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 Post subject: 38HE7/38HK7
PostPosted: Feb Thu 26, 2015 5:22 am 
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Hey everyone,

Can I use a 38HK7 to replace a 38HE7? What are the differences between the two? Accidentally broke my 38HE7 and all I have on hand is a 38HK7.

Thanks!

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 Post subject: Re: 38HE7/38HK7
PostPosted: Feb Thu 26, 2015 5:30 am 
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They're the same tube despite differing numbers.

Attachment:
38HE7-38HK7.jpg
38HE7-38HK7.jpg [ 105.41 KiB | Viewed 4364 times ]


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 Post subject: Re: 38HE7/38HK7
PostPosted: Feb Thu 26, 2015 6:41 am 
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Thanks!

I wonder why the numbering difference? I notice the envelopes are slightly different, is that it?

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 Post subject: Re: 38HE7/38HK7
PostPosted: Feb Thu 26, 2015 8:34 am 
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tube42 wrote:
Thanks!

I wonder why the numbering difference? I notice the envelopes are slightly different, is that it?
No, look at the boxes. They're marked 38HE7/38HK7.

I don't know, exactly, why but some tubes are double numbered.


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 Post subject: Re: 38HE7/38HK7
PostPosted: Feb Thu 26, 2015 11:44 pm 
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Location: Hutchinson KS
Happen to have a 1988 RCA tube price list folder and that tube lists for $34.00 The tv's it fit sold for $130 I believe!


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 Post subject: Re: 38HE7/38HK7
PostPosted: Feb Fri 27, 2015 12:00 am 
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SteveT wrote:
Happen to have a 1988 RCA tube price list folder and that tube lists for $34.00 The tv's it fit sold for $130 I believe!
Something's amiss with your 'price' because by 1975 RCA had completely switched from tubes to solid-state (except for the picture tube) in their television sets


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 Post subject: Re: 38HE7/38HK7
PostPosted: Feb Fri 27, 2015 6:02 am 
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Flipperhome wrote:
SteveT wrote:
Happen to have a 1988 RCA tube price list folder and that tube lists for $34.00 The tv's it fit sold for $130 I believe!
Something's amiss with your 'price' because by 1975 RCA had completely switched from tubes to solid-state (except for the picture tube) in their television sets

RCA may not have been using tubes in their TVs, but they were still selling tubes well past the date they stopped using them their selves.

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 Post subject: Re: 38HE7/38HK7
PostPosted: Feb Fri 27, 2015 9:13 am 
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Tom Schulz wrote:
Flipperhome wrote:
SteveT wrote:
Happen to have a 1988 RCA tube price list folder and that tube lists for $34.00 The tv's it fit sold for $130 I believe!
Something's amiss with your 'price' because by 1975 RCA had completely switched from tubes to solid-state (except for the picture tube) in their television sets

RCA may not have been using tubes in their TVs, but they were still selling tubes well past the date they stopped using them their selves.
Selling to WHO 13 years later? Anyone still using tubes, let alone a $34 tube in a $130 TV set, would have been out of their ever loving minds, and business.

I'm just saying that even if I believed the "$34" price it isn't representative of the tube era. Try a 1965 price sheet.


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 Post subject: Re: 38HE7/38HK7
PostPosted: Feb Fri 27, 2015 4:17 pm 
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Joined: Apr Sat 06, 2013 2:18 pm
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Location: New Hampshire
All sweep tubes were over $30 probably by the early 80's. Its one
of the main reason tube sets went away so fast. The other being
the huge increase in reliability IMHO. By the mid 80's the economy
was so good folks were junking 1st gen solid state sets just to have
the latest, especially remotes. They were the best years to be in
the TV sales & service biz......

As for 38HE7 / HK7 probably one came out then they realized they needed
slightly better specs so it got a new # & double markings.

73 Zeno 8)


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 Post subject: Re: 38HE7/38HK7
PostPosted: Feb Fri 27, 2015 6:50 pm 
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Location: Powell River BC Canada
I think as long as the big tube makers were going strong prior to solid state,
the Japanese tubes didn't undercut the Compactron market. At the very end of
tubes, there were some very attractive small screen portables, not imports, that
were sold in Canada for under $150. One Admiral model in particular frequently
crossed my bench in need of a 33GY7, quite costly then.

The first import tube small screen portable lacked style, and often had metal cases.
I imagine they hadn't mastered the plastic molding end of the game yet in the production
of an approved TV that weighed essentially what the CRT did.

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de
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Amateur Radio Literacy Club. May we help you read better.
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 Post subject: Re: 38HE7/38HK7
PostPosted: Feb Fri 27, 2015 8:29 pm 
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zeno wrote:
All sweep tubes were over $30 probably by the early 80's. Its one
of the main reason tube sets went away so fast. The other being
the huge increase in reliability IMHO. By the mid 80's the economy
was so good folks were junking 1st gen solid state sets just to have
the latest, especially remotes. They were the best years to be in
the TV sales & service biz......

