Toshiba TV29C90 problem; Image fades to black...

[Phil Hobbs]

On 07/31/2018 09:03 AM, Mr. Man-wai Chang wrote:

On 7/31/2018 8:13 PM, Paul wrote:
...
     however, an unsafe power level may be collected by a
     magnifying optic with larger aperture."

Looks like that baby is safe. Nothing to worry about.

There are counters with handheld laser scanner. And those handheld
scanners are NOT placed carefully to avoid customers, at least I saw
that in Hong Kong.

Did they do it deliberately? Is it a secret laser experiment? Well...

That beam is moving so fast that the dwell time on the retina is really,
really short--probably tens of microseconds. That helps a lot.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Mr. Man-wai Chang]

On 7/31/2018 10:09 PM, Phil Hobbs wrote:

That beam is moving so fast that the dwell time on the retina is really,
really short--probably tens of microseconds.  That helps a lot.

And you are not wearing those handheld laser scanners like a VR
glass/helmet ...oh well... Um....

Is there safety classification for VR glasses/helmets?

--
@~@ Remain silent! Drink, Blink, Stretch! Live long and prosper!!
/ v \ Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
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[Mr. Man-wai Chang]

On 7/31/2018 10:40 PM, Paul wrote:

*******

And what treatment is there for a retinal burn ?
I don't think there is any treatment, except for the
doctor to say he can't help you.

Stem cells?

Would retina of some very old persons be more vulnerable to Class 1
laser burn? OK, I know Class 1 is supposed to 100% safe. But ... you
know there may be exceptions.

--
@~@ Remain silent! Drink, Blink, Stretch! Live long and prosper!!
/ v \ Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
^ ^ (x86_64 Ubuntu 9.10) Linux 2.6.39.3
不借貸! 不詐騙! 不賭錢! 不援交! 不打交! 不打劫! 不自殺! 不求神! 請考慮綜援
(CSSA):
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[pfjw@aol.com]

On Tuesday, July 31, 2018 at 10:27:25 AM UTC-4, Mr. Man-wai Chang wrote:

On 7/31/2018 10:09 PM, Phil Hobbs wrote:

That beam is moving so fast that the dwell time on the retina is really,
really short--probably tens of microseconds.  That helps a lot.

And you are not wearing those handheld laser scanners like a VR
glass/helmet ...oh well... Um....

http://www.lasersafetyfacts.com/resources/Spreadsheet---laser-classes.pdf

Some useful information on laser classes.

And, yes, there are safety standards for VR glasses.

https://www.fi.edu/virtual-reality/product-safety-information

Peter Wieck
Melrose Park, PA

 

[Mr. Man-wai Chang]

On 8/1/2018 1:25 AM, pfjw@aol.com wrote:

And you are not wearing those handheld laser scanners like a VR
glass/helmet ...oh well... Um....


http://www.lasersafetyfacts.com/resources/Spreadsheet---laser-classes.pdf

Some useful information on laser classes.

Thanks

And, yes, there are safety standards for VR glasses.

https://www.fi.edu/virtual-reality/product-safety-information

Thanks.

--
@~@ Remain silent! Drink, Blink, Stretch! Live long and prosper!!
/ v \ Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
^ ^ (x86_64 Ubuntu 9.10) Linux 2.6.39.3
不借貸! 不詐騙! 不賭錢! 不援交! 不打交! 不打劫! 不自殺! 不求神! 請考慮綜援
(CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[Mr. Man-wai Chang]

On 8/1/2018 3:19 AM, George Herold wrote:

I think class 1 is less than 1mW in the visible.
We sell a class 3B laser.. it's in the NIR... no blink reflex.
(I always encourage people to buy extra laser goggles.)

Do you trust and buy Class 1 laser products manufactured by Chinese and
Asians?

--
@~@ Remain silent! Drink, Blink, Stretch! Live long and prosper!!
/ v \ Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
^ ^ (x86_64 Ubuntu 9.10) Linux 2.6.39.3
不借貸! 不詐騙! 不賭錢! 不援交! 不打交! 不打劫! 不自殺! 不求神! 請考慮綜援
(CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[pfjw@aol.com]

I try to purchase as little as possible of Chinese origin. Too often the quality is simply not quite there yet. Obviously there are exceptions - pretty much the entire smart-phone industry is centered in China. Another reason to avoid China is that it is fast becoming the most polluted country on the planet and working hard to get there as fast as possible. purchasing goods from more regulated sources, if possible, is better for the planet as a whole.

