Sunday, December 9, 2012

OHR100A Build

Finally the OHR100A arrived but in the end I had to nip down to our local postal sorting office to collect it as they were complaining about how busy they were and it was going to take time to deliver. 

The parcel was well packed with individual sections of the kit separately kept apart which made things easy for identification. Marshal certainly makes sure of doing a good job in packaging as everything is nice and secure.

So the build of the OHR100A begins. To start with I thoroughly checked the inventory to make sure I had everything; I ticked off each part as I went and seemed to be all there so I could get on and make a start. I don’t plan to rush it; I’m going to take my time and build in roughly 2 hour slots so that I don’t over do it and make silly mistakes. The first part is to install several diodes and the IC sockets making sure that all are correctly positioned on to the PCB board before soldering.

The instructions seem very clear, certainly as good as the Wonderlabs notes which helps greatly when a newbie like me is attempting something a little more difficult than the RockMites. Amongst the instructions is an overlay sheet with clear diagram of where each part should sit which is very useful.

6 hours later and I’ve installed the diodes, chips, chokes, resistors, trim caps and capacitors, the only problems so far have been a slight issue with soldering as I’m having to re-apply a small amount on a few components to the top of the PCB board as the soldering is occasionally not penetrating through the holes, this is more likely because of the solder I’m using but in actual fact probably helps in double checking that everything is soldered correctly.

Approximately 9 hours later and I've all but completed the PCB board. Just the IC's to slot in to place and add in the Molex connectors. The toroids were a little fiddly but I think that is probably due to lack of practice and experience, but once I had done the first the others seemed to wind OK. 

Interestingly in the picture below you can see my one mistake that I had to rectify, which was placing the transistor D105 in to U104. As soon as I done it I realised my mistake but then had the job of carefully removing the transistor and then soldering it in its correct position. The one thing I've learned is that as soon as you feel at all tired take a break because that's when mistakes are made!

Now I have to assemble the chassis with all its components which hopefully won't take too long and then just wire up and do the smoke test.......More to follow!

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