Can anyone help me ?

My spectravideo 738 won't start in basic, it only flashes Microsoft basic 1,0 in loop.

When i insert an modul in it, it will start in a game and works fine.

I can't play any disk games or cassette games.

Thanks, for any help !

something is causing the z80 to fetch a machine code jump instruction to 0. May be the rom damaged?

RAM most likely. Or in SVI.738 one of the ULA's managing the thing.

Open it up and see if any pf the IC's is in a IC socket. Then wiggle that a little to let the pins make better contact.
And check if this is a modified SVI.738, it is a perfect machine to experiment with! Maybe one pf the experimental wires is loose.

If that does not help, check the service manual.

Hello,

I can't help you with the issue that much because I'm not that skilled on MSX technics, but I think I can help you if you should need any IC's or other SVI738 parts. I have at least one SVI738 for spare parts at the moment. And also I'm from finland so the exchange of the parts would be easy.
I'd also vote for the bad contact of a certain IC.
From HansO's pages you can find scans of the mainboard, so you can locate RAM chips and ROM's for check.

open your MSX and check it
if exist a additionnal RTC board with a Battery desold it and retry start
if your MSX work Battery is dead

Thanx to everyone for your replies.

There's no battery in my Msx motherboard. Only empty place for it.
I have tried to check ic sockets with no help.
Maybe the rom is really damaged.
I'll have to check service manual

I also don't believe the problem is in ROM... If you live somewhere near Helsinki I can try to check it out if you drop the machine for me for a while.