25-09-2018, 09:37 PM
Good tip to look at the date codes, thanks. The latest chip has date code '76 others range from '73 to '75.
Funny you mention a power supply problem, when I tried to remove the main smoothing cap I found the veroboard strip cracked and it looed like the cap had never been joined.
I've corrected it and the hum bar has all but vanished, power supply should be 12V regulated by zener - its still a bit low. I'll scope it and see when I take it to the workshop.
Underneath is says 'Colour Test Gen. CMN6 cManor Supplies 1976'
A big transistor dropped out as I removed the board from the case, it looks like the second regulator 5.6 zener feding an emitter follower perhaps.
It was working, colour bars and crosshatch.
Board connections are labled:
12v
5V
(gnd)
ld
fd
mb
(gnd)
out
in
The second, smaller board says 'Random Interlace S.P.G. CMN 4' The output from is the only signal feeding the UHF modulator.
This board has been hacked around a bit some connections have been rremoved.
Havn't seen anything from Manor for a while now, they used to advertize in magazines.
Major component counts:
2x 555
4x7400
1x7493
1xTBA990Q
14 transistors
12 pots!
David.
Funny you mention a power supply problem, when I tried to remove the main smoothing cap I found the veroboard strip cracked and it looed like the cap had never been joined.
I've corrected it and the hum bar has all but vanished, power supply should be 12V regulated by zener - its still a bit low. I'll scope it and see when I take it to the workshop.
Underneath is says 'Colour Test Gen. CMN6 cManor Supplies 1976'
A big transistor dropped out as I removed the board from the case, it looks like the second regulator 5.6 zener feding an emitter follower perhaps.
It was working, colour bars and crosshatch.
Board connections are labled:
12v
5V
(gnd)
ld
fd
mb
(gnd)
out
in
The second, smaller board says 'Random Interlace S.P.G. CMN 4' The output from is the only signal feeding the UHF modulator.
This board has been hacked around a bit some connections have been rremoved.
Havn't seen anything from Manor for a while now, they used to advertize in magazines.
Major component counts:
2x 555
4x7400
1x7493
1xTBA990Q
14 transistors
12 pots!
David.
