Toshiba TV29C90 problem; Image fades to black...

Tek does not support it. So I need a used one - anyone have one for
sale?
Jim Yanik wrote:

beemererik@bellsouth.net wrote in
news:1165947495.260412.246950@79g2000cws.googlegroups.com:

One attenuator in my TDS744 is damaged. Can anyone tell me where I
might find a replacement or have it repaired.

Thanks.



www.tek.com,IF they still support it.
Otherwise,you may have to cannabalize another broken TDS744.

the entire TDS series of scopes were intended for module exchange service
only,unless TEK does the repair. That's Beaverton or DC Service centers.

--
Jim Yanik
jyanik
at
kua.net

 

[Jim]

N Cook wrote:

Could a Crate BV120H valve amp really blow 4x 12 inch 16 ohm speaker box ?

Yes, if speakers can't handle 30W.

Amp as received was set for 16 ohm output, I measured the speaker box
impedance at 13 ohm,

You mean you measured DCR, DC resistance. 13 is typical for 16 ohm
speakers.

or so, before connecting up just to be sure.

Very feeble and distorted sound. No signs of the reported burning smell,
output matching transformer primaries at about 50 ohm seemed ok and
secondaries not open circuit in the amp so turned to the speakers. The amp
o/p switch setting was set for 4 ohms instead of 16 ohms but as I measured
16 ohms I assumed a switch problem.

You can get flyback voltages sufficient to punch through windings in the
OPT, or sufficient to arc tube sockets. If it was good before the
mistake, and bad after, the answer is obvious.

Taking apart 2 pairs of paralleled 16 ohm speakers so settable as series
pair of 8 ohm for 16, or 4 paralleled for 4 ohm.
3 of these speakers are open circuit leaving one giving the 16 ohm reading ,
and the fourth one driving from another source is distorting.

Wait a minute. Conventionally wired 16 ohm cab with 16 ohms speakers
will have NO SOUND if three speakers are blown.

Can a valve amp really progressively burn out, in turn, 16 ohm speakers ?
Driving just one initially, I could understand, like the final remnant one
here.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

 

Scrim wrote:

"Andy Cuffe" <acuffe@gmail.com> wrote in message

I've seen a LOT of flat CRT Sony monitors with bad CRTs that cause
arcing and loss, or change of focus.
Andy Cuffe

acuffe@gmail.com

Hi Andy,
Thanks a lot for the info about the 'Neon' spark gaps having a dark coating
from new. I wouldn't have considered that possibility.
The intermittent blur seems to have stopped for now, but I always got the
impression it was worse in cold weather. My hope was that if it turned out
to be the tube I might help it with a bit of carefully placed thermal
insulation.

Scrim

not a chance. If the tube's arcing you might be able to clear the short
- you might even fix it with just flicking the neck if youre lucky.
Just dont break it or all hell will break loose.


NT

 

Scrim wrote:

"Andy Cuffe" <acuffe@gmail.com> wrote in message
news:89k0o21l64e8kevsecp8o8chjo8mj4ep8r@4ax.com...
On 12 Dec 2006 21:42:43 -0800, meow2222@care2.com wrote:
Homer J Simpson wrote:
"Scrim" <nospam@nospam.com> wrote in message
news:Qxzfh.64620$Pk.18615@fe2.news.blueyonder.co.uk...

Tell me what these Neon Bulbs are for?

They are spark gaps.

Seems a bit strange they all have darkened glass.

Those have darkened glass even when they are new.

To keep the strike voltage up?

NT

 

[Jim Yanik]

beemererik@bellsouth.net wrote in
news:1166054306.729212.290180@l12g2000cwl.googlegroups.com:

Tek does not support it. So I need a used one - anyone have one for
sale?
Jim Yanik wrote:
beemererik@bellsouth.net wrote in
news:1165947495.260412.246950@79g2000cws.googlegroups.com:

One attenuator in my TDS744 is damaged. Can anyone tell me where I
might find a replacement or have it repaired.

Thanks.



www.tek.com,IF they still support it.
Otherwise,you may have to cannabalize another broken TDS744.

the entire TDS series of scopes were intended for module exchange
service only,unless TEK does the repair. That's Beaverton or DC
Service centers.

