At a recent hamfest I purchased a HP 403 DB meter.On all ranges the meter needle remains to full scale.The batteries are missing. Can someone tell me the battery voltage? Any suggestions as to why the meter is at full scale? Has anyone a schematic of this unit? I have checked esr of cap as well as transistors.I would appreciate any comments.Please make comments in news group or at snipped-for-privacy@ncf.ca. Many thanks herbert
First of all, it is a RMS AC voltmeter that is also calibrated in dB, not DB. It has ranges from .001 VAC to 300 VAC full scale, or -60 dB to
+50 dB. A lot of these types of meters require the batteries to be installed for the power supply to operate properly.is a "Buy it now" listing for the original manual. The seller might tell you what you want to know, or you can just buy the manual for about $22, including shipping. Then you will not only have a schematic, but the calibration data, too.
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