Rescued a PVM 14M4 from a bad home

mikejmoffitt

Mickey's Coach
I spotted a PVM 14M4U in "as-is" condition for cheap, so I got it. From the picture I could tell it was missing the power button. I hoped that the button had simply broken in the past, and that the monitor might otherwise work.

...well, it arrived, and it looks like it's been mistreated in the past. It was missing two of the screws on the side, and the tube looked a little tilted. Once I opened it it became clear somebody else has been in here.

The right side tube mounting posts are just missing, so the tube is only mounted on the left side. From a quick glance, I saw some of the connectors were disconnected. A ground wire was just sitting in there loosely, not connected to anything - it's the one that should go to the neck board.

Because the tube is so tilted, the neck board was providing structural support against the back of the set. That's really bad. Of course, the power switch board was disconnected too.

I've got to at least fix all the ground connections before I feel safe turning this thing on. If I get it working, any idea what to do about the broken tube mount in the front? Does anyone have a spare front 14M4/14M2 bezel / plastic piece they'd like to sell me?
 

caughdrops

Twinkle Star Sprite
That's very cool that you rescued her in her moment of need! I just got a BVM 20G1U off Craigslist and it too needs some love. Gotta figure out how I'm going to polish a couple scratches out. I hope you find that bezel quickly, and that the neck didn't get messed up too badly!
 

mikejmoffitt

Mickey's Coach
Well, her'es what I did:

* Mounted tube to frame using zip-ties for the time being
* Rewired ground connections
* Using .1" headers, rebuilt cables going from A board to front controls board and speaker

Miraculously, the monitor works pretty well. It looks like somebody dropped it in the past...
 

mikejmoffitt

Mickey's Coach
The bottom side has a few small cracks here and there, and it's kind of bent inwards about half an inch. The front bezel's two huge screw posts for the tube are just totally missing, alongside a few less important screw posts inside. I think it was dropped on the face or bottom or something. All the wires going to the front panel and power switch were just totally missing, which was the really frustrating part.

For now I've hardwired it to the "on" position, until I can source or build a replacement power switch.

The only remaining issue is that it occasionally gets vertical jitters. It's a problem I've never seen before - not just the screen moving up and down, but rather individual scanlines jittering up or down. This shows up as odd bright lines (as a line overlaps the previous) and as dark lines (gaps between the lines). In other words, the line spacing sometimes deviates mid-frame.

It'll settle back randomly on its own, and it doesn't seem to correspond with temperature.
 

mikejmoffitt

Mickey's Coach
It generally looks great, but it'll go into this "vertical jitter" state every now and then. It shows up as a scanline being offset:

J6vTuFu.jpg
 

Wachenroder

Giga Shock!!
that looks pretty good all things considered. what are those lines and why does that occur. i see see those faint lines, never as bad as that but from time to time they flicker in and out. it happens in some games worse then others and its been bugging me.

whats that called and how can i stop it?
 
Top