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ANNOUNCEMENT - MMS1 - A 16 in 1 MULTI FOR JALECO MEGASYSTEM1(A) FROM CAIUS + HAMMY

Can see loads of 27c801 at -100 speed but not many at -150, will 100 work OK?
 
Damn. Bulk of these chips is expensive! I now see what you meant @Hammy about the total cost! I’m going to order 50 x 801’s in case there’s any duds.
 
What's the correct crystal to get for overclocking this board properly for the best game support?
 
ShootTheCore said:
What's the correct crystal to get for overclocking this board properly for the best game support?
Click to expand...
No clock change, its done on the clock dividers...
1# If you got a P10 processor fitted then i have a quick way
2# For a P8 processor requires 2 logic chips

If you already have a running setup of rodland it maybe worth messing now (game that is slow on original but benefits a great deal from the extra power and plays much better)

That said, this is totally experimental i want to do mod #1 but my boards are #2.
I don't want to desolder the processor, the PCB is terrible tracks and brutal ground planes so stuck in limbo until someone with P10 gives "easy mode" a go.
 
Dumb question- where do these ship from?

There's a couple killer titles in that list for sure!

I appreciate your patience with my shipping questions. You've been understandably busy the last few years. Offer still stands if I can help lessen the work load or get you transportation to help things ship quicker so things aren't overwhelming!
 
Looks like i will be building + shipping them so expect the normal lag.

I know you want to help,
The help i need is in person assistance , nobody wants to visit for a game of fuckin' street fighter anymore let alone mess around with things they don't know.
So there's zero chance of actual help with clearing the decks, the best thing to do is just let me get on with it, unless you want to visit? :P

Hammy said:
1# If you got a P10 processor fitted then i have a quick way
Click to expand...
According to this site P8 WILL overclock to 12mhz:
https://docs.google.com/spreadsheets/d/1E9eHd0uj0nzgwBMbIPbeGlZsbutGRyPTTVoYce7GmF0/pubhtml

I'll test it over the weekend!
 
Ok, i tested overclocking.

Good news the overclock works fine
Bad news my P8 @12 gets hot very quickly and crashes and won't boot up again until cool.
As expected it will need to be changed to something faster.

Other good news, CPU seemed to take the abuse and returned back to working after cooling down.
 
To perform the mod:

Lift pin 4 HC04, add wire to one side of switch
Pin 8 to other side of switch
Middle of switch = vacant HC04 pad

This switches between 6 & 12mhz , a big jump and as stated many times before, not recommended for P8.
 

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Hammy said:
Good news the overclock works fine
Bad news my P8 @12 gets hot very quickly and crashes and won't boot up again until cool.
As expected it will need to be changed to something faster.

Other good news, CPU seemed to take the abuse and returned back to working after cooling down.
Click to expand...

Do you think putting a big heatsink on it would be sufficient to mitigate the heat? Or is a part swap really the best solution here?
 
I'm not entirely surprised it crashes, that is a 50% overclock. From what I was told about fabbing these things, they're all made as P12's (or whatever the highest clock speed is) and tested, if they fail they're tested as P10's, and so on until they're stable and then that's what they're sold as. So in all likelihood, your P8 is a failed P12, etc.

I imagine you would need some serious active cooling which might be tricky as in terms of modern processors, it's an unusual shape for the purposes of heatsinks, etc.
 
ShootTheCore said:
Do you think putting a big heatsink on it would be sufficient to mitigate the heat? Or is a part swap really the best solution here?
Click to expand...
Part swap, or get lucky with a motherboard with P10 fitted from factory ;)
OR we build a 10mhz circuit....

bodgit said:
I'm not entirely surprised it crashes, that is a 50% overclock. From what I was told about fabbing these things, they're all made as P12's (or whatever the highest clock speed is) and tested, if they fail they're tested as P10's, and so on until they're stable and then that's what they're sold as. So in all likelihood, your P8 is a failed P12, etc.
Click to expand...

It's no surprise at all, TBH i was told the same about chip plants and that it works the same on ram, rom and other parts
how they are "graded" by testing, still to this day i think ;)

More of a surprise it booted with the clock mod and the other sections of the PCB don't rely on it being in sync.
 
I think Ill just do the swap and place sockets while im at it. Both cpus need to be replaced correct? So any 64pin 12mhz (or is 10mhz preferred) 68000 should do it?
 
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