You may have already found the solution at this point but I'll give you my experience with this set up so far.

It looks like the Pololu you have on hand is the S10V4F5? The one I have been using with a FunnyPlaying Retro Pixel IPS kit is the S7V7F5 and the specifications appear to be pretty close to the one you have on hand. Of course the S10V4F5 has the SHDN input as well. I don't think the SHDN would be used in the case of a DMG if I remember correctly from other posts I have seen, I would love for someone else to chime in on this to confirm though. At least according to Pololu's product page it would need to be "driven low or left floating." My only experience so far has been with the S7V7F5 model so I'm afraid I can't speak confidently beyond it but I have been happy with the Pololu branded components as a whole.

For the wiring I used my Pololu entirely in place of the original regulator, not in conjunction like a traditional backlighting method. The connection is like so:

Pololu        DMG CPU Board

VIN - - - - - VCC (green top)
GND - - - - - GND (green middle, marked with G)
              ( - ) (green bottom)
VOUT  - - - - ( + ) (red)

The connection on the CPU board that I am using for the regulator is right above where the audio board connects (the audio connection being the four through holes with the little triangle pointing to one of them) and the diagram above assumes the original green and red wires are still in place. If they're not, that's fine too. You can just use a 26 AWG wire to hook it up to the same area. The ( - ) connection (negative voltage rail) on the CPU board is not used at all in my case. After asking around I've found the FunnyPlaying IPS kit does not use the negative rail whatsoever. The CPU board schematics show the negative line going directly to the 3rd pin from the left on the ribbon cable connection if you are interested in tracing this connection on your kit to see if it's used.

I have a little 3M Command velcro-like pad trimmed down attaching the regulator to the wall of the battery compartment where the old regulator sat, makes it easy to remove the guts if needed but keeps the regulator from rattling around. I imagine some kapton tape could work too.

All in all I've been very pleased with this set up and have not had any apparent issues using the IPS along with an EverDrive X3 powered from a Pololu. Granted, the battery life has been shorter, but that's to be expected I think.

I documented some of these IPS related findings in a thread I made a few months ago (that you were kind enough to contribute to!) so if you're interested check back in on it here. Hope this helps you along your way!

Thanks for taking the time to write this out, it's a bit more clear now.

nitro2k01 wrote:

This is the same as if you would have a pre-pot prosound, and then a passive splitter connected to both line-in recording and headphones. The headphones are loading down the line, and the signal becomes distorted.

Plugging in a passive splitter with two headhones to the pre-pot was going to be my next test so good to know I was on the right track!

nitro2k01 wrote:

In addition, the headphones work as microphones in this case, so if you repeat the experiment and tap the headphones, this should come through in the recording. Another way to look at this is that the pot, which is maybe 100 kohm and the headphones which is maybe 8 ohms, are connected in parallel, both going to ground. The headphones are much lower impedance and effectively bypasses the pot.

This is super interesting, I did not know it would behave this way. If what I'm understanding is correct, before I play around with this any more, the sound signal direct from the CPU loses volume when powering headphones and introducing another set reduces the volume further. Since there's only so much signal pre-amp the more headphones introduced the lower the signal across all of them. Is the only downside to this a reduction in volume due to the signal loss or can anything get damaged?

I've been testing out a DMG ProSound set up that has a 3.5mm line-out connected to pre-pot and the built-in headphone jack connected to post-pot. Specifically the ASM v3 board.

I was curious how both lines would interract (as well as the speaker) so I tried different combinations of things and found something interesting: when a set of ear buds (or speakers) is connected to the line-out and another set of ear buds is connected to the internal jack the potentiometer (or perhaps more appropriately the post-pot headphones) affects the line-out headphones volume.

I recorded four different instances to a computer (with a line-in, not mic-in) using the line-out with just the internal speaker at max and min volume then another set with headphones plugged into the post-pot internal jack:

Line-out + Speaker Max: Full signal, good recording. Internal speaker audible, has hum
Line-out + Speaker Min: Full signal, good recording. Internal speaker muted, has hum
Line-out + Headphones Max: Low signal, poor recording.
Line-out + Headphones Min: Full signal, good recording.

