$12 Panasonic 308, part missing.

Greg G. · February 21, 2014, 08:08:46 PM

Quote from: twocvbloke on February 21, 2014, 07:57:36 PM
I'd say there's a fault in there, possibly a shorted relay or capacitor, as the fuse is visibly overheating and blowing (causing the arc), you could try a slow-blow fuse, but if there is a fault it could cause further damage...

In that case, I'm going to cut my losses and stop here. I don't have the know-how to investigate this further, or even the need, I already have a functioning 308.

twocvbloke · February 21, 2014, 08:50:28 PM

I'd say that was a safer bet, these are old units now so may have things wrong due to age, plus being 2nd hand means that anything could have happened to it prior to your purchasing it, such as a power surge or lightning discharge... $:-\$

Still, plenty more Panasonic 308 and 616 units out there to be hand if need be...

Bill · February 22, 2014, 12:11:10 PM

Those are some pretty hefty capacitors in there. Possibly their charge-up surge current is what is causing the fuse to pop, in which case a slow-blow fuse would be appropriate. Do you have the original fuse? As I recall, a slow-blow fuse often has the appearance of a coil of wire or a stretched spring (which is what it is) inside the glass envelope. A normal (fast-blow) fuse has a single piece of straight wire traversing the length of the fuse body inside the glass. No spring.

Bill

twocvbloke · February 22, 2014, 12:50:34 PM

Just looking inside my 616, and all the fuses appear to be slow-blows, ant they all seem to be specced as 125V T 2A (except the main fuse with the power switch, which is 250V T1.6A), I know the 308 is smaller than the 616, but thought I'd throw that info in...

Greg G. · February 22, 2014, 03:35:27 PM

Quote from: Bill on February 22, 2014, 12:11:10 PM
Those are some pretty hefty capacitors in there. Possibly their charge-up surge current is what is causing the fuse to pop, in which case a slow-blow fuse would be appropriate. Do you have the original fuse? As I recall, a slow-blow fuse often has the appearance of a coil of wire or a stretched spring (which is what it is) inside the glass envelope. A normal (fast-blow) fuse has a single piece of straight wire traversing the length of the fuse body inside the glass. No spring.

Bill

There's a picture of them in the first page of this thread, and you're right, they look like a stretched spring. So there's hope after all. I'll get some slow-blo fuses and see what happens.

Mr. Bones · February 22, 2014, 06:57:13 PM

Good Luck, Briny, I hope it works for you!

Keeping my fingers crossed...

Best regards!

Phonesrfun · February 22, 2014, 08:16:12 PM

Quote from: Brinybay

So there's hope after all. I'll get some slow-blo fuses and see what happens.

The way I see it, you have nothing to lose.

AE_Collector · February 23, 2014, 02:40:25 PM

I know nothing about the Panasonic PBXs in particular. My guess is that "Day Mode" means normal operation where as not being in Day Mode it is either in Night Mode or Power Fail mode. It likely powers up in Power Fail mode which probably hooks one or more trunks directly to certain stations through relays. Then after a self check it changes to Day Mode with a click as the relays operate removing the station / trunk connections and going into normal operation.

Terry

Greg G. · February 23, 2014, 03:14:25 PM

Quote from: twocvbloke on February 22, 2014, 12:50:34 PM
Just looking inside my 616, and all the fuses appear to be slow-blows, ant they all seem to be specced as 125V T 2A (except the main fuse with the power switch, which is 250V T1.6A), I know the 308 is smaller than the 616, but thought I'd throw that info in...

I didn't keep the original main power fuse, but fortunately I got a picture of it (page 2). It too appears to be a slow-blo (stretched spring look), so I may replace it as well when I get time to get down to RS.

twocvbloke · February 23, 2014, 03:30:02 PM

Quote from: AE_Collector on February 23, 2014, 02:40:25 PM
I know nothing about the Panasonic PBXs in particular. My guess is that "Day Mode" means normal operation where as not being in Day Mode it is either in Night Mode or Power Fail mode. It likely powers up in Power Fail mode which probably hooks one or more trunks directly to certain stations through relays. Then after a self check it changes to Day Mode with a click as the relays operate removing the station / trunk connections and going into normal operation.

Terry

Day and Night modes are basically just a way to switch between two separate programming modes, so you can program the system in Day mode to operate in one manner during the day, and then program the system to operate in a completely different way in Night mode, so it's more of a programming thing really...

the first extensions (in this case 11 to 13) are the power fail extensions which give direct access to external lines (no "Dial 9 for an outside line") when there's no power, so the relays that click are transferring the line control over to the system, so I guess powering up those relays (3 in this system) is probably too much for a fast-blow fuse...

AE_Collector · February 23, 2014, 07:01:58 PM

It will go into Power Fail mode even if the power is on but the system has failed. Thus when it has failed the relays are down connecting the power fail phones to the CO lines. Once it is powered up and has confirmed that all is well the system powers the relays up removing the power fail situation.

Terry

Greg G. · March 06, 2014, 09:24:05 PM

Ok, I got some slo-blo fuses and installed them. The main power fuse I found at the nearest RS, but I had to find the other ones online. I've powered it up 12-14 times, seems ok. I can see the fuse element move a tad bit at power up, but it seems to hold. I've got it plugged in and switched my incoming line and daily driver over to it to try it for a while.

FABphones · January 01, 2023, 11:13:01 PM

Old 2014 thread.

What was the end result after your test run Greg.

News:

$12 Panasonic 308, part missing.