Unusual vertical collapse

[Slypty]

This is a PVM-1953, I have never had it working.. came from a friend who had a few 'repair centres' work on it. Apparently it worked for a time then went out. The mainboard has had been worked on, and poorly. The vertical output transistors were replaced, as well as the horiz/vert. IC. The soldering job was horrid, so I actually re-did all that and replaced some bad caps.

Near the vertical power output, there was an open inductor as well as an open fusible resistor. In the PSU, there was an open .22 Ohm resistor near the output transformer in the secondary.. that leads both to the B+ and a 15V output. The B+ reads 113.8V and the 15V reads 17.4V. I have a good 120V B+ before the Sanken power B+ output control IC. (I should have 115V, spec is only 0.1V +/- tolerance.)

The open resistor in the PSU fixed the horizontal line so that it was no longer red, as well the power light would light up (before it wouldn't), but I still have vertical collapse.

The open resistor in the vertical power output area also had an effect on the line, but didn't fix it. Colors appeared at the end of the collapsed line after changing the resistor out.

What bugs me is that the vertical collapse line isn't your typical 'straight line across.' Why?

- The line doesn't stretch from end to end

- There's colors at the end of each side of the line. (Red on the far left, Blue on the far right)

It doesn't go 'straight' in to a solid white line. Instead it starts white and is thicker then slowly morphs in to what is shown in the pic.

I'm hoping the oddities of the collapse can help point out where to look. Maybe it's still a broken trace that I've overlooked. Hoping someone has seen something similar and found a fix.

[MIPS]

Is the high voltage low enough the picture has shrunk to where full horizontal deflection can't reach the sides?

[zeno]

Originally Posted by MIPS

Is the high voltage low enough the picture has shrunk to where full horizontal deflection can't reach the sides?

My thought too.
Also does the B+ for the vert outs come from the main PS or a FBT winding ?
Anothe thing is the main B+. 113VDC seems odd. Almost every set
has between 120 & 135 VDC. Maybe you have 2 probs.

73 Zeno
LFOD !