Pulse Tune
Offline

I recently completed the GBC frontlight mod using a frontlight and Osaka 7 LOCA from Hand Held Legend. The mod worked, but the screen isn't as bright as I was hoping it would be, and I'm wondering if it has to do with the way I installed it. I bought a power adapter so I could connect the Game Boy directly to power through a wall outlet, and when I do that I found the screen brightens up and looks really nice. But just running off of eneloop batteries, the screen is a bit dim.

On the bottom right of the PC board, I connected the black wire to the bottom of the four points and then the red wire to the top of the three points, as was shown on the HHL website:

But I found a post on reddit that seems to suggest that connecting the red wire to the top of the four points will make the screen brighter:
https://www.reddit.com/r/Gameboy/commen … h=bebf91dc

The HHL website says I can use the configuration with the red wire at the top of the four points, but I will need a 100 ohm resistor, correct? Do you think doing this will increase the brightness of my screen?

As a side note, I tried using the GB USB 64M smart card with it, and it makes the screen a lot dimmer than it is with a normal grey GB cart like Tetris. Any idea why that is? Does the flash cart suck up more power than a "legit" cart?

urbster1
Offline
Naptown

i did the mod using a kitsch-bent frontlight and soldered the red wire at the top of the four points, i did not add a resistor. sorry i don't have a picture but the screen is definitely very bright, so much so that i will probably add a switch so i can turn down the brightness. hopefully it shouldn't be a big deal to quickly re-solder it and test it out.

Pulse Tune
Offline
urbster1 wrote:

i did the mod using a kitsch-bent frontlight and soldered the red wire at the top of the four points, i did not add a resistor. sorry i don't have a picture but the screen is definitely very bright, so much so that i will probably add a switch so i can turn down the brightness. hopefully it shouldn't be a big deal to quickly re-solder it and test it out.

I emailed HHL and they think that the other configuration would be dimmer because of the resistor. I don't think the HHL frontlight would work without the resistor, as far as I know. Do you know if the kitsch-bent light is just brighter than the HHL lights? That's something I wish I knew before doing the installation, but it seems that people aren't really comparing them.

urbster1
Offline
Naptown

it will be brighter without the resistor according to HHL in the comments on this page, they say voltage is good up to 6V, but it may be too bright for you. you could always install a 1k trimpot instead of the resistor like i was planning to do, which allows you to adjust the brightness. it also shows not to use the KB configuration like i did. i couldn't speak to whether KB is brighter than HHL or not but most people seem to think they are roughly the same. also if you check out the pictures, there's a pretty clear voltage increase with DC vs battery power.

to answer the other question in your first post, yes the USB 64m smart card does use up more power.

Pulse Tune
Offline
urbster1 wrote:

it will be brighter without the resistor according to HHL in the comments on this page, they say voltage is good up to 6V, but it may be too bright for you. you could always install a 1k trimpot instead of the resistor like i was planning to do, which allows you to adjust the brightness. it also shows not to use the KB configuration like i did. i couldn't speak to whether KB is brighter than HHL or not but most people seem to think they are roughly the same. also if you check out the pictures, there's a pretty clear voltage increase with DC vs battery power.

to answer the other question in your first post, yes the USB 64m smart card does use up more power.

Thanks for the info. I got some non-rechargeable 1.5V batteries to try, and the brightness level with them is very near what it is with direct DC input, but it does dim over time anyways and it is inconvenient to be constantly buying new batteries. So I've been searching online for days trying to figure out what the issue is, and I think I've finally found it. gene.boy on Instagram posted this:
https://www.instagram.com/p/BLJtv5EB_BX/

Here's another point where I disagree with the official HHL instructions. In their video you're told to solder the + to the top pin of the 3 on the right, to avoid the system not booting or flickering. However, that's not a good idea. The top point on the right is the V input, which comes straight from the batteries. Why is this a problem? Because, as the batteries drain, your light will get dimmer and dimmer. So, with fresh batteries your light will be bright, and the light will gradually decrease along with the batteries' juice. Instead, you SHOULD use the point you're told not to, the top one of the 4 on the left. This point is the post-regulator 5v output which feeds the GB. The voltage out of here is constant (the regulator does the job of converting your batteries' changing V into constant V for the system) so your light will not change in brightness. However, you should not connect to it directly. The light will pull too much power, and this is what prevents the system from booting, and gives you that flickering. Instead, throw a resistor (I used a 47 ohm) in the connection. That way, everything will work fine, and your light will not randomly change brightness.

I'm experiencing the same issue; as the battery drains, the frontlight gets dimmer and dimmer until you can barely tell it's there. Another issue with using the upper-right solder point is that while playing a game, certain inputs can cause the frontlight to flicker. For example, while navigating menus in a Pokemon game, the screen flickers with every button press. From what I've heard, the upper-left solder point does not have these problems. So for an easier/more straightforward mod, kitsch-bent looks likes the way to go because you can hook it straight up to the upper-left solder point. For HHL frontlights, a resistor or trimpot is necessary for optimum results.

So I'll probably be buying a resistor or trimpot, not decided on it yet. I don't completely understand how the trimpot works -- if I buy a 1K trimpot, what are the lowest/highest settings? Would the lowest setting = 0 ohms, highest setting = 1000 ohms?

urbster1
Offline
Naptown

that's very interesting, and good to know. no, the trimpot doesn't go all the way to zero. have a look at this post for more info: http://chipmusic.org/forums/post/228693/#p228693

specifially these images:
http://imgur.com/RbBtBBK
http://imgur.com/yv6tAyw
http://imgur.com/5lGCl48
http://imgur.com/JsJlGvs
http://imgur.com/zI3rc5E
http://imgur.com/rKVhAPU
http://imgur.com/yVOLVHy
http://imgur.com/EaulwiB
http://imgur.com/W7pRHGB
http://imgur.com/wFy1PhI

edit: that gene boy instagram account is great! wish I had found it before I did my mod! though it still came out pretty good for a first try smile

Last edited by urbster1 (Oct 13, 2016 3:18 pm)

Starshine
Offline
Toronto, Canada

You want bright? Hook up the red wire to the top of the four points

Not sure if that'll be different on the HHL frontlight, but I use the Kitsch-Bent one, and that shit'll burn a hole through your retinas

Pulse Tune
Offline

I bought a trimpot and some 28awg wire a while ago from mdflyelectronics on eBay, so here's an update on how it went. I soldered everything together and it's working great now. One thing to be aware of is that when the resistance level is too low, the GBC shuts itself off after a few seconds. So if you want it at max brightness you will need to adjust the trimpot until you find a sweet spot that looks good to you and doesn't shut off the system. I didn't cut out a place to adjust the trimpot through the back casing, so I just found the sweet spot and put everything back together. Here's a few pictures of the results.



So I'm very happy with the end result! I would highly recommend installing this way if you get an HHL light, because soldering to a point with no voltage regulation causes the frontlight to dim fast. If you get a Kitsch-Bent light though you should be fine because it has a resister built-in, but you will be stuck at the highest brightness without a trimpot.

Last edited by Pulse Tune (Nov 13, 2016 4:49 am)