Sega Net City Restoration

[Thomas]

ネットシティSD（シットダウンタイプ）

It's been a year and a half since I received a trio of Cities from KC and I'm finally getting work done on the third and final City, the Net City. I have always liked the look of the Naomi/Net City series of cabinets so it was at the top of my list when cabinet shopping. Plus I wanted one cabinet with JVS support. The tri-sync monitor is cool too. I specifically requested an Old Net City instead of a New Net City only because I prefer the orange stylings. I had no idea that the New Net City has a superior monitor.


Here's what I got:

The guy making the delivery had a pickup with a small hydraulic lift cart that wasn't working. So we had to lift the cabinets out of the truck. The Astro and Blast went down okay. The Net has some extra weight and an awkward shape so it didn't come off the tailgate too smoothly. It took a hit to the back on the way down. Fortunately nothing looked damaged and the plastic monitor cover absorbed the impact.

I repeatedly requested and reminded KC to include a marquee holder and luckily he sent one. It wasn't attached to the cabinet when it arrived and I had to ask the delivery guy before he drove off to look for it under some stuff in the back of his truck and he found it. I had to be persistent to get that marquee holder and I'm glad to have it.

I disassembled and cleaned everything a full year ago and the parts have been all sitting in a pile since. Restoring the Astro and Blast Cities took a long time and I didn't want to deal with the Net until those were done. I did a quick test with a Dreamcast on the day the cabinet arrived just to make sure the monitor worked and that was it. I saw some convergence problems in the corners of the screen but otherwise the picture looked okay.

As usual everything was filthy dirty, the wiring a mess, missing fasteners, no locks, broken parts, damaged and yellowed paint, etc. Outside didn't look too horrible but the inside was nasty. Some disintegrated foam made the filth even worse. I'm still trying to determine where the foam originally was located. In the manual there's supposed to be some foam near the light fixture area but I'm not exactly sure where or what its purpose is.

The coin box was welded down in the back and I drilled through the welds so I could pull the box out for deep cleaning. There are screw holes already there so I only need to find some screws to fit and secure the box back down later.

Krud Kutter works well to remove most of the stains but doesn't restore the paint color completely. The paint is still various shades of greyish yellow white even after a thorough cleaning with undiluted Kutter.

 

[Thomas]

For the electronics I used an electric duster and a brush to clean off all the dust. The PCBs will get cleaned with alcohol later.

I couldn't find the manual online anywhere, maybe because it's the same as the Naomi and New Net City manuals and no one cares. But I really wanted a manual for the Old Net City so I bought one on Yahoo Shopping. Not only is it a photo copy but it's a used photo copy with dirt, stains, and bent edges. That's all I could find and it was less than $10 so I bought it along with an Astro and Blast manual which were also under $10. These are both easily found in PDF format online but I like having the originals. The wiring diagrams are especially nice to have on the large paper size instead of looking at a scan on a phone or PC monitor. Maybe later I'll take a look through the Naomi and New Net manuals to see what differences I can find. So far I noticed one thing different for the New Net: there is a fan attached to the rear vent. The Old Net doesn't have a fan. I should find a way to scan my manual and upload it somewhere. I'll add that to my to-do list.

I soaked most of the metal parts in vinegar for a few days to remove rust, rinsed with water and baking soda, then rinsed with hot water, then thoroughly dried. Some parts were very rusty, some not. I should have been more selective about which parts got a vinegar bath because some could have been left alone and saved me some time and preserved the plating. After removing the rust I brushed on two coats of Protecta Clear. I spent a lot of time researching products and methods for metal coating and decided that this Protecta Clear would be the best option for me. The small can was $28 and I used about half of it. It was easy to brush on and after it cured, it's hard, smooth, and completely odorless. I brushed Protecta Clear on the inside of the coin chute as well, directly over the rust.

Most of the nuts, bolts, and screws were sprayed with CRC 3-36. I also sprayed it on the control box hinge, the wheels, and any other moving parts.

The sides of the monitor cover had deep scratches. Too deep for any polishing to be effective. I sanded one side flat using grits 320, 400, and 600 then remembered that a heat gun may have quickly removed all of the scratches. Since I'd already sanded one side, I didn't try the heat gun and instead sanded the other side, then sprayed both sides with clear enamel paint.

 

[Thomas]

The monitor bezel/mask was badly stained and scratched. At some point the bezel had stickers on it which prevented the plastic underneath from discoloring so now the bezel has these light areas where the stickers were (the back of the bezel is this same light color and is what I used when matching the paint color later). I tried using a rotary buffing machine to bring back the color but it didn't make any difference. The buffing took out the scratches and brought back the gloss but the stains are too deep. And unlike the Astro and Blast bezels, the Net bezel is plastic, so I was a little worried about overheating the plastic and ruining it with the rotary. I thought about using sandpaper but this appears to be a coated plastic, similar to the control panel base on the Blast City. If I sand off enough material to restore the color I may not be able to bring back the gloss. Which means the bezel needed a re-paint to look pretty again.

