TV to watch Queen's Christmas Speech on? - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

FERNSEH · 20th Oct 2021, 2:58 pm

Quote:

Originally Posted by spamfritter

Perhaps I should re construct the design I watched may years ago. A B&W tube with a rotating colour strip drum. In its day it was a far better quality colour picture than a 3 colour CRT. Now where did I put that Nipkow disc ?

CBS system?
From the ETF: http://earlytelevision.org/cbs_color_system.html

Later today, assuming the 6BW7 valve can be inserted without recourse to removing the CRT the set will be given a taste of electricity via the variac.

DFWB.

broadgage · 20th Oct 2021, 2:58 pm

Obviously an early projection TV !
I recall seeing one in about 1968. Used a small and extraordinarily bright colour CRT and an optical system to project an image onto a screen or even a white wall.

The CRT was fan cooled. The alleged advantage of this design was better picture quality due to the narrow angle of the CRT.
The set was bulky and heavy, but fitted well into a large living room. For group viewing it could be placed between sofas or chairs and the image projected onto the opposite wall.

The picture was excellent even in a well lit room.

FERNSEH · 20th Oct 2021, 5:24 pm

By good luck rather than anything clever by me, the 6BW7 common IF amplifier is now in its valveholder.
Will carry out a few more tests before connecting up the mains through the variac.

DFWB.

jhalphen · 20th Oct 2021, 6:32 pm

Hi to all,

Hi Broadgage, maybe a Sony VidiMagic VP-62 Indextron single colour CRT projector.
Also made with a built-in Betamax VCR.

Beam-Index CRT with no shadow mask (ultra-bright).

see here, scroll down, lots of photos:
https://visions4netjournal.com/indextron/

Keep scrolling: detailed photos of the inner workings, PCB & CRT.

Thanks! to e-type2

Best Regards
jhalphen
Paris/France

Heatercathodeshort · 20th Oct 2021, 9:22 pm

I think the first TV Queens Christmas Message was in 1957. A murphy V310 would fit nicely. J.

Sideband · 21st Oct 2021, 10:28 am

I might use my KB Royal Star....if the tube holds out! Otherwise it will be the Ferguson '45'.

FERNSEH · 21st Oct 2021, 11:04 am

Yesterday evening the 24" KB was connected to the variac. With 150volts supplied there is activity from the line timebase. A neon screwdriver is seen to glow when in close proximity to the line output transformer.
85volts measured at the CRT first anode pin 10. Hopefully, this will rise to over 300volts when the full mains voltage is supplied.
The line output valve in this receiver is the Brimar 50CD6G, it seems to be OK in this set. In the past I've successfully replaced this valve with a PL36. A 75ohm resistor must be inserted in the heater chain.

DFWB.

bobhowe · 21st Oct 2021, 2:06 pm

Hi David looking forward to seeing first light

FERNSEH · 21st Oct 2021, 2:59 pm

Hi Bob,
today, the mains voltage supplied to the set from the variac was was raised to 240volts. Still no raster because the first anode voltage is only 110V.
There is a 6mm spark at the anode connector of the R19 EHT rectifier valve.
It's time to get brave and move the chassis to the workbench.
The attachment shows the component layout on the chassis. It's certain that the common IF valve was difficult to replace even on the 17" model, the OV30.

DFWB.

bobhowe · 21st Oct 2021, 5:49 pm

Hi David what is the next step after the set is on the work bench ? ( if you need a hand in lifting it I can call round & help you ) . Please can you post some pictures

FERNSEH · 21st Oct 2021, 9:17 pm

Hi Bob,
thanks for the offer of help but the chassis isn't all that heavy. The bench has been cleared to accept it.
Attachment shows the metal frame the chassis is mounted on. Not certain about this, was it made specially made for this set, or is it a part fitted to all 24" PV100 sets?

DFWB.

FERNSEH · 22nd Oct 2021, 11:03 am

The chassis in now on the bench. After clipping out C62 325volts is present at pin 10 of the CRT but still no raster on the screen.
It's evident a lot of wax capacitors will need replacing.

DFWB.

Station X · 22nd Oct 2021, 1:04 pm

Only 64 soldering days until Christmas!

bobhowe · 22nd Oct 2021, 1:51 pm

Quote:

Originally Posted by Station X

Only 64 soldering days until Christmas!

Plenty of time

bobhowe · 22nd Oct 2021, 2:04 pm

Quote:

Originally Posted by FERNSEH

The chassis in now on the bench. After clipping out C62 325volts is present at pin 10 of the CRT but still no raster on the screen.
It's evident a lot of wax capacitors will need replacing.

DFWB.

