Subject: BA11-F boxer muffin fan source ?

From: Tom Uban <[email-masked]>
Date: Tue Jun 17 07:42:00 2003

Hello,

I am restoring an 11/70 with a BA11-F chassis which uses 17 4.7"x4.7"x1.5"
115v muffin fans (as they all do) and need to find a good source for
replacements. Does anyone have any suggestions?

--tnx
--tom

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From: Tothwolf <[email-masked]>
Date: Tue Jun 17 19:27:00 2003

On Tue, 17 Jun 2003, Tom Uban wrote:

> I am restoring an 11/70 with a BA11-F chassis which uses 17
> 4.7"x4.7"x1.5" 115v muffin fans (as they all do) and need to find a good
> source for replacements. Does anyone have any suggestions?

I'd also like to find a source for 3 (maybe 4?) of these myself. The SGI
IRIS 1400 I have currently has 240V fans installed, and I'd like to
convert it back to 120V operation.

It appears the system was modified to run on 240V after it was shipped to
Europe. The only changes I've noticed have been that the fans were
replaced, some jumpers were resoldered in the power supply, the metal
plate with the IEC power connector appears to have been changed out, and I
think the power switch was also replaced. The metal plate with the power
connector has the 240V power requirement painted on it, so I know that was
replaced. It appears the original 120V plate may have also had accessory
outlets (can anyone prove or disprove this?), as there are some extra
wires behind it terminated with quick connect terminals. The original
power switch appears to have been a lighted 120V rocker, which was
replaced with an unlighted rocker. The current power switch is already a
candidate for replacement, as it is in pretty poor shape, and has
obviously arced a great deal in the past.

-Toth

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From: [email-masked] (Tony Duell)
Date: Wed Jun 18 16:00:07 2003

> replacements. Does anyone have any suggestions?

Are these really difficult to obtain? Last time I needed some, just about 
every _real_ electronics component supplier stocked them in 12V, 110V and 
230V versions. The only problem was the cost!

-tony

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From: Tom Uban <[email-masked]>
Date: Thu Jun 19 00:36:00 2003

>230V versions. The only problem was the cost!

No, they are just fairly expensive, especially if you need to replace a
large number of them. In my case, the fans in one chassis have seen enough
weather that they have rusted and become frozen in place. I've found a
source for about $10, but that is still a significant chunk of change...

--tom

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From: Mail List <[email-masked]>
Date: Thu Jun 19 05:24:00 2003

There is a pull out in some Sun desk side systems that has about 9 fans
on it. A system that size would sell for very little on eBay because with
it's size and weight, shipping would be significant, hence very low bidding.
Buy one and ask that they pull the fan modules, if they will, and viola, 
perhaps
a lot of used fans for a pretty low price.

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From: Tothwolf <[email-masked]>
Date: Thu Jun 19 06:55:01 2003

On Thu, 19 Jun 2003, Mail List wrote:
> > No, they are just fairly expensive, especially if you need to replace
> > a large number of them. In my case, the fans in one chassis have seen
> > enough weather that they have rusted and become frozen in place. I've
> > found a source for about $10, but that is still a significant chunk of
> > change...
>
> on it. A system that size would sell for very little on eBay because
> with it's size and weight, shipping would be significant, hence very low
> bidding. Buy one and ask that they pull the fan modules, if they will,
> and viola, perhaps a lot of used fans for a pretty low price.

I think the idea is to *not* steal such parts from other systems. As for
having 9 fans, IIRC they have 4. Often these fans are very worn anyway, as
they've seen a pretty hard life.

Maybe the best way to get these fans would be to order a case of fans
directly from a company such as Nidec or Papst?

-Toth

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From: Tom Uban <[email-masked]>
Date: Thu Jun 19 11:05:00 2003

I found a relatively cheap source of surplus fans at Pembleton Electronics,
here in my home state of Indiana, so I guess that I am set for now...

--tom

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From: "R. D. Davis" <[email-masked]>
Date: Fri Jun 20 12:22:00 2003

> here in my home state of Indiana, so I guess that I am set for now...

It would have been easier and quicker in the long run, considering how
long it took you to find a source for the fans, and the time it takes
to purchase them, to have repaired your fans.  Doh! :-) It really is a
simple process to disassemble a fan and pack the bearings with new
grease to make it spin freely again.  

...but then, far too many people have become lazily wasteful, just
replacing things rather than repairing them, then moaning about all of
the pollution, toxic-waste and related resulting problems.  Instead of
learning a lesson from this, and then repairing things and keeping
them longer, the dimwits look to more landfills and waste recycling,
as the "solution" when proper "recycling," e.g. repair rather than
replacement, could have prevented the problems in the first place.

-- 
Copyright (C) 2003 R. D. Davis The difference between humans & other animals: 
All Rights Reserved            an unnatural belief that we're above Nature & 
[email-masked]  410-744-4900  her other creatures, using dogma to justify such
http://www.rddavis.org         beliefs and to justify much human cruelty.

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From: Tom Uban <[email-masked]>
Date: Fri Jun 20 13:02:00 2003

>grease to make it spin freely again.

