Sunday, August 16, 2015

A new PSU... KPO SPS-30-II ... PART 2: Installing the missing part

So I promised part 2 soon , so here it is :)

This week my order of 10 clixons (50c N.O.) arrived.....
And today i had time to add this to my latest PSU.....

So again i got rid of 13 screws....


And i looked at an empty spot where a clixon should be......


The holes you see there are only in the metal sheet they use for a heat sink... they are not drilled through.... which took me about a minute to fix.... 2 nice holes all the way through.....

I installed the clixon.....


You can see the slightly smaller black bolts i used to install the clixon. You would say this is as it came from the factory if you would not know better....

When wiring up everything, I noticed it that it would be better to rotate the fan 90 degrees, so the wire would exit the fan close to the clixon. (2nd picture)




The fan they use i this model is not (how surprising)  an expensive one.... I might replace in time with one which is better (at least one with a ball bearing)
I am not sure yet as it might also be handy to have a "noise" warning if it becomes too hot.




After that it was just a bit of soldering and the job was done.....


I put back the cover, screwed in 13 screws.... and reinstalled it on the shelf....
Again, I now have no fan noise if everything is in idle mode.... nice and quiet....

So from a silent shack, I wish you 73's!

Alex
PA1SBM

4 comments:

  1. waar heb je de clixon besteld?

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    Replies
    1. Hier:
      http://www.ebay.com/itm/10pcs-KSD301-Temperature-Controlled-Switch-Thermostat-50-C-N-O-Normal-Open-/301193012567?hash=item462080a557

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  2. Hello Alex,

    I also modified my PSU (same brand) with a 50°C Klixon. But I put a 200R /5W resistor in series with the fan. When the kixon switch on, the resistor is bypassed giving the full voltage to the FAN. If you want a picture I can send that to you. The resistor is soldered on the kliwon tabs.
    Best 73s,
    Philippe - F4GRT (at)sfr dot fr

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  3. Hi Tibor,
    The fan in my unit is fairly silent as it is, and it only powers my dualband tranceivers, so no high load anyway.

    I did this mod in all 3 of my other 30amps PSU's and it works like a charm... yes at the point it gets hot the fan goes on full, and it becomes somewhat more noisy (not much as i have papst low noise fans installed) and as the clixon needs the temp quite a bit lower to turn off, it cools it back down a lot. I used one of my PSU's for a IC7600 when in a 24hr contest. It turned on once, even though we were using full power.

    in both types of PSU's the clixon is very close to the power transistors. so it will kick in on time.

    As for the noise, in my own shack i never put much continuous load on my PSU so its always quiet. i rather have it turn on on a rare occasion then being on all the time on a low level. I try to have my shack audio noise free... i only want to hear my radio, and i manage to do so...

    Thanks for reading my blog!

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