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Dmitry, It always puzzled me that the manual advised you to bypass the over-voltage protection shutdown in the situation of a potentially damaging over-voltage condition. Seems to me that is only

Hello, During a recent repair my 8662A went into shutdown due to the high input voltage at the linear regulator (A7A1) input. Service sheet 56 directs one to ground the collector of A7A1Q16 and then

Hi Stephen, do you still have the 5265A for sale? im in Australia, thanks Ben

Yes 8478B is a transfer power standard for 7mm connectors . It’s very stable , the matching is not the best but with a good VNA are used as transfer standard on most national lab. The efficiency are

If it was used in a standards lab it more than likely has option H01 which guarantees a VSWR < 1.05 at 50MHz , usually either the 8478B-H01 or 478A-H75 or H76 are used for the power level accuracy

This one came from an auction at McDonnell Douglas plant in St. Louis - It was in their standards lab - a long time ago. AFIK the "B" version is the only one available from HP Cheers! Quoting Lothar

I haven’t seen any 8478B used as transfer standard , we used them with some special option to calibrate the 50MHz reference on 43x series meters , for sensor calibration we used a weinschel system2

Could you have used a single point frequency measurement n the VNA? I know the 8510 will do that. But I am sure the experience was educational - thanks for the education - it would have taken me a bit

I actually have one of these and treat it VERY carefully whenever I use it - which is infrequently Cheers! Bruce Quoting Lothar baier <Lothar@...>:

I certainly would call $14K outrageously expensive. Cheers! Bruce Quoting Lothar baier <Lothar@...>:

Hi, Following the comments by G Edmonds in this thread he recommended loading the PSU -40V rail more heavily to resolve the PSU shutdown error occurring immediately after start-up. Pleased to say that

They certainly can be, and certainly are, used as transfer standards. Further, NIST will calibrate them. (they won't calibrate any other type of RF power sensor, unless something has changed very

i wouldnt call it a transfer standard , weinschel/tegam makes sensors that use the same principle that are heated (1109/1111)? that are used with system 2 units to calibrate sensors , they are

first of you have to consider that the 8478B just as the older 478 series requires a lot of manual assembly steps as it was designed in a time when there was no such thing as surface mount parts or

It is directed at a captive audience. This piece is used as the transfer standard for making power measurement calibrations and is required for certain procedures. If you want to play in a certain

Hello, There is one more issue to consider. Long lines give delays. Once I wanted to measure the loss of a coaxial cable on a vna. Was an interesting experience: no response. Until I realized the

Dan - Excellent ob - maybe you should publish the Gerber Files for the new motherboard ? Cheers! Bruce Quoting "Daniel Nelson via groups.io" <djn@...>:

OMG, who would have thought......................

For those of you who possess the older (hopefully working and accurate) 478A coaxial thermistor mount it might come as a surprise that the price of the present replacement – the Keysight 8478B mount

Tony: I also replaced the power supply with a group of Meanwell Supplies. Wrote it up. In the files section under: HP 8662A_8663A Pwr Supply Changeout.pdf (