The plastic front panel obviously needed new paint due to it being extra yellow as it is on all Old and New Net Cities. The right side of the bottom part that attaches to the control box was broken so I first filed down the plastic, then used Plastic Fusion to attach a washer. After the epoxy dried for a day or two I sanded it flat.

I also used Plastic Fusion on both sides of the top to repair cracks.

The bottom part of the panel had some cigarette burns that I sanded down then filled with Plastic Fusion, then sanded flat once dry.

 

[Thomas]

After peeling off the badly yellowed rubbery part of the emblem sticker, I found that the sticker was well preserved underneath. Since I already bought a new sticker and I like the rubbery part, I removed the old sticker completely. In the photo the areas around the sticker are lighter because I put some hydrogen peroxide over it and left it in the sun for a few hours to see if that would get rid of the yellow. It didn't change the sticker color but it did lighten the plastic of the front panel so the "retrobright" method might work for the front panel. I prefer re-painting even if the hydrogen peroxide is effective.

The control box lower was in good shape except for some black scuff marks that I mostly was able to remove with a Magic Eraser. Enough so that it's only noticeable when viewed from below and up close. The top part that meets with the control box upper is the same type of coated plastic as the control box upper (and just as stained and damaged) while the lower part is not coated plastic. The color and sheen of this lower part is slightly different from the rest of the cabinet. I decided to only paint the part that meets with the control box upper since the control box lower is in good shape.

The control box upper was scuffed and stained and since I'm already painting the front panel it makes sense to paint this as well. And I want the color of the control box and front panel to match.

The dummy button was really difficult to remove and I eventually got it out by spraying some lubricant and using large pliers and some 3M friction tape wrapped around the top of the bolt.

There was a nasty hole in the back of the control box lower. I don't know why it was needed or why the person who made it needed to make it so big and ugly. The wires routed out of the hole are connected to the coin mechanism and I don't know what external thing it would have been connected to.

To repair the hole I used a 3M fiberglass repair kit. It's not made for plastic but it adhered to this plastic well. Because this repair is in the back and mostly out of view, I didn't spend much time on making it perfect. I skipped adding filler and only sanded it a little before painting.

The front panel screw caps were all either missing or broken so I bought 3D printed ones from Arcade Invaders. These aren't smooth and needed two rounds of primer and sanding before applying the base coat.

 

[Thomas]

I also painted the new old stock coin entry that I bought from Tops/Sophia Corp. I still think it's weird that these are sold unpainted.

I used the same painting products and process as I used with my Blast City here and here.

In the back of the cabinet was a port cover taped down. The side taped down to the floor is lighter and less yellow than the other side that was exposed. I assume this lighter, unexposed side is close to the original paint color and this is the color that I tried to match when buying paint. For the clear coat I had planned to use semi-gloss because the original paint is not as glossy as a high gloss clear. But after polishing the bezel I saw that the sheen is more glossy and I don't know how Spraymax 2K semi-gloss will look so I stuck with 2K high gloss ("clear glamour") for everything. I did all the painting at the end of October just before the weather turned cold.

Pretty good color match. The port cover is the original paint. Too bad the lower part of the cabinet isn't the same color.

I planned to use the rotary buffer to remove some of the yellow from the doors, then use a brush to paint the scratches. But when it came time to address the doors, I realized they were in worse shape than I remembered. The buffer made the paint a little lighter but it was still much darker and more yellow than the original paint. Filling in the scratches with the paint I used on the plastic parts made it look terrible because the color was too different. So instead, I brushed any bare metal or rusted spots on the insides, then sprayed the fronts with a different coor. I used a darker, more yellow color on the doors so that it would better blend with the door frames.

I buffed the sides of the cabinet base and door frames by hand and that helped lighten the paint a little. The cabinet base is still darker and more yellow than the parts that I painted and the bottom of the door frame is even darker. I suppose I should have sprayed the entire cabinet from the beginning.

I decided to try Spraymax 2K semi-gloss ("clear satin") on the doors and the gloss level is too low so I'm glad I used high gloss on the other parts. I will sand and buff them later and that should increase the gloss level a little. I used the same paint that I sprayed on the doors for touch up around the door frames and cabinet base even though it's not quite dark enough. It will look okay in normal room lighting.

I used some white appliance touch up paint on the inside on some rusted spots and the bare metal where I had drilled through the welds.

 

[Thomas]

I added 1" Scotch felt pads to the legs and 3M friction tape around the wheels. And fresh grease in the bearings.

At least half of the cable clamps were either broken or torn off and the adhesive dried out. For the ones that weren't broken I replaced the adhesive pads with some square 3M double sided adhesive pads that work well.

