atcomsystems.ca/forum Forums Other TDM Phone Systems 1A2 and Comkey Telephones & Systems 551KSU Key # 3 no light, or hold

Aloha and Mahalo (Thank you!) in advance if it takes me a few days to respond.

Thank you to Silversam, our moderator and Arthur for your help with my last problem!!

I have a 551C KSU and 4 sets. Key # 3 has no light or hold on all sets. Dial tone is good.

I have tried different 400G cards and still same problem.

I have checked my punches and they seem to be ok.

Any clues where to start testing?

Thank you again,
David

David -

Go to the KSU and disconnect all of the wiring you put on (NOT the factory wiring). Put a meter set for a low AC scale (you're looking for 10VAC) across the 3L & LG connections. With a screwdriver or a jumper lead, short the 3A and A1 terminals together. You should hear the relay on the 400 card kick in and the meter should register 10 Volts AC. Remove the short and the relay should release and the voltage drop to 0 volts.

If it does, then the problem is in the wiring or the phones you've got. Most likely cause is a reversed LG/L pair (Red/Brown). Install the wiring and the phones one a t a time till you locate the problem.

If it doesn't then you've got a problem in the KSU and we'll get to that if we have to.

Sam

thank you i will try to work on it over this weekend. Aloha