I have previously prototyped a circuit board containing a mixture of surface mount chips and through-hole resistors/caps. I hand-soldered this original board and it experiences minimal voltage drift.
In order to speed things up, I started using reflow soldering for the surface mount components and doing the through-hole components by hand. I did not clean the boards after the reflow soldering, although I did use a stencil to apply the solder paste. The only difference between the original board and the reflow boards is the addition of a final gain stage on the pcb.
This new board experiences a large amount of signal drift while it is powered on. I have tried cooling the board while it is powered on, and this appears to reduce the drift, however, the new board does not heat up anymore than the older one. When I say there is a fair amount of drift, I mean that I can physically see the signal rising to rail on my o-scope. (~300 mV increase over a few minutes on a signal that is around 1.5Vpp).
Could this signal drift be from moisture in the flux? The through-hole components are rather tightly packed on the board, and the main area where the drift is present is on a high - order filter (with G=10). The filter chip has a pitch of 0.65. I can't really see what else the issue could be.
Any help would be much appreciated.
In order to speed things up, I started using reflow soldering for the surface mount components and doing the through-hole components by hand. I did not clean the boards after the reflow soldering, although I did use a stencil to apply the solder paste. The only difference between the original board and the reflow boards is the addition of a final gain stage on the pcb.
This new board experiences a large amount of signal drift while it is powered on. I have tried cooling the board while it is powered on, and this appears to reduce the drift, however, the new board does not heat up anymore than the older one. When I say there is a fair amount of drift, I mean that I can physically see the signal rising to rail on my o-scope. (~300 mV increase over a few minutes on a signal that is around 1.5Vpp).
Could this signal drift be from moisture in the flux? The through-hole components are rather tightly packed on the board, and the main area where the drift is present is on a high - order filter (with G=10). The filter chip has a pitch of 0.65. I can't really see what else the issue could be.
Any help would be much appreciated.