sundance-communications.com/forum Forums TDM Business Telephone Systems Toshiba Telephones & Systems DK424 Expansion Cabinet Problem

Have a 6 cabinet 424 system and cabinets 3 and 4 are equipped with analog and digital stn cards. All ports on these 2 cabinets are dead. Power on all cards and power supplies checked ok, but no dial tone on either RSTU or PDKU cards. Suspect an off-prem extension(s) connected to analog port(s) may have brought a surge into the system and fried something.

No dial tone on analog cards and digital sets come up with "vacent" when called.

I suspect that the small circuit board full of IC's attached to the left side of the backplane on the expansion cabinet is blown. This is essentially the brain of the expansion cabinet?

Comments?

First off press all of the power supply reset buttons and test. If that doesn't do it, pull all of the cards out of those cabinets and insert them back one at a time and test.

Thx Pat.

Already tried that. Pulled out all cards from both cabinets. reset all 3 breakers on both PS's. Cycled power on both. Pushed back in 1 RSTU card. Still no dial tone. Figured a card could be loading down the PS but it seems that is not the case. Have installed many 280 and 424's and while it is not common to lose that board on the left side, we did see it once. The site is a hospital and is 8 hours drive from our office. Makes it hard to try different things without first sending the parts to site. Sent these 2 boards today. Hope to have some answers tomrrow.

Any other ideas would be welcomed and appreciated....

Have you looked in programming to see if cabinets and cards appear.
Have you cycled the system from cabinet no1 with processor.?

Any tinkerers there that work for the hospital ?

Did you check the Amphenol connectors on the cards
and mdf to see if theres a wet mop or you name
against the mdf.

Water anywhere?

Problem solved. It was a burnt ribbon cable interfacde board on the 3rd cabinet. Was responsible for knocking out the 3rd and 4th cabinets. Replaced this board and all working again. Thx to those that responded.

That's a rarity! Good job.

:thumb: :banana:

Great catch