Motto: Working under humax conditions is a basic humax right.
REASON: Constant overheating of capacitors and transformer on the supply
board of my IRCI5400.
It's my pleasure to help you with this article but DO NOT FORGET:
220 V AC is good for HUMAX not for human !!!
Disconnect the power supply from your box before you start. Don't proceed
with any changes to your IRCI5400 if you feel confident about many things in
life but not electronics. Don't do anything if you are not sure you can do it
well without diagram.
You can make life of your electrolyte capacitors much easier if you use fast
ceramic capacitors (connected parallel to the electrolytes at the back of the
PCB). I used 105 M Z5U63 - 1,0 microF/63V. This is just a little help - do not
expect miracles. Do not apply if you are not an expert.
You need two fans 12V DC/0,17A 40x40x10 mm (as used with CPUs), material to
build the wall (for example PCB) and adhesive elastic band - Duck Tape or thick
two sided fixing tape should do just fine.
Simple rule: red to red black/red to black/red.
The idea is to make fans blow from mainboard towards the power supply board,
NOT reverse. Be careful.
Connected to +8 V DC. I used +5 V at first but the fans wouldn't start reliably,
so I had to change it. Both fans need only 0,14 A.
Black/red wire is connected to the ground via plug to the left side of the connector
supplying main board. Connection point for +8 V is situated to the right of
the transformer, next to the capacitor 470 microF. ATTENTION: The left radiator
is connected to 220 V current. Do not look for +8V anywhere near left side of
transformer.
19th of July: My IRCI5400 seems pretty cool now. The low level background
noise of fans spinning could be annoying to High-End-Audiophile but is acceptable
for me... Or is it?
20th of July: No, my previous statement wasn't true - the whole lot makes
way too much noise. So I made the following changes: The fans are now fixed
using two sided Duck Tape attached to only two points (diagonally). Also added
a red luminescence diode to the + wire.
Now you can see much better where the supply points are.
What is the red luminescence diode for? It was the simplest way to lower
down the voltage supplied to the fans. 6.6V and 119mA and both of them still
start without any trouble and make much less noise.
NOW THE MOST IMPORTANT BIT: Use Duck Tape to fix our fan board inside
using two mount points shown on the pictures above. Only two mount points to
avoid hard, acoustic connection to the housing. The wire bundle supplying main
board can go above our fans adding extra stability once top cover is put back
in place.
The result: humming is barely noticeable even for an audiophile. It's
all working, fans do their job just fine and the hard working capacitors and
the transformer are OK. All accordingly to the basic humax rights.
With best thanks to TOM for the introduction to digital Sat TV
Zbigula, Europe, 21th July 2001 [All photos by author]
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