Non-standard cost-saving: how we learned to repair Nortel 1120 office IP phones on our own

This story dates back to 2006, when, as part of a project to move our company to a new office, it was decided to move from a Meridian station to a modern IP-station Nortel CS1000 (Later this station became known as Avaya CS1000). Together with the station, we had to replace all telephone sets with new ones (at that time) 1120 and 1140.

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Figure 1. Avaya / Nortel 1120E IP telephone.

Five years passed, and in 2011 the phones began to fail. Users of these devices over time encounter mainly two problems: the problem with the handset lever, which stops pushing up, and the problem with the device itself, which first starts to reboot, and then at some point stops turning on completely. At first, we did not attach much importance to these breakdowns, and simply bought new devices to replace the ones that broke. However, the devices continued to break down ... The cost of a new phone with our discount is about $ 250, or about ten thousand rubles. We kept the broken devices for some time in our warehouse, and at some point, in order to save money on the purchase of new devices, we decided to send them for repair to a service center. The fact is that repairs are much cheaper than buying a new device: repair of one telephone costs an average of 2500 rubles. Thus, we were able to reduce the company’s costs by solving the problem of failed phones by about four times. It would seem that this could be stopped, but ... Phones continued to fail at an ever faster pace. In fact, with a total fleet of approximately 900 devices, 5-10 devices per week were out of order. This greatly worried the IT department. There was even an assumption that it might be the firmware version of our Cisco 4510 PoE switches, but updating the firmware did not improve the situation, and then we realized that it was all about the devices themselves. At this point, we decided to figure out what, in fact, breaks down in the phone over time and what needs to be done for the repair. we managed to reduce the company's costs by solving the problem of failed phones by about four times. It would seem that this could be stopped, but ... Phones continued to fail at an ever faster pace. In fact, with a total fleet of approximately 900 devices, 5-10 devices per week were out of order. This greatly worried the IT department. There was even an assumption that the matter may be in the firmware version of our Cisco 4510 PoE switches, however, updating the firmware did not improve the situation, and then we realized that it was all about the devices themselves. At this point, we decided to figure out what, in fact, breaks down in the phone over time and what needs to be done for the repair. we managed to reduce the company's costs by solving the problem of failed phones by about four times. It would seem that this could be stopped, but ... Phones continued to fail at an ever faster pace. In fact, with a total fleet of approximately 900 devices, 5-10 devices per week were out of order. This greatly worried the IT department. There was even an assumption that it might be the firmware version of our Cisco 4510 PoE switches, but updating the firmware did not improve the situation, and then we realized that it was all about the devices themselves. At this point, we decided to figure out what, in fact, breaks down in the phone over time and what needs to be done for the repair. but ... Phones continued to fail at an ever faster pace. In fact, with a total fleet of approximately 900 devices, 5-10 devices per week were out of order. This greatly worried the IT department. There was even an assumption that it might be the firmware version of our Cisco 4510 PoE switches, but updating the firmware did not improve the situation, and then we realized that it was all about the devices themselves. At this point, we decided to figure out what, in fact, breaks down in the phone over time and what needs to be done for the repair. but ... Phones continued to fail at an ever faster pace. In fact, with a total fleet of approximately 900 devices, 5-10 devices per week were out of order. This greatly worried the IT department. There was even an assumption that it might be the firmware version of our Cisco 4510 PoE switches, but updating the firmware did not improve the situation, and then we realized that it was all about the devices themselves. At this point, we decided to figure out what, in fact, breaks down in the phone over time and what needs to be done for the repair. that the thing is still in the devices themselves. At this point, we decided to figure out what, in fact, breaks down in the phone over time and what needs to be done for the repair. that the thing is still in the devices themselves. At this point, we decided to figure out what, in fact, breaks down in the phone over time and what needs to be done for the repair.

So, we disassemble the phone. The problem with the locking lever is solved immediately and very simply, you just need to bend the wire spring in a new way, which depresses the lever. How to do this, it becomes clear with the disassembled apparatus. But we still have a problem with the electronics - a non-

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bootable device ... Figure 2. 1120E phone with the back cover removed. The yellow rectangle is the phone’s power supply board.

