Pilot monochrome TV Model unknown

[Theodosea]

Just acquired this tv but there are no model markings on this - only the 'Pilot' badge - does anyone recognise the model?

Regards Nick

[Mike Watterson]

Might be a Spacemaker PT650

https://www.radiomuseum.org/r/pilot_spac...pt650.html

[Theodosea]

Having looked at your link it certainly looks like the PT650 but the remains of the model designation label on the rear cover shows PT and 50 clearly but the number before the 50 is not a 6 it is more like two 1's so 'PT 1150' but can find no reference to this model??

Nick

[Mike Watterson]

What's your screen size?

The same chassis is often used at different screen sizes.
Yours is likely the same chassis and a smaller screen. That one is the 21"

From R &TV S 1960-61 Spacemaker models
PT 450 17" Table
PT 452 17" portable (transportable)
PT 650 21" Table

Live chassis, Band I & III 405 line
Remove chassis screws from underneath cabinet.
Two different tuner units used.
Same schematic for all three, though with variation for the 21" (yours looks like 17").

From R &TV S 1960-61 Spacemaker models
PT 451 17" Table
PT 651 21" Table
Live chassis, Band I & III 405 line, with Band II FM Radio
Two different tuner units used.
Very similar to PT 450 & PT 650

1960 may have been the last year of Pilot TVs. Ultra bought the company in 1959 and later Thorn (Ferguson) owned Ultra.

I only find those 5 models of Pilot PT xxx. They are better known for radios, originally based on the USA Pilot designs (1935).

[Theodosea]

Mike, I have just measured the screen and this is 17" I am still confused as to why the model designation label reads PT 1150? 
Regards Nick

[Mike Watterson]

A mistake. It should be PT 450. Imagine the open style 4 with the horizontals worn off

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[Mike Watterson]

Also no Irish 625 till 31st Dec 1961 or Jan 1962, so can't be an Irish Export version. Pilot wouldn't have been selling TVs in mainland Europe. The Trader Sheets and R &TV S don't generally cover export models (typically radios had SW instead of LW) or Irish models (radios without VHF in case of UK models with VHF as UK FM is 1955 and Ireland was maybe 1962?). Ireland TV was a mix of 405 and 625 depending on if UK TV could be received and only really from 1962. Germany VHF-FM from 1949 and the 625 was in Europe somewhere 1948-1950s. Belgium had sets with 2 kinds of 819 and 625 line. I think only UK and used 405 lines: 1935 -1939 & 1946-1962, with UK and parts of Ireland 405 1962 to 1985.

[Theodosea]

Many thanks for your help Mike, as this TV is a 405 line model I assume I am going to need a converter in order to feed video in via the aerial socket? can you please remind on the details for these converters?

Regards Nick

[Mike Watterson]

Only for watching and a help with alignment. Others that have a converter will give better advice.

There was still 405 line TV when I last was repairing 405 sets!

The #1 item is probably capacitors. Likely a 1959 design and made late 1959 or in 1960, so may use paper dielectric capacitors. Not all have a waxed cardboard case. Some are "Modseal" which is now crumbling black or dark reddish material. Some are metal cans with rubber bungs at each end. Generally 470 pF to 1 uF. All need replaced.

Mica, ceramic or plastic delectric caps will be fine.
Any Electrolytics may reform (use a 30V PSU and 10mA current limit, 50mA max). The current should drop to less than 1mA after 4 to 10 hours if OK. If there is no current (or a lot of hum eventually), then an electrolytic may be dried out.

Ensure it's in a warm dry place for days in case the LOPT (EHT transformer) is damp.

Only replace valves with an open circuit heater, to start with.

Don't power up without checking main rectifier and replacing the paper dielectric caps.

Almost all the repair & restoration is possible with no signal. A full screen of noise/snow and hiss on audio. Not worth spending money on a converter if you don't get that far.
Some PC graphics cards and some Raspberry Pi models can do 405 line, but that is only baseband video and you'd still need a pair of modulators for video and sound. An AM signal generator (60 MHz band) can help fault find if the video or audio is dead after doing all the normal stuff. The Line drive is only 10.125 kHz so you might hear it.

The mains or line drive boor (about 800V?) or EHT can be fatal.

[Mike Watterson]

The main HT / PSU Electrolytic may have 3 or 4 in one can. These explode nicely if the main rectifier is leaky or short.