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CV1737

Sensibly equivalent to:
3NP4 MW6/2
See also:
Mullard Projection TV Advert - Mullard Projection TV No.2 Advert - The Optics of Projection Television - Forward Projection in the Home - Review of Philips Projection Television
    
Extras ▼

 

The CV1737 is a monochrome projection TV tube with a metal backed screen. These tubes were found in projection television receivers of the early 1950s the Mullard code was MW6/2 and they were made in Holland.
The base is a special 5 side contact design The larger of the segments of the base is the outer metalising and spark trap. The literature says that this must be grounded and that the capacitor formed by the outside metalising and the inner anode coating can be used as the EHT smoothing capacitor. This practice is now standard on picture tubes.
The deflection and focus are magnetic. The deflection angle is 30.5 degrees, very small, but the final anode voltage is 25 kV in a device with a raster of 40 x 55 mm maximum it is an extreme value. Mullard published details of how to generate the EHT required, and this incorporated a trippler on the output of the high frequency transformer. The projection TV advert shows the EHT generator.
The picture produced by back projection was typically 21 inches across the diagonal. The picture was best viewed in subdued light as was the recommendation for all viewing at the time.
The screen is perfect, a sign of an unused tube. In use the phosphor would burn and the raster shape would be seen. In use an EHT interlock to the timebases was required. This would cut the EHT in case of a raster collapse and protect the screen from instant destruction.
The UK government procurement code CV1737 can be seen below the Mullard MW6/2 identification.
The Ct5 base.
The screen with the EHT collar to prevent corona discharge.
The EHT connection is at the bottom of the glass collar allowing a good insulated seal.
The screen is 55 mm in diameter. A typical raster size was quoted as 34 x 46 mm. The phosphor is 57 mm in diameter on the inside of the screen.
The end window envelope is 20 mm in diameter and, excluding the CT5 base pins, is 260 mm tall.
Reference: Datasheet. Type CV1737 was first introduced in 1950.

 

Pin Connections
Ct5
1
2
3
4
5
tc
h
g1
k
h
a1
a

 

Absolute Maximum Operating Conditions
CRT
Vh
Ah
Va
Vg
mAa
6.3
0.3
25,000
-40
150uA
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated March 20, 2017.
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