As for 38HE7 / HK7 probably one came out then they realized they needed
slightly better specs so it got a new # & double markings.

73 Zeno 8)
So fast? The transistor was invented in 1947 and the more logical question would be why did it take so long?

The first transistors were expensive and quite limited in both power and frequency but that would change as they lent themselves to improved manufacturing techniques (improved performance and lower cost, not to mention the other obvious advantages) that tubes did not and, for example, the first integrated circuit appeared in 1958. By 1965 'all solid state' portables appeared with the tube's last holdout being 'power', keeping them alive in some sections until finally removed entirely around 1975. By 1988 'all solid state' was so passé that they no longer advertised it.

RCA's last issue of their "Receiving Tube Manual" was RC-30 in 1975 so you can see why I argue a 1988 'price list', if valid, has no bearing on 'TV Set' tube prices. There simply weren't any TV sets made with a 38HE7 and hadn't been for over a decade.


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 Post subject: Re: 38HE7/38HK7
PostPosted: Mar Sun 01, 2015 1:12 am 
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New tubes at electronics distributors were expensive in the 1980s. A lot of them were out of production, and distributors were selling off old stock, knowing there was a limited supply, i think. Higher power tubes were never all that cheap, and if they were, it was only when they were being produced in mass quantitiies. i fixed a 1970 vintage tube tv in the mid 80s, it cost almost $100 to replace the weak tubes. they really did go for prices like that unless you found them surplus or at a hamfest, in the 80s people were dumping tube stuff, i got bushel baskets of tubes at hamfests back then, just by hanging around the dumpster as people were packing up. At one hamfest, i bought a pair of working Pilot monoblock tube amps for $9, and sold a (needed work) Dynaco Stereo 70 amp for $10.


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 Post subject: Re: 38HE7/38HK7
PostPosted: Mar Sun 01, 2015 4:23 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 3423
Location: Olympia WA USA
Many older folks (my main customer base) did not want the new solid state sets.
When they first came out, many servicers had no idea of how to service them. At least in my area.
Many of my customers had console TV's 25" typically, and there was no way they ( The wife) would give up that "Beautiful" console they paid up to $1500.00 for. As long as CRT's were readily available they wanted those sets going. Often the repair bill (with the svc. call) came to $300.00 or more.
They paid it and didn't squeak much. If you knew what you were doing, you were able to make a good living back then. There were too many "tube changers" and "Trunk Monkeys" around in those days.
Now days, the big consoles are out and the "flat screen" sets are all the rage, even if they don't last over a few years.
I was still repairing the tube sets well into the 90's for the older folks too. Another reason was that they had figured out how to use the remote control and didn't want to have to learn all "The new fangled buttons " all over again. They wanted on, off, vol. up & down and channel change.

At my age, now I feel the same way. Too many dad blasted buttons to accidentally hit with failing eyesight and/ or not so good motor skills, and screws things up. (I still can't figure which button I hit on the remote to the big TV here that shut down the surround system and I can't get it working again. That happened right after Jillian was killed).

Not to mention the ensuing "fun" when one of the cats decides to walk across the remote while its laying beside me in the chair...... (Chile Con Kitty time) :D :wink:

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 Post subject: Re: 38HE7/38HK7
PostPosted: Mar Mon 02, 2015 2:52 am 
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FrankB wrote:
Many older folks ...

Not to mention the ensuing "fun" when one of the cats decides to walk across the remote while its laying beside me in the chair...... (Chile Con Kitty time) :D :wink:


Oh, your cats do that to you too? Hmmm, I only have four cats. They like to park themselves on top of warm vacuum tube equipment ... Sound familiar?

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 Post subject: Re: 38HE7/38HK7
PostPosted: Mar Mon 02, 2015 2:51 pm 
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Joined: Apr Sat 06, 2013 2:18 pm
Posts: 476
Location: New Hampshire
Flipperhome wrote:
zeno wrote:
All sweep tubes were over $30 probably by the early 80's. Its one
of the main reason tube sets went away so fast. The other being
the huge increase in reliability IMHO. By the mid 80's the economy
was so good folks were junking 1st gen solid state sets just to have
the latest, especially remotes. They were the best years to be in
the TV sales & service biz......

As for 38HE7 / HK7 probably one came out then they realized they needed
slightly better specs so it got a new # & double markings.

73 Zeno 8)
So fast? The transistor was invented in 1947 and the more logical question would be why did it take so long?

The first transistors were expensive and quite limited in both power and frequency but that would change as they lent themselves to improved manufacturing techniques (improved performance and lower cost, not to mention the other obvious advantages) that tubes did not and, for example, the first integrated circuit appeared in 1958. By 1965 'all solid state' portables appeared with the tube's last holdout being 'power', keeping them alive in some sections until finally removed entirely around 1975. By 1988 'all solid state' was so passé that they no longer advertised it.

RCA's last issue of their "Receiving Tube Manual" was RC-30 in 1975 so you can see why I argue a 1988 'price list', if valid, has no bearing on 'TV Set' tube prices. There simply weren't any TV sets made with a 38HE7 and hadn't been for over a decade.