That's all for now. I still have a lot of work left to do.

 

[garou81]

@Thomas Is there a reason your using plastic fusion over something like bondo?

 

[Thomas]

@Thomas Is there a reason your using plastic fusion over something like bondo?

Yes, Plastic Fusion is for plastic. Bondo is generally used on metal, wood, and fiberglass.

Edit: to be more clear, Super Glue Plastic Fusion is an epoxy for bonding plastic to plastic or plastic to something else. Normally when someone says "Bondo" they are talking about the Bondo brand filler that is for metal and wood. But there are many products under the Bondo brand and probably some that are made for bonding plastic.

 

[Adrick]

Nice post @Thomas I like the way it's going

 

[Hackcell]

found it!

 

[c1v1ta]

Good stuff, man. Another excellent restoration!

 

[Thomas]

Over the past week I started working on the electronics. I know it's standard practice to replace all of the electrolytic capacitors in arcade cabinets, and I also know some people may think it's a waste of time and capacitors to pull out every old capacitor regardless of its condition. I'm in favor of pulling them all out, even if they show no signs of trouble and everything is working properly. I think of it as preventive maintenence.

I replaced all of the power supply capacitors and I didn't see any signs of leakage or swelling (I haven't seen any bad capacitors yet in any of the three cabinets I bought). I don't have an ESR meter so I couldn't check ESR. I checked the capacitance on some with a multimeter and the readings were all good.

I thought about replacing the thermal paste on the transistors but decided I didn't want to bother with it. Probably unnecessary anyway.


I changed the fan to a Sanyo Denki.

I put the power supply back in and confirmed with a meter that the voltages are all correct. The voltages measured at the power connector for the Naomi were the same as the voltages measured on the integrated circuits inside the Naomi (plus/minus a few centivolts), which is good. I turned the 5v supply down to be 5.04v when measured on the ICs. I suppose a more accurate way to measure would be to remove the case from a Naomi game cartridge, then measure the voltage on the game ROMs while the game is running. I may do this later.

The monitor picture quality looked okay but I felt it could be better, and it definitely needed some help with the convergence in the corners. I don't think I like that the settings are done digitally as it seems like something extra that can fail and be more difficult to fix. I'd rather have potentiometers. I'm already having trouble with the Mode button working consistently. One feature I do like is being able to change the settings all to factory default. The size and position was all wrong for a Naomi and the contrast and brightness were both set to maximum. After a reset it looked better but the picture became too dark.

There's a little screen burn as expected, particularly at the bottom where "Insert Coin" is burnt in pretty bad but it's something I can tolerate. The geometry was also not bad other than some waviness on the sides. Actually it was quite good. The squares are squares and not a mix of curved rectangles and squares. The colors looked good too.

Pulling off the CRT cover is very difficult and it seems like I'm doing it wrong. According to the manual, it pulls straight off after the bolts are removed. But I need to pull very hard to get the top part with the small bumps to separate from the light fixture. I don't see any way to loosen the light fixture to allow the cover to pull away easily. I prefer to remove the entire light assembly with the CRT cover so I can separate them without breaking anything.

 

[Thomas]

Aside from the CRT cover, I like how easy it is to work on the Net City compared to my other two cabinets. It's great being able to access the monitor chassis without removing the entire monitor from the cabinet.

I replaced every electrolytic on the chassis, added new solder to some of the joints, then cleaned the boards with alcohol and Kimwipes. I like to remove the flyback transformer completely and remove all of the old solder from its pads and pins. This makes it easier to work on the board and clean it, plus the transformer pads and pins get all new solder when reinstalled for a solid connection. Some of the pads came completely off while removing the transformer but those are for unused pins fortunately.

This version of the MS-2933 board has two bipolar 4.7uF 50v capacitors. I only had one, and when I tried to order a second from Digikey there were none available in stock with a 105 degree rating. None on Mouser either. So I used two 10uF polarized capacitors connected in series (negative to negative). Maybe not ideal but it works. I added silicone on top to keep them from moving.

Before putting the chassis back in I pulled off the deflection yoke to clean out the old broken convergence strips and tape around the tube and inside the yoke. And to clean some of the dirt and grease off. The strips were all brittle and fell off with a light touch.

 

[Thomas]

After putting the chassis back in with new capacitors, the monitor brightness increased, which I really wasn't expecting. In fact, it was a little too bright. That must mean at least one of the old capacitors was failing after all. I expected the convergence to be a mess with all those strips removed but it wasn't too much different. Still bad in all four corners, mostly the top two.

After spending a while fiddling with new convergence strip placement, I got the grid lined up pretty well. Not 100% perfect but as good as it can get I think. I added ASI 388 silicone to the end of the strips in case the adhesive on the strips fails. I also added Permatex dielectric grease around the inside and outside edge of the anode cap when I put the chassis back in place.

