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Old 24th Jul 2020, 11:03 am   #1
FERNSEH
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Default A TV set with mains EHT - in 1953!

In the 1953 HMV sales catalogue we see the full range of the new "Highlight" models, the popular 1824 series. Also, the huge 21" model 1820 introduced the previous year and a much older model, the TV-radiogram combi model 1902B.
The 1902 was introduced in 1948 along with the console models 1805 and 1806. All these models have mains derived EHT and fifteen inch models employ the TA15 CRT. TA10 in 10" models.
In the catalogue the 1902B is offered as a "London" receiver and alternative models for other BBC transmitters.
Surely in 1953 HMV wasn't offering a TV set with mains derived EHT? Perhaps the B suffix indicates this old model was modified to an RF EHT system like the 1820 has. Was the London model a TRF? In 1953 it was known in the industry that Band three TV services were only a few years away.

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Old 24th Jul 2020, 11:45 am   #2
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Default Re: A TV set with mains EHT - in 1953!

There were a couple of quite late mains EHT receivers David. The Ekco TC165 with 10kv voltage doubled is an interesting one. I'm too chicken to replace the 15" Mazda CRM151 that has zero emission. Now that's a surprise!

Murphy produced another monster the V176. Another CRM151 with a voltage doubler mains EHT supply. The later B versions of the original TRF unit employed in the E.M.I. 1902, 1805/6 etc may have been superhets. I have all the data somewhere in my EMI service data.

All the models from the 1807 onwards were simply horrible. They were mostly scrapped by the time I entered the trade full time in 1964. They were certainly hated by every TV guy that I knew. Of course there were the odd good ones but they should all have been good coming from the original designers of the 405 television Service.

With the tragic death of Alan Blumlein in 1942 the television design team at EMI appears to have fallen apart. The last quality receiver from EMI was the 1805 series with mains EHT from 1948/9. They had a very long service life and I encountered a couple of 15" consoles in the mid 1960's! The TA15 was available into the 60's as replacements in these originally very expensive receivers. John.
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Old 24th Jul 2020, 3:31 pm   #3
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Default Re: A TV set with mains EHT - in 1953!

Hi John,
Nothing wrong with retaining an old model in production if there is a demand for that style of set but surely the electronic design of the chassis could have easily been modernised? Line flyback EHT should replace that dangerous mains derived EHT and a five channel RF chassis similar to the one fitted in the 1820 could have been considered. By 1953 having a different RF chassis for each of the five BBC channels is absurd.

DFWB.
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Old 24th Jul 2020, 4:28 pm   #4
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Default Re: A TV set with mains EHT - in 1953!

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Originally Posted by FERNSEH View Post
Hi John,
Nothing wrong with retaining an old model in production if there is a demand for that style of set but surely the electronic design of the chassis could have easily been modernised? Line flyback EHT should replace that dangerous mains derived EHT and a five channel RF chassis similar to the one fitted in the 1820 could have been considered. By 1953 having a different RF chassis for each of the five BBC channels is absurd.

DFWB.
Redesigns cost money. There had been a war on. In any case, the 'world of safety' was not what it was now, anyone working on the set would have been expected to know about the dangers, and that was sufficient. Alarming but true. I think Pye's post war B16T had mains derived EHT too.
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Old 24th Jul 2020, 5:00 pm   #5
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Default Re: A TV set with mains EHT - in 1953!

Fascinating to compare the prices: the model 1820 on sale for 253 Guineas equates to something like £7400 in 2020 money!
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Old 24th Jul 2020, 5:16 pm   #6
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Default Re: A TV set with mains EHT - in 1953!

Continuing to use mains EHT does smack of design staleness, though- all those miles (?) of fine copper wire on a laminated core vs. the multiple-pie of the RF EHT generator with much less wire and a (possibly surplus) 6V6G etc. singing away and blatting the Light programme! Even if confidence hadn't quite progressed to LOPT-derived EHT.
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Old 24th Jul 2020, 5:35 pm   #7
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Default Re: A TV set with mains EHT - in 1953!

I have an Ultra W7016 sat here for restoration ,possibly around 1953 with mains EHT.
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Old 24th Jul 2020, 5:39 pm   #8
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Default Re: A TV set with mains EHT - in 1953!

G6Tanuki wrote, "Fascinating to compare the prices: the model 1820 on sale for 253 Guineas equates to something like £7400 in 2020 money!"
I did have an HMV 1820 in my collection, it was owned by a wealthy man who lived in Newcastle. Also a 1902, where that came from I can't remember. I regret selling the sets on to other collectors now.
In 1953 you couldn't buy a new car for 253 Guineas, the cheapest or should we least expensive new car was the 103E Ford Popular.

stevehertz wrote: "Redesigns cost money. There had been a war on. In any case, the 'world of safety' was not what it was now, anyone working on the set would have been expected to know about the dangers, and that was sufficient. Alarming but true. I think Pye's post war B16T had mains derived EHT too."

We really need sight of the amended service manual for the 1902B to ascertain if any modifications had been carried out to the original design. I did read that the Pye B18T was designed in 1943, some of the design cues follow the 1939 models 9C and 12C. The 915 chassis.

DFWB.
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Old 24th Jul 2020, 5:45 pm   #9
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Default Re: A TV set with mains EHT - in 1953!

Nothing at all wrong with mains derived EHT - our living room carpet had a big burn on it caused by something I did round the back of our 1805 when I was about 3 years old.

