SMR-4 mkII power supply testing


I have a little problem with my power supply test on the SMR-4 card
I have a perfect 5.00V on the red point but a 0V on the green …

Is there any process to isolate the problem ?


What is the voltage of pin 5 of the LT1054? Is this chip correctly oriented?

See this

I Don’t know witch is the pin 5 but lower/left :-1.47V and lower/right : 14V

With the notch pointing upwards you count anti-clockwise. 1-8.

so the pin 5 is: -1.47V
(thanks for the info :wink: )

Is your power supply delivering an AC or DC supply? What is the voltage at pin 8?

@pichenettes: I think that’s the 14-volt one, which makes it slightly higher than expected, although there’s no load on the PSU as yet.


yes the pin 8 is 14V … and when I test my power supply i have 18.6V (and my switch is on the 9V …)
I think the problem came from here …
Do you think I kill some components with that S****** ?
And do you have product recommandation for take a real one? :slight_smile:

thanks all for the support (and sorry for my bad french/english speak)

You might have killed the LT1054 with the very high voltage at the output of your power supply. Try changing this part and use a power supply with a more reasonable output (7.5V to 9V). Here are some recommendations.

ok i’ll buy a new LT1054 and a good power supply.
Thanks for the support !