08 February 2022, 16:19 | #1 |
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a500+ 5v to ground
i have a 500+ and if i test between 5v and gnd i get a short and the test metre buzzes.
is this normal for the 500+ or should the 5v be totally separate like the 12v and gnd. could someone with a fully working system check if they have continuity between 5v and gnd if i check the floppy power 5v to gnd buzz if i check the electrolytic caps i get the same. im trying to fix this machine as i have green screen or with diagrom green/red screen which is chip mem, am i going down a rabbit hole for nothing |
08 February 2022, 18:57 | #2 |
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That usually means there's a short to ground. In fact if you use voltage setting then it should read 0v...
Any host of components can cause this including failed resistors or caps. You could do simple test over resistors and capacitors 1st to confirm there is not continuity. If there is... that component has shorted. |
08 February 2022, 20:34 | #3 |
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There will always be a connection, but it should not be low resistance.
If there was a short, you would not even get any color screen... the power supply would just crowbar and shut down. |
08 February 2022, 23:23 | #4 |
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buzzer (continuity tester works on lowest ohmic range - for example 200 ohms) if total impedance will be less than for example 10 ohms then i assume it will beep - this of course depends how multimeter is designed, also remember than capacitors sink current unless they are charged - large electrolytic capacitors may sink substantial current before they fully charged - this look like shortcut from multimeter perspective.
And of course if Amiga sink during normal operation something like 2A on 5V line then it looks like 2.5 ohm resistor from power supply perspective... So it may buzz and this doesn't mean that something is broken. |
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