Henry 5k blower mod

I wanted to quite down the noisy 5K.

It has a temp sensor in the air going through the tubes that controls the blower speed.

It is now as quite as the Collins 30S-1!!!!!!!!

I also have done a few more mods shown below.

The EBM blower on the custom shock mount plate next to the noisy Dayton blower

The Blower mounted


Next I fixed the air flow through the tubes

What really needed addressing was the chimney set up.

The chimneys were the same diameter and made it tough to get air through the tube

In the Photos you will see how I made them have less back pressure



Before and after

After !

Boring it out.


The thermal switches that control fan speed


After this I decided to further reduce back pressure by modifying the RF deck cover

I used fan grills for safety. The air is flowing better and noise is further reduced.


Last but not least holes and fan guards installed on top of cover plate

This really helps the amp to get the hot air out


Input and output relays were not timed right so I changed to two high speed output relays in parallel




I also wanted to light the meters.

I used yellow leds. I defused the lens with 400 grit sandpaper. When it is in standby the meters are dark and when it is in operate they light up.

In the photo the light is washed out. In normal light they look like 47 light bulbs

Meter lens removed.

I drilled right through the meters and pushed the LED's in from behind


Last mod is a pair of jacks across the cathode fuse so when the fuse is removed plate current can be measured with a high quality meter. It also will allow me to pull the fuse and add series diodes by plugging them in the jacks and lower idle current. After I figure out the number of diodes I can install them.The amp was designed for 4kv on the plates and currently has 5kv. So it is idling a little high.