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Argus25 · 3rd Oct 2017, 7:17 pm

One bit of information that might help......is the height control roughly in the middle of its range or is it to one side, if so which side ? If the fault is in the plate load, such as the impedance going higher there (due to a faulty VDR in the yoke assy as suggested) the control would probably need to have been turned for a higher level grid drive to the pentode, which could result in the scan distortion.

Despite the fact that you have replaced the valve with a new one, this would be the type of fault seen with a low emission output valve (pentode section) too, so if you have another one, do try it too.

3rd Oct 2017, 7:17 pm	#22
Argus25 No Longer a Member Join Date: Oct 2016 Location: Maroochydore, Queensland, Australia. Posts: 2,679	Re: Frame cramp Baird M676 help One bit of information that might help......is the height control roughly in the middle of its range or is it to one side, if so which side ? If the fault is in the plate load, such as the impedance going higher there (due to a faulty VDR in the yoke assy as suggested) the control would probably need to have been turned for a higher level grid drive to the pentode, which could result in the scan distortion. Despite the fact that you have replaced the valve with a new one, this would be the type of fault seen with a low emission output valve (pentode section) too, so if you have another one, do try it too.