CurtPalme.com Home Theater Forum

Zebra · Joined: 02 Jul 2020 Posts: 93 Location: NJ USA

Does anyone here have any experience with one of the older 480i only 7" crt projectors?

Looking at the specs on this site, most of these units seem to have a stated light output around 400 lumens. It's a lot lower than I'm used to working with. Am I being unrealistic to expect one to produce a 50-60" 4:3 image in a dimly lit room?

What sort of throw / distance do I need to project a 50" or 60" image with something like a Sony 1020 or a Vidikron VPF 40se? I can't seem to find this info anywhere.

I thinking of grabbing one of these old units for an arcade light gun cab I picked it (it's crt monitor broke). Finding larger size CRT monitors with RGB is getting harder but some of these 15khz crt projectors are being thrown away.

I have only used some of the later and brighter 9" CRT projectors. My experience with these old 480i only units is limited. I'm wondering if they are worth rescuing for vintage gamers?

Is there any reason why they wouldn't work well with a higher gain screen? I have a 1.6 gain Sony Dynaclesr portable 80" ALR screen in storage. I'm wondering if I can make up for the limited light output with it.

My 29"CRT arcade monitors are fine for most old games but I'm thinking that Time Crisis would be better on a 50" or 60" screen....

**Curt Palme** · Posted: Mon Aug 31, 2020 12:45 am Post subject:

You're going to have age related issue. I'd grab one of the latest CRTs able to do 480i like a Barco 70X series. Brighter tubes, longer lasting, and will display 480i just fine. All Vidikrons that they made themselves were awful projectors, they were fine with they rebadged the Electrohome series.

garyfritz · Joined: 08 Apr 2006 Posts: 12088 Location: Fort Collins, CO

400 lumens is plenty for the size of screen you want. The formula is Gain * Lumens / squarefeet = foot-candles. A 60x45 4:3 screen is 18.75 sq ft, so 400/18.75 = over 21 ftC. That's more than enough for a dimly-lit room -- wouldn't even have to be all that dim.

**AnalogRocks** · Posted: Mon Aug 31, 2020 2:14 am Post subject:

I have a pair of SONY 1040's I use for Halloween. 50-60" picture off the top of my head would be somewhere between 5-7 feet. They work great on high gain screens although SONY curved theirs. I have one of the 15 gain 4:3 screens. Never did try Timecrysis on it. I did try that with a D50 and Stewart Studiotek 1.3 gain, 110" in a not darkened room on the PS2. It didn't work. If you can score a 50 or 60 inch high gain 13-15 gain it would be great.

Eyes:
https://www.youtube.com/watch?v=NN7H_2ziBQU

https://www.youtube.com/watch?v=F3q-wd6CWYs

garyfritz · Joined: 08 Apr 2006 Posts: 12088 Location: Fort Collins, CO

High-gain screen?? I would think a 13-15 gain with 400 lumens would be enough to fry ants. Like I said, 400 lumens should put over 20 ftC on a 60x45 screen. That's assuming you're not displaying a bright image, since the CRT is current-limited to how much area it can light up. But with a typical dark-ish video game I would think it would come close to the rated lumens. Was the D50 too dim? It's rated 800 lumens, so it should do fine with a larger image, especially with 1.3 gain.

My 8500 was rated 1200 lumens, and it had no trouble lighting up an 85x48 1.3 gain screen -- 12-14 ftC if I remember right. And that was using only a 16x9 area on the phosphor, so you could have displayed an 85x64 image with the same brightness.

**AnalogRocks** · Posted: Mon Aug 31, 2020 3:03 am Post subject:

garyfritz · Joined: 08 Apr 2006 Posts: 12088 Location: Fort Collins, CO

110" should be about 40 sq ft. That's pretty big got 800 lumens, but should still be more than watchable with 20 ftC in bright areas. Hard telling how much light the Guncon wanted tho.

**AnalogRocks** · Posted: Mon Aug 31, 2020 4:08 am Post subject:

Zebra · Joined: 02 Jul 2020 Posts: 93 Location: NJ USA

Zebra · Joined: 02 Jul 2020 Posts: 93 Location: NJ USA

**AnalogRocks** · Posted: Mon Aug 31, 2020 2:49 pm Post subject:

There is no pitch as it were. The pitch on a TV tube is controlled by the shadow mask. Projection tubes dont have this.

What we have is the difference be tween ES - Electro Static focus sets, and EM - Electromagnetic Focus sets. ES sets work like a traditional TV tube. The older the tubes get the softer they look. Elecromagnetic sets hold the focus all through the life of the tubes.

