. I suspect something in the power supply
>since both H & V are affected. Currently running the set with a
>voltmeter on B+ which is running about 155V, waiting for something to
>go wrong. But I can't sit around watching the set, just check it
>intermittently. Anyone had similar problems with this or similar
>Sonys. Photofact folder is 2564, putting manufacture date at sometime
>in 1987 or early 1988. If anyone has a pdf of this folder, please let
>me know.

My money would be on the STRXXXX voltage regulator that most Sony's of
that era had. They are a common failure, although they usually do go
intermittent.
Andy Cuffe

acuffe(a)gmail.com
From: hr(bob) hofmann on 29 Dec 2009 21:11
On Dec 28, 11:00 pm, Sylvia Else <syl...(a)not.at.this.address> wrote:
> hr(bob) hofm...(a)att.net wrote:
> > On Dec 28, 8:36 pm, Sylvia Else <syl...(a)not.at.this.address> wrote:
> >> Franc Zabkar wrote:
> >>> On Sun, 27 Dec 2009 21:54:47 -0800 (PST), "hr(bob) hofm...(a)att.net"
> >>> <hrhofm...(a)att.net> put finger to keyboard and composed:
> >>>> Just had a Sony Model KV-1380R given to me a couple of days ago.  Only
> >>>> problem is simultaneous but intermittent horizontal and vertical
> >>>> shrinkage of about 20%, on a random basis.
> >>> It sounds like the EHT is increasing substantially. Does the set have
> >>> separate horizontal deflection and EHT generation circuits? Is there a
> >>> H-stat?
> >>>http://www.repairfaq.org/samnew/tvfaq/tvsonyhstat.htm
> >>>http://www.repairfaq.org/samnew/tvfaq/tvmohstat.htm
> >>> - Franc Zabkar
> >> Would also make the image brighter, wouldn't it?
>
> >> Sylvia.- Hide quoted text -
>
> >> - Show quoted text -
>
> > Sylvia:
>
> > It might, it is hard to tell if the image gets brighter since I have
> > never actually seen it make the transition from normal to shrunk.
>
> Perhaps get a video camera and recorder on it? Would also tell you
> whether the change is abrupt, or somewhat gradual, which you presumably
> also don't yet know.
>
> Sylvia.- Hide quoted text -
>
> - Show quoted text -

good point!
First  |  Prev  |  Next  |  Last
Pages: 1 2 3 4
Prev: IFR-2398 Spectrum analyzer HELP
Next: How to convert old NuTone Intercom IM-4006 cassette to iPod