Another TEA (Test Equipment Arrival
):
My new dual input power meter arrived safe and sound!
As I wrote some weeks ago I just bought a HP 438A power meter "for parts" for less then $70 delivered.
Yesterday it was delivered and when I opened the double card board box I was really surprised because it was packed using those foam-filled plastic bags that fit around the packaged item as the foam expands. Very nice! The meter was very well padded on all sides and couldn't move a bit. I haven't seen any other ebay seller doing this so far. Not even the "professional" surplus sellers I came across so far. This surplus seller really did a professional job, even in packaging.
The auction pictures of the HP 438A showed the error message "No Channel A/Error 31" which just says that there's no sensor detected -what is normal when none is connected.
The front needs a bit of overall cleaning and a special treatment to get rid of some sticker residue:
As this is is a printed plastic sheet: what can I use for cleaning without damaging it?
The power supply section with the fan looks dirty with all the dust blown in by the fan, but basically no obvious failures:
The main processor board A3 isn't very exciting, it also needs cleaning and checking of the tantalum caps:
Oh, by the way: The battery cell on this board shows >3.2V and seems to be fairly "fresh".
The main input amplifier board A5 looks good so far:
But the input amplifier board A4 shows that it needs repair: several caps are bad, one is even corroded off the board on one side!
Interestingly this 438A basically works: Before I inspected the inside I did a quick test with an 8481 Sensor (-30dBm to +20dBm): Entering and saving of the cal factor as well as zeroing and calibrating worked fine.
I wonder how that is possible with that number of bad caps on the input amplifiers.
Anyway, I am happy that nothing blew up when I powered it up. Should have inspected the inside first.
Cleaning on either the outside and the inside and replacing the bad parts will give me a fully functioning dual port power meter, I think.