> > Oooh, didn't know about the diodes. Are there any specific ones that you
Err, no... There is this witch-hunt against capacitors, but other components are never considered > think should be replaced no matter what? If not, are there any tests you > would recommend? There are several supplies derrived from the flyback transformer. Let's take as an example the Ball Brothers VT100 monitor on page 43 of the printset on bitsavers. There is a -120V line, used for the control grid (g1), produced from the primary side of the flyback by CR110 and C117. I think if this failed it wouldn't damage the flyback, though There is a +32V supply for the video amplifier, produced by CR114 and C121 A 400V supply for the the first and focus anodes (OK, g2 and g3 across the Pond [1]) -- CR113 and C120. If either of those play up in can cause the flyback to overheat, The 11.5kV final anode voltage is produced by CR1 and smoothed by the capacitance of the CRT. I think CR1 is integral with the flyback transformer though. [1] In the UK we call all CRT elecrodes after the control grid (first grid) 'anodes' which makes sense as they are run +ve wrt the cathode. In the states, everything between the cathode and final anode (the aquadag coating on the CRT flare running at 10kV or more) is a 'grid'. Now something has just struck me. The adjusment for the first anode, if present (it isn't in this VT100) is known as the 'screen' control. What I do not know is if it's called that because it controls the overall brightness of the CRT screen, or because it sets the voltage on what is called G2 across the Pond, and which would be the screen grid of a tetrode or pentode. Does anyone know the reason? -tony