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Electronics => Repair => Topic started by: essem54 on July 15, 2019, 09:35:15 am

Title: Need HP 437B front connector pinout.
Post by: essem54 on July 15, 2019, 09:35:15 am

Hi.

I need the pinout for the 12 pin front connector power sensor for my HP 437B, which wire color to which pin (A,B,C,D,E,F,G,H,J,K,L,M).

Thanks in forecast for any valuable informations.

Regards essem54.

Title: Re: Need HP 437B front connector pinout.
Post by: rf+tech on July 15, 2019, 10:38:45 pm

Hello essem54,

The connections are likely to be the same as on the HP 435.

The HP 435 service manual can be downloaded from Electrotanya:

https://elektrotanya.com/hp-435b_00435-90040_power_meter_sm.pdf/download.html (https://elektrotanya.com/hp-435b_00435-90040_power_meter_sm.pdf/download.html)

The attached file is page 83, from this manual, and shows the wire numbers. The wire numbers follow the resistor color code, such that wire 904 will be white, black, yellow.

Best regards,

RF+ Tech

Title: Re: Need HP 437B front connector pinout.
Post by: essem54 on July 16, 2019, 08:21:33 am

Hi.
Thanks for your research but unfortunately seems HP doesn't keep the same color code from 435 to 437B.
All wire are single color and I have a grey wire and a violet wire, this two wire color are not used in the 435 (to be seen in attachement).

Need the same doc but for the 473B.

But tnx again for your help and regards.

essem54.

Title: Re: Need HP 437B front connector pinout.
Post by: rf+tech on July 16, 2019, 09:21:37 pm

As far as I know, both power meters use the same series of sensors. At the meter end, only seven conductors are required.

The "extra" wires are likely paralleled and used as guard connections, as shown in the 435 schematic.

Studying some sensor schematics may provide more details.

RF+ Tech

Title: Re: Need HP 437B front connector pinout.
Post by: essem54 on July 17, 2019, 07:34:12 am

Tnx for additional info and advice, i will carefully open the sensor and hope to solve my problem, just found that there are at least 2 differents power sensor PCB and that the white and yellow wire are inverted depending on the PCB used, funny HP.

Not too far away from buying a Siglent SSA 3021X to make my RF power measurement.

Regards essem.

Title: Re: Need HP 437B front connector pinout.
Post by: MarkL on July 17, 2019, 10:13:07 pm

Sensor schematic in this doc (page 1-15):

  http://literature.cdn.keysight.com/litweb/pdf/08481-90049.pdf (http://literature.cdn.keysight.com/litweb/pdf/08481-90049.pdf)

Tony_G has done a teardown of a 437B with high res photos here:

  https://www.eevblog.com/forum/testgear/hp-43x-series-power-meters-a-progression-teardown/msg892876/#msg892876 (https://www.eevblog.com/forum/testgear/hp-43x-series-power-meters-a-progression-teardown/msg892876/#msg892876)

But it unfortunately doesn't show enough detail on J4 to the front panel.  Maybe you could ask him to send you a more detailed photo of that area.

The document above describes the sensor disassembly procedure, but I wouldn't open it unless absolutely necessary.

It also looks like there are printed 437B service manuals on ebay, but verify it has the schematic before purchasing.

Title: Re: Need HP 437B front connector pinout.
Post by: essem54 on July 18, 2019, 07:47:37 pm

Thanks for informations.

I send PM to Tony_G, wait and see.
No schematic within the original service manual, I already own.

Thanks again:

essem54