Europlus white box before Reset

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Last seen: 7 years 7 months ago
Joined: Mar 16 2016 - 04:41
Posts: 22
Europlus white box before Reset

Hi, When I switch on one of my Europlus's I get a white box filling the screen. I need to press Reset to get the Applesoft prompt. I've run the dealer diagnostic disk and all checks out fine. Every thing works fine from reset onwards.

No cards installed.

Any ideas? One of the logic gates?

Thanks

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Last seen: 3 months 1 week ago
Joined: Dec 3 2015 - 20:45
Posts: 63
Re: Europlus white box before Reset

It would have to be the NE555 chip at location A13 or transistor Q5 or nearby cap/resistor. That generates the reset at power on at the same pin 40 of the 6502 as the reset key itself.
R26 and C4 form the RC network for the power on reset delay. Unfortunately that IC is probably not socketed. Could look around that area for damage, crud too.

Larry G

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