CurtPalme.com Home Theater Forum

[1031]

Ok. Here is latest mod. On this popular thread i posted little fan mod that has been great, it reduced greatly rear heatsink temp + internal temp. was lower also -> https://www.curtpalme.com/forum_archived/viewtopic.php@t=9608.html

Only problem was that gonvergence took some time to stabilize, mostly because heatsink was cooled better from the startup..
I decided to design controller that starts fan at certain temperature and then tries to keep heatsink temperature steady.

(Look at this pdf ->1031 marquee rearheatsink fan controller 12v.pdf)

It is based to NTC-resistor that is connected to "voltage divider"(Ntc+R4) and that voltage is feedet to OP-amp´s inverting input.
Noninverting input gets adjustable "reference voltage" from R2 trimmer, that trimmer sets temperature point where fan is started. R1 trimmer is there to adjust gain of corretion (temperature/voltage to fan) without it (infinity resistance) that acts much like comparator-> fan on or off
Output of OP-amp is connected to base of transistor Q1 via r3 (220ohm) transistor acts like current amp. rest of componencs are for filtering (c3,c1) R1 (2,2ohm) is there for filtering+ it acts like fuse also (fusible 0.5w) D1 is there for correct polarity (ie. connecting voltages reversed does not harm any components) And those optional trimmers are just for alternative type of trimmers for board.

Here is how it works:
Time / Temperature / voltage to fan/ does fan spinn
17.55 / 24 / 1,39 / No
18.00/ 25 / 1,39 / No
18.05/ 30 / 1,40 / No
18.10/ 34 / 2,35 / No
18.12/ 35 / 4,70 / No
18.13/ 36 / 5,90 / No
18.14/ 36,5 / 7,30 / Yes
18.15/ 37 / 7,75 / Yes
18.20/ 38 / 8.80 / Yes
18.25/ 38 / 8,82 /Yes
12.30/ 38 / 8,88 / Yes
18.40/ 39 / 8,97 / Yes
19.00/ 39 / 9,10 /Yes

I have external powersupply (12v) that runs some of fans (belly+ that extra rear heatsink fan) So i desingnet alterative version if someone wants to build version that operates from same voltage (24v) that marquees belly fans are feedet.

Here are scematics and board layout pictures

And yes convergence is much more stable with this fan mod

Edit: 24v versions addet (24v in to the controller,12 volt out (max)to fan

[HK-Steve]

Jarmo,
Very nice,


Will be a nice addition to my 4x 120mm fans on the rear heatsink for me.



How much current is the board limited to ??




Cheers
Steve

[1031]

[1031]

One note..I have not yet build those pcb´s (i´m doing few board within 2-3 weeks) So after then i test those two (12v and 24v versions) how those work. So before someone starts to build own board.. it is better to wait until i have tested those.
But this is so simple device that experiment pcb is good enought , if you dont have access to PCB etching

[Nashou66]

Hey jarmo you can send those cad files to alberta PCB in canada, they are not that expensive, i bet 10 boards would be about 100 dollars, and more boArds would be less. Then you could sell the kits or just the boards. How big is the PCB?

I really need to upgrade my eagle software and get into PCB layout again, its lots of fun.

Athanasios

[1031]

[HK-Steve]

Hey Jarmo,
24v versions for me please.
But I could also use a 12v version.


Have a Great New Year to all.


Cheers
Steve

[Nashou66]

Hi Jarmo, I added your work to the Marquee Modifications and Performance enhancement thread right after your link above and also added the Link on the first page of the thread. i am adding direct links in the beginning to all the mods and any other important info i think any new reader would want to jump to.

http://www.curtpalme.com/forum/viewtopic.php?p=201825#201825

https://www.curtpalme.com/forum_archived/viewtopic.php@t=9608.html



Athanasios

[1031]

Little update. here is how i installed that card.