Non-standard cost-saving: how we learned to repair the Nortel 1120 office IP phones by ourselves
This story began in 2006, when in the framework of the project to move our company to a new office, it was decided to switch from a Meridian station to a modern Nortel IP station CS1000 (Later this station became Avaya CS1000). Together with the station, we had to replace all the telephone sets - with the new (for those times) 1120 and 1140 devices.
Figure 1. Avaya / Nortel 1120E IP Phone.
Five years have passed, and in 2011 the phones began to fail. Users of these devices eventually face mainly two problems: the problem with the tube lever, which ceases to be wrung out, and the problem with the device itself, which first starts to reboot, and then at some point ceases to turn on completely. At first, we did not attach much importance to these breakdowns, and simply bought new devices to replace broken ones. However, the devices continued to break down ... The cost of the new phone with our discount is about $ 250, or about ten thousand rubles. We kept broken devices in our warehouse for some time, 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 repair costs much cheaper than buying a new device: repairing one phone costs an average of 2,500 rubles. Thus, we managed to reduce the company's costs of solving the problem of failed phones by about four times. It would seem that one could stop at that, but ... The phones continued to fail at an ever faster pace. In fact, with a total fleet of about 900 vehicles, we lost 5-10 vehicles per week. This worried the IT department. There was even an assumption that the matter may be in the firmware version of our PoE switches Cisco 4510, but the firmware update did not improve the situation, and then we realized that the problem was in the devices themselves. At this point, we decided to figure out what actually breaks down in the phone with time and what needs to be done for repairs.
So, 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 presses the lever. How to do this becomes clear when the device is disassembled. But we still have a problem with electronics - a non-bootable device ...
')
Figure 2. Phone 1120E with the back cover removed. Yellow rectangle - the phone power supply board.
Look carefully at the photo of the phone's insides - here you can see that another rectangular board is attached to the motherboard of the device from above. A careful study of it turns out that this is the power supply board of the phone. We assumed that the problem lies precisely in this board and rearranged the exact same board from the working phone to the broken one. Hooray! "Broken" phone earned. Repeating the operation for other broken phones gave the same result. Thus, we realized that the phone ceased to turn on due to some problems with the power supply board. We assumed that, in general, all cases of non-loading of the phone are related to the malfunction of this board, and decided to buy a box of new power supply boards - 96 pieces for about $ 2,000. Each board 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 an unrivaled speed of solving the problem - the fee changes directly at the user's workplace for 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 registered by us, the problem is caused by this very small power supply board.
Figure 3. Faulty phone power supply board with marked inflated filter capacitors C123 and C132.
And then we asked ourselves the question - was it necessary to buy new power supply boards at all? Maybe we ourselves can repair the failed board? 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 at 10 V, which are outlined in the photo above with red circles. By pulling the board out of a faulty phone, you will most likely find that one or both of the capacitors are “bloated”, which clearly indicates their malfunction. Thus, to repair the board, you just need to replace these capacitors. To speed up the process, we change both capacitors at once, not paying attention to their appearance. And in order for new capacitors not to fail in the future, let's apply a small circuit design trick - we solder the ceramic SMD capacitor 0.1 microfarad at 50 V in parallel with them.
Anticipating possible questions, I will immediately note that this method of repairing the board, according to the statistics already accumulated, 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 concern this.
Figure 4. Electrolytic capacitors.
Figure 5. Ceramic SMD capacitors in the tape.
So, for the repair of the boards, we will purchase 300 electrolytic capacitors ECAP 470 / 16V 0811 105C and 300 ceramic capacitors CERCAP 0.1 / 50V 0805 KX7R for the future. I took such a number, since it is from this figure that good wholesale discounts start at terraelectronica.ru; All 600 capacitors cost about 1000 rubles. We also need a soldering station, solder, flux or rosin, suction, tweezers and a brush, and it is highly desirable to have a tripod or a small vice to fix the repaired board.
Figure 6. Faulty boards assembled into a package, awaiting 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 done normally. Thus, the cost of repair in this case is actually the cost of three capacitors, that is, about 10 rubles. I deliberately do not take into account the work, as well as the cost of rosin and solder - it is a penny. Thus, we managed to reduce the cost of repairs by a factor of sixty (!) Compared to the cost of a new power supply board. Replacing capacitors on one board takes about five minutes - this is the time that needs to be spent on removing faulty capacitors and sealing new ones, followed by testing the board. Five to seven boards collected during the week are repaired at home on Friday evening for one hour.
Figure 7. A neat column of repaired boards is growing.
Let's now calculate the savings already received from these 60 phones: ~ 600r * 60 = ~ 36,000 rubles compared to buying new boards; ~ 2,500r * 60 = ~ 150,000 rubles compared to the cost of repairing the phone in the official service center, and finally, ~ 10,000r * 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 — to do this, the figures above should be multiplied by six (we expect a flat linear trend over the course of 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 have found a simple way to repair Nortel 1120 devices of the old series, which allows significantly (by several orders of magnitude) to reduce repair costs, while simultaneously providing an unsurpassed speed of restoring the efficiency of a failed device. In order to repair the power supply board, no special knowledge and skills are required, just the ability to hold a soldering iron in your hands is sufficient. 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 problems similar to ours with Nortel 1120 devices.
Attention, an important note . The problems described in this article apply only to phones manufactured under the Nortel brand. Avaya released Product Correction Notice (PCN) 1745B in June 2011, which confirms the possibility of problems with the power supply board. This document also lists potentially problematic machine batches. Later, the phones of the same models were produced with the Avaya logo. For all the time of their use (since 2010) we have not identified such problems with them. The power board of these devices has been reworked, the design of its connectors has changed. Accordingly, old revisions of power boards are not compatible with new devices, and vice versa.
