Hello does anyone out there know if you can use an HP model 428A probe with a 428B meter? They apear to have the same physical interface.

Thanks,
Al

:Hello does anyone out there know if you can use an HP model 428A probe with a 428B meter? They apear to have the same physical interface.
:
:
:Thanks,
:Al
Hello Al, yes you can do. The difference between the A and B model is only in the chopper unit of the meter.

Lutz

::Hello does anyone out there know if you can use an HP model 428A probe with a 428B meter? They apear to have the same physical interface.
::
::
::Thanks,
::Al
:Hello Al, yes you can do. The difference between the A and B model is only in the chopper unit of the meter.
Lutz Volk *Nachrichtentechnik*
Schwarzdornweg 6
D- 41189 Mönchengladbach
:
:Lutz

:Hello does anyone out there know if you can use an HP model 428A probe with a 428B meter? They apear to have the same physical interface.
:
:
:Thanks,
:Al

::Hello does anyone out there know if you can use an HP model 428A probe with a 428B meter? They apear to have the same physical interface.
::
::
::Thanks,
::Al

Hi Al,

THe 428A probe is identical to the one used in the 428B. The early HP meter was the model 428A (1958-1961) and the probe nomenclature stayed the same from 1958 through the mid 1970s. If you bought a 428B in 1963 you received a probe marked 428A. Same probe from 1958 through 1988 or so when they stopped making the instrument. The B meter extended the range to 10A and used a solid-state current feedback amp. Lutz's reference to the chopper changing is incorrect - both A and B units utilized vacuum tubes for probe drive and demodulation. The "chopper" was a vacuum tube based switched capacitor arrangement utilizing twin center tapped transformers. An innovative design by Chuck Forge, way ahead of its time. -DS