Hi all: I have a strange thing happening on a TDA 100. Just in the last week once a day in the morning it seems that the phones on a DHLC8 will start to blink rapidly and cut in and out for about two minutes. The customer states that they also hear a loud chirping noise almost like a bird. I came out twice to check the phones because the customer said that the phones were cutting in and out. However when I would get on site the phones were working fine. I asked for a list of the extensions that were being affected and it turns out that all of them were KXT 7731's. On this system there are about 10 7731's and 16 KX-DT343's. The digital phones are not affected. I Swapped out the DHLC8 but the problem remains. So yesterday I came out reset the system, powered it down and reseated all the cards. then I checked the error log and found that on that morning the error log showed that there were 31 error messages. Error code 11, sub code 10000, and error message "DC power down. This is listed under Major alarm, but the alarm light is not on. All of these errors happened between 10:19am and 10:21am. about a 2 minute period. I cleared them all out and returned this morning and found that the same thing had happened again. From 8:19 am to 8: 20 am the same error had happened. This problem only happened once in the morning and not again all day. Does anyone have any idea what may be happening. Thanks, any input would be helpful.

I would start with replacing the power supply and see if the problem continues.