Refresh on diode test

[angka]

Have this situation where diode (forward bias) check requirement is 515(+/-50)mV .
Using diode test feature of a DMM, can only achieve 600(+/-5)mV.
DMM : 34401A & FLUKE 87
To my knowledge, for silicon diode is approximately 0. 7V (0. 3V for germanium).
Does that mean the diode is defective ?
DMM not appropiate or inaccurate ?
Did I missed out anything ?

Appreciate any feedback,
angka

[RFCAL]

the diode is not defective.It means that particular diode fires with less than normal (0.7V) voltage.The 0.7Volts is an approximation anyway.

[angka]

the diode is not defective. It means that particular diode fires with less than normal (0. 7V) voltage. The 0. 7Volts is an approximation anyway.

But the test result must be 0. 515V (+/-0. 050V).
Any suggestions?

[calibr8tor]

There is a good explanation on diode test at this website.        See if it helps.   

www. allaboutcircuits. com/vol_3/chpt_3/2. html

[RFCAL]

any bias resistors involved in the circuit? This happened once to me--manufacturers were switched on a particular part number.This lead to the diode firing outside the knee region due to the bias resistors involved.We ended up redisigning the bias resistors.

[angka]

any bias resistors involved in the circuit?
unfortunately, no bias resistors involved.  The 2 test probes are directly across the diode.
Maybe I should check if there's any amendment to the test procedures.
The requirement of 0.  515V (+/-0.  050V) is a bit odd to me.  Is there such a thing like a custom design diode ?