New Tube advice Please

[bazzae123]

Having just received my Toshiba CRT back from having yet another tube fitted I've noticed that it now has a LG/Philips tube fitted. Is this a good thing? The geometry is still out with a obvious bow across and down one side but what's more alarming/annoying is the top of the picture jumps up a set of pixels half way across the screen giving a step appearance. Does anybody know what is causing this? I will contact the service engineers again but I would like to be armed with some of my owm answers and not blinded with science by them given their track record to date.

[bazzae123]

Can somebody please clarify that this is OK. Having adjusted contrast/colour/brightness etc using AVIA all the setting seam to be near the top end of the scale up in the 60% region or over where as the previous new tube were around the 40% or lower. Is this OK or does it indicate an underlying problem.

Any help on this would be appreciated. TV is a Toshiba 32ZD08B fitted with a LG/Philips tube.

[hornydragon]

the step you talk about is present on a friends cheapie deccacolour set. Manufacturers use all sorts of tubes I rate the LG/Phillips tube, Sounds like something might be up see if it settles down, how many tubes have been fitted??? If its killing alot of tubes I would say their is a fault in the chassis, what was the problem before and do you think the new tube is better PQ than the one it replaces???

[GaryB]

The step that you can see at the top of the screen should usually be hidden by the slight overscan that most sets have. If you can get to the Service Menu, a slight increase in height may help. It's unlikely that the bow at the bottom of the picture can be cured but again, the Service Menu may help.

The movement in the settings can be caused by several things:

1. Different characteristics of the new tube.

2. Changes in the A1 (final Anode) voltage. This should normally be adjusted as part of the set up after fitting the new tube but getting it exactly right is a bit of an art. If it's set too high you normally get a slightly washed out picture, possibly with very faint flyback lines in dark areas of the picture.

3. The engineer who fitted the new tube may have altered the preset Colour/Contrast/Brigtness in the Service Menu.

Philips tubes are generally OK but they have had reliability problems in the last few years.

[bazzae123]

Thanks guys,

First tube from new lasted 2 years. Second one fitted lasted until I saw it come back from the repair shop as it had severe bowing on all axis's and couldn't be correct when the engineer called. The third is the present one with the Philips tube. The colours with this tube seem to be much more vivid than the previous two but it still has a severe bowing on both sides. To me, the contrast seems to much as flesh tones are reddish but I can't seem to correct it.

[bazzae123]

One other thing that might be worth mentioning is after the first new tube was fitted the TV was returned to me mostly set-up as I had left it. This time all the setting were default even the channels had to be restored. It was like a new TV out of the box. Does this sound correct when fitting a different tube manufacturer from the TV itself? Something don't seem right to me.

Bazza