All tubes age or burn in, as the phosphor is used up. So on an ES set with 20 000 hours you'll have odd color from the tube burn and that soft - blur together - look where the scan lines blur together. EM sets will keep that crisp scan line look with browning tubes.
You know that look you get on the old arcade monitors where the whole screen looks brown.

See here: http://www.curtpalme.com/TubeCondition.shtm

**Curt Palme** · Posted: Mon Aug 31, 2020 5:24 pm Post subject:

Zebra · Joined: 02 Jul 2020 Posts: 93 Location: NJ USA

Zebra · Joined: 02 Jul 2020 Posts: 93 Location: NJ USA

**AnalogRocks** · Posted: Mon Aug 31, 2020 8:53 pm Post subject:

Get two, an old SONY for 480i(maybe 240p) and a 9" for everything else.

**Curt Palme** · Posted: Mon Aug 31, 2020 9:18 pm Post subject:

banzairun · Joined: 10 Jul 2006 Posts: 129 Location: NJ

So you're just using a Playstation that you want to project? or are you using arcade guts?

Time Crisis deluxe (1-3) all used off-the-shelf consumer-grade 50" Mitsubishi PTVs. The game boards feed RGB to a S-video board for the PTV input, so many front projectors will be able to take that input directly. I've owned a pile of the arcade games and would usually just grab free/cheap mits sets to "retube" them, rather than actually retubing the sets, as I do with the Toshiba & Hitachi sets for Sega arcade games.

I wouldn't put much thought into which projector you use if you want to use a front projector to play around with. The shittier the projector, the less tight focus it will have, if that is what you are looking for, but the older projectors won't be as bright. The better the projector, the more space you'll have between the scan lines (projection CRTs don't have a dot-pitch, as previously stated), so this is why people used line doublers and scalers back in the day; it wasn't to "increase resolution" as some seem to think, since you can't actually do that. It just adds more scan lines to the image, meaning it's using more of the tube face, and hence more light thrown to the screen.

If you can find a Barco 7-series, those are probably the best 7" sets, are small and have good light output. You can directly feed a CRT projector (or your Ikegami) video from an arcade board as long as you use a level shifter PCB (games output 3-5vp-p and consumer gear expects .7vp-p signal levels). Sega made them for all their projection games, so they're pretty easy to source, or you can just use a Gonbes 8200 in the signal chain (they're junk, but are cheap and work). The Ike' might be okay with higher video input levels - some PVMs are OK with it, but it's better to level-shift it down to the standard level if possible.

You can always de-focus the image slightly if you're sensitive to how sharp the image looks. This is sometimes done with CRT projectors (particularly with the blue tube) just to brighten the image a little bit. You can do it with your Ikegamis as well if it's bugging you. If you have any Nanao monitors in your 27" games, those used the best tubes of anything you'll have around and they tend to last a while. K7000s look fine, but the Zenith tubes in most of them very commonly have soft focus and weak color guns - I've re-tubed probably 100 of them at this point from TV sets. The later ones with RCA tubes generally have good tubes.

For arcade monitors, the dot pitch on most tubes 25" and up will all be roughly the same, it was only often on the smaller tubes they actually made them with a finer dot pitch. 24kHz (medium resolution, or "EGA" from the PC-world) 19" arcade monitors used M48 CRTs instead of A48 CRTs, since the finer dot pitch of an M-series CRT makes a difference, but 25" medium res monitors all used the same standard A63-size CRT, no matter the resolution.

I guess I have some insight here as I've had a pile of CRT projectors and still have about 1000 arcade games, so I've mixed them together a few times over the last 25 years, but I generally just play with dedicated games these days, and don't even have a CRT PJ set up at the moment, even though I still have about a dozen sitting around.

Also, just FYI: your "29" monitors" are actually 27" (A68-size CRTs), we're in the USA, we measure viewable area, not total tube envelope size. Only Japan calls them 29s.

barclay66 · Posted: Wed Sep 02, 2020 2:45 pm Post subject:

**Curt Palme** · Posted: Wed Sep 02, 2020 2:56 pm Post subject:

Well, that's definitely news to me! With every module I've had here, it was always set to 480i output, the scanning lines were REALLY clear on the screen. Smile

Tim in Phoenix · Joined: 21 Oct 2006 Posts: 4409 Location: Phoenix

Guys

I have never heard mention of line doubling with Marquee decoders. Fire one up and look at ** for the scan rate. Likely 15.75.