Posted under Hardware & Knowledge Base & Networks & PC
Permalink
Tags Gotcha, Tip
We had a power cut recently and as a result, the Procurve 1810 switch in my garden office stopped working. After investigating, I discovered the PSU was faulty, likely blown by a voltage glitch during the power cut/restoration (it was also pretty old having been purchased in 2009). I had a spare PSU and a spare switch, but wanted to have a replacement on hand in case another one blew. I dismantled the old PSU to see if it had an internal blown fuse that I could replace. It used a very non standard screw to hold the case together, a bit like a torx but with a centre spigot. I managed to undo it with a torx, but even then the case was very hard to prise open – they definitely did not want you to dismantle it! Once I had it apart there was no fuse so I declared it completely dead.
The issue was that as the kit is proprietary HP, it uses a completely non standard DC connector on the switch that I could not find a PSU for readily anywhere. As the switch is old, there were a few places offering compatible PSUs, but I could not be certain that they had the correct DC connector. The frustrating thing was that the PSU requirement was a standard one, 12v 1.25A, which was available cheaply in many places with a standard 5.5mm x 2.1mm DC connector, and I had a spare one of these. Whilst I also had a PSU with an adapter on the end and a choice of DC connectors especially for this kind of situation, none of the choices I had matched the Procurve PSU connector.
I had a couple of the 5.5 x 2.1 soldered cable mounting female sockets so elected to chop the DC cable off the old supply and make my own adapter. I left plenty of cable length so I could easily chop the end off and redo it if the adapter went wrong in future. Some care was needed soldering the cable socket – I used heat shrink sleeving over the centre pin joint, as the outer soldered joint was very close. I also used some larger heat shrink over the whole thing. In retrospect, I wondered if I could have added another piece of heat shrink over the outer soldered joint as well, having squeezed the end crimp solely over the outer cable run, not both. However, I think I was borderline tight as it was re getting the plastic cover on, and all the heat shrink was fine. In future I might consider just heat shrinking both connections separately and not using an outer one at all, but the tricky balance is that there is no overall cable clamp and I liked the idea of an overall heat shrink.
The existing soldered cable sockets I originally obtained from Maplin are available on Amazon here. You can also buy pre wired sockets with a length of cable (which would need an inline cable-cable-joint) but the only ones I could find were panel mount sockets rather than cable mounted.
Comments Off on HP Procurve 1810 – blown power supply