Products > Test Equipment
Advantest R4131 Series Spectrum Analyser
(1/1)
Greenkit:
My R4131c has lost its baseline trace i.e.: no display of 'grass' or input signals. Numerical screen information of frequency tuned, span, etc is present and can be changed from the keys as normal. Sometimes the baseline appears at switch-on from cold, then freezes within a few seconds; in this condition the marker can be turned on and tuned along the baseline. Investigations so far indicate that this coincides with the 10V and -13.5V lines starting up properly on the YTO control/IF board: these lines require a full +15V from the PSU, a Fuji PTA 465, to get them going. There are no sub-rails present with a warm start.

In my case both the + and -15V lines are low, at around 11.5V. The Fuji supply also generates +5.2V and +12V rails, which are within 0.1V of nominal. All rails are reasonably clean on a 'scope.

Does anyone have a schematic of the PTA 465? There's nothing in the Advantest Operations manual. At 30 years old its electrolytics have probably seen better days, but I'm curious to know if this is a common fault in this series of SAs: restoring 'solid' supply rails may help, or am I looking at something worse / CPU related?

Any experience gratefully received: thanks for taking time to read...



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