resistors incorrect readings

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53peter
Posts: 1
Joined: Sun Jan 15, 2017 2:26 am

resistors incorrect readings

Post by 53peter »

Hi all,
Iv'e just put together the DSO Shell boards but when I check the resistors after soldering some seem to be incorrect. Here is what I am getting. Also can't get 0V on V1,2 and 3 here is what I am getting at the moment.
I looked at the troubleshooting section but the soldering seems to be OK.

Resistor values
R1 : 465K
R2 : 464K --- R2 seems way out should be 5.1M
R3 : 10.88K
R4 : 10.88K
R5 : 616
R6 : 618
R7 : 266
R8 : 140
R9 : 88
R10 : 30
R11 : 15
R12 : 15
R13 : 150
R14 : 1K
R15 : 674
R16 : 150
R26 : 120
R27 : 120

Voltage Check
Input : 9.10v
V+ : 8.12v
AV+ : 6.57v
V- : -6.53v
AV- : -5.31v
V1 : 3.1mv
V2 : 2.7mv
V3 : 5.9mv
V4 : 1.44v
V5 : -0.96
jye1
Posts: 1221
Joined: Wed Feb 20, 2013 4:58 pm

Re: resistors incorrect readings

Post by jye1 »

When measuring the resistors did you do that with your finger off the leads? If not human body resistance will make the reading smaller.

All the voltages look good. V1 - V3 can be considered 0V since there always some error due to the characteristic of the opamps.
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