Question Replacing an old fan

[Sefirosu]

Hi all,

I have an old PC monitor and I need to replace the very old fans inside because they are so loud.

My question is will this new fan be a compatible replacement with the monitor? Specifically I am asking this as it lists the old fans Current: 0.23A, Watts: 2.76 but the new fan says the current at 12V DC is 0.16A which is obviously lower. I used a voltage to watts calculator which says the watts for the new fan is approx. 1.92 which also lower, not sure if this will be an issue or not.

Old fan (click specifications): https://www.thermalfx.com/fans/80/MMF-08C12DS.html

New fan (click technical data): https://www.arctic.ac/uk_en/f8.html

I appreciate any help. Thanks in advance.

 

[jay32267]

"the power being lower" shouldn't be an issue...at least from a PSU standpoint.

What I'm saying is....it should run fine.

Although being it is lower power....(if the new fan is the same efficiency as the old fan).....you will get less airflow.....this may or may not be an issue.

 

[Sefirosu]

"the power being lower" shouldn't be an issue...at least from a PSU standpoint.

What I'm saying is....it should run fine.

Although being it is lower power....(if the new fan is the same efficiency as the old fan).....you will get less airflow.....this may or may not be an issue.

Sorry, I've just realised that the old fan link is incorrect. This is the specs of the old fan according to the original datasheet: http://www.excesssolutions.com/mas_assets/acrobat/ES2304.pdf

MMF-08C12DL
Rated voltage [V] 12
Rated input [W] 1.08
Rated current [A] 0.09
Rotational speed [min-1] 2030

So actually, the new fan's amps is higher. This could be a problem now, right ? (Possibly not enough power to give to the fan?)

 

[tennis2]

No problem at all.
I also doubt that that OEM junk fan is somehow more efficient than Arctic as far as requiring less input voltage.

You said this can is in a "monitor"? Are you confusing the computer case/tower with the monitor (aka, the component with the screen on it)

If you want something quieter, I actually own and like the Enermax TB Silence

 

[Sefirosu]

No problem at all.
I also doubt that that OEM junk fan is somehow more efficient than Arctic as far as requiring less input voltage.

You said this can is in a "monitor"? Are you confusing the computer case/tower with the monitor (aka, the component with the screen on it)

If you want something quieter, I actually own and like the Enermax TB Silence

Great, thanks.

No, It's an old CRT monitor made by NEC in the late 90's - NEC XP29 Plus. The old fans are super loud which is why I want to replace them. The problem is, is that the monitor shuts down/won't turn on if the original fans are removed or replaced. Therefore, I have to use 2 new fans and one original fan and bridge all the sensor wires to one JST header and somehow the monitor will detect the fans and turn on. I assume it's the start up voltage or something causing it to only detect the original fans or the exact 2030 RPM or above of the original fans, I don't know. Other people have tried Noctua's with no luck either.

They also all run at 12V so I'm using DC-DC converters to lower the three fans to 9V. Anyway that is another story 😀

But yea, I chose the Arctics because they also run at 2000 RPM max same as the originals and were only £12 for 5! I know there are better options out there like the one you posted but I think the Artics should do ok.

 

[tennis2]

Is this an old arcade machine?

 

[Sefirosu]

Is this an old arcade machine?

No, it's an old CRT presentation monitor. Manual: https://drive.google.com/open?id=1ZE5Cgq9fIRTKoD2Vx9pX4jc53xvemVJF

 

[AllanGH]

Oh GEEZE!

I actually ran 2 of these on my computer, back in the 90's--they were the very best set of CRT monitors that I ever laid eyes on--and, yeah, the fan noise was...uh...noticeable.

I can think of a few ways you might cheat their system:

Remove the blades from an old fan hub, and connect it up to make the detection circuits happy, then run the fans you want in there from tapped voltage from the internal PS, with a speed control tacked-on. (Very temporary fix, but easy to implement.)

