[AmigaMan]

Hello all.

I'm finally getting back to working on my Predicta Holiday. Got a nice and bright CRT, but no vertical lock, and weak horizontal.

I've only done the basic recap so far, so I haven't yet looked into the resistors and couplates. They're next, after a long period of waveform tracing and value checking.

My question now is about the vertical integrators used in these sets. It's a part of the couplate K3, and the integrator itself is indicated in the Sams as a resistor with a capacitor plate across it. I've seen these before in other sets, most recently in my Zenith porthole. In that case I had an NOS spare, so I didn't need to dig into it too far.

So how might I be able to build an equivalent with discrete components? I've read about others making them out of a series string of 3 or 4 resistors with capacitors to ground between them, and I think that would work fine as long as the filtration covers the correct range with minimal gaps.

The values for the resistor and capacitor elements in the original integrator are clearly stated, and they are 90 kΩ and 4000 pF respectively. I can easily divide out the resistance, but capacitance I'd assume would be tricky since the parallel array of capacitors is separated by resistors.

So have any of you made a good K3 replacement, or vertical integrator replacement in general?