21 of 25 people found the following review helpful
on January 18, 2011
The actual video resolution of the Sharper Image EC-PJ10 Entertainment Projector is 219x238 pixels (= 50,370 total pixels), not even VHS quality, which is a far cry from the 640x480 pixels (= 307,200 pixels = VGA) advertised on the internet -as well as on its retail packaging. Really. Project an image on the wall and measure it for yourself. Just remember that each projected R,G, or B rectangle is only a subpixel. The horizontal image resolution is, oddly, much rougher than the vertical image resolution. The over-all picture quality is actually worse than an old analog color TV screen. And the image, due to the cheap lens, falls off on the left and right edges, with blurred colors. Even a concave projection screen will not improve the image fall-off at the edges. The projected image from the 120VAC portable device is only viewable in a totally dark room. And, when projected against a smooth white wall, is still weak and dark. Even children may have a problem with a video resolution this rough.
But read on.
A simple, quick fix is to pick up a white projection screen with beaded glass surface (not uncommon at yard sales), to literally double the brightness of the projected image. The maximum recommended projected image on the screen, in a totally dark room, is 36.5" x 26.25" (= 45" diagonal measure), with a lens-to-screen distance of 6 feet (the maximum distance also recommended by the supplied User Manual). I consider a white, beaded glass projection screen required basic equipment for any and all video projectors, no matter how bright the projected image is.
Another quick, but effective, fix for the over-all poor focus and blurred color, is to fashion a simple black cardboard aperture and slip it into and behind the internal projector lens: Cut out a 47mm diameter disk of black construction paper, and then cut out a 24mm diameter aperture inside the disk, creating a ring. Turn the projector upside down and unscrew the six phillips head screws on the bottom of the unit. Turn the projector right side up and carefully lift off the entire top of the projector and lay it upside down on the table, next to the projector. It will not be necessary to unplug any of the internal cables/wires for this procedure. Next, unscrew all eight phillips head screws along both sides of the lens barrel housing (underneath the video circuit board). When loose, carefully lift up the lens housing, slightly, and unscrew the lens completely out (or just pull the lens straight out, if completely loose). Take the black paper aperture disk and carefully tamp it inside the rear of the projector lens tube until it snugs against the smaller diameter internal lens retainer. Reassemble the projector. This simple trick will greatly sharpen up the projected image, but reduces the lens aperture to f3.2 and darkens the projected image somewhat, and darkens the projected image even more at the corners. After making and testing several aperture masks, the f3.2 aperture seemed to be the best trade-off, between clarity and brightness. The new f3.2 aperture will cut the over-all brightness of the projected image in half, but the second-hand white, beaded glass projection screen will double the projected brightness. The pixelated coarseness of the LCD will now be more visible than ever, but the over-all image will be surprisingly sharp, and even the colors will now be amazingly crisp, vibrant, and accurate.
The Sharper Image EC-PJ10 Entertainment Projector is now a serious (well... not quite serious) device that is an absolute delight to watch digital broadcast TV and DVD movies on.
Although the device has left and right stereo-in jacks, there is only one 2" mono speaker inside, which is not amplified. So it's always best to pipe your sound through a quality stereo sound system instead.
The unit has no keystone correction (a trapezoid image on the screen, caused by an off-center position of the projector), so I modified the projector, by adding a standard camera tripod screw socket, and then mounted the projector, on a camera tripod. The projector is then vertically centered to the screen and elevated it until it is, horizontally, about 1/3 up from the bottom of the screen, and then angled slightly upwards so that the image fills the projection screen. I completely removed and tossed both leg supports. The original support legs will easily shear off standard audio/video plugs and also damage the input jacks, if the special OEM right-angle audio/video plugs are mistakenly not used.
Replacement bulb for the projector:
Flood (35º-40º beam): EXN 50W/12V MR16 12 Volt halogen lamp. Flood (35º-40º beam) projects an even, center-to-corner, overall image brightness.
