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Thread: Help Me Select Parts to Repair and Upgrade these 1.2w Projectors (Pics Inside)

  1. #1
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    Default Help Me Select Parts to Repair and Upgrade these 1.2w Projectors (Pics Inside)

    I have 2 Shinp 1.2w RGB projectors that need some TLC. They share a model number but the red modules differ in wavelength and quantity. One has a single 600mw 655nm (at least that's what the sticker says) and the other has 2x 638nm (assuming 300mw x2?). Both of the Green modules are 532nm 100mw and the blue modules are 450nm 500mw. Total output is supposed to be 1.2w.

    Here's what they look like.

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    My experience is limited. I've swapped modules, galvo assemblies, and some aligning and pot trimming in the past, but never attempted to "upgrade" components.

    See below for my maintenance/repair issues, which is most important to me.

    1. As you can see, one of them projects "sloppy" or "vague" renditions of what it's supposed to. What components should I be looking at to find the cause of this? (yes, I know the one on the right needs serious aligning.)

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    2. The blue module (same unit) is always on. When the in "blackout" mode, there is a constant (albeit dimmer) blue beam emitting. It's like a power supply or driver is reducing the voltage to the module but not enough to shut it down completely. Suggestions to fix this?

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    This is where the upgrade comes in, which is of secondary importance.

    3. Both projectors are too heavy on the blue output (white still looks very blue). I'd like to upgrade the R+G modules. How do I find and select compatible modules? Do I need to measure specific volt or amps somewhere with a DMM and then search accordingly? I'm thinking 200+mw green and I'm not sure on the red. I thought the current 600mw 655 would be brighter to the eye than it is.


    Once these issues are resolved, I'll possibly upgrade scanners (currently 20k published).

  2. #2
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    Hi Majik,

    Yeah, this is what you get when you purchase the lower end Chinese projectors. As with many things, you get what you pay for. The good thing about purchasing low end stuff is that you can upgrade it without significant fear of breaking it as you wouldn't loose as much as botching the improvement of an expensive, higher quality build. That's how I started, anyway.

    Regarding your first question, the galvos in picture number one and on the left of the two in pictures 3-6) look like super-cheap open loop galvos. Open loop galvos are just too sloppy for graphics applications. You could do basic abstracts and basic beams with them, but they just aren't up to the task of graphics. The ones in picture two are 15Kpps closed loop or 20K closed loop scanners. The corners are not bad at whatever scan speed they are set for. I'm surprised they are the same model number as this is a huge difference in quality alone. Sadly, there is no saving or tuning those open loop scanners. Thankfully you can replace them fairly easily with a better set.

    The differences in the red modules is significant as well. A 655nm module is much deeper red than 638nm and much less bright to the human eye assuming the beam characteristics and power are similar. The 2x638nm may be single mode or multimode reds. Its hard to tell from the pics. In any case, the 655nm module is . . not ideal and something to target for upgrade after those open loop scanners.

    Its anyone's guess what the actual powers are from any of these modules without a meter, but if they were relatively accurate, I'd say the primary issue regarding the 'heavy blue' is a combination of a fat multimode blue beam (those are usually the worst beam spec of cheap red/green/blue modules) and not enough power out of the 532nm green modules. I'd say to target 200mw 532nm (or 520nm) for a better white. Even with these upgrades, you are still going to end up with a tight green beam, surrounded by fatter red and even fatter blue . . but you'll gain experience by upgrading!

    Finally regarding question #2, this is an issue with either a floating ground causing voltage on the modulation line to the blue module or a bias setting potentiometer that needs to be adjusted down a bit. Measure the voltage on the modulation line to the blue when the projector should be projecting nothing and see if its over 0V. If not, finding out what pot is what if they aren't labeled is going to be tricky. Maybe take some detailed pics of that module?

    Let us know what you find!

    -David
    "Help, help, I'm being repressed!"

  3. #3
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    Thank you, David.

