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Replacing the noisy fan in the PEB


kl99

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Hi,

I am currently trying to perform the FAN replacement within the PEB.

It is the push button PEB.

 

So far I have managed to disassemble everything and removed the original 110v fan.

http://www.mainbyte.com/ti99/peb/peb_box_project.html

 

post-27826-0-93418200-1420575394_thumb.jpg

 

post-27826-0-26884700-1420575406_thumb.jpg

 

But what to do with the wires that went into that fan?

How to best isolate those 110V wires?

 

post-27826-0-69213000-1420575416_thumb.jpg

 

And instead of soldering the power connector of the new 12V fan to the internal power supply I would prefer to connect it to the 12V MOLEX connector that goes to the disk drives. I have an adapter like this:

adapter-molex-4pin-f-molex-4pin-m-fan-2p

 

Thanks for any replies.

I hope to finish this before going to sleep...

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You could easily avoid the extra cables if you don't mind soldering two little connections.

The photo below (ripped off of the Mainbyte site) shows where you connect the 12v leads.

 

peb_17.jpg

 

As for the left over AC leads you could terminate them with electrical tape... or add a power tap for a low powered item you want to come on at the same time you turn on the P-Box.

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This is how I have isolated the wires that did go to the original 110V fan, the blue isolation tape was done 3 times just to be sure.

 

post-27826-0-97575400-1420639873_thumb.jpg

 

Here is the fan. I didn't reuse the nuts from the original fan because my smallest wrench was size 6 and that was slightly too wide. Will try to get better tools next time.

Maybe its an interesting note that the "screws" that hold the nuts are fixed on the PEB, you can not replace them by other stuff (plastic ones or whatever comes with your fan).

 

post-27826-0-36349400-1420639942_thumb.jpg

 

post-27826-0-04812300-1420639962_thumb.jpg

 

My fan came with a 3 pin Molex connector. Instead of soldering it directly to the internal power supply, I chose to use one of the many adapters that were lying around in my appartment from PC tooling.

The adapter is shown above. It is 2 pin only, but relax the 3rd pin is only sending optional feedback data like RPM to the mainboard. The 3rd pin is never used to control the speed of the fan.

You can see nicely how I wired the fan power connector to the big molex connector that goes to the disk drive(s).

 

post-27826-0-66917900-1420639985_thumb.jpg

 

The project is almost done, the PEB is closed already and the new fan was running fine on first tests, although I can barely hear it.

This new fan runs below 10db.

 

Thx to everyone who supported me, kl99

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  • 4 weeks later...

I followed the same process as kl99 and the fan replacement I'm using draws power via a similar adapter to the one kl99 posted (it is connected in line between the floppy power and floppy drive). Didn't recall just how loud the original PEB was until I set up my system a few weeks ago. Using an iPhone app (I don't vouche for it's accuracy), the noise level in my home office is ~38db with all electronics turned off. With the original PEB running the noise level rose to ~84db. After changing the fan, the noise level with the PEB running is ~42db with the new brushless fan. Makes a huge difference, and now the dog no longer runs off when I fire up the TI... :thumbsup:

 

Thanks to the Mainbyte site, kl99, and the helpful community here as this is definitely a worthwhile upgrade.

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  • 2 weeks later...
  • 1 year later...

ok, I have 2 PEB's where I want to change the fans.

 

Incredibly how loud these things are. What was TI thinking? Might have been ok for the server room, but surely not to have one on your desk.

Both PEB's are in the toggle version, not the push button version (does that matter?)

 

How much time does this take? Anything else that would make sense doing while the PEB is dismantled?

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ok, I have 2 PEB's where I want to change the fans.

 

Incredibly how loud these things are. What was TI thinking? Might have been ok for the server room, but surely not to have one on your desk.

Both PEB's are in the toggle version, not the push button version (does that matter?)

 

How much time does this take? Anything else that would make sense doing while the PEB is dismantled?

 

It takes 500 hours to get to the fan.

2 minutes to replace it and 600 hours to put everything back.

