maximun speed with real msx2 hardware

Hello, interesting, have you been able to do tests with Msx Super Turbo circuit that i sent you time ago with Megaflashrom SD in a F9S? Even with the MSX2+ XV with Turbo ON the Megaflashrom SD hangs with Turbo, all other cartridges works, i tested new things but even the cart hangs when Turbo Is ON in a slowdown slot. Then it seems Sony Machines: HB-F700S, HB-F9S, MSX2+ HB-F1 XV cant handle Turbo with Megaflashrom SD (using Msx Super Turbo) Let me know if you discover something with Megaflashrom SD problems with Turbo and Sony´s.
Regards.

Hi, no philips yet, no osc, no much time for test, also i´ll have to make mod on philips to allow Superturbo works, and that spend time, will be cool if you could make tests on philips, for now i´m in more projects and dont have the time.

Hello, watching the pictures (let me know usuario_msx2 if i´m wrong) Z80 is with socket and changed probably for a 10Mhz version, i cant see right the label, the VDP is with socket and seems be VDP9958 conversion because the cable solders on its solder side and a Diode is placed on WAIT pin that goes to another point, probably to Z80, also a fan placed above vdp9958 to avoid overheat. I didn´t see any ram expansion, if i´m right the ram is original and is DRAM HM50464P-12 (32k? and 120ns?) x8 = 256K, 128K for VRAM and 128K from MAIN RAM, i´m not sure. The Bios seems be with socket, but also seems be the original Bios with Label Philips, if it is the original probably have more than 100ns, also i can see a white pcb that seems be a power supply adapter, and the Kit Turbo with zilog divider Z0858110PSC and jumpers for select different crystals:
Crystal 12,000 /2 =6Mhz
Crystal 19,66 /2 =9,83Mhz
Crystal 18,432 /2 = 9,216Mhz
Crystal 14,31818 /2= 7,159Mhz
Another Crystal unknow value
If that is correct the bios and DRAM have a lot of milisecons but the kit Turbo even works ok at fast speeds, in Superturbo i remember that using original DRAM on F9S and F700 the msx hanged when Turbo was ON (using high crystals), DRAM should be changed for SRAM, time ago a forum user called Retrofan told us that in its F700P the MFRSCCSD+512K SRAM worked ok with Turbo Kit 7Mhz and in his F700P he used DRAM KM44C256BP-7 (70ns) expansion, on mine F700S tests i was using SRAM LPE-512K (55ms i think) and Turbo kit hanged only with MFRSCCSD+(no SRAM expansion on my cart), on mine machine the kit 7mhz worked ok with another carts.
Could be any issue with DRAM or SRAM that makes MFRSCCSD dont work ok with "Superturbo" when Turbo is ON? its seems that your Turbokit works ok even using DRAM, the Retrofan´s F700P also used DRAM but his cart had internal 512KSRAM expansion, the cart can handle its own SRAM ,yes, but maybe not SRAM internal in combination with Superturbo?
If the 8235 info above is correct and the Bios is slow and the DRAM have 120ns , i think if we install a Superturbo on that machine with a higher crystal more higher than 5Mhz probably the msx will hang with Turbo ON, this is an speculation, on mine tests with Superturbo ON in F9S the machine only can handle a little more than 5Mhz with original F9S DRAM and original bios, and original F9S DRAM is MB81464-12 (120ns) and original bios probaly 120ms to 150ms.
Could be that all machines with kit turbo that works with MFRSCCSD are using DRAM? The cart can handle SRAM, but maybe there is a problem with SRAM in combination with Superturbo with that cart, i dont know.
Another option is noise on CLK signal, but if that is true that problem dont affect to another carts with Turbo ON, and remember that Konami Ultimate Collection and the Megaflashrom SCC+ 8Mb (the older) worked ok with Superturbo and Turbo ON, and those carts hardware practically is the same as the MFRSCCSD have. If all that carts hardware are the same i dont understand how a CLK noise can only affect to the MFRSCCSD and not the others. If CLK noise is the problem probably will affect all those carts: Konami Ultimate Collection, Megaflashrom SCC+ 8Mb and MFRSCCSD, but only affect to the last one, i dont know, this is speculation.
If mine info is right, the internal MFRSCCSD FPGA is running at 21.48Mhz (3.58Mhz x6), so if we put a higher speed the internal result is multiplied x6 ,if thats true should be happen incompatibilies at high speeds, anyway seems kit 7mhz work, but not superturbo, and when all carts tested worked ok with superturbo and no with MFRSCCSD should be a reason, maybe how works the FPGA is a problem for Superturbo+SRAM+Fast Bios and not for Kit Turbo+low DRAM+low Bios?

Then, if the behaviour of the Philips is similar to F9S or F700 or XV, Superturbo shouldnt work with high crystals with a DRAM 120ns and low BIOS 120ns to 150ns, probably get 5mhz is possible with that config or not, should be needed put fast DRAM 70ns or SRAM 55ns, and BIOS 70ns (better than 90ns) to get like 8Mhz working, if not the machine can hang or not when Turbo ON, i never tested it on a Philips. A theory could be that the circuit or design of Superturbo is fast + fast SRAM + fast BIOS + High Crystal could makes for some reason or unknow reasons the FPGA that are running at 21.48Mhz (3.58Mhz x6) works out of balance and then the machine hangs when Turbo is ON in the case of the MFRSCCSD and Sony, or SUperturbo is incompatible at all with the cart for other reasons, this is only a speculation, on Philips maybe how its designed and the zilog divider CLK signal+ 9.83Mhz + low DRAM + low BIOS makes a balance that allows MFRSCCSD works ok with Turbo, should be great try on Philips fast DRAM then SRAM and fast BIOS, probably you could get more speed or even stable 10Mhz, if the MFRSCCSD still works OK with fast DRAM / SRAM and BIOS then if you wish we could try the Superturbo we talked built in a cart, because with that low DRAM, no SRAM and BIOS probably Superturbo will hang at a range like 5Mhz or little more like happen in Sony machines, but Philips is different, could be get more Mhz or not with that config, to be pretty sure will be better low the ms.

Hello, usuario_msx2 i dont think i´ll build that cartridge for you because time ago i sent to you a complete superturbo kit tested, with the hope you could make tests on Philips, some days ago you told me on a mail that for sure you have the circuit, but you shouldn´t find yet, dont worry anymore, dont look around for it anymore because i found it here today:

The Japanese legend translation (behind the kit) to English:

"I got a board from overseas people! It seems to be an additional board for operating MSX 2 etc. with actual Z 80 at 7 MHz.Thanks to Mr.Eduardo!"

Mr.Eduardo = usuario_msx2

Yes, today i was searching info in the Tsujikawa site and i found the same circuit i sent to you time ago usuario_msx2, exactly the SAME, same components, same OK behind the board, the same i sent to you, i know my staff. After that you even pretend that i´ll build another superturbo in a cart to make test? Are you kidding me?
I´ll ask to Tsujikawa about it. You could tell me, about that Superturbo i sent time ago, that you sent it to Tsujikawa, but you lied to me, telling me that you have it for sure at home, and after that you even demand to me that i´ll build a new one in a cartridge for test, forget it, i´ll talk to Tsujikawa if he can try things, no with you. Also i´ll get soon as possible a 8235 or 8245 to make tests.