Aastra 9133i phone problem - Page 1
Forum section: electronics / general

author: dfmischler
author_rank: Frequent Contributor
timestamp: June 07, 2013, 12:52:54 pm
content: I'm not really expecting much out of this, but you never know. There are a lot of smart, experienced people here.I have about twentyAastra 9133iphones at work. This is an out of production SIP phone that can be powered by 802.3af POE (Power Over Ethernet), or with a 48V wall wart. It has two 10/100 ethernet ports with a two port switch so you can daisy chain the ethernet (but not POE) to another device. It works very well with open source PBX software (e.g.Asterisk,Elastix). It is based on theBroadCom BCM1113 chip. I can easily get asales flyerfor this chip, but not a real datasheet. Broadcom is notoriously closed about their hardware. Aastra provides firmware and manuals for download, but will apparently only talk to me if I am a reseller.Two of the phones sometimes fail to restart after power cycling, which can be caused by an ethernet switch reboot. They both have the same manufacturing date code: 20061212. When this occurs, the symptom is that the 6 LEDs at the top right of the phone stay on, and the 2-line LCD display does nothing. My guess is that the CPU in the phone failed to start running for some reason. If you unplug the phone and wait for a while (I don't really know how long, but overnight is always enough) and plug it back in it will work. So maybe a cap is not discharging properly in the reset circuit, or something like that. There are no aluminum electrolytic caps in the phone, although there do appear to be tantalum surface mount caps. Internal voltages seem OK, and there doesn't seem to be a ripple problem. There are no obvious differences between the circuit boards that sometimes fail and the ones that are rock solid. All of the phones are running the same firmware (1.4.3.1001).This is not that big a problem because these phones are cheap on ebay. But it bugs me. So how do I find the reset circuit without a data sheet so I can test my theory? Or do you think I should just give up and burn a hole in the main chip and keep the other parts in case I need them?

author: amyk
author_rank: Super Contributor
timestamp: June 07, 2013, 01:05:36 pm
content: You'll need to do some reverse-engineering...There maybe test points for a serial port on the board. These chips usually have a UART and will print out messages to it, or perhaps even let you enter debugging commands.

author: Psi
author_rank: Super Contributor
timestamp: June 07, 2013, 02:20:03 pm
content: This is a longshot but have a look on the main CPU/MCU reset line when its non functional.Sometimes they have a voltage detector, like a KIA7019 or similar, which resets the mcu once the cpu voltage stabilizes.I've seen these dye before and cause mcu/cpu starting issues

author: dfmischler
author_rank: Frequent Contributor
timestamp: June 10, 2013, 12:53:36 pm
content: Quote from: amyk on June 07, 2013, 01:05:36 pmNone of the labeled test points or connector pins on the board look like serial data from a UART. Just voltages.Quote from: Psi on June 07, 2013, 02:20:03 pmIt's a 256 pin BGA on a 4 layer board so even if I had a pinout for the BCM1113 I don't know if I could find the reset circuit without help.I got a pinout for the RAM (Samsung K4S641632H-UC75) so I can definitely see if the CPU is running by watching an address line, but it hasn't failed yet this morning.

author: dfmischler
author_rank: Frequent Contributor
timestamp: June 10, 2013, 01:47:49 pm
content: Quote from: dfmischler on June 10, 2013, 12:53:36 pmExcept for TP3 which has a slow ugly ramp at powerup (takes over 6ms for it to go high). So that is probably checking the reset circuit.A cap labeled C101 also shows a very similar waveform. There is room for a discharge resistor labeled R13 right next to it.I guess I'll open up one of the good phones and see if R13 is installed, or if C101 has a different value, etc.I still don't have proof that the CPU is not running when the phone fails, but while I have had a few failures on the bench I can't make it fail on command.

author: amyk
author_rank: Super Contributor
timestamp: June 11, 2013, 10:28:32 am
content: Could it be specifically how the switch power cycles them that's causing the issue, and not just any old power-cycling? If you're just unplugging/replugging, it might look different.And post some pictures, it's hard to troubleshoot without seeing what the board looks like.

author: dfmischler
author_rank: Frequent Contributor
timestamp: June 11, 2013, 06:35:12 pm
content: Quote from: amyk on June 11, 2013, 10:28:32 amAgreed. I have had it fail with a wall wart, and with a slightly different switch from the same manufacturer, but I have my spare Cisco SGE2000P hooked up just to troubleshoot this. This is the same switch used when the field failures have occurred, and running the same firmware, etc. I must have rebooted it 100 times yesterday with no joy.I also realize that the problem could be a bad batch of BCM1113's, or bad soldering under the BGA, or something else I won't be able to fix.Anyway, I have attached a couple pics below, and you can get bigger images from the IMG_xxxx.JPG files athttp://www.frontiernet.net/~dmischler/

author: dfmischler
author_rank: Frequent Contributor
timestamp: June 12, 2013, 06:23:13 pm
content: I have a failure to look at. The A3 line on the RAM runs a little when I reset the CPU, then stops low. That's not what it looks like when things are working, but the CPU is running (at least for a while). I'm probably not going to pursue this any further unless a bright idea emerges.