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Keithley 197 troubleshooting

Hi all, I have a disabled Keithley 197 DMM. This is an older model, but it has a nice GPIB interface, so I'd like to get it working.

When turned on, it displays the message "cErr". According to the manual

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keithley197.pdf) this means that there's a problem with the NVRAM that stores the calibration data. I've tried bypassing this error by pressing the buttons as recommended on page 5-9 of the manual, however the cErr reappears.

The NVRAM chip is a little 8-pin DIP chip apparently. I'm having trouble identifying it. It's labeled:

X2443P

8432ES

Anybody know what this chip is, or can give me any other advice in getting this DMM working? Thanks,

Dan

Reply to
Dan Lenski
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The X2443P is a Xicor NMOS nonvolatile static RAM, 16 bits X 16 words, tristate,

750ns, Vcc = 5V

I searched briefly for anything that would be a good sub for it, but came up empty. Maybe you can do better.

--
Dave M
MasonDG44 at comcast dot net  (Just substitute the appropriate characters in the 
address)

Life is like a roll of toilet paper; the closer to the end, the faster it goes.
Reply to
DaveM

I forgot to mention that the X2443 is a serial 16x16 RAM. I did happen to find one web site that lists the X2443 in stock

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but no price, so you're at their mercy.

Cheers!!

--
Dave M
MasonDG44 at comcast dot net  (Just substitute the appropriate characters in the
address)

> Life is like a roll of toilet paper; the closer to the end, the faster it 
> goes.
>
Reply to
DaveM

Thank you, Dave! Sounds like it's a pretty obsolete part :-) Maybe someone makes a pin-compatible serial RAM in a larger size?

I think I'll do the other tests on the device to make sure everything else is working, then try to track down this part.

By the way, how'd you find out what it is? Alldatasheet.com and Google weren't much help to me.

Dan

Reply to
Dan Lenski

I found it at

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That's the only datasheet web site that even came close, but still no complete datasheet; just a list of basic specs. Not even a pinout...

Cheers!!!

--
Dave M
MasonDG44 at comcast dot net  (Just substitute the appropriate characters in the 
address)

Life is like a roll of toilet paper; the closer to the end, the faster it goes.
Reply to
DaveM

basic

We scanned several Xicor data books for our datasheet site but didn't realize they were scanned at the wrong resolution. The books were sent for recycling before we realized. This is one of those scans which gives some detail on X2443.

It's almost unreadable but here it is anyhow.

formatting link
formatting link

Regards DatasheetArchive.com

Reply to
administrator

Thanks for the follow-up!!! Very kind of you to post those pages. Databooks going to a recycler!!!!???? ACKKKKKK!!!!!!!!!!!!!!!

--
Dave M
MasonDG44 at comcast dot net  (Just substitute the appropriate characters in the 
address)

Life is like a roll of toilet paper; the closer to the end, the faster it goes.
Reply to
DaveM

Perhaps it needs to be calibrated and the error will disappear.

Reply to
carneyke

Yeah, I've tried to go through the calibration procedure but it won't go into it... as soon as it begins it puts up the "cErr" message. I think this means the NVRAM is actually dead, not just blanked.

Dan

Reply to
Dan Lenski

Dan, I still think it needs calibration. Does the unit have a rear panel cal enable switch or an internal jumper for cal enable. You need a manual if you don't have one. Keithley website may have a downloadable version. When you power up and get the "cErr", press one of the soft keys (rel, db, sto or rcl). That will bypass the error and let it operate with a flashing "c" indicating cal constants lost. The manual i have indicates different cal procedures for the different firmware versions. You need a manual. BTW the soft keys (previously mentioned) need cleaning or they don't makle contact. Good Luck, Kevin

Reply to
carneyke

Kevin, thanks for the tips. I do have the manual, and have tried this. Unfortunately, when I press one of the soft keys it flashes all zeroes (like when just turned on), and then returns to the cErr message in about 0.5 seconds.

The manual doesn't say what to do in this case, although it says to try replacing the NVRAM IC if the cErr persists...

Dan

Reply to
Dan Lenski

Damn it's a good meter too, lots of digits. If you really need it, Keithley always provided good service at reasonable rates. I don't know if they will service that model. I have a Keithley 197 on my bench at work. I keep it for the min-max function to "trap" intermittent problems. Good Luck, Kevin

Reply to
carneyke

And, they do sell parts... Peter

Reply to
Peter Matler

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