On the other hand, most Asian countries starting with Japan, South Korea and others have a very nearly fanatical commitment to quality as it applies to automobiles and similar moving parts.

Peter Wieck
Melrose Park, PA

 

El sĂĄbado, 29 de noviembre de 1997, 4:00:00 (UTC-4), Andy Cuffe escribiĂł:

Could someone please identify this Zenith capacitor (# 22-7672-05).
It's one of the large orange ones from the early 80's that always fail.

If anyone has a list of the values for all the 22-7672-XX capacitors I
would find it very useful.
--
Andy Cuffe

I have that capacitor.

 

[John-Del]

On Wednesday, August 29, 2018 at 11:05:14 PM UTC-4, orgo...@gmail.com wrote:

El sĂĄbado, 29 de noviembre de 1997, 4:00:00 (UTC-4), Andy Cuffe escribiĂł:
Could someone please identify this Zenith capacitor (# 22-7672-05).
It's one of the large orange ones from the early 80's that always fail.

If anyone has a list of the values for all the 22-7672-XX capacitors I
would find it very useful.
--
Andy Cuffe


I have that capacitor.

You should contact the OP directly. There's a small possibility that 1) he's not monitoring this group after 20 years and 2) he may not have waited 20 years to scrap that antique.

 

[Allodoxaphobia]

On Thu, 30 Aug 2018 04:33:17 -0700 (PDT), John-Del wrote:

On Wednesday, August 29, 2018 at 11:05:14 PM UTC-4, orgo...@gmail.com wrote:
El sĂĄbado, 29 de noviembre de 1997, 4:00:00 (UTC-4), Andy Cuffe escribiĂł:
Could someone please identify this Zenith capacitor (# 22-7672-05).
It's one of the large orange ones from the early 80's that always fail.

If anyone has a list of the values for all the 22-7672-XX capacitors I
would find it very useful.
--
Andy Cuffe

I have that capacitor.

You should contact the OP directly. There's a small possibility that
1) he's not monitoring this group after 20 years and 2) he may not
have waited 20 years to scrap that antique.

Or, 3) he died.


sheesh!!!! googlegroppers!

 

[John-Del]

On Thursday, August 30, 2018 at 9:32:21 AM UTC-4, Allodoxaphobia wrote:

On Thu, 30 Aug 2018 04:33:17 -0700 (PDT), John-Del wrote:
On Wednesday, August 29, 2018 at 11:05:14 PM UTC-4, orgo...@gmail.com wrote:
El sĂĄbado, 29 de noviembre de 1997, 4:00:00 (UTC-4), Andy Cuffe escribiĂł:
Could someone please identify this Zenith capacitor (# 22-7672-05).
It's one of the large orange ones from the early 80's that always fail.

If anyone has a list of the values for all the 22-7672-XX capacitors I
would find it very useful.
--
Andy Cuffe

I have that capacitor.

You should contact the OP directly. There's a small possibility that
1) he's not monitoring this group after 20 years and 2) he may not
have waited 20 years to scrap that antique.

Or, 3) he died.

Ghoul...

 

>"he may not have waited 20 years to scrap that antique. "

If I had one of those I would restore it or at least make it work if the CRT was good.

 

>"It's puzzling enough why people reply to old posts,"

Seems most of them are on Google. They're probably doing a search and when they get hits they neglect to notice the date.

 

[John-Del]

On Thursday, August 30, 2018 at 8:58:47 PM UTC-4, jurb...@gmail.com wrote:

"he may not have waited 20 years to scrap that antique. "

If I had one of those I would restore it or at least make it work if the CRT was good.

I have a customer with a late version of the Zenith Vertical Chassis. The old bat insisted I fix it for her again a few months ago (put in a tripler about two years ago). It was shrinking left and right and blooming, and I remember fixing a bunch of these for the same problem. When I pulled my schematic I remembered that carbon resistor that overheats and goes up in value behind the 9-90 module. Looked pretty good with the sweep back to normal; strong tube. If she ever calls me to dump it, I'm putting it my truck and driving it over to your house.

