Author Topic: Looking for Keithley 177 DMM Schematic.  (Read 6375 times)

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Offline Jay_Diddy_B

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Looking for Keithley 177 DMM Schematic.
« on: February 11, 2014, 09:57:46 AM »
Hi group,

I am looking for a nice, readable, schematic for the Keithley 177 DMM.

I have found the one on the Keithley website that is complete, but barely readable.

I found another one which was very readable, but only half the schematic.

I have one of these for repair.

Many thanks !!

Jay_Diddy_B

 

Offline wiss

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Re: Looking for Keithley 177 DMM Schematic.
« Reply #1 on: February 11, 2014, 10:06:06 AM »
Register at keithley.com and download it from there?
 

Offline Jay_Diddy_B

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Re: Looking for Keithley 177 DMM Schematic.
« Reply #2 on: February 11, 2014, 11:11:25 AM »
Wiss,

Thank you for the reply. I have registered with Keithley and downloaded the manual. This is where I got the one with unreadable schematics. The file size is 2740kB (according to Windows).

Here is a sample of the schematic:



Thanks,

Jay_Diddy_B
 

Offline wiss

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Re: Looking for Keithley 177 DMM Schematic.
« Reply #3 on: February 11, 2014, 12:02:18 PM »
Sorry, a bit quick to reply...
You only need the scematics? I can see if there are any at work...
 

Offline wiss

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Re: Looking for Keithley 177 DMM Schematic.
« Reply #4 on: February 11, 2014, 07:58:18 PM »
I did find a 177 so there is a reasonably high probability that the manual is somewhere in the building, the person responsible for it is not here until Thursday, I`ll ask then.
 

Offline wiss

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Re: Looking for Keithley 177 DMM Schematic.
« Reply #5 on: February 13, 2014, 08:07:56 PM »
No luck :(
It might be somewhere but it will take a large amount of time to locate it...
 

Offline Jay_Diddy_B

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Re: Looking for Keithley 177 DMM Schematic.
« Reply #6 on: February 14, 2014, 12:11:39 AM »
Wiss,

Thank you very much for your efforts.

I will try and fix the meter with the schematic in the manual that I have.

Jay_Diddy_B
 

Offline MBY

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Re: Looking for Keithley 177 DMM Schematic.
« Reply #7 on: February 18, 2014, 01:32:45 AM »
I had exactly the same problem trying to fix my Keithley 177 and building a RS232 interface for it. I ended up with trying to recreate the schematics and after many hours I got what I suspect is a accurate redraw.

Hope it helps! I cannot guarantee that every connection I've drawn is correct, but I succeeded both in fixing my DMM and to create a RS232-interface using a AVR.

I hope its not the power supply that is the problem in your case. I redraw almost all BUT the power supply, since it worked ok for me.



« Last Edit: February 18, 2014, 01:36:43 AM by MBY »
 

Offline Jay_Diddy_B

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Re: Looking for Keithley 177 DMM Schematic.
« Reply #8 on: February 18, 2014, 03:01:58 AM »
MBY,

Thank you for providing the re-touched schematic. I found a manual here:

http://exodus.poly.edu/~kurt/manuals/manuals/Keithley/KEI%20177%20Instruction.pdf

This manual is little cleaner than the manual from the Keithley website. Unfortunately it contains only half of the schematic. It does include the power supply section. I have attached the pdf with the power supply section.

I have three of these meters that I got in a package deal with a 175, 197 and three 177. None of the working.

All of them, except one of the 177 are repaired.

The two 177 had dirty switches, I cleaned the switches and then cleaned the board. The remaining 177 has a bad ICL71C03, the main chip.

Thank you again!!

Regards,

Jay_Diddy_B

 

Offline lowimpedance

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Re: Looking for Keithley 177 DMM Schematic.
« Reply #9 on: February 18, 2014, 01:52:38 PM »
Just to note that the RACAL DANA 4003 DMM is a rebadged Keithley 177.
On ebay there is a seller 'teoulet' (Tucker electronics) selling manuals and they have currently a listing for the 4003 manual, which in the photo is the main schematic and P/S schematic.
They are actually quite readable so you can "re touch" your crummy copy if any part of it is not readable!!.
Look for 'DANA manual 4003 '!. and see what I mean.

I have a 4003 but alas I do not have the handbook, and also have to get by with the awful copy as well.
You call that current ?.......
I'll show you current !
 the odd multimeter or 2 or 3 or 4...or........never mind
 

Offline Jay_Diddy_B

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Re: Looking for Keithley 177 DMM Schematic.
« Reply #10 on: February 18, 2014, 02:20:36 PM »
Hi,
Here is the schematic picture from the teoutlet listing.


Regards,

Jay_Diddy_B
 


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