A good, inexpensive, off-the-shelf lamp is the Phillips brand name (Ordering Code: BC50MRC16/FL36 12V), which bench tested at 3500ºK, with a clear flat protective glass cover over the bulb, and a 36º flood beam.
The replacement lamp must have a GX5.3 base, and a dichroic reflector.
The best color temperature for either bulb is "white, bright white, or daylight" (4100ºK-4900ºK),
projecting colors onto the screen that are true and accurate.
The Geek Stuff (a few more technical notes):
- The internal LCD screen measures 41mm wide x 29.5mm tall (= 50.5mm/2" diagonal measure).
- The internal OEM lamp seems to be: EXN 50W/12V MR16 halogen lamp (I bench tested at 3800ºK), with a GX5.3 base, and projects a 36º beam. The advantage of a 12 Volt halogen bulb, as a video projector unit, is that it is far more resistant to shock, vibration and rough handling than the fragile tungsten filament inside a 120 Volt halogen bulb, especially important when the video projector is used and handled by children.
The reflector of the internal OEM lamp has a dichroic coating, which is transparent to heat, while reflecting only visible light to the internal LCD. This is important, since all halogen lamps produce far more heat (500ºF) than visible light. Note that using a standard opaque aluminum coated reflector will project both light and intense heat into the internal LCD, and will eventually destroy it. Dichroic reflectors are easily identified by holding the lamp up into the light, and being able to see through the reflector, with its reddish, transparent characteristic.
Also, be sure to never touch the tiny halogen bulb, inside the reflector, with your bare fingers. Doing so will create an exact frosted-white image of your fingerprint on the bulb the next time the unit is turned on (500ºF operating temperature), ruining the bulb.
- The internal main power circuit board ports 120VAC, from your house current, via a simple relay, over to the 120VAC-to-12VAC power converter board for the MR-16 lamp.
Also, 6 color-coded wires route directly to the internal video board:
Black: GND (for Red, above)
Blue: GND (for Orange, above)
Also, the temperature overload sensor, mounted on the steel MR-16 lamp housing, is wired directly in to the main power board.
- The internal video board connects to the external Power, Volume, Contrast, and Color buttons via 6 color-coded wires:
- A single, clear convex-plano condenser lens, 58mm diameter x 12mm thick (110mm from the lamp filament), provides even illumination for the internal LCD image screen.
- The projector lens (single element, glass, convex, 42mm diameter x 7mm thick) has a focal length of 3" (at infinity = moderate telephoto), with a f2.1 aperture, for you experimenters out there who might want to try out a salvaged, high quality flat-field projector lens: I installed a 5" f3.5 projection anastigmat lens, from an old 35mm slide projector (standard 36mm x 24mm, 43mm diagonal format) and, even though the format of the Sharper Image Projector is 17% larger, the vintage telephoto lens provides excellent sharpness and brightness. And another benefit is the Sharper Image projector can now be positioned 9.5 feet from the projection screen, conveniently out of the way, with the lack of keystone correction much less of an issue.
- The internal GX5.3 base for the projector lamp is 12VAC, powered by a high-frequency 35kHz - 40kHz (NOT your typical low-frequency 50Hz - 60Hz) electronic driver/transformer. So simply plugging in one of those new 12VAC LED MR-16 lamps will cause early lamp failure.
But a cool-white (6000ºK) LED lamp produces excellent color fidelity onto the screen, by the way, for you experimenters. And besides, the OEM 12VAC 50 watt MR-16 halogen lamp has its own internal 120VAC-to-12VAC power converter board that is simply wired and easily removable: Raw 120VAC from your house current is ported from the main power board, via a simple relay, over to the 120VAC-to-12VAC power converter board for the MR-16 lamp.