    Quote Originally Posted by dkumpula View Post
    Yeah, this is what you get when you purchase the lower end Chinese projectors.
    I absolutely agree, and I understand that these are nowhere near the caliber of what you've built (they were only $450 brand new), but I do think they're a good platform to learn with. However, the sloppy graphics are a fairly new symptom. Mind you, I've been using these projectors for several years (average of 10 hours per month). When brand new, the graphics were symmetrical between both projectors.

    Quote Originally Posted by dkumpula View Post
    Regarding your first question, the galvos in picture number one and on the left of the two in pictures 3-6) look like super-cheap open loop galvos. Open loop galvos are just too sloppy for graphics applications. You could do basic abstracts and basic beams with them, but they just aren't up to the task of graphics. The ones in picture two are 15Kpps closed loop or 20K closed loop scanners. The corners are not bad at whatever scan speed they are set for. I'm surprised they are the same model number as this is a huge difference in quality alone. Sadly, there is no saving or tuning those open loop scanners. Thankfully you can replace them fairly easily with a better set.
    Are new scanners a surefire solution to the sloppy graphics? Please recommend a budget friendly replacements, bearing in mind that these are strictly used for beam shows. Something like the AL-20k From Goldenstar?

    (BTW...I just looked at the pictures and have no idea how you were able to distinguish the difference between them, let alone know the specs!)

    Quote Originally Posted by dkumpula View Post
    The differences in the red modules is significant as well. A 655nm module is much deeper red than 638nm and much less bright to the human eye assuming the beam characteristics and power are similar. The 2x638nm may be single mode or multimode reds. Its hard to tell from the pics. In any case, the 655nm module is . . not ideal and something to target for upgrade after those open loop scanners.
    10-4. So how do I find a suitable replacement? I mean, I've seen modules with a wide variety of voltage and amperage requirements. I have no idea what I'm working with...

    Seems to me like the 638nm could be replaced with the 500mw Mitsubishi Modules on DTR?

    Quote Originally Posted by dkumpula View Post
    I'd say to target 200mw 532nm (or 520nm) for a better white. Even with these upgrades, you are still going to end up with a tight green beam, surrounded by fatter red and even fatter blue . . but you'll gain experience by upgrading!
    Something like this 200mw 532nm MODULE on eBay? I have a few 50mw modules lying around that look similar to this case/heatsink. Is it easy enough to replace the diodes with a higher power rating and use the same driver? Or just swap the existing diode for a more powerful one? I have been known to solder a few things...

    Quote Originally Posted by dkumpula View Post
    Finally regarding question #2, this is an issue with either a floating ground causing voltage on the modulation line to the blue module or a bias setting potentiometer that needs to be adjusted down a bit. Measure the voltage on the modulation line to the blue when the projector should be projecting nothing and see if its over 0V. If not, finding out what pot is what if they aren't labeled is going to be tricky. Maybe take some detailed pics of that module?
    Above my comprehension level. Floating ground? Bias setting potentiometer? How do I know where the modulation line is? And of course none of the pots are labeled. I can certainly take detailed pictures. I assume you want pictures of the driver? The module just has +/- wires running to it.



    If I can successfully repair this one projector for a reasonable cost, learn a few things and gain some confidence along the way, I won't mind dropping more money into upgrades down the road. If it's going to cost me $300 just to repair it to OEM, I might as well purchase a brand new one for not much more. If that same $300 will yield me a much better projector, I'm all in.

  4. #4
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    Now that I think about it...are their any popular and/or common build logs on this forum (or elswhere), with a materials list of commonly used components? On my audio boards, several proven DIY speaker designs are readily available, complete with a materials list, cut sheets, wiring diagrams etc. Some members have even pieced together component kits that make it easy to get started.

    Obviously, lasers are more of a niche hobby, but does anything similar exist for the laser community?

