Neil,
Do you have a scanned PDF of the manual for the 1350 DMM? If you do, could
you post it somewhere on the net? I recommend the sharing service at
http://www.c-c-i.com/exchange/. You don't need an account, no signup, no
credit card, etc. Totally free.
Just upload the file there and let us know that it's there.

A friend has one of those meters and needs the manual for it.

To your problem, what kind of voltage reference did you use to calibrate the
1350? If it wasn't accurate, then that means that the basic DC voltage
function of your 1350 is calibrated incorrectly, and all other functions
and ranges will read incorrectly. All functions and ranges are dependent on
the basic DC voltage calibration in the DMM being accurate.

Dave M


wrote:
Hello,

I have an old Data Precision (USA) 1350 "3 1/2" Digit LED type
Multimeter from the 70's era. It works great, except after
performing a calibration the low K ohm scales are displaying readings
are generally out by more then 5 percent.

So, the first step of calibration is adjusting the time base or
oscillator to 40 KHZ( +/- 200Hz) for the AD7107. The next step is the
Gain calibration by inputing a DC reference voltage of 1.900 volts,
and adjusting a pot to this voltage on the display. The last step is
balance, where a lead wire is tied back from the red banana jack to
pin 36 (Hi Ref) AD7107, and is adjusted to 50 millivolts (+/- 50mv)

The multimeter readings are very good, except for the Low resistance
scales.

Does anyone have any ideas on why?

Examples: 475 ohm 1% resistor it reads 430 ohms.
2K Ohm 1% resistor, it displays 1861 ohms

Thanks,
Neil