I didn't need to make any changes to the geometry after putting the new strips in, which is surprising to me. I only needed to adjust the screen position. I'm impressed with how good the geometry is on this monitor. Much better than my MS8 and MS-2930 monitors.

Before moving on to adjust the colors, I cleaned the screen with isopropyl alcohol, then with Invisible Glass cleaner. Next, I turned down the flyback Screen knob very slightly because the image was too bright even with default factory settings. I also reset the "hidden" settings to default. I was confused at first when I didn't see settings for colors and geometry in the settings menu or on the chassis. I looked in the MS-2931 manual and found that additional settings are accessible by pressing and holding the three settings buttons. I also turned up the Focus knob on the flyback slightly.

Oddly, the default value for contrast was set close to maximum. I turned that down to almost the midway point, enough so that the second column on the color test screen is just barely visible. I then made some small adjustments to the cutoff and gain settings for both red and green. Now the picture quality looks excellent. After reading about how great the New Net City monitor is I was feeling left out. But this Old Net City monitor really looks great.

 

[Adrick]

One question @Thomas do you have any idea where the plastic fusion is sold, I have a white frame with a crack, what I don't know is if it is a hardener or if it is just to fill gaps ????

 

[Thomas]

One question @Thomas do you have any idea where the plastic fusion is sold, I have a white frame with a crack, what I don't know is if it is a hardener or if it is just to fill gaps ????

Plastic Fusion is sold in hardware stores and Amazon and probably a lot of other places. If you can't find it, look for any two part epoxy for gluing plastic. That's all it is. It's a glue with a hardener.

 

[Thomas]

Plastic Fusion is sold in hardware stores and Amazon and probably a lot of other places. If you can't find it, look for any two part epoxy for gluing plastic. That's all it is. It's a glue with a hardener.

Something like this: https://www.amazon.es/ClearWeld-Qui...72629321&sprefix=plastic+epoxy,aps,227&sr=8-7

 

[nonosto]

wonderful.

 

[Adrick]

Something like this: https://www.amazon.es/ClearWeld-Quick-Setting-Epoxy-50112/dp/B009EU5ZM0/ref=sr_1_7?__mk_es_ES=ÅMÅŽÕÑ&crid=1S0UGW0KTHXZX&keywords=plastic+epoxy&qid=1672629321&sprefix=plastic+epoxy,aps,227&sr=8-7

Thank you very much, it has very good reviews, I will buy the one from Amazon ,It has been a great help to me

 

[Thomas]

Next on the work list: audio amplifier. I replaced the electrolytic capacitors and the thermal paste on the heat sinks and transistors.

The original speakers were completely dead (maybe caused by the unloading mishap?) which is fine since I wasn't going to use them anyway. I read that people are replacing them with car speakers and that is what I did as well. The original speaker impedance isn't indicated on the speakers and when I tried to measure their resistance, I didn't get a reading (because they are broken). But the manual does list them as 4 ohm so car speakers are okay. I'm using Focal Auditor RCX-100 speakers. They fit perfectly.

The speaker location in this cabinet is just barely out of the danger zone for magnetic interference. If the speaker is moved forward so that the front of the speaker is directly below the screen, or tilted up or down, I can see discoloration on the screen. Even in the normal position I can see a very slight warping of the image on screen compared to when the speaker is not installed. Because of this I wrapped the magnets with four layers of sheet metal. Even four layers wasn't enough to fully shield them but it's enough to not see any change on screen when installed. If I were to place the monitor in vertical position it would be a few inches closer to the speakers. Even then the speakers wouldn't cause discoloration but I think I would add some sheet metal around the outside of the plastic enclosure to be certain. I plan on keeping this monitor in horizontal position because none of the JVS vertical shooters interest me (sorry, not an Ikaruga fan).

https://lessemf.com/shielding-faqs/


I took apart the CRT cover/speaker enclosure during cleaning so I added new silicone sealant inside.

I put the new speakers in today and the sound quality is very good and very loud. Better than expected. I don't need to upgrade the audio amplifier.


My florescent light wasn't working when I got this cabinet and the bulbs aren't easy to find in the USA. Since I was already ordering some things from Yahoo Japan Shopping, I bought some new bulbs and new starter bulbs. The bulbs were less than 200 yen each.

The bulbs in my three cabinets are each from different manufacturers and there are two different model numbers among them, FL20SD-B and FL20SS・D/18. Both models are nearly identical and both are compatible with any of the three cabinets. These are the specifications:

color temp: 6500K
diameter: FL20SD-B = 32.5mm, FL20SS・D/18 = 28mm
length: 580mm
power: FL20SD-B = 20w, FL20SS・D/18 = 18w
starter bulb: FG-1E
life: 8,500 hours
lumens: 1,070