  5. #5
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    Quote Originally Posted by Majik View Post
    I absolutely agree, and I understand that these are nowhere near the caliber of what you've built (they were only $450 brand new), but I do think they're a good platform to learn with.
    Definitely!

    However, the sloppy graphics are a fairly new symptom. Mind you, I've been using these projectors for several years (average of 10 hours per month). When brand new, the graphics were symmetrical between both projectors.
    OK, so I am likely wrong about the one set being open loop scanners. Although any set of decent scanners should have lasted longer than those have (assuming they weren't being abused), there could be several things that have gone wonky with them - from tuning issues to power supply issues. To be honest, it isn't worth trying to diagnose the problem with such a cheap set. I'd just replace them. For beams only, the AL-20K set that you mention should be fine.


    10-4. So how do I find a suitable replacement? I mean, I've seen modules with a wide variety of voltage and amperage requirements. I have no idea what I'm working with...

    Seems to me like the 638nm could be replaced with the 500mw Mitsubishi Modules on DTR?
    That one needs to be corrected which requires cylindrical lenses, a driver, a multimeter and a good bit of patience at a minimum. CDBeam, Absolom and others have shared their correction findings for several diodes over the years, so you can look at one of those threads to gain an idea about what would be required. Warning - those new diode findings threads are often as long and wrinkled as a . . . <insert your punch-line here>.

    Something like this 200mw 532nm MODULE on eBay? I have a few 50mw modules lying around that look similar to this case/heatsink. Is it easy enough to replace the diodes with a higher power rating and use the same driver? Or just swap the existing diode for a more powerful one? I have been known to solder a few things...
    Replacing the diode in a 532nm set-up is considered advanced work that even very seasoned builders wouldn't touch. You are better off buying as you discovered - although you generally want analog not TTL. TTL can only be turned on and off limiting a RGB projector to 7 colors, where-as analog can be dimmed to combine to make a near-infinite number of combinations. If the rest of your laser modules are TTL, then you'd be fine with the one your pointed out.

    Above my comprehension level. Floating ground? Bias setting potentiometer? How do I know where the modulation line is? And of course none of the pots are labeled. I can certainly take detailed pictures. I assume you want pictures of the driver? The module just has +/- wires running to it.
    There should be two sets minimum going to the blue driver. One is power in and the other is modulation in. There is also one set (possibly two) going from the driver to the diode module (diode power and possibly fan power). Trace the lines from the blue module back to the driver (likely one of those matching stacked boards). I'd guess the white pair of wires is your modulation in line. Just measure the voltage across that pair when the projector shouldn't be displaying anything and see if the voltage is greater than 0V. If so, this will lead to another set of instructions to diagnose the root cause. If not, you just need to adjust the bias pot down slightly. There are two pots on those boards, but I can't tell from the pic which is which. The other pot controls the power going to the diode, which would blow the diode if you turned it up too much. It should be fairly safe to dial down each pot counterclockwise a little (like less than one revolution) to make the static beam stop. Keep track of what you do to return the pot to the same place if you got the wrong pot - or better yet, attach a better picture of the driver so we can see which pot is which.

    If it's going to cost me $300 just to repair it to OEM, I might as well purchase a brand new one for not much more. If that same $300 will yield me a much better projector, I'm all in.
    Yup, understood. Purchasing new but cheap only gets you back to where you started though. Seriously, sometimes these things aren't worth the effort to fix, but in this case, I suspect it would be educational and relatively inexpensive.

    Quote Originally Posted by Majik View Post
    Now that I think about it...are their any popular and/or common build logs on this forum (or elswhere), with a materials list of commonly used components? . . but does anything similar exist for the laser community?
    Ahh, yes, somewhere buried in PL there are such things. In addition, Laser Enthusiast Meetings (LEMs) are a great place for education and on-the-spot assistance from kind, knowledgeable laserists. If you share your location, we can point you out to the closest one and badger you to attend it.

    Happy hunting!

    -David
    "Help, help, I'm being repressed!"

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