[time-nuts] HP 53131A - reset security code

Bob Camp kb8tq at n1k.org
Wed Dec 24 02:04:54 UTC 2014


Hi

I believe you will find that when you do the cal it will ask you:

Security yes/no?

(answer yes)

Enter your key?

(enter a random number)

Enter your key again?

(re-enter random number)

Security enabled. 

No, that is not a direct quote of what happens. It’s purely a guess based on the process used on other gizmos.

Yes, there pretty much *has* to be a “wipe the memory” command somewhere. I would not find it surprising if the answer involves a trip back to HP for service. I doubt they will do much on a 53131 now that they have killed off support. 

What to do:

1) Try the usual guesses 123, 1234 etc.

2) Try the end of the serial number on the counter

3) Try 53131

Again - only a guess. It does fit the given information - no magic code listed anywhere / Magic code does exist. 

Bob

> On Dec 23, 2014, at 8:34 PM, Tom Van Baak <tvb at LeapSecond.com> wrote:
> 
> Ulli,
> 
> You're right. The actual procedure is not described in the manual(s):
> 
> Operating Guide 
> http://cp.literature.agilent.com/litweb/pdf/53131-90055.pdf
> 
> Programming Guide
> http://cp.literature.agilent.com/litweb/pdf/53131-90044.pdf
> 
> Assembly-Level Service Guide
> http://cp.literature.agilent.com/litweb/pdf/53131-90039.pdf
> 
> Component Level Information
> http://literature.cdn.keysight.com/litweb/pdf/5989-6308EN.pdf
> 
> But I have three ides for you.
> 
> 1) The last PDF shows U14 is AT28C64B (www.atmel.com/Images/doc0001h.pdf) so if all else fails, you can use a logic analyzer on the address(13) / data(8) pins and see what's in the EEPROM. With some experimentation by you or others on the list we can locate the calibration security. This has the advantage of getting the existing code, without having to clear the entire EEPROM. Some other HP bench instruments use an onboard jumper to override the cal lock, but I don't see that on a 53131A. So perhaps there is a magic front panel sequence or SCPI command to clear NVRAM.
> 
> 2) Search for 53132 at http://www.ko4bb.com/manuals/index.php and grab the 4 EPROM's. Do a 16-bit merge of U8/U10 and U9/U11 and look for ascii strings. All the SCPI words are in there and not all are documented. For example near the words SYST and CODE and SEC[URITY] is ALL and DEL[ETE]. Probably safe to try. Lots of interesting output strings, both for GPIB and for internal debugging. Even the words EEPROM CLEAR, along with "Oooh! That tickles. I don't know that vector." which we also see in the Z3801A, etc.
> 
> There's also a hidden "SERVICE MENU", complete with Easter egg:
>   MLB TEAM KRISTI BITTNER, LEE COSART, ERIC INGMAN, GARY JACOBSEN, SOOK-LAN LOH, ROB MITCHELL, ROBIN POSKUS, DON SCHREMP, DANA STOFFERS, AND GEORGE TSAI
>  SOFTWARE L. COSART G. JACOBSEN S. LOH R. POSKUS D. STOFFERS
>  HARDWARE K. BITTNER E. INGMAN D. SCHREMP
>  MECHANICAL G. TSAI
>  PROJECT MGR R. MITCHELL
>  BASEHIT -- 53132
> 
> 3) There's a pForth interpreter in this instrument too. Note pr_eeprom_debug and wr_eeprom.
> 
> That's enough hints to keep someone on the list (Magnus?) busy over Christmas. Of course, if anyone knows the "confidential procedure", they should just let us know...
> 
> Thanks,
> /tvb
> 
> ----- Original Message ----- 
> From: "Mod Mix" <modmix at t-online.de>
> To: <time-nuts at febo.com>
> Sent: Tuesday, December 23, 2014 3:04 PM
> Subject: [time-nuts] HP 53131A - reset security code
> 
> 
>> Hi,
>> 
>> I got a used HP 53131A to which I added a stability option board (ocxo).
>> In order to calibrate the device, a security code is needed - I don't 
>> know it. The seller doesn't know it. It's not the facorty set code.
>> Advice on how the reset the non-volatile memory would be much appreciated.
>> 
>> Thank you very much & happy Christmas
>> 
>> Ulli
>> 
>> From the 53131A service guide:
>> A calibration security code feature allows you to enter a security code 
>> (electronic key) to prevent accidental or unauthorized calibrations of 
>> the Counter. The security code is set to 53131 or 53132 (corresponding 
>> to the model) when the Counter is shipped from the factory.
>> If you forget your security code, you can reset the security code to the
>> model-number default by resetting all of the non-volatile memory to a 
>> default state (Contact Agilent Technologies for this confidential 
>> procedure).
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