Hi David are you going to do a blanket change of capacitors or do them one at a time & see what faults disappear

FERNSEH · 22nd Oct 2021, 9:55 pm

Replaced the boost capacitor C63 (0.4uF 750V) and boost HT smoothing capacitor C62 (0.5uF 750V).
Result, an increase of CRT first anode voltage, now 350V. The voltage across C63 is now 550V.
But still no illumination of the CRT screen.
CRT has a pentode gun but the method of construction is quite different from the Mullard/Philips bent gun assembly.
Voltages on the CRT socket are: pin 1 grid 110V. Pin 11 cathode about the same as pin 1. Pin 10 first anode 350V. Anode 2 199V. Final anode 15.5KV.
No amount of adjustment of the ion trap yields any results on the screen.
Looks like the CRT is faulty?

DFWB.

FERNSEH · 23rd Oct 2021, 2:52 pm

NEWS FLASH! The CRT is OK. The reason why there was no image on the screen was caused by shorted wires inside the tube base. Turning the base a few degrees has cleared the short circuit. The position of the ion trap magnet is different to the usual line up to pin 3 as it is in Philips/Mullard tubes.
In fact the picture is very bright, far brighter than I expected from a large CRT operating on 15KV.
I'll turn my attention to the frame timebase. No doubt all waxie capacitors will need replacing.
That metal frame really should be removed. It looks like the sort of thing that would be fitted in a Dynatron TV.

DFWB.

FERNSEH · 23rd Oct 2021, 8:13 pm

Results from todays capacitor changing session in the frame timebase.
Good linearity and plenty height adjustment. The pictures don't show it, but the interlace is perfect. With use the CRT is becoming really bright.
The seven waxies are from the frame timebase and the black Hunts Moldseal was the sync separator coupling capacitor
The 18Kohm resistor was the line output valve screen feed resistor.
Vision AGC performance is poor, having to use the sensitivity control to adjust the contrast. Likely the AGC decoupling capacitors are leaky. Vision AGC can be improved by replacing the 6BW7 common sound and vision IF amplifier with a Brimar 9D7 vari-mu pentode. However, the difficult to locate and insert 6BW7 is in position and it can remain there.

DFWB.

bobhowe · 23rd Oct 2021, 8:37 pm

Hi David that tube looks like it has got low miles on see you are putting your Weller soldering Station to good use

FERNSEH · 23rd Oct 2021, 8:40 pm

Hi Bob,
after many years using all sorts of horrible soldering irons, including some expensive ones I'm back to using the Weller soldering station again.

DFWB.

View Poll Results: Which TV should The Queens' Christmas Speech be watched on
KB 24' Regina	8	57.14%
Philips 19TG108U	1	7.14%
None of the above.	5	35.71%
Voters: 14. You may not vote on this poll

20th Oct 2021, 2:58 pm	#22
broadgage Nonode Join Date: Jan 2010 Location: North Somerset, UK. Posts: 2,129	Re: TV to watch Queen's Christmas Speech on? Obviously an early projection TV ! I recall seeing one in about 1968. Used a small and extraordinarily bright colour CRT and an optical system to project an image onto a screen or even a white wall. The CRT was fan cooled. The alleged advantage of this design was better picture quality due to the narrow angle of the CRT. The set was bulky and heavy, but fitted well into a large living room. For group viewing it could be placed between sofas or chairs and the image projected onto the opposite wall. The picture was excellent even in a well lit room.

20th Oct 2021, 5:24 pm	#23
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: TV to watch Queen's Christmas Speech on? By good luck rather than anything clever by me, the 6BW7 common IF amplifier is now in its valveholder. Will carry out a few more tests before connecting up the mains through the variac. DFWB.

20th Oct 2021, 6:32 pm	#24
jhalphen Hexode Join Date: Jul 2004 Location: Paris, France Posts: 350	Re: TV to watch Queen's Christmas Speech on? Hi to all, Hi Broadgage, maybe a Sony VidiMagic VP-62 Indextron single colour CRT projector. Also made with a built-in Betamax VCR. Beam-Index CRT with no shadow mask (ultra-bright). see here, scroll down, lots of photos: https://visions4netjournal.com/indextron/ Keep scrolling: detailed photos of the inner workings, PCB & CRT. Thanks! to e-type2 Best Regards jhalphen Paris/France

20th Oct 2021, 9:22 pm	#25
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: TV to watch Queen's Christmas Speech on? I think the first TV Queens Christmas Message was in 1957. A murphy V310 would fit nicely. J.

21st Oct 2021, 10:28 am	#26
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,571	Re: TV to watch Queen's Christmas Speech on? I might use my KB Royal Star....if the tube holds out! Otherwise it will be the Ferguson '45'. __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....

21st Oct 2021, 11:04 am	#27
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: TV to watch Queen's Christmas Speech on? Yesterday evening the 24" KB was connected to the variac. With 150volts supplied there is activity from the line timebase. A neon screwdriver is seen to glow when in close proximity to the line output transformer. 85volts measured at the CRT first anode pin 10. Hopefully, this will rise to over 300volts when the full mains voltage is supplied. The line output valve in this receiver is the Brimar 50CD6G, it seems to be OK in this set. In the past I've successfully replaced this valve with a PL36. A 75ohm resistor must be inserted in the heater chain. DFWB.

