Re: Checking X/Lisa Voltages

From: James MacPhail <gg__at_email.domain.hidden>
Date: Mon, 08 May 2006 14:59:37 -0700

>As I'm new to a voltmeter, I'm confused as to what to ground to when
>I'm checking these items.
>The C21 gave me the correct reading when I grounded to the case.
>The rest are way off using this method. Is my power supply suspect or
>my voltmeter skills ?

I would guess that the "way off" readings were due to a poor connection.

The chassis is connected to digital ground inside the power supply, but there are a couple of problems with using it to measure voltages accurately, most notably that it is not necessarily at exactly the same ground potential as the circuitry.

To make precise measurements, pick a ground on the circuit board itself. One near the source of power (the card edge) would be the best choice, as farther away may read at a slightly different potential.

I think a suitable location is the negative side of capacitor C47 or C50 on the I/O board.

HTH, James

--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "LisaList" group. To post to this group, send email to lisalist_at_email.domain.hidden To unsubscribe from this group, send email to lisalist-unsubscribe_at_email.domain.hidden For more options, visit this group at -~----------~----~----~----~------~----~------~--~--- Received on 2006-05-08 15:01:37

This archive was generated by hypermail 2.4.0 : 2020-01-13 12:15:20 EST