Re: A couple of PET drive problems...

From: Bryan Pope (
Date: 2007-03-29 04:50:48

And thusly were the wise words spake by
> > Is there a webpage that describes how to measure the I/O signals?
> Have a look at the NRFD (Not Ready For Data) signal first. This 
> signal tells the computer that the drive is not able to receive data 
> at all at this moment. So have a look at this signal first: (L) means 
> active and the computer will wait until it is (H). So if it is (L) 
> indeed, check the level all the way up to the I/O ICs in both the 
> drive and computer.


	I finally got my logic probe and checked the NFRD signal.  
When the 2031 is turned on it is Hi but then goes (and stays) Lo.  
Contrast that with my working 2031 which starts Lo but then 
goes (and stays) Hi.  Neither were connected to the computer 
when I turned them on.

	I checked past FB8 and it is also Lo.  What do you mean 
by other I/O ICs in the drive since it looks like NFRD is output 



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