Didn`t do me any harm - though I think my Mum may have had words with my Dad.

The 1805 set died circa 1957 due to a duff tube - quite common in those days I believe. My Dad intended to replace it with a 21 inch tube that he got when he was at Mullards but never got round to doing the mods required.
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Old 24th Jul 2020, 5:46 pm   #10
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Default Re: A TV set with mains EHT - in 1953!

HamkishBoxer wrote: "I have an Ultra W7016 sat here for restoration ,possibly around 1953 with mains EHT."

Is a 15" CRT model?

DFWB.
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Old 24th Jul 2020, 6:37 pm   #11
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Default Re: A TV set with mains EHT - in 1953!

I think it is 15" and I hope the crt is ok.It is a console model that came from 1 owner in Gainsborough Lincs,I remember at the time (years ago) I was not keen on having another tv.
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Old 24th Jul 2020, 6:52 pm   #12
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Default Re: A TV set with mains EHT - in 1953!

barrymagrec wrote: "Nothing at all wrong with mains derived EHT - our living room carpet had a big burn on it caused by something I did round the back of our 1805 when I was about 3 years old"

There's the Marconi version of the HMV 1805 upstairs in the stock room.
Doubt if I'll ever get around to fixing it.

DFWB.
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Old 24th Jul 2020, 7:15 pm   #13
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Default Re: A TV set with mains EHT - in 1953!

I seem to recall working on an English Electric model, of around the same age, which had mains-derived EHT. This was about 1962, & there were still quite a few other models around using this technique.

One hand in the pocket!

David.
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Old 24th Jul 2020, 7:19 pm   #14
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Default Re: A TV set with mains EHT - in 1953!

The 1805/06/ 1851/1902 series was so reliable I think they were scared to change the design. They knew mains EHT had good regulation and the EHT transformer was of a very reliable construction. It produced 7kv for the aluminised TA10 and TA15 tubes that gave incredibly bright pictures. They were a very expensive range of models heavily advertised in posh magazines and a poor reputation would have been a disaster. I have only known one EHT/HT/Heater transformer to fail and that was in my Marconi 10" TV/Radio console VRC52A. Mike Barker did the rewind. They are very high performers. I can't think off hand of any other late mains derived EHT models. Regards, John.
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Old 24th Jul 2020, 7:24 pm   #15
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Default Re: A TV set with mains EHT - in 1953!

Quote:
Originally Posted by HamishBoxer View Post
I have an Ultra W7016 sat here for restoration ,possibly around 1953 with mains EHT.
Lovely! I have a W470 from 1947. It's a cracker and easy to service. The superhet IF panel has quite a number of .01uf decouplers. The let down is the 9" CRM92 Mazda tube. Mine was as flat as a pancake but if you wait long enough a good one always turns up, and it did.

Go on plug it in! John.
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Old 24th Jul 2020, 7:57 pm   #16
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Default Re: A TV set with mains EHT - in 1953!

Quote:
Originally Posted by FERNSEH View Post
G6Tanuki wrote, "Fascinating to compare the prices: the model 1820 on sale for 253 Guineas equates to something like £7400 in 2020 money!"
I did have an HMV 1820 in my collection, it was owned by a wealthy man who lived in Newcastle. Also a 1902, where that came from I can't remember. I regret selling the sets on to other collectors now.
In 1953 you couldn't buy a new car for 253 Guineas, the cheapest or should we least expensive new car was the 103E Ford Popular.

stevehertz wrote: "Redesigns cost money. There had been a war on. In any case, the 'world of safety' was not what it was now, anyone working on the set would have been expected to know about the dangers, and that was sufficient. Alarming but true. I think Pye's post war B16T had mains derived EHT too."

We really need sight of the amended service manual for the 1902B to ascertain if any modifications had been carried out to the original design. I did read that the Pye B18T was designed in 1943, some of the design cues follow the 1939 models 9C and 12C. The 915 chassis.

DFWB.
I said B16T, but you're saying B18T. Not sure if that's intentional or not but obviously they're different sets and for sure the B18T was Line flyback derived EHT.
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Old 24th Jul 2020, 8:12 pm   #17
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Default Re: A TV set with mains EHT - in 1953!

Sorry, I meant B16T.

DFWB.
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Old 24th Jul 2020, 8:42 pm   #18
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Default Re: A TV set with mains EHT - in 1953!

Quote:
Originally Posted by FERNSEH View Post
barrymagrec wrote: "Nothing at all wrong with mains derived EHT - our living room carpet had a big burn on it caused by something I did round the back of our 1805 when I was about 3 years old"

There's the Marconi version of the HMV 1805 upstairs in the stock room.
Doubt if I'll ever get around to fixing it.

DFWB.
My Dad may still have the mains transformer in his garage if you need one - I think I have the KT44 in my loft....

Rest of it went donkeys years ago.
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Old 24th Jul 2020, 8:45 pm   #19
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Default Re: A TV set with mains EHT - in 1953!

Yes John,I must get it to the workshop.
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Old 24th Jul 2020, 9:16 pm   #20
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Default Re: A TV set with mains EHT - in 1953!

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Originally Posted by barrymagrec View Post

My Dad may still have the mains transformer in his garage if you need one - I think I have the KT44 in my loft....
Rest of it went donkeys years ago.
Actually, I believe the mains transformer is missing in the Marconi VRC52.
Alternatively, if you fancy coming up to Geordieland you can have the set.

DFWB.
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