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John-Del
Guest

Fri Aug 31, 2018 4:45 pm   



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

Sun Sep 02, 2018 12:45 am   



On 08/30/2018 07:33 AM, John-Del wrote:
Quote:
On Wednesday, August 29, 2018 at 11:05:14 PM UTC-4, orgo...@gmail.com
wrote:
El sábado, 29 de noviembre de 1997, 4:00:00 (UTC-4), Andy Cuffe
escribió:
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


Guest

Sun Sep 02, 2018 7:45 pm   



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


Guest

Mon Sep 03, 2018 6:45 am   



Umm, we used to bump the heater and then let the thing run for about a week.. I have seen them get better and better with a moderate boost and then last a very long time.

We never rejuved a camera tube but someone told me and I found out that is you keep one of those old cameras running for days and days looking straight at a white surface it rejuved them somewhat. There was really no way to boost the filament, there was no room for anything.


Guest

Wed Jan 09, 2019 5:45 pm   



On Wednesday, August 2, 2000 at 3:00:00 AM UTC-4, GHilgenber wrote:
Quote:
I have a ford ranger and the cassette player has a lot of static the radio
plays fine.I have demagnetizer and cleaning tapes I was thinking of using
acetone on the heads?


Use a cleaning tape or the like . Chemicals and liquids can harm rollers and other plastic / rubber parts . Alcohol will dry out the oils in plastics and rubber , causing them to harden . Acetone will tend to dissolve these materials .

Terry Schwartz
Guest

Wed Jan 09, 2019 5:45 pm   



On Wednesday, January 9, 2019 at 10:07:57 AM UTC-6, wri...@gmail.com wrote:
Quote:
On Wednesday, August 2, 2000 at 3:00:00 AM UTC-4, GHilgenber wrote:
I have a ford ranger and the cassette player has a lot of static the radio
plays fine.I have demagnetizer and cleaning tapes I was thinking of using
acetone on the heads?

Use a cleaning tape or the like . Chemicals and liquids can harm rollers and other plastic / rubber parts . Alcohol will dry out the oils in plastics and rubber , causing them to harden . Acetone will tend to dissolve these materials .


All those materials are 19 years older than when this topic was initiated.... So yeah, I bet they're dried out.

Look165
Guest

Wed Jan 09, 2019 5:45 pm   



Just clean with a Q-tip and that's all.
Cleaning tape is usefull.

writemj_at_gmail.com a écrit le 09/01/2019 à 17:07 :
Quote:
On Wednesday, August 2, 2000 at 3:00:00 AM UTC-4, GHilgenber wrote:
I have a ford ranger and the cassette player has a lot of static the radio
plays fine.I have demagnetizer and cleaning tapes I was thinking of using
acetone on the heads?
Use a cleaning tape or the like . Chemicals and liquids can harm rollers and other plastic / rubber parts . Alcohol will dry out the oils in plastics and rubber , causing them to harden . Acetone will tend to dissolve these materials .



Guest

Wed Jan 09, 2019 8:45 pm   



On Wednesday, 9 January 2019 16:12:46 UTC, Terry Schwartz wrote:
Quote:
On Wednesday, January 9, 2019 at 10:07:57 AM UTC-6, wri...@gmail.com wrote:
On Wednesday, August 2, 2000 at 3:00:00 AM UTC-4, GHilgenber wrote:

I have a ford ranger and the cassette player has a lot of static the radio
plays fine.I have demagnetizer and cleaning tapes I was thinking of using
acetone on the heads?

Use a cleaning tape or the like . Chemicals and liquids can harm rollers and other plastic / rubber parts . Alcohol will dry out the oils in plastics and rubber , causing them to harden . Acetone will tend to dissolve these materials .

All those materials are 19 years older than when this topic was initiated.... So yeah, I bet they're dried out.


cleaning tapes are almost hopeless anyway. Wet cleaning is the only effective option.

Don't use rubbing alcohol, it contains oil. Vodka is fine. Clean the pinch wheels as well. All must be bone dry before putting a tape in.