 

That line started with the EC line. The best of them IMO was the GC line, ideally a 25GC45 or 50. They continued the type of chassis but started using those hybrid resistors in the later ones.

Another goodie from back then was the Magnavox T995 chassis, I would take one but I want the older version with the volume under the tuners that actually had good sound. I had a GC Zenith with good sound as well, both of them later went with speaker speakers, and the Magnavox ones switched to a volume control with a shitty taper, the older ones were nice and smooth.

Those were part of my "good" lie of sets when I was in business. They got 30 days on everything, 90 on parts and a year on the CRT. there was NEVER a TV in my main showroom with a rejuvinated CRT. Then we had the discount sets. If I zapped the tune that's where it went, and I told people they were, but all was not lost because ?I had one of the best rejuviators - a B & K 467. It had a very nice touch and didn't destroy the cathode. They gave you a stack of ONE YEAR warranty cards to give the customers with a set that had a zapped CRT.

One advantage we had was a good source for rebuilt CRTs. I forgot the name of the place but a old German guy ran it, did all the work himself. Gave a 3 year warranty. I think he was called Willie.

 

On Friday, 31 August 2018 05:39:54 UTC+1, jurb...@gmail.com wrote:

That line started with the EC line. The best of them IMO was the GC line, ideally a 25GC45 or 50. They continued the type of chassis but started using those hybrid resistors in the later ones.

Another goodie from back then was the Magnavox T995 chassis, I would take one but I want the older version with the volume under the tuners that actually had good sound. I had a GC Zenith with good sound as well, both of them later went with speaker speakers, and the Magnavox ones switched to a volume control with a shitty taper, the older ones were nice and smooth.

Those were part of my "good" lie of sets when I was in business. They got 30 days on everything, 90 on parts and a year on the CRT. there was NEVER a TV in my main showroom with a rejuvinated CRT. Then we had the discount sets. If I zapped the tune that's where it went, and I told people they were, but all was not lost because ?I had one of the best rejuviators - a B & K 467. It had a very nice touch and didn't destroy the cathode. They gave you a stack of ONE YEAR warranty cards to give the customers with a set that had a zapped CRT.

One advantage we had was a good source for rebuilt CRTs. I forgot the name of the place but a old German guy ran it, did all the work himself. Gave a 3 year warranty. I think he was called Willie.

Zapping CRTs ruins them. As emission falls again, as it does, severe smearing occurs. A much better fix is to boost the heater voltage: this lasts. I wasn't a big fan of 10% boost, 33% does the job on most sets. An extra turn on the LOPTF does that easily & cheaply on most sets.

I did try 66% voltage boost on a couple of really bad ones just for experiment's sake, and surprisingly it worked & kept working. One (Sony Trinitron) was so bad that nothing was visible at all on screen, even in a dark room. What kind of strange person kept using it until it reached that point who knows. Anyway the result was plenty of output on all channels, but colour tracking was lousy. That kept working for years until I tired of it.


NT

 

I always tried boosting the filament first. Zapping was the last resort.

Even boosting the filament kept it out the prime stock category.

 

[John-Del]

On Friday, August 31, 2018 at 7:43:22 AM UTC-4, tabb...@gmail.com wrote:

On Friday, 31 August 2018 05:39:54 UTC+1, jurb...@gmail.com wrote:
That line started with the EC line. The best of them IMO was the GC line, ideally a 25GC45 or 50. They continued the type of chassis but started using those hybrid resistors in the later ones.

Another goodie from back then was the Magnavox T995 chassis, I would take one but I want the older version with the volume under the tuners that actually had good sound. I had a GC Zenith with good sound as well, both of them later went with speaker speakers, and the Magnavox ones switched to a volume control with a shitty taper, the older ones were nice and smooth.

Those were part of my "good" lie of sets when I was in business. They got 30 days on everything, 90 on parts and a year on the CRT. there was NEVER a TV in my main showroom with a rejuvinated CRT. Then we had the discount sets. If I zapped the tune that's where it went, and I told people they were, but all was not lost because ?I had one of the best rejuviators - a B & K 467. It had a very nice touch and didn't destroy the cathode. They gave you a stack of ONE YEAR warranty cards to give the customers with a set that had a zapped CRT.