Yes, having repaired PDP-11s back in the day for Purdue University, I
am completely aware of both the pros and the cons of repairing muffin
fans. In this case, the fans have a fair amount of rust inside of them
and I some are just plain shot as a result. It didn't take me all that
long to find a source and the price that I got on a large purchase made
it all that much more worth while.

>replacement, could have prevented the problems in the first place.

Sure, if the machine had been in my care in the first place, then it
never would have sat in conditions which would have allowed the fans to
become rusted. And the original boards would not have been sent to the
scrapper for metal reclamation either. Fortunately, I have enough spare
parts to make this machine whole again and I would consider that to
be a pretty good case of "recycleing" on the whole. Does this still
qualify me as "lazily wasteful" and a "dimwit"?

--tom

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From: [email-masked] (Tony Duell)
Date: Fri Jun 20 16:34:00 2003

> No, they are just fairly expensive, especially if you need to replace a

Ah, right... I know the problem, having started to restore some I2S image 
processor/display systems (9 fans per rack, and I have a total of 5 racks).

At the time I was doing this, Greenweld had some surplus fans in stock 
for about half the normal price. I think I must have bought just about 
all they had. This is no help to you, of course :-(

-tony

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From: [email-masked] (Tony Duell)
Date: Fri Jun 20 16:35:13 2003

> grease to make it spin freely again.  

Not always... I mentioned those I2S machines in another message. Some of 
the fans in those had been powered for so long while stuck solid that the 
windings had overheated and burnt out. And the bearings were in very poor 
shape. Yes, I _could_ have rewound them, flash-tested them, and fitted 
new bearings, but it made more sense to buy a new fan....

> replacing things rather than repairing them, then moaning about all of

I hope you don't include me in that!

-tony

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From: "R. D. Davis" <[email-masked]>
Date: Fri Jun 20 20:08:00 2003

> and I some are just plain shot as a result. It didn't take me all that

Ouch.  Rust is not fun.  At least you got to the system before everything
was rusted out.  Good luck with it!

> qualify me as "lazily wasteful" and a "dimwit"?

No, sorry, I can't say that you qualify for those.  To qualify, you
need to become more like the average person in the post-1970's U.S.,
or, better yet, the average politician. ;-) My remark was aimed more
at our throw-away society in general than this list.

Hopefully you were able to salvage some ICs from the boards before
sending them off to the scrapper.

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From: "R. D. Davis" <[email-masked]>
Date: Tue Jun 24 22:10:00 2003

> new bearings, but it made more sense to buy a new fan....

Yes... in a case like that, buying a new one makes much more sense,
and then save the old ones for spare parts, or, for later repair
in case the fans turn into unobtanium. 

> I hope you don't include me in that!

Of course I don't!  You're the one who told me how to rebuild the fans
in my 11/44. :-) [grouch mode on] I was just griping about the
throw-away society in which we live... "it's old and broken, so toss
it out and buy new" or "he's old and not functioning properly, so
dispose of him by tossing him into a nursing home," etc.  It makes no
sense and doesn't say much good about humanity. [grouch mode off] Just
the other day, I repaired a Westclox alarm clock... the "real" type of
clock with hands and a dial, not one of those blasted digital display
annoyances.  A very simple repair, actually, which involved replacing
the neon lamp which illuminates the dial.  Granted, the clock cost
under US$10 IIRC, but I still think that this repair was more sensible
than replacing the clock.

Interestingly, I learned something interesting about failing neon
lamps.  The failing lamp would light in the daylight, but flicker
dimly in the dark.  I never realized before that neon lamps were
light-sensitive.  Can anyone explain this?

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From: William Donzelli <[email-masked]>
Date: Tue Jun 24 22:20:00 2003

> light-sensitive.  Can anyone explain this?

The ambient light provides just a little bit of energy and helps the neon 
fire. A radioactive source would do the same. Sometimes, when the tube is 
getting a little tired, that little bit of energy makes the difference.

Some bits of older phone gear had internal lamps just to give all of 
the gas tubes a stable environment.

William Donzelli
[email-masked]

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From: [email-masked] (Tony Duell)
Date: Wed Jun 25 19:08:39 2003

> in case the fans turn into unobtanium. 

You think I _didn't_ keep the bits of the old fans? Of course I did :-). 
And some of them have already proved useful in restoring other fans....

> clock with hands and a dial, not one of those blasted digital display

Actually, IMNO the 'real' type of clock doesn't use electrical parts at 
all. It's entirely mechanical. And yes, I do fiddle with those from time 
to time too...

> than replacing the clock.

Of course...

> light-sensitive.  Can anyone explain this?

I first saw this on the PSU neons in my 11/45 system (see, it's on-topic 
:-)). They would light steadily with the CPU pulled out on the slides, 
but would fliker when it was pushed back in. I first thought it was a bad 
connection and spent a long time checking.

Then I realised it was due to light falling on the neon bulb. Apparently, 
light will cause some photoemision from the cathode in the neon, and 
maybe will also cause a bit of photoionisation of the neon gas itself. 
This causes the bulb to strike at a lower voltage.

This was a problem when ROMs consisted of an array of neon bulbs with a 
photomultiplier pointed at them. It was common practice to illuminate all 
the neons just before one was required to strike (and to gate out the 
resulting pulse from the PM output) (See, for example 'Cold Cathode Tube 
Circuit Design').

-tony