[Techtoolslist] HP 1650A Logic Analyzer

[John Honniball]

Jose Luiz Martins wrote:

> The power source clicks and the voltages are not correct. 7V instead

> of 12V, 4,5V instead of 5V and oscillating.


Clicking is a sign of current overload. Oscillation is a sign
of too low capacitance, i.e. not enough smoothing.


> I have not experience in PS repair, but someone told me that the

> electrolytic capacitors may be dry due the time it was stored (as well

> as de condition, one it was in Rio de Janeiro, and at summer time, the

> room temperature may be more them 120F)


Yes, that's quite possible. May be best to see if any electrolytics
have begun to bulge on top. If so, replace then right away.


> Could someone confirm that please ?


Another possible failure is tantalum capacitors. They fail short
at any time, and will overload the supply. I had one fail today
in a Tek scope module (5A22N). It smoked a resistor, too. Worth
checking, if there are tantalums on the power supply rails on the
boards of the 1650A.

-- 
John Honniball