21st Oct 2021, 2:06 pm	#28
bobhowe Heptode Join Date: Jun 2005 Location: Sunderland, Tyne and Wear, UK. Posts: 661	Re: TV to watch Queen's Christmas Speech on? Hi David looking forward to seeing first light __________________ Kind regards, Bob.

21st Oct 2021, 2:59 pm	#29
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: TV to watch Queen's Christmas Speech on? Hi Bob, today, the mains voltage supplied to the set from the variac was was raised to 240volts. Still no raster because the first anode voltage is only 110V. There is a 6mm spark at the anode connector of the R19 EHT rectifier valve. It's time to get brave and move the chassis to the workbench. The attachment shows the component layout on the chassis. It's certain that the common IF valve was difficult to replace even on the 17" model, the OV30. DFWB. Attached Thumbnails

21st Oct 2021, 5:49 pm	#30
bobhowe Heptode Join Date: Jun 2005 Location: Sunderland, Tyne and Wear, UK. Posts: 661	Re: TV to watch Queen's Christmas Speech on? Hi David what is the next step after the set is on the work bench ? ( if you need a hand in lifting it I can call round & help you ) . Please can you post some pictures __________________ Kind regards, Bob.

21st Oct 2021, 9:17 pm	#31
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: TV to watch Queen's Christmas Speech on? Hi Bob, thanks for the offer of help but the chassis isn't all that heavy. The bench has been cleared to accept it. Attachment shows the metal frame the chassis is mounted on. Not certain about this, was it made specially made for this set, or is it a part fitted to all 24" PV100 sets? DFWB. Attached Thumbnails

22nd Oct 2021, 11:03 am	#32
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: TV to watch Queen's Christmas Speech on? The chassis in now on the bench. After clipping out C62 325volts is present at pin 10 of the CRT but still no raster on the screen. It's evident a lot of wax capacitors will need replacing. DFWB. Attached Thumbnails

22nd Oct 2021, 1:04 pm	#33
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: TV to watch Queen's Christmas Speech on? Only 64 soldering days until Christmas! __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

22nd Oct 2021, 9:55 pm	#36
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: TV to watch Queen's Christmas Speech on? Replaced the boost capacitor C63 (0.4uF 750V) and boost HT smoothing capacitor C62 (0.5uF 750V). Result, an increase of CRT first anode voltage, now 350V. The voltage across C63 is now 550V. But still no illumination of the CRT screen. CRT has a pentode gun but the method of construction is quite different from the Mullard/Philips bent gun assembly. Voltages on the CRT socket are: pin 1 grid 110V. Pin 11 cathode about the same as pin 1. Pin 10 first anode 350V. Anode 2 199V. Final anode 15.5KV. No amount of adjustment of the ion trap yields any results on the screen. Looks like the CRT is faulty? DFWB.

23rd Oct 2021, 2:52 pm	#37
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: TV to watch Queen's Christmas Speech on? NEWS FLASH! The CRT is OK. The reason why there was no image on the screen was caused by shorted wires inside the tube base. Turning the base a few degrees has cleared the short circuit. The position of the ion trap magnet is different to the usual line up to pin 3 as it is in Philips/Mullard tubes. In fact the picture is very bright, far brighter than I expected from a large CRT operating on 15KV. I'll turn my attention to the frame timebase. No doubt all waxie capacitors will need replacing. That metal frame really should be removed. It looks like the sort of thing that would be fitted in a Dynatron TV. DFWB. Attached Thumbnails

23rd Oct 2021, 8:13 pm	#38
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: TV to watch Queen's Christmas Speech on? Results from todays capacitor changing session in the frame timebase. Good linearity and plenty height adjustment. The pictures don't show it, but the interlace is perfect. With use the CRT is becoming really bright. The seven waxies are from the frame timebase and the black Hunts Moldseal was the sync separator coupling capacitor The 18Kohm resistor was the line output valve screen feed resistor. Vision AGC performance is poor, having to use the sensitivity control to adjust the contrast. Likely the AGC decoupling capacitors are leaky. Vision AGC can be improved by replacing the 6BW7 common sound and vision IF amplifier with a Brimar 9D7 vari-mu pentode. However, the difficult to locate and insert 6BW7 is in position and it can remain there. DFWB. Attached Thumbnails

23rd Oct 2021, 8:37 pm	#39
bobhowe Heptode Join Date: Jun 2005 Location: Sunderland, Tyne and Wear, UK. Posts: 661	Re: TV to watch Queen's Christmas Speech on? Hi David that tube looks like it has got low miles on see you are putting your Weller soldering Station to good use __________________ Kind regards, Bob.

23rd Oct 2021, 8:40 pm	#40
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: TV to watch Queen's Christmas Speech on? Hi Bob, after many years using all sorts of horrible soldering irons, including some expensive ones I'm back to using the Weller soldering station again. DFWB.