iasis inc. ia7301 Computer in a Book

[Novell2NT]

Hey Guys,

I have been enjoying working with my ia7301 computer in a book, but I have run into a slight problem.
Chapter 7 is about writing and reading tapes, and I am not having any luck with this right now.
It may be the PS I am using, where it supplies the +5VDC needed, I am not sure it will supply enough current,
as it is only rated for 0.9A.
I have placed a scope on the Read and Write lines, and I noticed the the write line had a nice looking sine wave,
it was only getting up to 900 mvpp, The book clearly states that I should see something like 2Vpp.

I have tried two separate tape recorders and a several different tapes.

So, I guess the first thing I need to know, is what would be the proper PS ratings for an 8080 SBC, including
the proper current ratings needed.

 

[Dwight Elvey]

The output filter can not provide 2 Vpp. What is the encoding method? Is it KC byte standard or some other higher speed method?
Most anything that can record will be able to handle KC. other methods require better quality recorders.
Most recorders should have no issue with 900mv p-p.
They may have meant the signal at the 74LS175, before the filter.
I should note that some methods even require the correct polarity of signal ( Polymorphics BiPhase at 9600 baud is an example ).
What does the input circuit look like?
Dwight

 

[Novell2NT]

This tape drive problem somehow resolved itself. Using the original +5VDC 0.9A power supply, that I started with and the Realistic CTR-80 recorder. This recorder produces a nice square wave.

What is the url to Al's archive site, so that I can post the book up there?

 

[Dwight Elvey]

If the computer is running, it is likely fine at .9 amps.
Look at the power line while running. If it stays flat, it is fine.
Dwight