NAOJ GW Elog Logbook 3.2
Yuhang, Eleonora
On Tue evening 9/06 we found out that some of the ADC channel were not working fine and one of the two power supplies was delivering the maximum current (3 A) and the saturation led was on.
I switched it off and on but after ~30 min it stated to saturated again. A strong smell of overheated plastic was present around the ADC/DAC modules. I switched it off for the night.
Yesterday after confirming that DACs were working fine we check the ADC channels one by one. Here what we found:
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 |
| no sign | no sign | no sign | strange |
strange |
strange | OK | OK | OK | OK |
strange |
OK | OK | OK | OK | OK |
We suspected the first card of the AI module (channel 1-8). We extracted the module form the rack and we confirmed that the first card had a very strong smell of burnt but we couldn’t individuate the broken component (we coudn't remove the card from the module to check the bottom part). We disconnected the card from the alimentation and reconnect again the AI module to the power supply. No saturation occurred since then. We will consider how to replace it.
Note that ADC channel 11 even if is not connect to the broken card shows a strange feature (see pic 3). This channel is now used to acquire OPLEV INPUT SUM and it is not used in any control loop but the problem should be investigated.
