[Test-Equipment] HP1740A Beam problem

[David DiGiacomo]

>Wondering if there's any 1740A expertise out there.  At first I thought I
>had a blanking problem because the retrace was visable, but then the problem
>worsened when the beam intensity became so high as to probably be damaging
>to the phosphor.  Intensity control has a minimum effect, focus works.
>First thinking it was a gating problem, I substituted the A3 PCB with one
>from another unit I have...no change.  All DCvoltages are within spec.

This kind of scope problem is usually due to a diode failure in the CRT
grid DC restore circuit.  In the 1740A, this is CR3-CR6 on the A15 HVPS
board.  If the diodes are OK, check the capacitors.

David DiGiacomo