My thinking is opening the potentiometer to the headphones is treating the original audio source like water, relieving the line-out full "pressure" and allowing the headphones to draw on it when opening the pot.

From what I understand both the pre and post sound mods bypass the internal amp while the speaker is still tied to an amp. I would think this explains why the speaker doesn't take away from the line-out signal since it takes the direct audio -> amp -> speaker. This also leads me to assume if the internal headphone jack is left stock and tied to the amp it would not affect the line-out signal, like the speaker.

Is this close to the correct thought process or is there more at work here? Or is this off completely?

I've seen it recommended (after experimenting) not to use headphones simultaneously with the line-out. Is this because it can be damaging to internals or peripherals or is it because of the signal loss to the line-out depending on heaphone volume?

Thanks for any insight!

Another small update after more reading around on the r/gameboy Discord that may be useful information for some people: if your IPS kit does not put a load on the -19v line and you are using a stock DC regulator there is a risk of popping a diode/cap on the DC board. The working solution looks to be removing the diode or adding a resistor- in addition, and perhaps more relevant to chip music, it appears this fix may also rectify audio issues related to IPS screens.

catskull wrote:

The other option is to get one of the new IPS lcd kits and then eliminate the built in regulator completely and just use your 5v regulator. Haven't tried that myself yet but I heard that it works fine.

I've gotten to the point of gathering parts for an IPS build using the FunnyPlaying kit so I'm starting to explore this idea a bit more. I have another Pololu on hand and would love to be able to replace the built in regulator altogether with the Pololu but not sure if the FunnyPlaying kit depends on the -19V in any fashion.

I remember reading a blog post or similar somewhere that some of the components may actually use the negative line as a ground but I may be remembering that incorrectly. I've referenced bit 9's board schematic thread, particularly the front of the CPU board that has -19V going to pin 3 on the LCD ribbon cable as well as the LCD board and its schematic. The LCD replacement board for the FunnyPlaying IPS kit doesn't appear to have anything attached to pin 3 (third from the right) but I don't know for sure. To my untrained eye there don't appear to be any components using that line as a ground but if it is the case I wonder if the -19V line and the GND can both be tied to the GND on the Pololu from the CPU board...

ScanianWolf wrote:
Knife Crimes wrote:

I can't think of anything that would connect the issues you report with LSDJ to the replacement power regulator. Maybe a coincidence? Others might know better than me.

It should be added that the CleanPower board outputs 6V instead of 5V if I understood correctly from the previous posts.

I was doing a little reading and came across a Reddit thread where the specifications of the CleanPower were discussed. One iteration of the board is confirmed to output 6v instead of 5v and subsequently cause issues with flash cartridges. Efficiency was also addressed and it's not quite there yet, either.

So it appears the higher voltage of the earlier board can cause issues with flash carts and, therefore, lead to crashes with LSDj. To hear the efficiency of the v2 is still poor is a bit discouraging, perhaps another revision will resolve things.

Acquired one of the v2 boards a while back and finally had some time to test it out. Happy to report the output is about 5v and the negative is about -18v (analog multimeter). As to flash cart/backlight combos, I wasn't able to test how much amperage it can provide so I'm not sure if that diode is still needed. It also runs significantly cooler than the stock DC board it replaced so my original issue seems to be resolved with this. Thanks for everyone's input up to this point

As an update to the CleanPower board, thanks ScanianWolf for the voltage output testing. It looks like they have updated the CleanPower board to a new version with different components and layout. Am hoping they use 5v instead of 6v with this new version but that remains to be seen.

That does look really clean- the one I just did is for more all purpose, games, music, software. The next one I was considering piecing together more for music with a capacitor swap for the lower frequencies and darker color combos, maybe blackout. That's super interesting to learn about the noise intereference based on palletes, thanks!

Oh thats pretty neat- I didn't realize the new IPS displays don't require the old power boards at all. I plan to mod another DMG at some point in the future and may give that route a go.