NT

The Real Bev
Guest

Thu Jan 10, 2019 5:45 am   



On 01/09/2019 11:03 AM, tabbypurr_at_gmail.com wrote:
Quote:
On Wednesday, 9 January 2019 16:12:46 UTC, Terry Schwartz wrote:
On Wednesday, January 9, 2019 at 10:07:57 AM UTC-6,
wri...@gmail.com wrote:
On Wednesday, August 2, 2000 at 3:00:00 AM UTC-4, GHilgenber
wrote:

I have a ford ranger and the cassette player has a lot of
static the radio plays fine.I have demagnetizer and cleaning
tapes I was thinking of using acetone on the heads?

Use a cleaning tape or the like . Chemicals and liquids can harm
rollers and other plastic / rubber parts . Alcohol will dry out
the oils in plastics and rubber , causing them to harden .
Acetone will tend to dissolve these materials .

All those materials are 19 years older than when this topic was
initiated.... So yeah, I bet they're dried out.

cleaning tapes are almost hopeless anyway. Wet cleaning is the only
effective option.

Don't use rubbing alcohol, it contains oil. Vodka is fine. Clean the
pinch wheels as well. All must be bone dry before putting a tape in.


The heads are metal. No worries about hardening. Who told you there
was oil in rubbing alcohol? It's alcohol and water. Period.


--
Cheers, Bev
"I've learned that you can keep puking long
after you think you're finished." -- SL

gregz
Guest

Thu Jan 10, 2019 9:45 am   



The Real Bev <bashley101_at_gmail.com> wrote:
Quote:
On 01/09/2019 11:03 AM, tabbypurr_at_gmail.com wrote:
On Wednesday, 9 January 2019 16:12:46 UTC, Terry Schwartz wrote:
On Wednesday, January 9, 2019 at 10:07:57 AM UTC-6,
wri...@gmail.com wrote:
On Wednesday, August 2, 2000 at 3:00:00 AM UTC-4, GHilgenber
wrote:

I have a ford ranger and the cassette player has a lot of
static the radio plays fine.I have demagnetizer and cleaning
tapes I was thinking of using acetone on the heads?

Use a cleaning tape or the like . Chemicals and liquids can harm
rollers and other plastic / rubber parts . Alcohol will dry out
the oils in plastics and rubber , causing them to harden .
Acetone will tend to dissolve these materials .

All those materials are 19 years older than when this topic was
initiated.... So yeah, I bet they're dried out.

cleaning tapes are almost hopeless anyway. Wet cleaning is the only
effective option.

Don't use rubbing alcohol, it contains oil. Vodka is fine. Clean the
pinch wheels as well. All must be bone dry before putting a tape in.

The heads are metal. No worries about hardening. Who told you there was
oil in rubbing alcohol? It's alcohol and water. Period.


Heads have some insulating material imbedded. Real rubbing alcohol is
supposed to have oil to prevent skin drying too much. Most don't. Isopropyl
or ethyl cleans heads.

Greg


Guest

Thu Jan 10, 2019 9:45 am   



On Thursday, 10 January 2019 04:12:57 UTC, The Real Bev wrote:
Quote:
On 01/09/2019 11:03 AM, tabbypurr wrote:
On Wednesday, 9 January 2019 16:12:46 UTC, Terry Schwartz wrote:
On Wednesday, January 9, 2019 at 10:07:57 AM UTC-6,
wri...@gmail.com wrote:
On Wednesday, August 2, 2000 at 3:00:00 AM UTC-4, GHilgenber
wrote:

I have a ford ranger and the cassette player has a lot of
static the radio plays fine.I have demagnetizer and cleaning
tapes I was thinking of using acetone on the heads?

Use a cleaning tape or the like . Chemicals and liquids can harm
rollers and other plastic / rubber parts . Alcohol will dry out
the oils in plastics and rubber , causing them to harden .
Acetone will tend to dissolve these materials .

All those materials are 19 years older than when this topic was
initiated.... So yeah, I bet they're dried out.

cleaning tapes are almost hopeless anyway. Wet cleaning is the only
effective option.

