Only Blinking "@"

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Only Blinking "@"

Postby ingowerner » Sep Tue 29, 2009 3:19 pm


My replica 1 TE is ready soldered now, but a first test shows only the blinking "@" on the screen. The reset-button has no function. I have controlled all solder points, all voltages are there.
My father had controlled all too, he is an electronic technician. I have controlled all pieces of the kit, there are ok.

What can I do, any idea?


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Postby vbriel » Sep Wed 30, 2009 12:30 pm

Well, the fact that the @ is there is a good sign. The part of the circuit not functioning is the CPU section. This is the hardest to troubleshoot.

Things to check:

Oscillator installed correctly. There is one corner that is pointed. If installed incorrectly, no clock to the CPU.

Chip installation. Check the CPU, 6821, EPROM, RAM, etc and make sure they are installed with no bent pins.

Check all solder locations, many times, this is the issue.

Some of the parts like the 6502, 6821 and EPROM are subject to failure when shipped. If you think everything is good on the board, you can ship it in and I will troubleshoot and repair it for free.

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