Look carefully at the photo of the insides of the phone - here you can see that another rectangular board is attached to the motherboard of the device on top. A careful study of it turns out that this is the board of the phone’s power supply. We assumed that the problem was precisely in this board and rearranged the exact same board from a work phone to a broken one. Hurrah! The "broken" phone has earned. Repeating the operation for other broken phones gave the same result. Thus, we realized that the phone stops turning on due to some problems with the power supply board. We suggested that, in general, all cases of phone not loading are related to the malfunction of this board, and decided to buy a box of new power supply boards - 96 units for about 2000 US dollars. Each fee cost us about $ 20, or 600 rubles, and thus, we were able to reduce the cost of repairing the device by another four times, while ensuring unsurpassed speed in solving the problem - the board changes right at the user's workplace within 5 minutes (it should be noted that this operation makes a very strong impression on the average user). Our assumption turned out to be correct - in 100% of cases of phone breakdowns that we registered, the problem is caused by this very small power supply board.

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Figure 3. Faulty phone power supply card with marked swollen filter capacitors C123 and C132.

And then we asked ourselves the question - did you even need to buy new power supply boards? Maybe we ourselves can repair failed boards? It turned out that yes, we can. After a careful study of the faulty board, it turned out that the problem was caused by two filtering electrolytic capacitors C123 and C132, with a capacity of 470 microfarads per 10 V, which are circled in red in the photo above. Pulling the card out of the faulty telephone will most likely reveal that one or both of the capacitors is “bloated”, which clearly indicates a malfunction. Thus, to repair the board, you just need to replace these capacitors. To speed up the process, we immediately change both capacitors, without paying attention to their appearance. And so that new capacitors do not fail in the future,

Anticipating possible questions, I’ll immediately note that this method of repairing a board according to already accumulated statistics works in 95% of cases. In the remaining 5% of cases, it is required to change other elements, but in this article we will not touch on this.

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Figure 4. Electrolytic capacitors.

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Figure 5. Ceramic SMD capacitors in tape.

So, for repair of boards we will buy for future 300 electrolytic capacitors ECAP 470 / 16V 0811 105C and 300 ceramic capacitors CERCAP 0.1 / 50V 0805 KX7R. I took such a quantity, since it is with this figure that good wholesale discounts on terraelectronica.ru begin; all 600 capacitors cost about 1000 rubles. We also need a soldering station, solder, flux or rosin, a suction, tweezers and a brush, and it is highly desirable to have a tripod or small vise to fix the repaired board.

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Figure 6. Failed circuit packs pending for repair.

Result: at the moment, by the simple replacement of capacitors since the beginning of 2013, sixty phones have already been repaired. All phones after the repair work normally. Thus, the repair cost in this case is actually the cost of three capacitors, that is, about 10 rubles. I deliberately do not take labor into account, as well as the cost of rosin and solder - this is a penny. Thus, we were able to reduce the cost of repairs sixty (!) Times compared with the cost of a new power supply board. Replacing capacitors on one board takes about five minutes - this is the time that you need to spend on removing faulty capacitors and sealing new ones with subsequent testing of the board. Five to seven boards assembled during the week are repaired at home on Friday evening for one hour.

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Figure 7. A neat column of repaired circuit boards is growing.

Let's now calculate the savings already obtained from these 60 phones: ~ 600r * 60 = ~ 36,000 rubles compared to buying new boards; ~ 2,500 rubles * 60 = ~ 150,000 rubles compared to the cost of repairing a phone in an official service center, and finally, ~ 10,000 rubles * 60 = ~ 600,000 rubles compared to the cost of new devices.

Two months have passed since the beginning of the year, so that we can easily calculate the expected annual savings - for this we need to multiply the above figures by six (we expect a flat linear trend during the year). Depending on the chosen base for comparison, we will receive 216,000 rubles, 900,000 rubles and 3,600,000 rubles of annual savings, respectively.

Conclusions: we found a simple way to repair old Nortel 1120 devices, which can significantly (by several orders of magnitude) reduce repair costs, while at the same time providing an unsurpassed speed of recovery of a failed device. For the repair of the power supply board does not require any special knowledge and skills, just the ability to hold a soldering iron in your hands. Replacing capacitors helps in 95% of cases; in the remaining 5% of cases, you can simply buy new power supply boards from the manufacturer. We hope that this article will help everyone who is experiencing similar problems with our Nortel 1120 devices.

Attention, important note. The problems described in this article apply only to phones manufactured under the Nortel brand. Avaya in June 2011 released the Product Correction Notice (PCN) 1745B , which confirms the possibility of problems with the power supply board. This document also lists potentially problematic batches of devices. Later, phones of the same models began to be produced with the Avaya logo. For the entire time of their use (starting from 2010), we did not reveal such problems in them. The power board for these devices has been redesigned, the design of its connectors has changed. Accordingly, the old revisions of the power boards are not compatible with new devices, and vice versa.

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