--
Jim Yanik
jyanik
at
kua.net

try Ebay,or Google search for other test equipment sales,although they will
tend to keep broken scopes themselves,for their own parts sources.

TDS 744*A* models should use the same basic parts.(different SW)

--
Jim Yanik
jyanik
at
kua.net

 

[Homer J Simpson]

<meow2222@care2.com> wrote in message
news:1166061269.592965.89730@f1g2000cwa.googlegroups.com...

To keep the strike voltage up?

Could be. And maybe to avoid scaring the purchasers.

 

Homer J Simpson wrote:

meow2222@care2.com> wrote in message
news:1166061269.592965.89730@f1g2000cwa.googlegroups.com...

To keep the strike voltage up?

Could be. And maybe to avoid scaring the purchasers.

good point. I guess thats why they dont use mercury fill then

NT

 

[mhancock84]

I just purchase a 60 inch projection pioneer sd-p6091 t.v. and was
wondering if anyone can help me out here....

I will turn the t.v. on and it will work fine for 2-3 minutes and then
the volume will turn up by itself and the t.v. will cut off. I know it
sounds weird but does anyone have any idea what could be wrong? Could
it need a new switch or am i just s.o.l.

Any feedback would be appreciated....


--
mhancock84
------------------------------------------------------------------------
mhancock84's Profile: http://www.futurehardware.in/member.php?userid=308
View this thread: http://www.futurehardware.in/showthread.php?t=241635

Future Hardware - http://www.futurehardware.in

 

[Andy Cuffe]

On Wed, 13 Dec 2006 23:43:33 GMT, "Scrim" <nospam@nospam.com> wrote:

Hi Andy,
Thanks a lot for the info about the 'Neon' spark gaps having a dark coating
from new. I wouldn't have considered that possibility.
The intermittent blur seems to have stopped for now, but I always got the
impression it was worse in cold weather. My hope was that if it turned out
to be the tube I might help it with a bit of carefully placed thermal
insulation.

Scrim

I used a 21" Sony for quite a while with a CRT that was acting like
yours. It was ok most of the time, but would occasionally act up for
between a few seconds and a few minutes. Eventually it settled down
to the point where it would only act up every few weeks. After about
a year I found a broken non-Sony monitor with the same Sony CRT and
did a swap. It never acted up again.
Andy Cuffe

acuffe@gmail.com

 

[N Cook]

Jim <askme@beforeyousend.com> wrote in message
news:12o188odrp41acf@corp.supernews.com...

N Cook wrote:

Could a Crate BV120H valve amp really blow 4x 12 inch 16 ohm speaker box
?

Yes, if speakers can't handle 30W.


Amp as received was set for 16 ohm output, I measured the speaker box
impedance at 13 ohm,

You mean you measured DCR, DC resistance. 13 is typical for 16 ohm
speakers.

or so, before connecting up just to be sure.
Very feeble and distorted sound. No signs of the reported burning smell,
output matching transformer primaries at about 50 ohm seemed ok and
secondaries not open circuit in the amp so turned to the speakers. The
amp
o/p switch setting was set for 4 ohms instead of 16 ohms but as I
measured
16 ohms I assumed a switch problem.

You can get flyback voltages sufficient to punch through windings in the
OPT, or sufficient to arc tube sockets. If it was good before the
mistake, and bad after, the answer is obvious.


Taking apart 2 pairs of paralleled 16 ohm speakers so settable as series
pair of 8 ohm for 16, or 4 paralleled for 4 ohm.
3 of these speakers are open circuit leaving one giving the 16 ohm
reading ,
and the fourth one driving from another source is distorting.

Wait a minute. Conventionally wired 16 ohm cab with 16 ohms speakers
will have NO SOUND if three speakers are blown.


Can a valve amp really progressively burn out, in turn, 16 ohm speakers
?
Driving just one initially, I could understand, like the final remnant
one
here.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

it would progressively have failed from collective 4 ohm to 5.3 to 8 to the
current overdriven and useless single 16 ohm one

 

[Ron(UK)]

N Cook wrote:

it would progressively have failed from collective 4 ohm to 5.3 to 8 to the
current overdriven and useless single 16 ohm one


Are you saying that the four speakers were all wired in parallel, to

give 4 ohms? That`s unusual for a 4x12 guitar cab. they would usually
be in series/parallel, giving 16 ohms, and allowing two cabinets to be
used with the amp. In which case, if any one speaker went o/c, its
'series twin' would stop receiving power but the other pair would still
work - until they were overloaded and blew.

