Schema power source HB-F1

Por lovemsx

Resident (41)

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15-11-2010, 09:10

Hello I bought a Sony MSX HB-F1, but he did not come with the power source, someone would have the scheme? Or someone would open a source for me over the layout, photo type, or set up a scheme? I'm waiting. Thank you.

I need to know if there is any upgrade memory mapped, to increase the ram to upgrade it and some 2 +.

Thank you Smile
Ricardo Taconi

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Por RetroTechie

Paragon (1563)

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15-11-2010, 09:39

Don't know if they're the same, but connector type & power requirements are very similar to what the Ultimate MSX FAQ says about the Panasonic FS-A1 power connector. You'll need an AC adapter with similar outputs (best = input matching your countries' mains voltage), and (harder) find a matching connector.

Edit: just checked my HB-F1 II power brick, it's marked with same info as for above model in MSX FAQ. When looking at the back of the computer, it's like this:

18V AC  (2) (3)   Ground
          (1)
         9V DC

If you're @home in electronics, it might be easier to add a 2-pin connector, put 15-18V AC in there, and modify power supply internally to derive +5V from that AC voltage (for example using a switching regulator a la LM2575 or something like that). Or put in +5V DC, and add one of those +5 -> +/- 12V DC/DC converter modules. Unfortunately there's not much room to work with inside the machine. :o

I need to know if there is any upgrade memory mapped, to increase the ram to upgrade it and some 2 +.
If it's similar to HB-F1 II, then there would be a S1985 engine chip inside. Meaning it should be relatively straightforward to expand to 256 or 512K (using a 512K x 8 bit SRAM). But this machine isn't a very modder-friendly one, eg. IIRC there's only 1 ROM, soldered in (no extra ROM sockets that you could use for additional ROMs/RAMs). Flimsy keyboard connector & lots of wiring between m/b & top half of case.

Por lovemsx

Resident (41)

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15-11-2010, 10:01

Thanks for the prompt replyWink

is the same yes, but need to mount a scheme here. He has +9 v dc input and 18VAC, and I could only connect using the 9v, he called normal, but I think you need to rectify the 18v to 12v, for the cartridges. Ex FMpac.

About his engine, the S1985 is yes. I think it should be fácill mapper expand it. I'll give it some research in the datasheet.

Por lovemsx

Resident (41)

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15-11-2010, 10:05

Its power supply is easy to open? or is it stuck? der to appreciate some pictures to post. If you forget a lot of work ok? Hugs

Por RetroTechie

Paragon (1563)

Imagen del RetroTechie

15-11-2010, 11:25

The interesting part of the power supply is inside the machine, but it's very simple. IIRC there's a simple 9V DC -> +5V regulator (a la 7805, perhaps heavier) stuck on a cooling plate. And some rectifier diodes, buffer capacitors + 7812 / 7912 to produce +12 / -12V. You don't need -12 that much, but you do need +12V because it's used in the video circuitry (-> possibly no video output if +12V is missing).

As for memory expansion: this thread might be helpful. Selecting the MA18 signal (for 512KB) might be tricky, and beware of Pseudo-SRAMs vs. regular SRAM. There's some slight variations on how to connect the SRAM control pins, but usually it's easy to find a configuration that works. Even if you get stuck @256K, that's a whole more useful than 64K main RAM. ._,

Por lovemsx

Resident (41)

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16-11-2010, 00:53

I tried to do some things here to expand the memory, but without success, I think it will be easier to expand with an internal mapper through a cartridge, because the S1985 has 3 slots left unused.

Por lovemsx

Resident (41)

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16-11-2010, 00:55

Now will someone could post some pictures of the external source of MSX? 18VAC 9VDC, I would appreciate it, because that is the most accurate. Wink

Por lovemsx

Resident (41)

Imagen del lovemsx

19-11-2010, 01:37

I managed to turn the MSX, I called with a pc power supply, turned it inside-12v. Had some tutorial exandir to his memory? considering that the mb64h444pf this msx has only 64kb of ram, how can I get another line of data? the data lines going from A0 to A7, A8 need, how to achieve this?