Fool the detection circuit with an Arduino and buffering circuitry to drive the new fans. (Permanent fix, and makes the use of any contemporary fan possible, but more involved from an engineering standpoint.)

Find direct replacement fans for the unit. (Probably not the direction you want to go in the first place, and may not even be possible anymore.)

 

[Sefirosu]

Oh GEEZE!

I actually ran 2 of these on my computer, back in the 90's--they were the very best set of CRT monitors that I ever laid eyes on--and, yeah, the fan noise was...uh...noticeable.

I can think of a few ways you might cheat their system:

Remove the blades from an old fan hub, and connect it up to make the detection circuits happy, then run the fans you want in there from tapped voltage from the internal PS, with a speed control tacked-on. (Very temporary fix, but easy to implement.)

Fool the detection circuit with an Arduino and buffering circuitry to drive the new fans. (Permanent fix, and makes the use of any contemporary fan possible, but more involved from an engineering standpoint.)

Find direct replacement fans for the unit. (Probably not the direction you want to go in the first place, and may not even be possible anymore.)

That is cool I didn't expect anyone to post that owned two themselves. I have two as well and they are really great but yes fan noise is a real nuisance.

Thank you for the suggestions. I especially like the second idea but I'd have no idea how to do that! I can only solder lol. Another guy who had one of these and gave me some advice did something similar, he said:

I made it quiet

After much experimentation I discovered that the XM29 only seems to like it's original fans. Any replacement fan I tried span but the monitor turned itself off after 5 seconds as it normally does in the case of fan failure. I'm not entirely sure why that is. I found a datasheet for the original fans but they didn't seem to be anything special. Maybe they have unusual hall effect sensors on the RPM line or are not open collector.

Anyway, eventually I did discover that the XM29 is fine with it's original fans running on 5V instead of 12V. The lower RPM doesn't seem to bother it. Unfortunately the fans won't start at 5V and are not that quiet even then. I gathered up a few spare parts I had lying around and came up with the following solution.

I picked the quietest of the original fans and attached it to a little circuit using an LM317 voltage regulator and an ATtiny13 microcontroller. I could have used a 555 timer instead of the microcontroller but I didn't have one to hand. The LM317 is set up to provide 5V for the fan to run on. The 317 is controlled by the voltage to the adjust pin, which is normally connected to a potential divider which itself is connected to ground on one end. Rather than connecting to ground I connected it to a pin on the MCU. The MCU holds the pin at 5V for two seconds which causes the LM317 to supply ~10V to the fan, enough to get it started. The MCU then drops the pin down to GND and the LM317 produces 5V to keep the fan running. The MCU also monitors the fan's RPM to make sure it doesn't stall.

For the other two fans I replaced them with Panaflo silent ones running at 5V (generated by in-line zener diodes). Because the XM29 does not seem to like their RPM sensor output I simply connected their sense lines to the original fan. Having three sense lines commoned to one sensor doesn't seem to cause any problems.

He then sent me this image:

I tried to change it and added extension cables (to save cutting the original wires + give extra length which is needed for the new fans) and use DC-DC regulators instead of diodes.

Ideally I would like to do something such as your second suggestion but I don't have the knowledge with that stuff so I think the picture above will do. You think its ok?

 

[tennis2]

Uh, I'm sure there's a good reason, but..... why hasn't this been converted to a modern LCD?

 

[Sefirosu]

Uh, I'm sure there's a good reason, but..... why hasn't this been converted to a modern LCD?

This video probably explains it much better than I can:

View: https://youtu.be/RAi8AVj9GV8?t=21


Tldr; for gaming. They can handle native resolutions for old games unlike LCD's and are also lag-less. The games look incredible on these high end CRT monitors especially. Just this one has a few very annoying fans 🙁

 

[AllanGH]

Ideally I would like to do something such as your second suggestion but I don't have the knowledge with that stuff so I think the picture above will do. You think its ok?

