IIe won't reboot

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Last seen: 1 month 1 week ago
Joined: Nov 12 2017 - 18:34
IIe won't reboot

The IIe I've been building from parts now has developed a new issue. When I turn it off and back on it displays the last thing on the screen and beeps several times without rebooting. Even if I leave it off for 10 - 20 seconds it does this. The reset button is dead for now, so I don't know it it would work or not if pressed.

Any ideas?

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Last seen: 12 hours 53 min ago
Joined: Dec 19 2008 - 21:01
Re: IIe won't reboot

Caps not draining... bleeder resistor in the power supply has failed or needs a recap.

Measure the voltages after you turn it off and see how fast they go down.

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Last seen: 1 month 2 weeks ago
Joined: May 27 2013 - 13:01
Re: IIe won't reboot

Replace your RAM with different ones until the problem disappears.

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Last seen: 17 hours 48 min ago
Joined: May 27 2009 - 01:37
Re: IIe won't reboot

But first check the voltages with power off and check the bleeder resistor for the caps.

CWJ_Wilko's picture
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Last seen: 3 weeks 1 day ago
Joined: Jun 2 2015 - 23:38
Re: IIe won't reboot

Am I missing something here... shouldn't the autostart ROM still be resetting things on power up?

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Last seen: 2 days 18 hours ago
Joined: Jun 18 2010 - 13:54
Re: IIe won't reboot

Reset, yes. But if the WARMSTART byte at $3F4 retains its value ($45) through the power down, then the machine will try to do a warmstart via $3F2/3. If those bytes (or anything they point to) get trashed, then you're likely to crash.

You can always do an Open-Apple/Control/Reset to force a cold boot (or just hold the Open-Apple key as you turn on the computer).

BTW, I don't believe most Apple PSU's have bleeder resistors on the caps (no real need to).

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Last seen: 1 month 1 week ago
Joined: Nov 12 2017 - 18:34
Re: IIe won't reboot

I finished the machine for my friend's birthday and he's happy with having to wait 15-20 seconds after turning the machine off to turn it back on. I told him the PSU may be going and he'll just replace it with a modern one at some point.

Thanks for the suggestions.

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