 

4962 screws.

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There is one "advantage" to the loud/audible fan: it helps to remind you the PEB is turned on.

 

Back when the quiet fan replacement was 'all the rage', there was an uptick in peripheral card repairs, often because someone forgot to turn off the now-silent PEB before removing or inserting a card. A visible warning aid, such as one or more top-down visible LEDs, is a good idea to round out the fan replacement.

Edited by InsaneMultitasker
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There is one "advantage" to the loud/audible fan: it helps to remind you the PEB is turned on.

 

Back when the quiet fan replacement was 'all the rage', there was an uptick in peripheral card repairs, often because someone forgot to turn off the now-silent PEB before removing or inserting a card. A visible warning aid, such as one or more top-down visible LEDs, is a good idea to round out the fan replacement.

Or a kill switch attached to the cover.

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There is one "advantage" to the loud/audible fan: it helps to remind you the PEB is turned on.

 

Back when the quiet fan replacement was 'all the rage', there was an uptick in peripheral card repairs, often because someone forgot to turn off the now-silent PEB before removing or inserting a card. A visible warning aid, such as one or more top-down visible LEDs, is a good idea to round out the fan replacement.

 

I second that. With my ATX PSU replacement in the PEB, it's really hard for me to tell if the PEB is on at all, and I frequently have to look at the switch position to verify...

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  • 1 month later...

ok,Incredibly how loud these things are. What was TI thinking? Might have been ok for the server room, but surely not to have one on your desk.

 

You must have never been around an actual IBM PC of the same vintage then. The public library I worked at for my first job had a genuine IBM PC XT as the main circulation desk computer and it sounded like a jet engine starting up when you turned it on. It was later replaced with a much quieter IBM PS/2 - but I suspect the loudness of the TI fan is just a product of the time it was made.

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  • 1 year later...

The easy way to isolate those power-bearing wires is with a bit of heatshrink over the connector. Easily cut off and it won't fail over time or leave residue like tape.

 

Like Greg, I went with an AC fan, mostly because I had several 120v fans on hand when I did the swap some three decades ago. 12v fans were not as common back then and 120v AC fans were plentiful and cheap in surplus. Rather than have the big PEB hogging the desktop, I had it on a low platform next to the desk. That kept the fan noise level even lower. A power bar handled the whole system with one switch.

 

My dual-in-the-PEB drives were already taxing the 12v line, so I ended up powering only one drive at a time from the PEB supply.

 

My "stock" TI had four drives, though the TI controller only allows three. The two in the PEB were drives A(1) and A(2), with a simple SPDT switch to send the 12v line to enable either drive singly. Drives B and C were outboard with their own beefy supply. Worked great to have two boot disks to choose from with B & C used for data, files or more programs. I tended to keep the same disks in each drive, which made it more of habit to know which one I wanted to boot with. It helped a lot with eliminating disk swapping to run another program for some little thing, then returning to the main task at hand. When writing programs, a flip of the switch and I could make a backup copy on another drive and floppy without changing the DSK# or filename.

 

The switched power concept could be extended to have B(1), B(2) drives and so on. In my stash was a long ribbon cable already made up that held more drive connectors than I ever needed. All I needed to do was wire up the switch for the 12 v lines to the drives.

-Ed

Edited by Ed in SoDak
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  • 2 weeks later...

I ended up using a ac voltage fan as they can run off the same power the old fan did.. and I don't have to jerryrig anything to the 12/5v lines got them at frys https://www.frys.com/product/8726151?site=sr:SEARCH:MAIN_RSLT_PG

 

Greg

 

Just to confirm, with an AC Fan, I wouldn't need to solder anything. I can just use the push-connector terminals that the current fan attaches to?

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Just to confirm, with an AC Fan, I wouldn't need to solder anything. I can just use the push-connector terminals that the current fan attaches to?

Correct and it will not be silent there is no such thing as a fan that moves good amount of air quietly that is that size it will be about 40% quieter which is a distinct Improvement.

 

Sent from my LG-H830 using Tapatalk

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