For this current one I’m trying to keep it as close to stock ‘feeling’ as possible, if that makes sense. Picked a backlight close to the pea soup color as well. If possible I’d like to keep the original LCD and shell for this one in tact.

Thanks again for the suggestions and responses!

Yes, thank you for replying, I have. I had considered it initially but it looks like it provides 6v instead of 5v and possibly a higher negative voltage value for the LCD based on an earlier version in the screenshots. I don't know how giving 6v to 5v logic would work in the long run and the same for the negative voltage for the LCD. I’m ignorant when it comes to this but anything I searched for when feeding higher volts to a lower rated line wasn’t always a good practice in general. For the DMG specifically I couldn't find anything more about it..

Hello all,

I apologize, this may be a bit long, but I want to be thorough.

I recently finished my first DMG CPU-06 overhaul including capacitor replacements, backlight (HHLv3 built in resistors), 'bivert' module (HHL v2), pro sound (post pot), and supplemental Polulo S7V7F5 step-up/step-down regulator for the rest of the system. The stock DC CONV DMG (version with single 33uf25V cap) is supplying LCD and backlight power only.

I'd read in several places that older power boards such as the one in my model have poorer efficiency than the later CPU-08 versions (that include DC CONV2 DMG) so they can't take additional load such as a backlight and/or flash cartridge without straining themselves to the point of mechanical failure.

This set me out on a search for an aftermarket power solution. I've seen a thread here and a few others elsewhere that people were starting to design an alternative power board but none have come to fruition that I can find (except one, see bottom *). Then I saw some comments from BennVenn on a post or two where people wanted to replace the power board with just a Polulo. He mentioned the stock power supply needs something on the 5V rail in order to supply the negative LCD voltage, one of his suggestions being a backlight. So this led to setting up my old DC CONV DMG power board with the lighter duty of powering only the backlight and LCD letting the Polulo supply the rest to the system. My understanding is that the DMG uses ~150mA under load (depending on cartridge) and that backlights may use ~10-40mA so this should give plenty of headroom for the old power board.

It's been a joy to use so far and I've done a few sessions in LSDJ. But, I noticed when it's been on for 30 minutes to two hours recording audio that the lower left corner is 'slightly' warm. Not hot, but not cold either. Only after an hour or two the batteries (Alkaline, non rechargeable) are in a similar state, not hot, but not cold. 

So this is where I'm concerned- I have the stock DC CONV DMG with a backlight drawing a supposed ~40mA on the 5V rail direct to its + tab with built in resistors and supplying the negative voltage to the LCD panel. Ground is connected from power board to CPU board as well. I would think, if anything, the DC CONV DMG board would be less strained and less likely to heat up but this doesn't seem to be the case.

This might be barking up the wrong tree but I had the thought that since the negative from the LCD runs through the DC CONV DMG it may have to do with the 'bivert' module install. Then again I'm probably wrong on this and it's handled by the Polulo instead. But to potentially rule it out I've double checked that there was continuity between the connections that should have it and made sure there weren't any shorts. I've read some about it but have very little understanding on floating inputs, mostly that they should be connected to VCC or ground if not used. The module's product page states 'Grounding for the remaining pins for increased reliability' and it uses the 74HC04D hex inverter so I wouldn't think that to be a cause but not sure how to test if it might be a lemon either.

I feel like I've checked the replaced capacitor values and orientations at least three times now so I don't think there's anything there...

I've written all this, and done a ton of reading, and the thought occurs to me that maybe that's just how the old power boards are- they all give off the slightest amount of heat that doesn't have anywhere to go so it just accumulates in that corner. I don't know, I set out to put together a DMG that hopefully would last me for years and can't escape the feeling something might not have been done right or I'm missing something.

Given this I'd appreciate anyone's input on what I could check or if I'm just overly concerned about my console. Thanks for reading and for being such a valuable resource through the whole process!

* The power board mentioned earlier is called a "CleanPower Regulator" board made by RetroSix in the UK that HHL has started stocking as well. Screenshots show it's a 6V rail instead of 5V so I wanted to wait until it's been out for a while to see other people's thoughts on it.