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Switching H/V yoke polarity on Sony PVM for CW/CCW tate – safe approach?

Locutus73

Locutus73

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Hi everyone,

I’d like to ask for some advice regarding a setup I’m working on with Sony PVM monitors for tate gaming.

Until recently I was only using a Sony PVM-20M2MDE for everything (arcade + consoles), but I’ve just added a PVM-14M2MDE specifically for vertical (tate) games.

IMG_4175.jpeg

IMG_4174.jpeg


My idea is to keep the 14” permanently rotated 90° CCW, since:

  • it looks much cleaner in my setup (only top/right side visible)
  • it fits better aesthetically in my room
  • when rotated CW I get a slight purity issue in one corner
However, I’ve run into the classic problem:

  • some games (e.g. many CAVE shmups) require CCW rotation
  • others (e.g. older Namco titles) require CW rotation
So ideally I’d like to switch between CCW 90 ↔ CW 90 without physically rotating the monitor.

Proposed solution​

From what I understand, on CRTs this can be achieved by:

  • inverting H+/H-
  • and V+/V- at the yoke
This should result in a 180° image rotation, which—since the monitor is already physically at 90° CCW—effectively lets me switch between CCW and CW tate.

This is something commonly done on arcade monitors, so I’m not too concerned about the concept itself.

My idea was to implement it using:

  • two DPDT ON-ON switches (one for H, one for V),
    or possibly a single DPDT x2 (ganged) switch

Concern​

I’ve been advised against doing this with standard switches because:

  • the horizontal deflection circuit involves high voltage pulses
  • typical panel switches may not be suitable (arcing, insulation, etc.)
At the same time, I vaguely remember seeing similar mods discussed here on Arcade-Projects, and possibly even some safer implementations.

Questions​

  1. Has anyone here implemented H/V inversion via switches on a PVM or arcade monitor?
  2. Are there specific switch types (high insulation, industrial, etc.) that are considered safe for this?
  3. Would a relay-based solution be more appropriate?
  4. I also recall someone mentioning a protection circuit that ensures the circuit is never open (i.e. cuts power if switching state is invalid).
    Does anyone have details on that approach?
  5. Any other safe / clean alternatives to achieve CCW ↔ CW switching without physically rotating the monitor?
I’ll attach photos of the monitor in both CCW and CW orientations for context.

Thanks a lot in advance—any insight or experience would be really appreciated 🙏
 
djsheep said:
Change the rotation in the game settings if possible, if not, just pick up the monitor and flip it around.

Anything else is either more problematic or costly.
Click to expand...
Yeah, that's my current approach, I'm just exploring alternatives... I mean, costly could not be a problem (I mean if not excessively costly), it's problematic solutions which worry me.
BTW while I'm continuing flipping the monitor, I'd like to mitigate the purity issue I have exclusively when rotating it CW... any suggestion?
 
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Locutus73 said:
BTW while I'm continuing flipping the monitor, I'd like to mitigate the purity issue I have exclusively when rotating it CW... any suggestion?
Click to expand...

It should clear up on its own over a few days. If you're inpatient, you can use a degaussing wand or ring but don't get it closer than 2-3 inches to the set or it can damage the wires in the aperture grille.

Honestly, I'd use a flat panel display on a rotating mount instead of a CRT if you plan on swapping between games in different rotations frequently.
 
FrancoB

FS Thread 'MS9 (NAC/Egret 2) + Toshiba PF (NNC) Yoke Flip Kits'

Updated version of a kit I used to make.

The kit plugs into the CN401 (Vertical) and CN501 (Horizontal) connectors of the MS9 chassis. Flipping the switches reverses the polarity/image:

i-sH7Zhh8-S.png


This is useful for games that are output 180 degrees from 'standard' and can not be rotated via dips and/or it's not possible to physically rotate the CRT.

Egret 2 Version:

i-GmSBbqq-XL.jpg


i-pQ6K36Q-XL.jpg


i-gpzMm4h-L.jpg


i-Q2ttnvJ-XL.jpg



NAC Version:

i-h6J5sC2-L.jpg



Similar to E2 version but with longer wires to suit having the monitor set either horizontally or vertically...
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Here's an idea.
 
ShootTheCore said:
It should clear up on its own over a few days. If you're inpatient, you can use a degaussing wand or ring but don't get it closer than 2-3 inches to the set or it can damage the wires in the aperture grille.

Honestly, I'd use a flat panel display on a rotating mount instead of a CRT if you plan on swapping between games in different rotations frequently.
Click to expand...
Interesting. First I have ever heard this regarding getting too close.
 
Anyway the PVM has an automatic degauss procedure on power up and a manual degauss button... neither of those seems to be effective against the purity issue I have exclusively when the monitor is 90° CW.
I'm waiting hoping it will settle down in a few days, but it's still there.
 
The automatic degauss isn’t very strong or sustained though - hence why I recommended the degaussing wand or coil.
 
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