Hi Andre, 256 bytes shows a problem with adress line VIDRAMA8. A8 is not affected, otherwise the machine won't be able to boot and run the monitor. I think this may just be a faulty video RAM ( 2k x 8 SRAM at U29) or the 74LS157 at U15. Christian Am 26.10.2014 21:38, schrieb A. Fachat: > Hi, > > On Sunday 19 October 2014 21:21:22 you wrote: >> Hi Andre, >> on your pictures it looks like you built something to generate the 50 Hz >> square signal, so the signal is there ? > Yes, I built a small 555-based circuit for that. > >> My CBM 700 sometimes shows the cursor and does not start up. >> Wiggling a bit at the eprom adapters helps. >> The rom sockets are bad, I have to replace them. >> Maybe your roms have contact problems too. >> Try removing the basic roms, the machine schould then start into the TIM >> monitor. > Thanks, that was a good tip. Now I can boot into the monitor and even enter > commands. > > However, there seem to be some display addressing problems. Parts of the > screen are displayed twice (each 256 bytes). You can, however, enter commands > into the screen when in the "overwritten" area, and execute them. So to me it > looks like it's a screen addressing problem. > > https://www.flickr.com/photos/afachat/sets/72157647798386959/ > > André > > > > Message was sent through the cbm-hackers mailing list -- Christian Dirks Toast_r@Idealine.info Message was sent through the cbm-hackers mailing listReceived on 2014-10-29 23:00:02
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