Due to Hall C target problem, there were impact on Hall A cryotarget last night. First around 10 pm, there were fluctuation of the cryo temperature (HALOG 335712), apparently at that time Hall C's target problem started: they had a loop fan failure and started to reduce load. Around 11 pm, I was called that our LH2 target temperature rose above alarm level (19.5K), apparently due to cryo 15K supply temperature (CTD673) increase (it usually should be ~13.5 K, went to 15.5K) (HALOG 335715). TO tried to open J-T to increase our cryo flow, but it did not help. (Note: usually when both halls use cryo to near maximum and supply temerature starting to rise, we should not increase cryo-load by opening J-T. Instead, we (both A and C) should reduce load to allow ESR supply temperature to not increase). After Hall C further reduces their load and ESR stabilized, our target became normal. Then around 1 am, Hall C started to warm up their target (reduced flow to 0) due to the problem with the fan. When this happened, the cold return temperature from Hall C rose up from mid 20 K to 55 K at around 3 am. This lead to the supply temperature rose again to 15.5K.(HALOG 335740), which caused our target LH2 temperature went above 19.5K alarm limit (HaLOG 335739). I was called. Since the supply temperature was stable at 15.5K and there is only Hall A load, I increased the flow from 12g/s to 15 g/s (supply temperature only rose very slightly). The target was back to normal operation condition again. Note to TO: when target temperature increases, TO should monitor the cryo 15K supply temperature CTD673 and 15K flow (Hall A CFI6731A and Hall C CFI6731C). Often it is due to the increase in supply temperature. In this case, if the load of A and C is already near maximum, do not increase load further (by opening J-T valve). Instead, try to reduce the load: take away beam on cryotarget, HP heat power should go off automatically, and reduce fan speed (to 10%, 24 Hz). It is important if the temperature rises is fast, when liquid is boiling off, TO should make sure to reduced the fan speed (to 10%, 24 Hz), since without liquid, high speed fan will be burned, which could cause long down time to repair.