One advantage we had was a good source for rebuilt CRTs. I forgot the name of the place but a old German guy ran it, did all the work himself. Gave a 3 year warranty. I think he was called Willie.


Zapping CRTs ruins them. As emission falls again, as it does, severe smearing occurs. A much better fix is to boost the heater voltage: this lasts. I wasn't a big fan of 10% boost, 33% does the job on most sets. An extra turn on the LOPTF does that easily & cheaply on most sets.

I did try 66% voltage boost on a couple of really bad ones just for experiment's sake, and surprisingly it worked & kept working. One (Sony Trinitron) was so bad that nothing was visible at all on screen, even in a dark room. What kind of strange person kept using it until it reached that point who knows. Anyway the result was plenty of output on all channels, but colour tracking was lousy. That kept working for years until I tired of it.


NT

In my experience, boosting filament delivered the shortest amount of service life of any method.

Back in 1981, RCA had a short run of bad HV transformers (quickly resolved).. The trans was mostly conventional but had a single brown wire for CRT filament from one of the exterior terminals that went to the CRT board. As originally installed, the wire was routed between the metal frame of the trans and the chassis (metal back then).

If the trans was replaced and the brown wire was routed by the core and not between the frame and the chassis, the filament would pick up a few hundred milivolts by induction and add it to the normal 6.3. Several months after the trans was installed, the CRT would be shot. Fortunately, this happened in warranty. RCA quickly added a bulletin and a service note in the replacement trans that described how to properly route the filament wire.

Zenith in the 90s had a bunch of tubes suffer heater to cathode shorts. Most guys would thread two or three turns of bell wire around the HV trans core and feed the filaments directly (after cutting the grounded filament circuit). This would allow a full floating filament supply that wouldn't pull the cathode low even if the fil should short to the cathode. Problem was, guys would just wire so the filament looked the right color temperature but if the final voltage was much above 6.3, the tube would tire in a few months.

The solution was to use a TRMs meter (15K cycle AC from the fly) and adjust with winding count and/or a resistor to ensure the filament stayed at or even a bit smidge below 6.3TRMS AC. I did those and got many years out of those repairs.

Going back farther, we used to install hang on filament boosters in TVs with weak tubes to allow customers time to either save for a new TV or a CRT swap. Typical life of a boosted tube was two to six months.

I bought a new B&K 467 (still have it and two others from closed shops) and the life of the CRTs after boosting was 6 months to two years. The Sencore was supposed to be better but I never had one of those. In any case, we never sold a boosted tube of any type.

 

[Phil Hobbs]

On 08/30/2018 07:33 AM, John-Del wrote:

On Wednesday, August 29, 2018 at 11:05:14 PM UTC-4, orgo...@gmail.com
wrote:
El sĂĄbado, 29 de noviembre de 1997, 4:00:00 (UTC-4), Andy Cuffe
escribiĂł:
Could someone please identify this Zenith capacitor (#
22-7672-05). It's one of the large orange ones from the early
80's that always fail.

If anyone has a list of the values for all the 22-7672-XX
capacitors I would find it very useful. -- Andy Cuffe


I have that capacitor.


You should contact the OP directly. There's a small possibility that
1) he's not monitoring this group after 20 years and 2) he may not
have waited 20 years to scrap that antique.

You just have the attention span of a goldfish, is all.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

On Friday, 31 August 2018 16:10:01 UTC+1, John-Del wrote:

On Friday, August 31, 2018 at 7:43:22 AM UTC-4, tabby wrote:
On Friday, 31 August 2018 05:39:54 UTC+1, jurb...@gmail.com wrote:

That line started with the EC line. The best of them IMO was the GC line, ideally a 25GC45 or 50. They continued the type of chassis but started using those hybrid resistors in the later ones.

Another goodie from back then was the Magnavox T995 chassis, I would take one but I want the older version with the volume under the tuners that actually had good sound. I had a GC Zenith with good sound as well, both of them later went with speaker speakers, and the Magnavox ones switched to a volume control with a shitty taper, the older ones were nice and smooth.

