With all due respect yes it very much is, the solder used in the manufacture of the DMG is leaded, and any electronics engineer would always endeavour to use the same type of solder where possible as mixing unleaded with leaded is not a good idea, for example: http://www.eevblog.com/forum/beginners/ … ee-solder/

There are also other considerations to take into account, as nitro2k01 has already said leaded is generally much easier, and it provides much better wetting - especially helpful in larger voids such as the holes in in the hhl bivert pcb, where it is essential that the solder flows freely between the bivert pcb contacts and the original leaded solder joint on the DMG pcb below it.

Currently I've got a spool of 96.5/3/0.5 tin/silver/copper. 0.38mm diameter. Works out pretty well for me! Though I should probably step back from the ledge, I'm not saying it's 100% always bad advice to say "don't use lead-free solder", but I think in the context, the lead content of the guy's solder is so irrelevant that giving that advice is not going to help in any way.

Which type of unleaded do you use?

I keep both on my bench and the difference to me is negligible.

Leaded solder is generally easier to solder properly by hand because it melts at a lower temperature and it's eutectic, ie solidifies at a single temperature rather than having a transition range between its liquid and solid phase. You can get decent lead free solder nowadays, but as a general recommendation it still holds true.

This is not based in reality.

Also don't use lead free solder, use leaded.

It is all explained if you read through the thread, it seeems that catskull had installed the hhl bivert board in a dmg that had previously just had a chip install, where the traces had been cut incorrectly, the cut traces were causing the issue with the hhl bivert board, as it does not require traces to be cut. In your original thread a poster suggests that your install does not have an adequate solder connection, which I am inclined to agree with, try re-hitting your solder joints on the pads on the bivert board, enough solder needs to flow onto the dmg pads below for it to work.

I am having the same issue, how did you resolve this? Can you add a picture also?

I see. Yeah the traces were cut originally when I didn't use the hhl board. I actually like the non destructive nature of the hhl board, especially considering its only a few dollars.

What I meant was that while the mod was incorrectly installed, this problem existed and could have damaged the CPU or inverter (but probably didn't). Although thinking about it, I forgot this mod board has you lift the pin, so the inverter output would never have been connected to the CPU output unless there's an excessive blob of solder that touches the pad. Which also means that you shouldn't really have to cut the traces at all if you're careful when installing the board.

Oh by the way, here's the rom I was using to test with: https://archive.org/download/palette_202407/palette.gb

Fredrik Brundin made it for me, what a nice guy!

Jul 29 2024: replaced dead google drive link with hopefully permanent archive.org

Wait how do you figure? It looks to me like that pad wasn't connected to anything.

Those easy chips are such a pain. Last one I did I just tore the chip off and wired it in, cause it kept missing the points.

Yes. And also, if you don't also cut below the via, you're connecting an output to an output! The deadly sin. (At least potentially deadly to the chip outputs although it probably didn't cause permanent damage in this case.)

Or, you could use a smaller inverter chip and use one of the grounds in the 6 pin array. Hmm!