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Kaypro 1 1986


Mar 3, 2023
has turbo rom 3.4 on it.

anyways, i have data coming into the video chip but nothing coming out.. everything else looks like its running. maybe it doesn't access the disk when i turn it on, but i can't tell because no video is coming out. when i pull the video chip i get a raster on the screen.

I have an eprom reader coming and a blank eprom.
Does the A: Drive LED come on when Power is turned on?
If it does, try Powering down and opening the case. The row of pins where
the flat video connector push on to the motherboard needs to be removed.

When the connector is removed look at the Pins and see if they have a blueish
tint on them. If so take some fine emery cloth and clean the blueish tint off
the pins. My Kaypro II had this problem and that fixed it.

Last edited:
I'm actually using the kaypro 4 chassis..since I know the monitor and power supply are good...there is no signals on the lines...

There are Address Lines, Data Lines, Clock Frequencies, Control Lines etc for the Z80.
Which ones are you talking about?

Start with the Z80 and check the Inputs to the CPU that are Control Inputs plus the Clock Signal.

The Control lnputs to the CPU need to be HIGH. and a good Clock Signal. After that comes the Address
Buss and Data Lines.



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oh the kaypro 1 has video controller chip..it has data going in..but nothing is coming out..

I hope its that chip because it has 3 custom array chips by kaypro.