Those were part of my "good" lie of sets when I was in business. They got 30 days on everything, 90 on parts and a year on the CRT. there was NEVER a TV in my main showroom with a rejuvinated CRT. Then we had the discount sets. If I zapped the tune that's where it went, and I told people they were, but all was not lost because ?I had one of the best rejuviators - a B & K 467. It had a very nice touch and didn't destroy the cathode. They gave you a stack of ONE YEAR warranty cards to give the customers with a set that had a zapped CRT.

One advantage we had was a good source for rebuilt CRTs. I forgot the name of the place but a old German guy ran it, did all the work himself. Gave a 3 year warranty. I think he was called Willie.


Zapping CRTs ruins them. As emission falls again, as it does, severe smearing occurs. A much better fix is to boost the heater voltage: this lasts.. I wasn't a big fan of 10% boost, 33% does the job on most sets. An extra turn on the LOPTF does that easily & cheaply on most sets.

I did try 66% voltage boost on a couple of really bad ones just for experiment's sake, and surprisingly it worked & kept working. One (Sony Trinitron) was so bad that nothing was visible at all on screen, even in a dark room. What kind of strange person kept using it until it reached that point who knows. Anyway the result was plenty of output on all channels, but colour tracking was lousy. That kept working for years until I tired of it.


NT

In my experience, boosting filament delivered the shortest amount of service life of any method.

Back in 1981, RCA had a short run of bad HV transformers (quickly resolved). The trans was mostly conventional but had a single brown wire for CRT filament from one of the exterior terminals that went to the CRT board. As originally installed, the wire was routed between the metal frame of the trans and the chassis (metal back then).

If the trans was replaced and the brown wire was routed by the core and not between the frame and the chassis, the filament would pick up a few hundred milivolts by induction and add it to the normal 6.3. Several months after the trans was installed, the CRT would be shot. Fortunately, this happened in warranty. RCA quickly added a bulletin and a service note in the replacement trans that described how to properly route the filament wire.

Zenith in the 90s had a bunch of tubes suffer heater to cathode shorts. Most guys would thread two or three turns of bell wire around the HV trans core and feed the filaments directly (after cutting the grounded filament circuit). This would allow a full floating filament supply that wouldn't pull the cathode low even if the fil should short to the cathode. Problem was, guys would just wire so the filament looked the right color temperature but if the final voltage was much above 6.3, the tube would tire in a few months.

The solution was to use a TRMs meter (15K cycle AC from the fly) and adjust with winding count and/or a resistor to ensure the filament stayed at or even a bit smidge below 6.3TRMS AC. I did those and got many years out of those repairs.

Going back farther, we used to install hang on filament boosters in TVs with weak tubes to allow customers time to either save for a new TV or a CRT swap. Typical life of a boosted tube was two to six months.

I bought a new B&K 467 (still have it and two others from closed shops) and the life of the CRTs after boosting was 6 months to two years. The Sencore was supposed to be better but I never had one of those. In any case, we never sold a boosted tube of any type.

I'm surprised to hear this. I had very good results with filament voltage boosting, the odd ones I kept lasted very well. I don't know at this point why the difference.

What voltage boost % were you using? In what way did the tubes end up ruined? Tubes soon tire if _under_volted.

You mention hang-on boosters, I presume you mean 10% boosting transformers. 10% isn't enough to be adequate for long. It'll tickle it up a bit, but not enough to be really worthwhile.

The zero emission Sony Trinitron I experimented on got 66% heater voltage boost, it ran yellow hot rather than orange. I was surprised to find it ran happily for years like that, but it did. Obviously I never sold it. It was my main set for years, then a second for years more. I kept 2 heavily experimented on trinitrons - the other ran missing the psu board.


I was familiar with Sencore boosted tubes. It didn't always work, tube life was not usually as much as a year and severe smearing always condemned them. Filament power boosting worked much better IME. And the Sencore didn't work on Sonys.

There was also anode voltage boosting, not something I'd consider reputable but I've encountered it being done with lousy tubes in junker sets. It does boost the output, but I wouldn't do it outside of an experiment never for sale.


NT