Ron(UK)

 

[N Cook]

Ron(UK) <ron@lunevalleyaudio.com> wrote in message
newsOCdnZWjluZ_qhzYRVnytAA@bt.com...

N Cook wrote:


it would progressively have failed from collective 4 ohm to 5.3 to 8 to
the
current overdriven and useless single 16 ohm one


Are you saying that the four speakers were all wired in parallel, to
give 4 ohms? That`s unusual for a 4x12 guitar cab. they would usually
be in series/parallel, giving 16 ohms, and allowing two cabinets to be
used with the amp. In which case, if any one speaker went o/c, its
'series twin' would stop receiving power but the other pair would still
work - until they were overloaded and blew.

Ron(UK)

Crate BV412R, Blue Voodoo
2 separate permanently wired paralleled pairs of 16 ohms so 9 ohms each
section.
Switched so they are in series to give 8 + 8 = 16
or paralleled to give 8//8 = 4 , ie all 4 in paralle

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

 

[Homer J Simpson]

"mhancock84" <mhancock84.2isgpd@nospamplease.com> wrote in message
news:mhancock84.2isgpd@nospamplease.com...

I just purchase a 60 inch projection pioneer sd-p6091 t.v.

Used or new?

 

[GregS]

In article <elrtg5$ro3$2@usenet01.srv.cis.pitt.edu>, szekeres@pitt.edu (GregS) wrote:

I have not found any fixes for paper skewing/jamming other than the
obvious cleaning. Funny the way it works with only one roller on the side,
of course it sucks in the paper on this side only.

Woops.

Found two toys inside.

greg

 

[Xtrchessreal]

N Cook wrote:

Ron(UK) <ron@lunevalleyaudio.com> wrote in message
newsOCdnZWjluZ_qhzYRVnytAA@bt.com...
N Cook wrote:


it would progressively have failed from collective 4 ohm to 5.3 to 8 to
the
current overdriven and useless single 16 ohm one


Are you saying that the four speakers were all wired in parallel, to
give 4 ohms? That`s unusual for a 4x12 guitar cab. they would usually
be in series/parallel, giving 16 ohms, and allowing two cabinets to be
used with the amp. In which case, if any one speaker went o/c, its
'series twin' would stop receiving power but the other pair would still
work - until they were overloaded and blew.

Ron(UK)

Crate BV412R, Blue Voodoo
2 separate permanently wired paralleled pairs of 16 ohms so 9 ohms each
section.
Switched so they are in series to give 8 + 8 = 16
or paralleled to give 8//8 = 4 , ie all 4 in paralle

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

I want to jump in here and ask another related question.

It sounds like there are at least two ways to wire a 16 Ohm 4x12 cab.
One way explained above where two pairs are 16//16 and then those are
series 8+8. Another way would be series two pairs 16+16 and then
32//32 to give 16.

Reading the discussion above it sounds like if the cab was wired like
the latter above a pair of the speakers in the cab blowing would have
meant the amp seeing 32 Ohms and the rest would not have happened.
Saving half of the speakers and the amp.

Is this correct?

 

[N Cook]

Xtrchessreal <XtrChessreal@gmail.com> wrote in message
news:1166126999.797840.113190@f1g2000cwa.googlegroups.com...

N Cook wrote:
Ron(UK) <ron@lunevalleyaudio.com> wrote in message
newsOCdnZWjluZ_qhzYRVnytAA@bt.com...
N Cook wrote:


it would progressively have failed from collective 4 ohm to 5.3 to 8
to
the
current overdriven and useless single 16 ohm one


Are you saying that the four speakers were all wired in parallel, to
give 4 ohms? That`s unusual for a 4x12 guitar cab. they would usually
be in series/parallel, giving 16 ohms, and allowing two cabinets to be
used with the amp. In which case, if any one speaker went o/c, its
'series twin' would stop receiving power but the other pair would
still
work - until they were overloaded and blew.

