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HP 8935 has false alarm for overvoltage duplex out


 

I get the duplex overvoltage message with the alarm sound which drives me nuts.
I am not even using the duplex out!? I mostly use RF I/O for my application. I tried measurement reset, but it continues with the alarm and message with no relief .
Is there a way to shut off the alarm?
I suppose this problem is telling me the power supply needs attention or something.

The test set seems to work otherwise.

Any help or insights would be greatly appreciated.

thanks,
Jim


 

Jim, duplex alarm is generally the 2 diodes right at the duplex output (in the input module).? Are leaky/open.

Rick

On May 3, 2024 2:14 PM, "J Mcvey wrote:

I get the duplex overvoltage message with the alarm sound which drives me nuts.


 

What kind of diodes are they?
I tried putting a load on the duplex port, thinking that might make it happy, but unfortunately it didn't help.


 

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The Diodes (2) to detect duplex port power were HSMS-2800-TR1 but are no longer available. The replacement is: BAS70-05?? the Mouser elect part is: 771-BAS70-05-T/R Good luck...Rick

_._,_._,_


 

On Mon, May 6, 2024 at 11:07 AM, rab@... wrote:
BAS70-05?
Thansk you very much. I'll get some before I open the beast.


 

opened the I/O module on the underside next to the I/O panel.
What are the silk screen number (s) for the detection? diodes?
I see some of tht SOT23 packages labeled CR1 to 4 and cr200 and cr201.
I sure wish schematics were available for this thing!