Figure 1. Avaya / Nortel 1120E IP Phone.
Five years have passed, and in 2011 the phones began to fail. Users of these devices eventually face mainly two problems: the problem with the tube lever, which ceases to be wrung out, and the problem with the device itself, which first starts to reboot, and then at some point ceases to turn on completely. At first, we did not attach much importance to these breakdowns, and simply bought new devices to replace broken ones. However, the devices continued to break down ... The cost of the new phone with our discount is about $ 250, or about ten thousand rubles. We kept broken devices in our warehouse for some time, 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 repair costs much cheaper than buying a new device: repairing one phone costs an average of 2,500 rubles. Thus, we managed to reduce the company's costs of solving the problem of failed phones by about four times. It would seem that one could stop at that, but ... The phones continued to fail at an ever faster pace. In fact, with a total fleet of about 900 vehicles, we lost 5-10 vehicles per week. This worried the IT department. There was even an assumption that the matter may be in the firmware version of our PoE switches Cisco 4510, but the firmware update did not improve the situation, and then we realized that the problem was in the devices themselves. At this point, we decided to figure out what actually breaks down in the phone with time and what needs to be done for repairs.
So, 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 presses the lever. How to do this becomes clear when the device is disassembled. But we still have a problem with electronics - a non-bootable device ...
')
Figure 2. Phone 1120E with the back cover removed. Yellow rectangle - the phone power supply board.
Look carefully at the photo of the phone's insides - here you can see that another rectangular board is attached to the motherboard of the device from above. A careful study of it turns out that this is the power supply board of the phone. We assumed that the problem lies precisely in this board and rearranged the exact same board from the working phone to the broken one. Hooray! "Broken" phone earned. Repeating the operation for other broken phones gave the same result. Thus, we realized that the phone ceased to turn on due to some problems with the power supply board. We assumed that, in general, all cases of non-loading of the phone are related to the malfunction of this board, and decided to buy a box of new power supply boards - 96 pieces for about $ 2,000. Each board 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 an unrivaled speed of solving the problem - the fee changes directly at the user's workplace for 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 registered by us, the problem is caused by this very small power supply board.
Figure 3. Faulty phone power supply board with marked inflated filter capacitors C123 and C132.
And then we asked ourselves the question - was it necessary to buy new power supply boards at all? Maybe we ourselves can repair the failed board? 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 at 10 V, which are outlined in the photo above with red circles. By pulling the board out of a faulty phone, you will most likely find that one or both of the capacitors are “bloated”, which clearly indicates their malfunction. Thus, to repair the board, you just need to replace these capacitors. To speed up the process, we change both capacitors at once, not paying attention to their appearance. And in order for new capacitors not to fail in the future, let's apply a small circuit design trick - we solder the ceramic SMD capacitor 0.1 microfarad at 50 V in parallel with them.
Anticipating possible questions, I will immediately note that this method of repairing the board, according to the statistics already accumulated, 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 concern this.
Figure 4. Electrolytic capacitors.
Figure 5. Ceramic SMD capacitors in the tape.
So, for the repair of the boards, we will purchase 300 electrolytic capacitors ECAP 470 / 16V 0811 105C and 300 ceramic capacitors CERCAP 0.1 / 50V 0805 KX7R for the future. I took such a number, since it is from this figure that good wholesale discounts start at terraelectronica.ru; All 600 capacitors cost about 1000 rubles. We also need a soldering station, solder, flux or rosin, suction, tweezers and a brush, and it is highly desirable to have a tripod or a small vice to fix the repaired board.
Figure 6. Faulty boards assembled into a package, awaiting 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 done normally. Thus, the cost of repair in this case is actually the cost of three capacitors, that is, about 10 rubles. I deliberately do not take into account the work, as well as the cost of rosin and solder - it is a penny. Thus, we managed to reduce the cost of repairs by a factor of sixty (!) Compared to the cost of a new power supply board. Replacing capacitors on one board takes about five minutes - this is the time that needs to be spent on removing faulty capacitors and sealing new ones, followed by testing the board. Five to seven boards collected during the week are repaired at home on Friday evening for one hour.
Figure 7. A neat column of repaired boards is growing.
Let's now calculate the savings already received from these 60 phones: ~ 600r * 60 = ~ 36,000 rubles compared to buying new boards; ~ 2,500r * 60 = ~ 150,000 rubles compared to the cost of repairing the phone in the official service center, and finally, ~ 10,000r * 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 — to do this, the figures above should be multiplied by six (we expect a flat linear trend over the course of 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 have found a simple way to repair Nortel 1120 devices of the old series, which allows significantly (by several orders of magnitude) to reduce repair costs, while simultaneously providing an unsurpassed speed of restoring the efficiency of a failed device. In order to repair the power supply board, no special knowledge and skills are required, just the ability to hold a soldering iron in your hands is sufficient. 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 problems similar to ours with Nortel 1120 devices.
Attention, an important note . The problems described in this article apply only to phones manufactured under the Nortel brand. Avaya released Product Correction Notice (PCN) 1745B in June 2011, which confirms the possibility of problems with the power supply board. This document also lists potentially problematic machine batches. Later, the phones of the same models were produced with the Avaya logo. For all the time of their use (since 2010) we have not identified such problems with them. The power board of these devices has been reworked, the design of its connectors has changed. Accordingly, old revisions of power boards are not compatible with new devices, and vice versa.
Source: https://habr.com/ru/post/171725/
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