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DS question for the day
Posted: 08 Apr 2010, 16:30
by CRBMoA
Dipshit question:
Bought a partially popped D&R Comp board. Checked and confirmed values on all the installed bits. Finished it and tried a 3080 I had in my parts bin. The board was built with a socket.
I don't have confidence in the chip (it is a left over from another build, and it never worked in that build) but I don't have another to try on hand.
Are there any common ICs that I could sub in the circuit just to get some noise and confirm the rest of the build?
Thanks!
Re: DS question for the day
Posted: 08 Apr 2010, 18:53
by mictester
CRBMoA wrote:Dipshit question:
Bought a partially popped D&R Comp board. Checked and confirmed values on all the installed bits. Finished it and tried a 3080 I had in my parts bin. The board was built with a socket.
I don't have confidence in the chip (it is a left over from another build, and it never worked in that build) but I don't have another to try on hand.
Are there any common ICs that I could sub in the circuit just to get some noise and confirm the rest of the build?
Thanks!
Not really. You could connect up a 741, but leave pin 5 bent out of the socket, which should give you some noise out, but you really need a 3080!
Re: DS question for the day
Posted: 08 Apr 2010, 19:04
by CRBMoA
Thank You very much!
Re: DS question for the day
Posted: 13 Apr 2010, 15:45
by CRBMoA
I have some 3080s on the way, but I am a DIYer, so I can't help but fiddle with it while I wait.
I measured voltages with only the +9v lead running to the board (no ground wire) and got:\
1 = 0.0
2 = 8.78
3 = 8.80
4 = 8.90
5 = 8.46
6 = 8.79
7 = 8.95
8 = 0.0
One and eight will creep up in mV on ocassion, which I attribute to 'Hell if I know?'.
I hooked up the ground wire, repeated the measuring, and got basically identical readings.
I also checked the IC, out of the circuit, with my continuity tester, got no beeps.
Checked the socket on the board. I have continuity on all socket contacts up to the first passive component, and I have no solder bridges or shorts that I can see.
Before I finished populating the board, I checked all of the components against the BOM and the schem. I could check a fourth time, but I believe them to be correct.
Does this mean anything?
Re: DS question for the day
Posted: 13 Apr 2010, 18:49
by mictester
CRBMoA wrote:I have some 3080s on the way, but I am a DIYer, so I can't help but fiddle with it while I wait.
I measured voltages with only the +9v lead running to the board (no ground wire) and got:\
1 = 0.0
2 = 8.78
3 = 8.80
4 = 8.90
5 = 8.46
6 = 8.79
7 = 8.95
8 = 0.0
One and eight will creep up in mV on occasion, which I attribute to 'Hell if I know?'.
I hooked up the ground wire, repeated the measuring, and got basically identical readings.
I also checked the IC, out of the circuit, with my continuity tester, got no beeps.
Checked the socket on the board. I have continuity on all socket contacts up to the first passive component, and I have no solder bridges or shorts that I can see.
Before I finished populating the board, I checked all of the components against the BOM and the schem. I could check a fourth time, but I believe them to be correct.
Does this mean anything?
Take the IC out of the socket again, and check the 1/2 rail bias circuit!