Author Topic: Panasonic 616 PBX Odd Malfunction  (Read 3277 times)

Offline James

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Re: Panasonic 616 PBX Odd Malfunction
« Reply #15 on: October 01, 2017, 01:30:13 PM »
I find it odd that, according to the diagram in the service manual, there's another capacitor in parallel with the 1 farad capacitor but with the polarity the other way around. I've never seen anything like that before. I wonder if that might be an error in the service manual.

Offline TelePlay

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Re: Panasonic 616 PBX Odd Malfunction
« Reply #16 on: October 01, 2017, 04:28:48 PM »
. . . according to the diagram in the service manual, there's another capacitor in parallel with the 1 farad capacitor but with the polarity the other way around. I've never seen anything like that before. I wonder if that might be an error in the service manual.

Can you scan or clip that diagram and post it?

And, is that diagram for a 616 with a battery backup or the newer 616 with the battery replaced by a large capacitor?
            John . . .

              

Offline James

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Re: Panasonic 616 PBX Odd Malfunction
« Reply #17 on: October 01, 2017, 05:53:05 PM »
The diagram is for the 616. It uses both a backup battery and the 1 farad capacitor. I had to make a copy by hand of the part of the circuit that I mentioned because the pdf file won't let me make a straight image copy.

Offline James

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Re: Panasonic 616 PBX Odd Malfunction
« Reply #18 on: October 04, 2017, 04:47:47 PM »
I replaced the 1 farad capacitor and it seems to be running fine. It hasn't gone into power failure mode yet. I've only been running it for about half an hour though. I'll keep running it for a few more hours to see if there are any changes.

Offline James

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Re: Panasonic 616 PBX Odd Malfunction
« Reply #19 on: October 04, 2017, 05:24:01 PM »
Unfortunately, it went into power failure mode after about an hour of being on. So, it looks like something else is causing the problem.

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Re: Panasonic 616 PBX Odd Malfunction
« Reply #20 on: October 04, 2017, 06:22:33 PM »
Could potentially be other capacitors in the system or power supply acting up, could be the "goo" they slopped about (assuming it's not been peeled off by now) that turns conductive as it ages causing the processor to go into power fail mode even if the power hasn't failed...

Offline James

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Re: Panasonic 616 PBX Odd Malfunction
« Reply #21 on: October 04, 2017, 06:59:41 PM »
I didn't notice any goo on mine. It seems that the longer I leave it powered off, the longer it goes before tripping in to power failure mode.

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Re: Panasonic 616 PBX Odd Malfunction
« Reply #22 on: October 04, 2017, 07:02:42 PM »
In that case it sounds like another capacitor has copped it somewhere inside the system, only way to reliably test them is to remove them one by one and test them with an ESR meter as capacitors can look physically okay on the outside, but internally be completely stuffed, quite an involved task really...  :-\

Offline James

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Re: Panasonic 616 PBX Odd Malfunction
« Reply #23 on: October 04, 2017, 09:07:32 PM »
I wonder if it's worth it. I could end up paying more for capacitors than what I paid for the pbx.

Offline andy1702

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Re: Panasonic 616 PBX Odd Malfunction
« Reply #24 on: October 22, 2017, 04:53:31 PM »
I got a load of dead LCD monitors once which I brought back to life by changing the capacitors. About half the caps were obviously blown (the tops bulged upwards and goo spilling out. The problem was the other half though. They looked ok on a visual inspection but were in fact equally dead.

Just get a big bag of caps from your local electronics shop and replace them all. It's definitely worth doing because once completed the PBX should effectively have a new life. However if you buy another working PBX it might only be a few months before the old caps in that one start failing.
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Offline James

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Re: Panasonic 616 PBX Odd Malfunction
« Reply #25 on: October 23, 2017, 11:07:57 PM »
It's funny that if I leave it off for long enough, it will run for a long time before it goes into power failure mode. It makes me suspect that it has something to do with the 10,000 mfd capacitor in the power regulator. That one takes a really long time to discharge.

Offline andy1702

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Re: Panasonic 616 PBX Odd Malfunction
« Reply #26 on: October 24, 2017, 01:25:24 PM »
You could well be right. It sounds logical to me. Try changing that one and see what happens then.
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Offline James

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Re: Panasonic 616 PBX Odd Malfunction
« Reply #27 on: November 03, 2017, 07:42:31 PM »
I replaced the 10,000 mfd capacitor and the two 6,800 mfd ones in the power regulator and I've been running the pbx for almost 5 hours so far without any problems. I'm going to keep it on overnight and see if there are any changes. This is the longest it's been working since I got it so it looks promising.

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Re: Panasonic 616 PBX Odd Malfunction
« Reply #28 on: November 04, 2017, 01:16:42 AM »
Fingers crossed those were the culprits, like I said before, they can look fine on the outside, but be dead (or almost dead) on the inside... :)

Offline James

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Re: Panasonic 616 PBX Odd Malfunction
« Reply #29 on: November 04, 2017, 12:21:54 PM »
I think I can safely say now that I think it's fixed. It's been running for 20 hours with no problems. I'll keep running it for a while more just to be really sure.

I have a tip for anyone else that needs to replace capacitors in a 616. Take measurements of the old capacitors so you can order ones that you're sure will fit. I made the mistake of not doing that so I had to be creative installing the new ones. I had to install one horizontally, otherwise it would have stuck out too much for me to put the front panel back on.