how to test my c64 PSU?

[13rian]

I have 2 different PSU's from c64s. Both say on the brick that they provide 9VAC and 5VDC. I salvaged the connector from a c64 so I plugged each one in and tried testing the voltages to be sure they were functioning. My results were not what I expected.

First PSU I measured 0.32 V on outer pins (should be 9?)

and 0 V where there should be 5 V.

Second PSU I measured 10.7 V on outer pins

and again 0 V where there should be 5 V.

I'm sure I am doing something wrong, the second PSU was powering a C=64 running Prophet64 as recently as last week.

I assume that to test AC I set the meter to the wavy line (~) and to test DC I set it to the 'solid-line-over-the-dotted-line'. Am I doing something obviously wrong?

Thanks.

- b

[Therezin]

The 10.7V I think should be ok, as long as you were testing without anything connected to the PSU - it will deliver a slightly higher voltage when there's no load on it. I think mine puts out about 9.8v or thereabouts. As for the 5VDC, this strikes me as very odd. You say the PSU was powering a C64 with no errors, so it must be working - but for that it should be giving 5VDC on the pins. I have to admit I'm stumped by this, anyone else come across it?

[13rian]

i should point out that this is most likely my error. i don't really know what i'm doing, but i have tried my best and can't figure out what's going on. i know i am testing the right pins because one of my PSUs only has the four pins, so i use that as my guide. i am NOT so sure that i am using the meter properly, but i don't see how else it would be done. sorry for the lame question, but i'm afraid it won't be my last :)

- b