I have recapped many a board that would boot, but would not load an operating system.
As a matter of course, I check the ESR and Capacitance of the caps I remove from the board. In most cases, they read within spec on the ESR meter and the capacitance meter.
Yet when I replace all the caps, install the board and reboot, the operating system loads properly.
I recently had a box I recapped last year, worked fine, then put it away for 6 months. On attempting to use the machine again, I found that would beep twice rapidly, start up, but with no video. The secret was to press the reset button, then the machine would boot immediately.
This got me thinking that the reason so many of these old boards boot, but won't load, is that their capacitors need to be reformed.
The capacitors are fine, but in a "deformed" state.
Recapping replaces these "deformed" caps and the board lives again.
The only reforming schematics I see are those where the cap is out of circuit, and the max rated voltage is applied to reform the cap.
Is there a way to cause the caps to be reformed or pre-formed by applying some load, so that recapping might be avoided?
Any thoughts?
As a matter of course, I check the ESR and Capacitance of the caps I remove from the board. In most cases, they read within spec on the ESR meter and the capacitance meter.
Yet when I replace all the caps, install the board and reboot, the operating system loads properly.
I recently had a box I recapped last year, worked fine, then put it away for 6 months. On attempting to use the machine again, I found that would beep twice rapidly, start up, but with no video. The secret was to press the reset button, then the machine would boot immediately.
This got me thinking that the reason so many of these old boards boot, but won't load, is that their capacitors need to be reformed.
The capacitors are fine, but in a "deformed" state.
Recapping replaces these "deformed" caps and the board lives again.
The only reforming schematics I see are those where the cap is out of circuit, and the max rated voltage is applied to reform the cap.
Is there a way to cause the caps to be reformed or pre-formed by applying some load, so that recapping might be avoided?
Any thoughts?
