If you can't (easily) find a 140V zener it is normal practice to replace it with two zeners in series. IE use a 62V and a 75V in series giving you 137V which will work perfectly in this circuit.

For repairs to these boards I use TIP47G (MUST have the 'G') for the drivers and MJE15032 for the output. Never had any issue using these parts and they are very easy to find.

Yes but the transistor only has 193V across it. The input voltage isn't what is applied across the devices. I have never had a failure using these but I do buy them from reliable places such as RS Components.

Using quality parts helps, but yes, should either of the drivers short (in a particular way) that would place excess voltage on the other driver. I add it's never happened to boards I have repaired in 30 years using quality parts.

If you really want to be super safe, use a TIP48 rated at 300V but I have never found it necessary. Sometimes overkill isn't always needed to achieve a reliable result.

When rebuilding this particular circuit a repair person should replace ALL active devices regardless, so your point is rather moot.

I try and use suitable parts that can EASILY be obtained at SENSIBLE prices.

I think you mean:

"Highly efficient SWITCHING designs"

Linear is what the originals are......

Actually it IS a debate, they have 100% for certain made an error in that wording.

This is their 5V section and it is, without any doubt, a switching supply as can be seen by the chip used and the toroidal choke.

Anyone can make a mistake and this is mistake on their part for sure.

switching (resized).png

Here is a different looking replacement to the other brands mentioned here listed on Pinball Life site.

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