Pilot PT450 CRT Type??

[Theodosea]

I am about to carry out an emission test on the crt of this tv using My B & K 470 tester but the tube fitted in this television is a Mazda - again half the label missing and numbers that are legible bear no relation to the service sheet or the tube type list to enable me to select the correct tube adapter,
Numbers I have are 2/703
The Mazda tube looks like an original fitment but who knows,
Nick

[ppppenguin]

To help us work this out, please give some basic information on the CRT. Screen size, neck diameter, base type. This last is most likely to to be B12A for a thick neck tube or B8H for a thin neck. If it's B12A, some pins are often missing so it's useful to know which ones are fitted.

Magnetic or electrostatic focus? Straight or bent gun?

[ppppenguin]

To help us work this out, please give some basic information on the CRT. Screen size, neck diameter, base type. This last is most likely to to be B12A for a thick neck tube or B8H for a thin neck. If it's B12A, some pins are often missing so it's useful to know which ones are fitted.

Magnetic or electrostatic focus? Straight or bent gun? Aquadag (graphite) coating on the outside?

Many CRTs had similar pinouts and characteristics. Obviously there are some that were exceptions..

[Mike Watterson]

I'd not bother unless you get everything working and it's dim!

R &TV S book says CME1703, which is a Mazda.

Note that the stated emission figures are for a new CRT and those can go far brighter than needed. Even 30% emission might be fine. We had an old TV from my grandparents that needed the curtains closed, as do most cheaper low power projectors today.

[Mike Watterson]

The CME1702 is a different base the CME2101 is the version for the 21" set.

Advert with data and base diagram, but fuzzy!
https://r-type.org/adverts/adv-0446.htm

[Mike Watterson]

I'd not bother unless you get everything working and it's dim!

Note that if the tube has not been in use for years, that running the heater alone for a few hours (no other connections) may boost emission.

It was also common to add a heater transformer in case of isolation failure or to boost the voltage a little to get some more life.

[Mike Watterson]

See also https://archive.bvws.org.uk/thevalvepage.../pilot.htm
Scroll down to "1959 Onwards"

[Theodosea]

Ok,
I have uploaded three photos of the Mazda tube,

7-pins - only five used, 17 inch screen - 11 1/2 inches front to back, neck size 28mm. 

Number on the paper label - 2- 703 
Regards Nick

[ppppenguin]

That sounds like a CME1703. The number "2" is probably a garble of one of the other characters. Be aware that this has a 12.6V heater, rather than the more common 6.3V. It's still 300mA so will work in a standard 300mA heater chain. The different voltage will make little difference but it's worth checking the voltage across the heater when it's in the set just to be sure. Then if you test it outside the set, you will know what heater voltage to use.

It can be replaced with the Mullard AW43-88 which has a 6.3V heater. There are many other near equivalents.

What really mattes is how it works in the set. If you get a bright picture then there's no point in testing the CRT.