Jump to content

NLCbanner2024.jpg.2478be509670e60c2d6efd04834b8b47.jpg

Cooling fan modification (4 images)

daz

By daz
in DIY Astronomer

Recommended Posts

daz

daz

Posted
Posted

Despite my best protests, I had to go shopping this morning, so no work on the conservatory (she's the one that will moan when the sprouts have gone cold from sitting in the draft!!!), so I decided to start the first in a series of simple modifications - A cooling fan on the rear plate of my 8" Skywatcher Newtonian.

This is fairly straightforward, not too much fiddly stuff.....

Materials required were:

- Standard PC cooling fan (£5 - £10)

- Case mounting 2.5mm DC power socket (£2 - £3)

- Matching male power plug (£2 - £3)

First task was to cut out a central hole in the plate the same diameter as the fan - 91mm.

I started by drilling a central pilot hole, and using a pair of compasses to draw the circle. Then using a jig-saw to cut the central hole

Also, drilled a hole to accept the case-mount DC socket, and the four corner holes for the fan screw fixings

image.jpg

As you can see, the hole is not dead centre, but it's not really important - asthetics more than anything else!

Make sure you file down any burrs - you don't want any cuts to cables or to you!!!

Second task was to fit the fan and socket in place - nothing too demanding here....

image.jpg

Third task then was to solder the fan wires to the socket. Before doing so, I rigged up a temporary cable, as I needed to check which way round the fan would spin. I needed it to suck air onto the mirror cell. So I snipped the the PCB connector from the fan lead, snipped back the YELLOW wire (this is used for feedback sensor to the motherboard normally - not needed here!) and soldered the RED lead to the centre pin of the socket.

The power lead has one lead marked with a white stripe, so I checked this and found this corresponded to the centre of the plug. So I attached this to the centre pin of the cigar-adaptor on my temporary lead. Plugged it in and switched on and Hey Presto! Worked first time, and in the right direction! Bonus!

I snipped the leads from the case-mounted socket, leaving a short stub of insulation so I knew which way round to solder, and cut the leads back to the right length before re-soldering in place.

image.jpg

Plugged the temp lead back in and checked all was working. All was! Checked voltage drawn at 11.7 volts, current was negligable, but as it will only run for around 15/20 minutes this is fine.

Finally, re-attach the plate to the back of the scope, and test!

image.jpg

With the scope dust cover off, there was a little air movement, certainly more towards the edges, but I knew the fan was spinning in the right direction. Put the cover back on and remove the off-axis cover and there was a good air flow through the tube.

Eventually, there will be a small switch box velcroed onto the tube with switches for the fan, a secondary/finder dew heater, but for now, my temporary cable will suffice.

Project Complete!

Link to comment
Share on other sites
daz

daz

Posted
  • Author
Posted

Thanks guys

It's looking clear here (am not am home at time of writing) so will be able to test. I plan to record the air temp and time how long it takes the temp to drop.

Will let you know...

Link to comment
Share on other sites
daz

daz

Posted
  • Author
Posted

Workbench purchased only 3 days ago - this was it's first project :clouds2:

£9.99 in Homebase - not to be missed!!

Anyway, the fog has decided to pay a visit, and the gremlins as I can't find my thermometer either :clouds2:

Forecast is not looking too bad for the next couple of days, so hopefully will get a chance then - and assuming I can find my bleddy thermometer!

Link to comment
Share on other sites
daz

daz

Posted
  • Author
Posted

Well, got out tonight and gave the new mod a run...

Still can't find my thermometer, but I ran it for 20 mins while I tidied up from DIY and I reckon that was all it needed! Not terribly scientific I know - I will make the necessary measurements when I get a new thermo........

Next project: Dew zppers for finder and secondary - URGENT!

Link to comment
Share on other sites
  • 2 weeks later...
daz

daz

Posted
  • Author
Posted

Seeing Caz's scope has reminded me.......

I found my thermometer, so over Christmas, I will measure the speed of cooling with and without the fan running so people can see the difference.

Link to comment
Share on other sites
  • 2 weeks later...
daz

daz

Posted
  • Author
Posted

It does - it takes some time, but it does get there. As you can see from my other post, this is now done and I just need the chance to test it!

Interestingly, I am exposed to the North. I think it may be worth notice things like wind strength and direction as well as temp/humidty. There is bound to be some common factor - not being any sort of meteorologist, I don't have a clue how to predict these things...

Link to comment
Share on other sites
  • 5 years later...
  • 2 weeks later...

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.