HOWTO: ViewSonic VX2000 Front Panel Hack

Here's a hack on the excellent ViewSonic VX2000 20.1" LCD monitor to retrofit its front panel with an older switch-based replacement. If that seems puzzling, read the following description of the problem and why I felt it necessary to do this hack. Or if you're ready to hack, just get right to it.

WARNING and DISCLAIMER This procedure is not for the technically faint of heart. It requires some basic electronics skill, such as proper handling of static-sensitive components. It is unlikely, but if you seriously screw up, you could kill your monitor, or worse, yourself. So if you're not completely comfortable with the procedure described here, please refer this work to ViewSonic service. I am not responsible if you mess up your monitor or suddenly feel drawn to a great white light (remember: run away from the light). Also, this procedure will definitely VOID YOUR WARRANTY if you still have one.

But...Why?

I have two ViewSonic VX2000 monitors in my studio that I've had since 2003. I love them. Recently, one of them started acting up -- specifically, it wouldn't power up with the front panel power button, or if it did, sometimes the front- panel buttons would seem to "press themselves" and bring up onscreen menus without my bidding. This got more and more common, so I decided to take action.

My VX2000s are out of warranty, so ViewSonic referred me to a California company called Edwards Service. They told me I'd have to ship my monitor to them in California, and that there'd be a $35 diagnostic fee to even look at it, then $105 flat labor fee to fix the monitor, plus whatever parts cost was required. This seemed pretty painful to me, since I was virtually sure the LCD and associated electronics were working fine -- the front-panel electronics were probably to blame.

The front panel "switches" on the VX2000 (well, at least the ones I have) are these touted "touch-sensitive" capacitive switches that are a high tech solution to the clearly obsolete physical switch. In other words, the marketing department needed more reasons to charge $1400 for these monitors (yes, that's how much they each cost when I bought them new). Too bad their shit capacitive technology proved unreliable, at least for me.

The capacitive front panel board in the VX2000, called "00.58702.001" is probably available as a replacement part. But I decided to check out my alternatives. I found a guy on the internet selling an older front-panel board, called "00.58705.001" that was ostensibly used in older models of the VX2000.

Since I could buy this older board for $10, I decided to give it a go, even though I could clearly see from the photographs that the board used old-school physical buttons instead of the capacitive touch switches on the board I had. But it had a good chance of being pin-compatible, so I went for it.

Lo and behold, it was in fact pin-compatible, and operated the monitor perfectly when I tested it, and the mount holes and button spacing was identical, as I had expected. So I was left with the problem of how to get the old fixed buttons to actuate the new physical buttons. That is what this hack is about.

Let's Get Hacking

In short: we're going to extend the old touch-sensitive button caps enough to press the new physical switches. Then we're going to stabilize the buttons so they stay pointing at the middle of the switch faces.

You can see here the way the old capacitive switches worked. There's a metal button cap that fits through a slot in the plastic front panel bezel. The button cap fits over a 15mm metal stud that is soldered right onto the board. The caps are affixed by friction alone, since they were captive in the old assembly, and easily removed.

The white squares you see on the board appear to be stabilizers to allow the studs to be flow-soldered at manufacturing time -- they're just square standoff washers essentially -- not switch bodies of any kind.

Here you can see a detail of the new board, with it's 19th-century surface-mount pushbuttons. The first problem is how to get the old metal button caps to press these new buttons.

By assembling the new board onto the bezel assembly I measured that I needed a 6.5mm stud sticking out of each button cap to get the buttons caps to touch the surface of the switches. I considered desoldering or cutting off part of the studs that were on the original board, but the throw of the surface mount buttons is only a fraction of a millimeter -- if I cut one to short I'd be in trouble, and there was little room for error.

So instead I decided to go for an approach that would afford me some adjustability. I hunted through my screw collection and found eight tiny screws that were roughly the diameter of the old studs. I screwed these into each button cap to give the required 6.5 millimeter length.

After retrofitting the button caps with their screw-extenders, I put all the button caps into the bezel assembly and mounted the new circuit board behind them. They were already marginally functional -- and clearly my adjustability was a good move since half the buttons weren't extended quite perfectly. A few turns on the little screwheads here and there and I had the buttons caps all reliably actuating the underlying switches.

Right away though, I noticed that the buttons weren't stable. The original capacitive assembly had completely fixed button caps -- no movement whatsoever. Now in the retrofitted setup they needed to move, and move in a roughly straight line into the switch face. The bezel itself was no help, providing virtually no support for the button caps, as can be seen in this detail of the back of the plastic bezel. Without support, the screwhead button cap extensions slipped off the switch centers. So how to stabilize the button caps?

One initial idea that seemed to have promise was to hot-glue two high-density foam or plastic blocks to the back of the bezel, above and below the button caps to stabilize them vertically. (Empirically they seemed to not really require any horizontal stabilization, so I ignored that.) It seemed like a good idea, but I couldn't think of a good material for the mod that I had sitting around. So on a whim I decided to take a look through some of the more obscure boxes in my hardware collection to see if I could find something simple and at-hand.

After not much searching I stumbled upon an ultra-simple solution -- fitting rubber grommets around each button cap provided the needed stability in both the horizontal and vertical axes. (I assume this is described somewhere in Electronics for Dogs.) It is difficult to surmise from the photograph, but the grommets are stretched a little around the button caps -- elongated in the horizontal direction.

I fitted all eight grommets and remounted the circuit board to see how things were lining up. It looked pretty good, but it appeared that optimally, I needed the button caps to be pointing a little up to be hitting the middle of the switch faces. I noticed that if I just sort of pushed them up, they'd stay there (within the grommet) but it was clear that eventually they'd re-center themselves and be pointing a little low of the switch faces.

So I decided to point them up, then hit them top and bottom with a little hot glue. This was not so much to affix them to the grommet -- friction was doing a fine job of that -- but more to keep them pointing up. The glue treatment worked well. Since the grommets were friction-fit to the button caps and the button caps had to move, I didn't hot glue the grommets to the bezel as I'd originally envisioned. They actually travel the 1/3mm along with the button cap when you press the buttons in from the outside of the bezel.

Below you can see in cross section how the button caps line up nicely with the switch faces.

The only part left was buttonup, which was a snap. The replacement front panel board was actually quite a bit smaller than the one it replaced, so it was quite a bit easier getting the whole assembly to snap into place than with the original.

Retrofit Completed

All in all this was a very satisfying hardware hack. I'm not much good at the physical parts of these kinds of hacks (versus, say, the electronics aspects when needed), but this one worked out well. Hopefully some of the approaches shown here will be of benefit should you run into a similar hardware-hacking challenge.