So fast as in repair. In 71 almost every set that came in was all tube or hybrid.
Ten years later almost none were. The cost of tubes & multiple problems were
the problem. Also prices were coming down & color was considered perfected by
most.
As for the switch over through the 50's it was cost. By the mid 60's most majors
had some SS B&W sets but big bucks. Here is Zenith first SS set. Super rare,
Ive never seen one or knew anyone that had.
https://www.youtube.com/watch?v=wPyNGwDK1RE
This set was probably $200, you could get a tube GE 12" for $80-$90.
The era is interesting & I got to work through most of it until TV's became
disposable after 2K.

73 Zeno 8)


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 Post subject: Re: 38HE7/38HK7
PostPosted: Mar Tue 03, 2015 3:17 pm 
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Joined: Jan Wed 13, 2010 3:28 pm
Posts: 270
Location: Surrey BC Canada
"Here is Zenith first SS set. Super rare,
Ive never seen one or knew anyone that had.
https://www.youtube.com/watch?v=wPyNGwDK1RE "

I had one Zeno.

aprox 20 years ago, i had this set kicking around ( for quite a few years.(might stll be around-will have to look)).
worked well. it was my 1st camping tv(used it for sunday motorsports coverage). i also loaned it out to my camping buddies so they could watch indy racing on sundays in the bush(if they could pick cbc tv network).
iirc, it was positive ground so you had to be carefull not to "short" the tv chassis to the negative ground body of cars(ran set through a cigarette lighter socket-never had the battery pack).
it was heavy but tough! got kicked around a bit.
i never realised it was a rare set and the 1st Zenith ss tv!
thanks for the memories!
RonL

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 Post subject: Re: 38HE7/38HK7
PostPosted: Mar Tue 03, 2015 9:59 pm 
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Joined: Mar Tue 03, 2009 11:12 pm
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Location: Hutchinson KS
RCA parts distributors gave out free tube price list booklets up until the late 80's if not beyond. How else are service call guys able to price the tubes on calls? I happened to have an old 1988 booklet laying around and that is where I got my price for a 38HE7 tube. Incidentally it lists the 38HE7 and the 38HK7 as seperate tubes! Same price, 34 dollars! I so remember servicing tube tv's way up into the 90's. For giggles, a 2CW4 nuvistor sold for 38.30, 3DS3 was 41.85,a 6J7 was 51.35!! What I thought was interesting, the 12SK7, 12SA7, 12SQ7 tubes were all 40.00! This is all 1988 dollars. Now that made people switch to solid state table radio's in a hurry!


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 Post subject: Re: 38HE7/38HK7
PostPosted: Mar Tue 03, 2015 10:39 pm 
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Location: San Jose, CA USA
I think a lot of the people who got into the tube supply business over the past 20 years were hoping that tube prices would go back to or beyond those levels, so that there would be a potential to make a lot of money. For most tubes, prices today are in the range of 5% - 30% of what they were at that time, with some notable exceptions, of course. In the last few years, you see a few places throwing in the towel on tube supply (e.g., Radio Daze). It would have been easy to lose a lot of money trying to sell tubes over the past 20 years, with the trend in prices generally downward.

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 Post subject: Re: 38HE7/38HK7
PostPosted: Mar Wed 04, 2015 3:13 am 
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SteveT wrote:
RCA parts distributors gave out free tube price list booklets up until the late 80's if not beyond. How else are service call guys able to price the tubes on calls? I happened to have an old 1988 booklet laying around and that is where I got my price for a 38HE7 tube. Incidentally it lists the 38HE7 and the 38HK7 as seperate tubes! Same price, 34 dollars! I so remember servicing tube tv's way up into the 90's. For giggles, a 2CW4 nuvistor sold for 38.30, 3DS3 was 41.85,a 6J7 was 51.35!! What I thought was interesting, the 12SK7, 12SA7, 12SQ7 tubes were all 40.00! This is all 1988 dollars. Now that made people switch to solid state table radio's in a hurry!
They had already switched almost 2 decades earlier, TV HV sections holding for a while longer but still long gone by 1988, and it's not surprising that 'new' tube prices increased as the market dried up. (That and the near hyper inflation during the late 70's).

I'm just saying you've got a mixed metaphor talking about "$34" tube prices used in a "$130" TV set that didn't exist in 1988. If you want to compare the cost of tubes in a TV set you have to go back to when they were manufactured with them.


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 Post subject: Re: 38HE7/38HK7
PostPosted: Mar Wed 04, 2015 4:56 am 
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Flipperhome wrote:
I'm just saying you've got a mixed metaphor talking about "$34" tube prices used in a "$130" TV set that didn't exist in 1988. If you want to compare the cost of tubes in a TV set you have to go back to when they were manufactured with them.

Certainly new sets that used tubes were not being made in 1988. But those TVs certainly did still exist in 1988 and people were still having them fixed. The price of the tube on the 1988 price list was what a do-it-yourself person would have to pay to fix their set. Some people would pay it.

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