Corrupt Kanji on Panasonic FS-A1FM firmware???

By neo.tokyo.2020

Supporter (3)

neo.tokyo.2020's picture

16-04-2018, 01:54

Hi,

I recently obtained a Panasonic FS-A1FM

Everything seems to work but the Kanji graphics are corrupted on the system firmware.
Does anyone know what is causing this? Can anyone shed light or help? The kana and romaji text seems fine.




Thanks

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By neo.tokyo.2020

Supporter (3)

neo.tokyo.2020's picture

16-04-2018, 01:56

to be more precise, there is a problem rendering the large characters, including Kanji, Kana, and Romaji:

https://www.msx.org/wiki/Panasonic_FS-A1FM#Firmware_2

By gdx

Paragon (1950)

gdx's picture

16-04-2018, 10:44

BIOS, BASIC, Disk-ROM, Kanji-ROM, Modem Rom and Firmware are all in this 512k Rom.
http://usbsecretbase.michikusa.jp/a1fm/fdc.html
Perhaps the MSB of address is defective.

By neo.tokyo.2020

Supporter (3)

neo.tokyo.2020's picture

16-04-2018, 12:52

gdx wrote:

BIOS, BASIC, Disk-ROM, Kanji-ROM, Modem Rom and Firmware are all in this 512k Rom.
http://usbsecretbase.michikusa.jp/a1fm/fdc.html
Perhaps the MSB of address is defective.

Thanks a lot for the info and link!

Though, I am out of my depth here, is there a solution for this?

Can I somehow reflash the ROM or would it need replacing?

Everything seems to work including the modem dialing, it's just the large character graphical corruption.

By Meits

Scribe (4924)

Meits's picture

16-04-2018, 13:03

You need to replace the rom, if it's broken. Flashing was not introduced when your MSX was produced.
It can be flashed to a new rom, but the old one has to be physically removed.

By Grauw

Enlighted (7012)

Grauw's picture

16-04-2018, 13:47

But it could also be that there is some problem with the upper address line to the ROM. The level 1 Kanji ROM data itself is 128kB, so as gdx surmised, if it’s located in the upper half of the combined ROM chip then a broken A18 address line could cause read issues with only the kanji. If the rest of the built-in software is in the lower half then it would not be affected by this.

I would say the best way to verify if the A18 address line to the ROM is ok is to test for continuity with a multimeter, and to visually inspect the traces and the solder joints.

If you’re not familiar with basic electronics yourself, I would say the best way to proceed is to find someone in your local circle or retro computer club who knows how to handle a multimeter and a soldering iron.

By mars2000you

Enlighted (5223)

mars2000you's picture

16-04-2018, 13:56

To make the things more difficult, there are actually 2 different Kanji-ROM in this computer, the 'standard' Kanji-ROM and the 12 dots Kanji-ROM. Both have a size of 128Kb.

My MSX profile