The 120VAC-to-12VAC power converter board is easily lifted out of its vertical slot and the 120VAC "In" wires and the 12VAC "Out" wires can be removed with a soldering gun. A cheap, simple, and basic 120VAC-to-12VDC voltage converter, magnetic-transformer circuit (50Hz-60Hz) can be soldered in to power one of the many new 12VDC MR-16 LED lamps. These can be readily salvaged from yard sales: Simply crack open and toss the plastic case, unsolder the four in/out wires, and the power converter will easily nest inside the projector, soldered to the existing wiring. Just be sure the amperage of the converter is appropriate for the new LED lamp, as they can be burned out by an amperage overload.
A 120VAC LED lamp could be direct-wired to run in this device, but the available selections and options of 120VAC LED lamps is very low, so I advise experimenters to opt for 12 Volt LED lamps instead.
The temperature overload sensor, mounted on the steel MR-16 lamp housing, is wired directly in to the main power board, so will remain perfectly functional through just about any lamp modification.
But most of these LED lamps are still not bright enough, as I have been unable to find a required minimum 10 watt LED 12VDC MR-16 cool-white (5000 - 6000ºK) 36º beam angle MR-16 LED lamp on the market, that would be a suitable replacement for the OEM 50 watt halogen lamp. But the WorldOfThought website (Australia) sells a CREE XLamp MC-E, 10 Watt LED MR16 Lamp: 790 lumens (measured at 700 mA drive current and 9.8W power consumption), Cool-White 6500ºK. But with a 30º beam angle, it may cause darkening at the corners of the projected screen image. Also, being a new and hot item, the price ($ 52.00+) is quite expensive for a MR-16 lamp.
- The portable projector consumes 65 watts, 120VAC, while running, and, when later tested with a 1 watt, 12VAC LED MR-16 lamp, drew only 6 watts, 120VAC, while running. So the internal MR-16 lamp voltage converter board is both efficient and smart. But only functional with halogen lamps.
* Note: On another Amazon.com post for this video projector, someone suggested using the GE 50-Watt Edison Halogen MR16 Narrow Floodlight Bulb, Model #23254, from Lowe's Building Supply (their Item #148820). But, after buying the GE Edison lamp and doing a bench test on it, I advise against using it.
Reasons for not using the GE Edison lamp:
- The lamp projects at a tested brightness of only 89% of the OEM lamp.
- The lamp bench tested at 3000ºK (warm white), in contrast to the OEM bench test of 3800ºK, which is a purer, brighter light temperature.
- The coiled tungsten filament, when viewed from the front, is broadside, giving the parabolic reflector little chance to project out an even light beam, causing a hot spot in the middle of the projector screen, with the brightness falling off to 75% at the corners. This contrasts to the coiled tungsten filament of the OEM lamp, which is edge-on, when viewed from the front, allowing the parabolic reflector to send out far more even illumination to the projector screen.
- The parabolic reflector is, in fact, a dichroic coating on the parabolic reflector, which is transparent to heat, while reflecting mostly visible light outward.simple aluminized mirror reflector, which reflects both heat and light outward from the coiled tungsten filament. This is important, since all halogen lamps produce far more heat (500ºF) than visible light. (I originally misstated that the lamp had a simple, opaque, aluminized reflector, which would have projected both light and heat directly into the internal LCD, but just observed the reflector transmitting heat away from the LCD. It was just not as obvious as the usual MR-16 lamps. Unfortunately, the Lowe's store website won't allow me to correct that part of my review.)
- The Edison Halogen lamp has a GU5.3 base, which is normally compatible with the GX5.3 lamp socket in the projector, but the two pins on the Edison Halogen lamp measured only 5.5mm long, in contrast to the normal 6.85mm pin length of GU5.3 and GX5.3 bases. In short, the Edison Halogen lamp does not snug securely into the GX5.3 lamp socket in the projector, and has to rely on spring pressure, from the socket, to hold the lamp securely in the steel MR16 lamp holder.
I'm still experimenting with, and hacking this device, just to see what it's good for. Stay Posted.