The HP 8600A Problem has Returned

[Chris K]

Originally Posted by Penthode

Curious that you indicated the voltage popped back to 5.0 v when you cooled the 723.

The current out is .43/.56 = about 0.8 amps. Which appears normal. Is there no way to conveniently measure the voltages around the 723?

Freezing the 723, the original 723, was what led me to replace it. I thought I had identified the issue...a faulty regulator. The unit ran fine for several weeks. Then the drop in output from 5.0V to 4.6V returned. The unit will read and display frequencies until the voltage goes down to about 4.8V DC. Lower than that starts the symptom.

[Chris K]

Voltages on the 723 from the back of the circuit numbered clockwise. The tab on the can is pin 7.



Working normally

[Kevin Kuehn]

It looks to me like the tab should be pin 10, because pins 7 and 8 should have the unregulated DC input on them.