The Big MegaFlashROM SCC+ SD Topic

Yes indeed your system will show 1024KB of total RAM, but that is pretty much it... The programs that can benefit anyway of RAM > 512KB are extremely rare... In this case especially as the RAM will be present in two different slots and not as one common 1024KB RAM. Usually programs use only the biggest memory block they can find and that would still be 512KB.

I think this is better to ask directly by mailing to the cartridge shop... These cartridges were not meant to be DIY, but I could imagine the correct answer depends of how late version of the cartridge you get. Original SCC+SD cartridges did not have option to buy with extra RAM.

If you ever decide to buy another MSX the extra RAM on the MFRSCC/SD might come in handy?

This question might only be answerable by Guillian.

My MegaFlashROM fails to completely flash games in some cases. This is entirely my system's fault, which is a Sony HB-F1XBJ. I have cleaned the cartridge contacts, and I have changed every capacitor, but these things have not solved the problem. Using the slow-flashing mode doesn't help, either.

Interestingly, the flashing process only fails if I have had the system on for a while - long enough for the PSU to get a little warm. I suspect that the power supply itself is the problem.

Before attempting complicated fixes, though, I wanted to ask: do the power rails in the cartridge have decoupling capacitors on them? If so, what are the values? Are they on both the +5V and the +12V sources? Finally, which source is used for flashing?

Since the system has no trouble at any time other than when flashing with the MegaFlashROM, I was wondering if I might be able to solve the problem by adding my own decoupling capacitors and filtering the power. I don't know whether I should try a 0.1uf ceramic cap, which would filter out high-frequency noise, or something like a 100uf electrolytic, which would help with large, low-frequency power fluctuations. I could try both at the same time. However, since I would be installing these caps on the bottom of the MSX's PCB, I don't have much space, so I'd really like to know which pins I should target and what capacitors are already in the cartridge itself.

Thank you!

Thank you very much for your reply, as well as for your generous offer to test and/or replace my cartridge.

Although I don't have another MSX to test with, I am still very suspicious of my HB-F1XDJ. I don't think that the entire series itself is bad, just that my particular unit is doing weird things.

For example, before I replaced the capacitors, it used to fail at flashing even before the system had been on for a while. Now, with all of the capacitors replaced, I have never seen it fail when I have just turned the system on. It's only after it's been on for 15 minutes or so and warmed up. In fact, the likelihood of failure seems to increase with each passing minute after I turn the system on.

I have a few 0.1uf ceramic caps lying around anyway. I might try putting one at the cartridge port and one as close to the power supply as I can get. Unless, of course, I find that Sony already did that.

The two 5V pins are merged inside the cartridge anyway, right? That would make it very easy to also try putting in a much larger cap, like 220uf or 470uf, just in case it really is some sort of larger power fluctuation that's causing the problem.

Thanks again!

im hoping for a opf version for this great cardrige that flashes the game in ram instead of rom. so that after reset the game is gona and i dont need to clean flash memory