Don't use rubbing alcohol, it contains oil. Vodka is fine. Clean the
pinch wheels as well. All must be bone dry before putting a tape in.

The heads are metal. No worries about hardening. Who told you there
was oil in rubbing alcohol? It's alcohol and water. Period.


I forget the official standard for it, but it contains rather more than water & alcohol. Looked it up last year.


NT

Look165
Guest

Thu Jan 10, 2019 10:45 am   



The body of the head is made of molded resin.
The magnetic element is made of polished folded iron.(try to look with a
microscope).
I go on saying that a good quality cleaning head is useful.
Don't forget to adjust the azimuth setting at the end.


gregz a écrit le 10/01/2019 à 09:07 :
Quote:
The Real Bev <bashley101_at_gmail.com> wrote:
On 01/09/2019 11:03 AM, tabbypurr_at_gmail.com wrote:
On Wednesday, 9 January 2019 16:12:46 UTC, Terry Schwartz wrote:
On Wednesday, January 9, 2019 at 10:07:57 AM UTC-6,
wri...@gmail.com wrote:
On Wednesday, August 2, 2000 at 3:00:00 AM UTC-4, GHilgenber
wrote:
I have a ford ranger and the cassette player has a lot of
static the radio plays fine.I have demagnetizer and cleaning
tapes I was thinking of using acetone on the heads?
Use a cleaning tape or the like . Chemicals and liquids can harm
rollers and other plastic / rubber parts . Alcohol will dry out
the oils in plastics and rubber , causing them to harden .
Acetone will tend to dissolve these materials .
All those materials are 19 years older than when this topic was
initiated.... So yeah, I bet they're dried out.
cleaning tapes are almost hopeless anyway. Wet cleaning is the only
effective option.

Don't use rubbing alcohol, it contains oil. Vodka is fine. Clean the
pinch wheels as well. All must be bone dry before putting a tape in.
The heads are metal. No worries about hardening. Who told you there was
oil in rubbing alcohol? It's alcohol and water. Period.

Heads have some insulating material imbedded. Real rubbing alcohol is
supposed to have oil to prevent skin drying too much. Most don't. Isopropyl
or ethyl cleans heads.

Greg



Guest

Thu Jan 10, 2019 12:45 pm   



And I suppose you have to pause your 25/hr 8-day-a-week smoking habit during this time too, right?

Pat
Guest

Thu Jan 10, 2019 3:45 pm   



Quote:
On Wednesday, August 2, 2000 at 3:00:00 AM UTC-4, GHilgenber wrote:

I have a ford ranger and the cassette player has a lot of static the radio
plays fine.I have demagnetizer and cleaning tapes I was thinking of using
acetone on the heads?


As other have pointed out, the OP made his request almost 19 years
ago, but since everyone here seems to be discussing the merits of
various head cleaning methods, I have a question. How can "static" be
a symptom of dirty tape heads? Drop outs - yes. Loss of highs - yes.
Static? Sounds more like a bad connection or static electricity being
generated somewhere.

Ralph Mowery
Guest

Thu Jan 10, 2019 4:45 pm   



In article <312172279568800599.965334zekor-comcast.net_at_news.eternal-
september.org>, zekor_at_comcast.net says...
Quote:

Don't use rubbing alcohol, it contains oil. Vodka is fine. Clean the
pinch wheels as well. All must be bone dry before putting a tape in.

The heads are metal. No worries about hardening. Who told you there was
oil in rubbing alcohol? It's alcohol and water. Period.


Heads have some insulating material imbedded. Real rubbing alcohol is
supposed to have oil to prevent skin drying too much. Most don't. Isopropyl
or ethyl cleans heads.



Rubbing alcohol seems to be a gernetic term by many.

One form is about 70% alcohol and some oils and water.

You can buy some that is about 90% alcohol and 10 % water with no other
oils in it. I have some here labled 91 % and some labled 99%. They are
isoprople alcohol and not labled rubbing alcohol. Alcohol absorbs water
from the atmosphere so before long the 99% will be much less if open to
the air.

Xylene was used at one time to clean the tape machinery. I am not sure
if it is in the stores any more or not.

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