MSX - Philips NMS 8255

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Wild Penquin
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Joined: Sun Sep 18, 2011 3:23 pm

MSX - Philips NMS 8255

Post by Wild Penquin »

Hi!

I installed the floppy emulator on an Philips NMS 8255 MSX2 machine. Sorry about this lengthy post and some bad English at places - I'm having a slight hangover and I'm not a native English speaker! Pictures are here.

I used polymorph plastic to make the new front panel to where the disk drives were. While doing that, I did some minor damage to the front panel :!: . Details below - in short: 1) The polymorph gets stuck very tightly on some kinds of plastics and 2) be careful if using a hot air blower near plastic, the melting point might be lower than you think!. So please read this carefully, if you're planning on doing something similar! :wink:

Also, when using polymorph plastic, some hot water and / or hot air blower is needed. So be careful and use common sense! I didn't get burned, btw :wink:

On the very close up pictures, you can see the scratches and dust on the cover of the NMS 8255. It has seen some life, and of course I could wipe some of it off ;-). Also, the damages I made can bee seen! It doesn't look that bad in reality, as in the close-ups.

*** About the workflow ***

After some experiments, finally I ended up making a 3mm sheet of plastic and working down from there. I used 3mm spacers, put them on a table with the heated polymorph and pressed with a glass oven tray to make the sheet. Some findings / problems:

- Some air bubbles tend to get between the plastic and the glass
- The sheets tend to warp while cooling down
- It is not easy to cut nice looking edges to the sheet.

If using any electrical tool (a drill to make holes, sanding etc...) the polymorph heats up and gets melt / soft. For this reason, using a dremel to make the edges is not a good idea (the plastic dust / cruft tends to get stuck on the edges, and it doesn't look nice). I used a carpet knife for cutting the edges where needed, after making the larger cuts with a dremel.

After making the sheet (which is slightly warped and bends easily), I also needed to:

- cut it to the shape (first with a dremel, and then with a carpet knife)
- make the holes for buttons, MMC card and the LCD screen
- Thicken the sheet around the LCD screen hole to match with the LCD screen thickness
- Attach some 2,5mm screws to where the LCD screen screw holes are (I put only 3 since that is enough, and matching a fourth one with the hole seemed difficult)
- Attach support beams to attach to the NMS case, make it more sturdy and compensate for the warping
- Cut some screws and make some holes on the beams for attaching (M3 screws are fine)
- Paint it black

Some thing I could improve (but don't want to use more time on this currently):

- The surface is a bit rough, I could make it more even with patience
- The edges could be nicer (by cutting with a hot metal ruler or similar, see below)
- The MMC card hole is slightly off and a bit large (I accidentally made it a bit too low and to the right first)
- A thicker (than 3mm) sheet wouldn't probably warp so much while cooling

But, I'm happy enough with this result :wink:.

:arrow: :arrow: :arrow: I made some experiments before / after making the panel, below I share them with you - and also describe how the panel got damaged! :arrow: :arrow: :arrow:

*** 1 - The abandoned "Philips NMS front panel mold" -approach, and how the NMS panel got damaged ***

At first, I tried to use the front panel as a mold for the polymorph plastic. I put the NMS 8255 fron panel down on a table, and then put warmed polymorph in to the hole and tried mold it in place to the desired shape. But the polymorph cools down from the surface too fast, so corners and edges get irregularly "rounded" and look very ugly. I noticed that if I take smaller hot pieces of polymorph, I got a nicer edge by making it gradually - but then I got seams on the edges of individual polymorph peaces, which looked very ugly, and which I was not able to remove. After a few experiments, I abandoned this approach.

I tried one more approach with this "mold" idea. I made a slightly larger sheet than needed, heated it with a hot air blower on a glass table, and pressed the NMS front panel on this piece of polymorph plastic. The result seemed good, expect... the excess area of the sheet got stuck on the black stripe on the NMS front panel. Well, I thought no problem - I'll just use the hot air blower again to heat the polymorph to remove it from the panel. But, the polymorph was attached very tightly to the black stripe, where the reset and power buttons are on the front panel - in fact so tightly, that I haven't been able to remove all of the polymorph from the stripe to this day (can be seen in the pictures). Also, the black stripe warps a lot and very easily if warmed! This also happened while I tried to heat the polymorph to detach it from the stripe. Because of this, and trying to remove the polymorph, the black stripe got detached. I re-heated it on a table, made it straight and put it back in the NMS panel :wink:

Also, while I thought that the front panel plastic has a much higher melting point than polymorph, apparently it is not that much higher - and, also, heating with a hot air the surface of the plastic needs to be much higher so that also the inside of the polymorph gets warm enough - or, you need to be very slow / patient. But I wasn't, so also the grey front panel plastic got slightly molten while removing the polymorph (immediately when I noticed this, I was a little more careful with the hot air blower onwards).

You can see the damages from the pictures!

*** 2 Cutting the polymorph sheet ***

After / while making the panel, I noticed I can get the nicest looking edges with a hot, straight object (a metal ruler, for example): heat the ruler (or similar metal thing, for example a straight knife) with a hot air blower / hot water, and press down on the line where a cut is needed (with the sheet lying on a table). Then cool the sheet with cool water (or just wait long enough). Sometimes the ruler gets stuck on the sheet - in this case it is much easier to remove after cooling the piece. This way, the cut won't be complete, but there well be a very thin part where the cut is needed, which can be finished with a carpet knife or similar. These new edges looks very nice.

I didn't want to start over after finding this out, since I had used already so much time with this thing and started to get bored with the project.

*** 3 Polymorph painting vs. dyeing ***

Also, while experimenting, I accidentally noticed that with the alcydic spray paint I have, you can also "dye" the polymorph plastic. After painting a chip of the plastic (and letting it dry), I re-heated it in a glass of water. I thought maybe the paint will come off or something, but it didn't - instead after shaping the plastic, the black paint got nicely mixed in the plastic. And, of course it is not soluble in water, so the water stayed clear as did my fingers ;-).

One might get a better result with this dyed polymorph. The paint also gets easily removed / scratched (or, there's some skin oil on the panel I made - I was too lazy the clean the piece I have before painting). With dyed polymorph there wouldn't be this problem.

*** That's all. ***

Hope this is helpful in case someone considers doing something similar in the future!

Cheers!

Jeff
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Re: MSX - Philips NMS 8255

Post by Jeff »

Nice mod and nice description !
Image2.jpg
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:wink:

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