Yes, but don't connect all of the sense leads together. Connect the sense lead of only the original fan, and leave the sense lead of the new fans disconnected.

The advantage of running a couple of these monitors is that it does heat up the house pretty well during the Winter months. 😉

 

[AllanGH]

Uh, I'm sure there's a good reason, but..... why hasn't this been converted to a modern LCD?

They are--hands down--the very best CRT monitors one could ever hope to have connected to any computer system. The image produced was very nearly perfect for my eyes. Granted, they lacked DVI and HDMI inputs, but that's to be expected, given their vintage.

For me, it was VERY difficult to finally let go of these monitors. Desk space and environmental heating were the decisive factors in finally doing so; and, while I got a very good price for them, I still regret letting them go.

Frankly, if I saw a couple of them, in excellent condition, up for sale...I'd have a hard time convincing myself that I shouldn't grab them.

 

[Sefirosu]

Yes, but don't connect all of the sense leads together. Connect the sense lead of only the original fan, and leave the sense lead of the new fans disconnected.

The advantage of running a couple of these monitors is that it does heat up the house pretty well during the Winter months. 😉

Ok, I will try without connecting the sensor wires together first. Hopefully the monitor will be ok with the new fans sensor RPM. However I'm doubtful as the other guy said it wouldn't work with his Panaflo fans sensor wire connected to the board which is why he bridged them all together.

He did say this too:

For the other two fans I replaced them with Panaflos running at 5V (serial zeners). Because the XM29 does not seem to like their RPM sensors I just attached their sense lines to the first fan. It doesn't seem to cause a problem having them commoned.

 

[Sefirosu]

They are--hands down--the very best CRT monitors one could ever hope to have connected to any computer system. The image produced was very nearly perfect for my eyes. Granted, they lacked DVI and HDMI inputs, but that's to be expected, given their vintage.

For me, it was VERY difficult to finally let go of these monitors. Desk space and environmental heating were the decisive factors in finally doing so; and, while I got a very good price for them, I still regret letting them go.

Frankly, if I saw a couple of them, in excellent condition, up for sale...I'd have a hard time convincing myself that I shouldn't grab them.

I don't know what your usage for your NEC's was but you should look at the Sony BVM-D24E1W* it is a colour grading monitor and although it doesn't handle the wide range of resolutions as the NEC, it ranges from 320x240 (240p) to 1280x720 (720p). It is also one of the only CRTs to do this as well as being a 16:9 display and is much sharper than the NEC. Of course it has a smaller screen but the NEC is 0.60mm pitch with 600-800 TVL whereas the BVM 24 is 0.25mm pitch with 1000 TVL.

The quality of the picture is insanely good and blows any plasma or lcd I've seen out the water. OLED has better black levels though.

An annoying thing with the NEC is all of the adjustments have to be made manually in the back of the case via potentiometers, adjusting poles on the CRT neck board area etc. With time these go out of spec so most of them require adjustments to be made. Some of the more modern pro-CRT's can be adjusted via the OSD menus.

Mine is sitting on the floor with a blanket over it (so the cat doesn't get electrocuted!) waiting for these fan parts to arrive. Hope it works!!

 

[AllanGH]

My use case, back in the 90's was just dual monitors for the PCs I was using, back then--at maximum resolution--and I just kept using them through the early 2000's. The nice thing was the additional inputs to use for various needs, now and then; and I did prefer the manual controls to OSD menus at the time.

I do, however, very much appreciate the monitors I have, now....LOL

 

[Sefirosu]

My use case, back in the 90's was just dual monitors for the PCs I was using, back then--at maximum resolution--and I just kept using them through the early 2000's. The nice thing was the additional inputs to use for various needs, now and then; and I did prefer the manual controls to OSD menus at the time.

I do, however, very much appreciate the monitors I have, now....LOL

Interesting. Yes it does have a lot of inputs only missing DVI + Component (analog-wise). I wouldn't want to use one as a PC monitor nowadays though either. Their use today is certainly niche.