EMP & Lightning Home Surge Protection
EMP - Click Here!
Global Test Supply
Linked Banner to your Product or Website
eCommerce website for sale!
Previous Thread
Next Thread
Print Thread
Rate Thread
Joined: Mar 2005
Posts: 25
Member
OP Offline
Member
Joined: Mar 2005
Posts: 25
I've had a 1A2 system with a 620A modular panel and a 641A modular panel with a 79B2 power unit using 4 CO lines on the 620A and one MOH on the 641A), which has been working perfectly for several years. Without warning the lamps on all four lines quit working. Additionally ringing on inbound calls rings continuously. I have dial tone on all lines and all telsets dial out correctly (without illuminated lamps) and all sets receive calls (with continuous ringing and no illuminated lamps). Hold does not work (disconnects inbound call after depressing hold button). There is a Melco ICM on the 5th line which continues to work correcting including buzzing appropriately and the lamp lights.

I have checked all fuses multiple times including with a continuity tester even though the pop-out is not out on any of the fuses. All the power unit fuses are tested with continuity tester and don't appear blown). I have rotated all the line cards with no difference in performance. I have replaced the interrupter with others of same model from two other power units. I have moved the interconnect cable from the 620 panel to each of the four jacks on the power unit to insure that the jack is okay. The interrupter motor does not make a sound, although I'm not sure it actually does on this unit. My experience with interrupters is only on a 551B shoebox.

I've exhausted all the tests I know how to perform.

Bottom line: None of the lamps illuminate and the ringer on inbound calls is continuous rather than interrupted.

Any suggestions on how to proceed? 10vac supply fried? Interrupter fried?

Bill Bentsen
_._,_._,_

Advertising Sponsor
Joined: Feb 2005
Posts: 12,321
Likes: 3
Member
***
Offline
Member
***
Joined: Feb 2005
Posts: 12,321
Likes: 3
Quote
Any suggestions on how to proceed? 10vac supply fried? Interrupter fried? I've exhausted all the tests I know how to perform.

Without even thinking further, did you check the voltages to see if they are all there?

-Hal

Last edited by hbiss; 01/22/21 03:43 AM.

CALIFORNIA PROPOSITION 65 WARNING: Some comments made by me are known to the State of California to cause irreversible brain damage and serious mental disorders leading to confinement.
Joined: Jan 2005
Posts: 15,301
Likes: 5
Moderator-Vertical, Vodavi, 1A2, Outside Wire
*****
Offline
Moderator-Vertical, Vodavi, 1A2, Outside Wire
*****
Joined: Jan 2005
Posts: 15,301
Likes: 5
Your 10 volts AC output from the 79B2 has failed. This voltage is used for all lamps and the interrupter motor. If you can locate the ST terminal in the upper left quadrant of the 620 panel, touch a known good ground to it. If the motor starts running, then it is you lamp ground that is missing. Again, this is an issue within the power unit itself. You might want to try to common all of the ground terminals on the power supply together just in case.


Ed Vaughn, MBSWWYPBX

Moderated by  ChrisRR, EV607797, Silversam 

Link Copied to Clipboard
Popular Topics (Views)
Forum Statistics
Forums94
Topics93,295
Posts634,125
Members49,497
Most Online5,661
May 23rd, 2018
Today's Birthdays
2connect, CTCINY, majortom1981, NaesNos, Not So Tech Smart, Shea Hale
Newest Members
NZAndy101, spunkysam, tn00247167, Dave McCann, Mitel Hotel
49,496 Registered Users
Get Tech Support Now! Click the banner below
Get Tech Support Now!
Top Posters (30 Days)
dexman 10
Toner 6
Advertising Sponsor Spot 2
EMP Shield for Commercial - Home & Vehicle
Use Coupon code SAVE - Click Here!
Who's Online Now
24 members (hitechcomm, nortelvoip, Nadeemkhattak, RATHER BE FISHING, Keyset6, Yoda, jsaad, Silversam, Carl Navarro, RM SYSTEMS, dexman, justbill, BobRobert, morephones, WJS, muddybl, www.telcom1.net, Touch Tone Tommy, Ruben, Coral Tech, Daniel, KRRath, JBean3329, Skunky), 392 guests, and 46 robots.
Key: Admin, Global Mod, Mod
Contact Us | Telephone System Tech Support | Terms of Service

Sundance Communications is not affiliated with any of the above manufacturers.
©Copyright Sundance Communications 1998-2021
Trusted Partners
landing page builder Antiransomware 300x250 Your Business Phone Service in the Cloud