Ron(UK)

Crate BV412R, Blue Voodoo
2 separate permanently wired paralleled pairs of 16 ohms so 9 ohms each
section.
Switched so they are in series to give 8 + 8 = 16
or paralleled to give 8//8 = 4 , ie all 4 in paralle

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

I want to jump in here and ask another related question.

It sounds like there are at least two ways to wire a 16 Ohm 4x12 cab.
One way explained above where two pairs are 16//16 and then those are
series 8+8. Another way would be series two pairs 16+16 and then
32//32 to give 16.

Reading the discussion above it sounds like if the cab was wired like
the latter above a pair of the speakers in the cab blowing would have
meant the amp seeing 32 Ohms and the rest would not have happened.
Saving half of the speakers and the amp.

Is this correct?

But how to wire 4x 16 ohmers for overal 4 ohm and best amp protection and/or
speaker preservation ? It is the 4 ohm setting that is likely to lead to
troubles in incompetent hands or even maybe persons deliberately getting
more welly

 

[David Naylor]

jerry74x wrote:

Hi i have a JVC TV, in the last two days when i plug it to the power the
on timer light turn on, you can hear the click of the relay, after few
seconds the light is turning on and off and nothing happen with the TV.
I heard about the c926 capacitor but i can't find it. I changed the Hor
Transistor but is not working. Where i can locate this C926 in this
board. Thanks for any help.


try this jump the relay the 2 angled connections on the relay plug in

the set and see if it operates ok. if so change out q 921 I believe.
this is the power ont transistor and goes quite often on these sets.
it calls for and npn darlinton transitor but I have had very good luck
with just a standard npn fast switching one...good luck. if the set
does not operate with the realy jump don't bother replacing the
transistor it is most likely the flyback

 

[James Sweet]

Scrim wrote:

meow2222@care2.com> wrote in message
news:1165988563.308387.127980@j72g2000cwa.googlegroups.com...

Homer J Simpson wrote:

"Scrim" <nospam@nospam.com> wrote in message
news:Qxzfh.64620$Pk.18615@fe2.news.blueyonder.co.uk...

Included amongst the components on the small PCB mounted on the end of
the
CRT are (what look exactly like) four wire ended neon lamps. I don't
have
much CRT experience, but still, was surprised to see these. The
service
manual refers to them as SG001 to SG301. For example, "SG001
1-519-422-11
SPARK GAP". Anyway, I haven't seen any light up, but they all have very
dark glass envelopes from internal electrode evaporation.
Can anyone:
Tell me what these Neon Bulbs are for?

They are spark gaps.

Seems a bit strange they all have darkened glass.


NT



Thanks for your thoughts folks.
The service manual is here:
http://www.eserviceinfo.com/downloadsm/17886/Sony_GDM-F520.html

You can see the 'neons' or Spark Gaps at the top right of the diagram on
page 30, located around the CRT base.

Before I took the case off, when I had the intermittent blur problem with
this monitor, occasionally I'd hear an electrical discharge (crack!) and the
focus would recover or at least change.
Googling I've found this, which was posted at this newsgroup earlier this
year:
http://groups.google.com/group/sci.electronics.repair/browse_thread/thread/d000b23669cfa864/225f9ba99b385945?lnk=st&q=+%22The+device+that+is+sparking+is+a+sealed+glass+bulb.%22&rnum=1&hl=en#225f9ba99b385945

This certainly sounds similar to what I'm describing, although another model
is involved.

Any further advice gratefully received,

Scrim

My G520 loses focus occasionally too and a power cycle fixes it. I got
rid of a similar model last year that would do the same thing, been
doing it for years and hasn't gotten any more frequent. Someone told me
it was a fault within the CRTs.

 

[James Sweet]

Those have darkened glass even when they are new.


To keep the strike voltage up?

It's part of the processing when they make it. Neon lamps are driven
hard for a time to cook impurities out of the electrodes, the spark gaps
are probably cooked a bit harder to get a uniform striking voltage.

 

[Homer J Simpson]

"GregS" <szekeres@pitt.edu> wrote in message
news:elrv2o$s4r$1@usenet01.srv.cis.pitt.edu...

I have not found any fixes for paper skewing/jamming other than the
obvious cleaning. Funny the way it works with only one roller on the side,
of course it sucks in the paper on this side only.

Woops.

Found two toys inside.

Beats a peanut butter and jelly sandwich.