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 Precedent chassis
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 Return to top of page · Post #: 1 · Written at 10:23:48 PM on 29 August 2011.
Blingbling81's avatar
 Location: Noosa, QLD
 Member since 31 December 2010
 Member #: 799
 Postcount: 301

Hi guys, I had a go at fixing my Precedent and got the high voltage rail now and tube turns on but no glow or snow but when you turn it off you see the white square shrink to a dot nice and bright I have replaced all caps where should I be looking next? Thanks Smile


 
 Return to top of page · Post #: 2 · Written at 11:56:21 AM on 5 September 2011.
Sue's avatar
 Sue
 Location: Daylesford, VIC
 Member since 13 January 2011
 Member #: 809
 Postcount: 311

Can you see lines on the screen when the brightness control is turned all the way up? There may something wrong with the video drive to the tube if you can't see lines or noise on the screen while the set's running.


 
 Return to top of page · Post #: 3 · Written at 8:01:39 PM on 9 September 2011.
TV Collector's Gravatar
 Location: Ballarat, VIC
 Member since 4 January 2011
 Member #: 803
 Postcount: 456

Check the high value resistors that connect to the picture tube grids. These tend to drift in value and are often open circuit.

If you measure the voltages at the picture tube base and let us know what you measure we can give you a better idea of what's wrong.

Caution: There will be a few pins with between 100 to 700 volts DC on them so make sure you work safely!


 
 Return to top of page · Post #: 4 · Written at 7:54:52 AM on 12 September 2011.
Blingbling81's avatar
 Location: Noosa, QLD
 Member since 31 December 2010
 Member #: 799
 Postcount: 301

Thanks guys I will hopefully get some time this wind to have a look and update. Smile When you say measure the voltages at the base you mean unplug the tube and check each pins voltage? Cheers


 
 Return to top of page · Post #: 5 · Written at 7:25:52 PM on 12 September 2011.
TV Collector's Gravatar
 Location: Ballarat, VIC
 Member since 4 January 2011
 Member #: 803
 Postcount: 456

Leave the socket plugged into the tube and measure with set running.

Looking at the pictures of your TV I can see 6 wires. The following going in a clockwise sequence, is what I think is correct for your TV.

Pins 1 and 12 are the heater connections (6.3 V AC between the two pins) all other pins are measured with meter positive to pin and meter negative to chassis. Make sure the Brightness control is turned to maximum otherwise the picture will be all black.

Grey Wire - Pin 1 - Heater
White Wire - Pin 2 - Grid 1 (Between 0 and 230 V)
Thin Yellow Wire - Pin 6 - Grid 4 (Focus - Between 0 and 600 V)
Thick Yellow Wire - Pin 10 - Grid 2 (Around 400 V)
Light Green Wire - Pin 11 - Cathode (Around 125 V)
Dark Green Wire - Pin 12 - Heater


 
 Return to top of page · Post #: 6 · Written at 1:40:03 AM on 9 April 2016.
Colinardo's Gravatar
 Location: Surrey Downs, SA
 Member since 5 April 2016
 Member #: 1901
 Postcount: 6

I have a similar though older (rounder tube) Precedent, I thought it had the same problem until I found a trimpot near the vert lin. and height trimpots that turned out to be a sub-brightness adjustment!


 
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