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Can you hear me now... over the fan? -- (Excellent new comment 12/13/2017)

Posted by --- Ω ---, 10 May 2015 · 1,698 views

Can you hear me now... over the fan? -- (Excellent new comment 12/13/2017)

The TI-99/4A section of Mainbyte.com is a great site for any TI'er.  There are a some really great ideas for system modifications listed there, both simple and complicated.  What really makes this site shine are the HIGHLY DETAILED instructions for the hardware modifications.  This place will give even a newbie the confidence to tackle jobs they normally might not have considered.
Now recently I went there looking for a potential new project for my TI, only to be reminded that I've been neglecting my backup box.  If anything ever happened to my primary box, I'd still want to maintain my hearing and sanity... so it was time to finally install the fan that had quite literally been sitting on my shelf for months.
I did not go into a lot of detail here, as the project is very well documented on the Mainbyte site.
When I opened up my P-Box, I was pleasantly surprised to see that it was not very dirty.  I guess this box got little use over the decades.
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Thanks to Mainbyte, the connection point is EASY  to find!   :)
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As you can see, there is plenty of room to work there, so even if you're a newbie or messy with a soldering iron, chances of a solder bridge are low.  Just check your work afterwards.
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The fan I purchased did not have RED and BLACK wires, so if you lose track of the wires, this model fan will NOT operate when you turn on the P-Box... until you hook it up correctly!
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The fan installed is only 15 Decibels!  I simply cannot hear it, but that might be my old age setting in.   :skull:   Anyway, the disk drive makes more noise than the fan!
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If you've not yet installed a fan in your P-Box(s) yet, you might want to give it a shot.  

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great mod :) I replaced my Monster fan with a nice quiet one with pretty blue LEDs :D

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I have mounted this one with 10 decibells :)    (hint,hint ;)


RED is BLACK and -PLUS- is +MINUS+ :)



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That's a little scary Schmitzi.  I know the TI fan was total overkill, but the fan you listed is measured at only 15.3 cubic feet per minute, that's roughly half of what the example at mainbyte shows.   Mine is close at 27.94 and even then I think it's a little on the low side, but since I keep my house at 71 year round, I figure I can live with it.


Maybe someone will jump in with some hard data or manufacturer recommended specifications?


While looking into one of those PC temperature monitors for my TI.  I found << THIS >>.   What do you think?  It's cheap, easy to siphon off power and the sensor can go in the power supply area... but how would you choose to mount it on your TI?



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My fan has blue LED lights, so now the P-box looks like a cool gaming rig. Hah!

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I decided to buy and install the temperature meter shown above.  The blog entry for that project is << HERE >>.

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After making the quiet fan mod, I will not run another PEB without it. 


It is so much more enjoyable to use without the stress created from that noise. The noise / sound of the PEB sure was iconic, but I now prefer it live only in my memories... 


This was really an easy mod. And so well worth it.   Thanks for tipping us off to this.


One question, do you ever see the temperature rise? Now that you have the display to monitor it?



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One question, do you ever see the temperature rise? Now that you have the display to monitor it?


Yes!  When I first turn it on it's the same temperature as the room, but slowly rises over time and then levels out.

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Nicely documented as always, Omega, thanks.  And certainly helpful to have this in addition to the Mainbyte.com how-to article.


I'm considering replacing my PEB fan, too.  I found a nice Cooler Master unit but...I'm unsure of the requisite size for this project.  I know I should carefully measure to confirm but seems easiest to just ask:  what's the physical size of the replacement fan you've used?  Is it a 92mm unit? Or maybe 80mm? 120?

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I decided to take the plunge on this project.  The whole undertaking required a bit more time than expected, but I’m quite happy with the results.

I thought it would be worthwhile to augment the documentation in this thread with some of the things I discovered:

(1)  I did measure the opening for the fan in the TI Peripheral Expansion Box (PEB); a standard 80mm PC case fan is the proper size.

I wanted something ultra-quiet that still moved a significant amount of air.  So I invested a few extra dollars in the Noctua NF-A8 FLX.  Here’s a shortened list of its specifications:
Size:  80x80x25 mm
Connector:  3-pin
Rotational Speed (+/- 10%):  2000 RPM
Airflow:  29.66 cfm (50.4 m³h)
Acoustical Noise:  16.1 dB(A)
Max. Input Power:  0.84W





(2)  I found it fairly challenging to solder the new fan into place because the surrounding components left me very little room to maneuver the soldering iron, even with the circuit board pulled away from the chassis.  Thankfully, I used very thin soldering wire and that made the melting/attachment fairly quick without much mess.





(3)  I decided to go the extra mile and measure noise levels before and after installation.  The new fan registers at a mere 20 decibels.  That’s slightly higher than the listed spec (16.1 decibels), but it’s still exceptionally quiet.

OFF (quiet room) = 33 decibels
ON (quiet room with original fan) = 77 decibels
ON (quiet room with new fan installed) = 53 decibels


(4)  Being energy conscious, I decided to measure the power consumption, too.  Again, noting the old fan is listed at 14 watts and the new fan is listed at less than 1 watt, the readings confirm 13.5 watts less power consumed.

OFF = 0 watts
ON (original fan) = 67.4 watts
ON (new fan installed) = 54.1 watts



Fun project!  And remarkable reduction in noise.

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Awesome update packed with good information.  I especially liked your readings of the sound levels and reduction in power consumption.  You've inspired me to to plug my TI into my Kill A Watt and see the bad news.  


On another note, I'm pleased that it all worked out for you and that this blog entry had some positive impact!  

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