Recently i was given a Linksys 12 volt 1000mA power supply unit which had been causing havoc to a users dsl connection. The user over a period of a few weeks had noticed his dsl router connection to randomly re-sync causing the isp's DLM system lowering his connection speed. At first it was thought that there was a line fault as there was sometimes a buzzing noise being heard on the telephone line. The user reported a fault to his telephone service provider. After a few days the telephone company's engineer had diagnosed the problem to be the user's equipment. I was called to see if i could help.
The fist thing i did was to go into the routers web configuration page to look at his router stats. I noticed that the router had been re-syncing multiple times and the line stats were very bad as well. The DL noise margin had crept up to 15db and the line attenuation of 36db didn't reflect to the lousy line rate of 800kbps.
To eliminate equipment i first tried a spare replacement belkin router. This immediately improved the line stats and line rate. So it was thought that the Linksys router was probably the cause of his problems and would probably be best to replace.
As the user was going on his annual holiday he asked me to repair or find a replacement router. I opened up the router and could not see anything wrong. Then i tried a replacement power supply and the router immediately was showing a more appropriate line stats.
So the problems was the power brick power supply. I decided to crack open the power supply.
The power supply was very basic consisting of a transformer, a pcb with four diodes and a smoothing capacitor. I tested the transformer on the secondary side which was giving out approx 17V under no load which seemed correct. I then tested the four diodes on the pcb which two tested unsatisfactory. The 2200uf smoothing capacitor also showed a capacitance reading of 83uf with an esr reading of 19.5 which defiantly was a sign of failure.
I replaced all four of the diodes with some spare IN5400 and soldered a new 2200uf 25V capacitor. The casing was glued back and the router and repaired power supply put back on the user's dsl line.
The results were a complete success as the sync rate immediately jumped up to a more respectable 7345kbps and the line noise lowering itself to 7db.
The cost of the the components replaced were under two British pounds and the client recently reported that he has never had his router work so well.
-- Another piece of electronic equipment saved from a journey to the ever growing landfill --
Check for more updates at http://www.punj.co.uk
punj
The fist thing i did was to go into the routers web configuration page to look at his router stats. I noticed that the router had been re-syncing multiple times and the line stats were very bad as well. The DL noise margin had crept up to 15db and the line attenuation of 36db didn't reflect to the lousy line rate of 800kbps.
To eliminate equipment i first tried a spare replacement belkin router. This immediately improved the line stats and line rate. So it was thought that the Linksys router was probably the cause of his problems and would probably be best to replace.
As the user was going on his annual holiday he asked me to repair or find a replacement router. I opened up the router and could not see anything wrong. Then i tried a replacement power supply and the router immediately was showing a more appropriate line stats.
So the problems was the power brick power supply. I decided to crack open the power supply.
The power supply was very basic consisting of a transformer, a pcb with four diodes and a smoothing capacitor. I tested the transformer on the secondary side which was giving out approx 17V under no load which seemed correct. I then tested the four diodes on the pcb which two tested unsatisfactory. The 2200uf smoothing capacitor also showed a capacitance reading of 83uf with an esr reading of 19.5 which defiantly was a sign of failure.
I replaced all four of the diodes with some spare IN5400 and soldered a new 2200uf 25V capacitor. The casing was glued back and the router and repaired power supply put back on the user's dsl line.
The results were a complete success as the sync rate immediately jumped up to a more respectable 7345kbps and the line noise lowering itself to 7db.
The cost of the the components replaced were under two British pounds and the client recently reported that he has never had his router work so well.
-- Another piece of electronic equipment saved from a journey to the ever growing landfill --
Check for more updates at http://www.punj.co.uk
punj
No comments:
Post a Comment