Keithley 2110 DMM - Error codes 603 and 607

[cio74]

Hello,

I have an issue with this Keighley meter, it does not pass self test and also seems not to care if the leads are attached and connected to anything, very little difference to the actual readings.

Test  Error
1. Err 603
2. Err 607

I have found this manual with codes http://instrumentationlab.berkeley.edu/sites/default/files/BSC01/Keithley-DMM_2110.pdf

page 180

603 Front-End MCU does not respond  The main CPU U1601 attempts to establish serial communications with the front-end processor U2001. Communication must function in both directions for this test to pass.
607 Buffer1 offset out of range  This procedure is to test the offset of buffer U507. The result is checked against a limit of 0 ± 0.1 mV

Here is a video of the unit with no leads attached and a jumpy display

Any idea what could have caused it? It is basically new, just opened although calibration back in 2013 and just shelved since then.

Thanks.

Cio

[cio74]

no reply, is it really a lost cause?...

[Nuno_pt]

Without an schematic of the unit, I couldn't find any on Google it's difficult to know the path to follow.
You could try to buy a service manual for the 2110 with the schematic of the DMM, and follow the path from U1601 to U2001 to see if there is any blow up part, or voltages not present.
Since U1601 is trying to establish two way comm with U2001, something must be failing along this path.

And the 607 can be appearing because of the 603.

Without schematic will be reverse engineering, following the path.

[cio74]

I don't know where to buy the service manual from.

I had the cover removed in a hope it may be some sort of lose connector or obvious defect but everything looks untouched.

[Mickle T.]

Keithley 2110 (Picotest M3510A) is based on the Keithley 2000 schematics.

[Nuno_pt]

If the 2110 is base on the 2000, the schematic of the 2000 is available on xdevs.com, TiN website, you could check there and try to see if you can follow the path.

I see a lot resemblances in there with my 2000.