Hello MSX world,
Some time ago I bought a broken MSX for very little money and I was told
there were problems with the screen. I thought the whole screen was black
and the computer would be dead. In that case the video processor would have
died and I could safely take the diskdrive to put it into my own MSX. But
of course I tested the computer and I found out there was something else
wrong with it. I will name the problems and I hope somebody recognizes the
complaints and tells me what is wrong with it.
First of all, the computer is an standard Philips NMS 8245. No extensions
are made to it and as far as I know it is in its original state.
- When I turn on the power the MSX logo comes up quite normal, but not all
vertical lines are drawn correctly. In fact one line is ok, the second
is black, the third is ok, the fourth is black, etc.
- When the computer boots it tries to read from the diskdrive. But only the
led is burning and the drive is not working. So there is no possibility
to boot disks.
- This means the computer gets into basic. Here the screen is not readable
because all the characters are replaced by crap. It is possible to type
something, but the computer does not make any difference between normal
letters and capitals. They result in the same crap on the screen. This
is when a letter is pushed with shift or with caps lock.
The caps lock seems to be working, at least the led on the computer
can be set and reset. But when just pushing caps lock for some seconds
does not result in a flashing led, but it is accepted as only one push.
When some letters are typed, it doesn't matter if it is real basic or
just
some nonsense the computer always reacts with 'Ok'. Or better with the
two characters that also appear when I type 'ok'.
- I tried the computer with a game cartridge called 'Guardic'. If it would
be damaged I would have a backup on disk for my old computer. But it
worked. I had sound and I could play. The only problem was the screen
again. I couldn't see what I was doing. All characters were messed up.
And the sprites for the plane were on the left top of the screen. So I
had to rely on the sound for what I was doing, put I managed to play some
levels before dying.
- Now I tried a MSX2 cartridge: 'Cheese II', the NEOS drawing program. Now
the pointer on the screen was always on the top of the screen and could
only be moved left and right. Like the MSX title screens there were
black vertical lines again in the same pattern: one black, one ok, one
black, one ok, etc.
While booting Cheese allows initialisation of the diskdrive, but the same
as with booting basic, only the led works.
If anybody knows what is broken on this computer please mail me. I first
thought of a broken video processor. I mean the VDP makes the interrupt
signals on which the screen is built up. This works ok. Also keys are
detected on interrupt and this works quite good either. But because the
diskdrive doesn't work I think there is something with the ROM or with the
I/O. But I really have no idea what is really the problem. So again, please
help me and if possible, please give me an estimation of the repairing
costs.
If these repairing costs are too much, I will move the diskdrive to my
VG8235/00. And I have a question on that one too. Can I just change the
drives and let it work or do I have to do more. I already have a new
diskrom installed for using an external 720 kB drive, but it would be nice
to have two 720 kB drives. So please give me some information on this one
too...
I hope somebody can understand all I have written and that somebody can
help me with my problem.
Greetings,
Jasper Lautenbag.
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email: [EMAIL PROTECTED]
www : http://huizen.dds.nl/~the-laut
