maddox@renoir.Berkeley.EDU (William Maddox) (11/12/87)
The 3b1 apparently uses a variable-speed fan. On mine, the speed varies rather erratically. Not only are the speed changes annoying to the ear, but the fan seems to be running slowly most of the time, such that the air leaving the fan is warm enough that I am concerned that the machine may not be adequately cooled. I also have an older 7300, which has two fans that appear to always run at a higher speed. It is quite a bit noisier, but runs cooler and is less annoying to listen to while trying to read or think. Has anyone else observed this behavior? Is it normal for the 3b1? Is there any way I can modify the machine to run the fan at full bore? Is there any reason why this would be a bad idea? Bill Maddox ...!ucbvax!renoir!maddox maddox@renoir.berkeley.edu
rab@bilanc.UUCP (Richard A. Bilancia) (11/13/87)
In article <21740@ucbvax.BERKELEY.EDU>, maddox@renoir.Berkeley.EDU (William Maddox) writes: > The 3b1 apparently uses a variable-speed fan. On mine, the speed varies > rather erratically. Not only are the speed changes annoying to the ear, > but the fan seems to be running slowly most of the time, such that the air > leaving the fan is warm enough that I am concerned that the machine may > not be adequately cooled. > > I also have an older 7300, which has two fans that appear to always run > at a higher speed. It is quite a bit noisier, but runs cooler and is > less annoying to listen to while trying to read or think. > > Has anyone else observed this behavior? Is it normal for the 3b1? > Is there any way I can modify the machine to run the fan at full bore? > Is there any reason why this would be a bad idea? I've owned an original 7300 since May 1985 that recently got fried by a direct lightning strike. The replacement is a new 3B1 that had the same single two speed fan that you described. However, while still under warranty the fan was replaced by AT&T after it stopped cooling sufficiently and caused the power supply to automatically shutdown (it has a thermostatically controlled switch). The replacement fan ALWAYS operates at the single high speed. Rich --- "Adversity is the crucible from which greatness is forged." - Ken Baker ____ ____ ___ / _ \ / _ \ / _ \ Richard A. Bilancia / / \_/ / / \_/ _ \ \\/ Computer Guidance & Support / / / / _ | | \ \ P. O. Box 620127 \ \ _ \ \ | \ | + | \ \ Littleton, Colorado 80162 \ \_/ \ \ \_| \ |_| /\_| \ voice: (303) 973-4035 \____/ \____/ \____/ ihnp4!sys1!bilanc!rab Multi-User Accounting Solutions attmail!bilanc!rab
lenny@icus.UUCP (Lenny Tropiano) (11/13/87)
In article <21740@ucbvax.BERKELEY.EDU>, maddox@renoir.Berkeley.EDU (William Maddox) writes: | | The 3b1 apparently uses a variable-speed fan. On mine, the speed varies | rather erratically. Not only are the speed changes annoying to the ear, | but the fan seems to be running slowly most of the time, such that the air | leaving the fan is warm enough that I am concerned that the machine may | not be adequately cooled. | | I also have an older 7300, which has two fans that appear to always run | at a higher speed. It is quite a bit noisier, but runs cooler and is | less annoying to listen to while trying to read or think. | | Has anyone else observed this behavior? Is it normal for the 3b1? | Is there any way I can modify the machine to run the fan at full bore? | Is there any reason why this would be a bad idea? | | Bill Maddox | ...!ucbvax!renoir!maddox | maddox@renoir.berkeley.edu I have experienced the same symptoms. The air from the "variable speed" fan on my UNIX PC 3B1 is warm... but I haven't had any problems with overheating. (In fact it keeps my room warm :-) ) I know from experience that if the fan dies, your machine will follow suit rather quickly. Those chips/power supply heats up real good! I notice the faster speed only when it is real warm. I guess it was a tradeoff for AT&T -- either two fans and lots of noise all the time -- or one variable speed fan and noise only part of the time? -Lenny -- ============================ US MAIL: Lenny Tropiano, ICUS Computer Group IIIII CCC U U SSSS PO Box 1 I C C U U S Islip Terrace, New York 11752 I C U U SSS PHONE: (516) 968-8576 [H] (516) 582-5525 [W] I C C U U S AT&T MAIL: ...attmail!icus!lenny TELEX: 154232428 IIIII CCC UUU SSSS UUCP: ============================ ...{uunet!godfre, mtune!quincy}!\ ...{ihnp4, boulder, harvard!talcott}! >icus!lenny "Usenet the final frontier" ...{cmcl2!phri, hoptoad}!dasys1!/
vanam@pttesac.UUCP (Marnix van Ammers) (11/16/87)
In article <30@icus.UUCP> lenny@icus.UUCP (Lenny Tropiano) writes: >In article <21740@ucbvax.BERKELEY.EDU>, maddox@renoir.Berkeley.EDU >(William Maddox) writes: >| >| The 3b1 apparently uses a variable-speed fan. On mine, the speed varies >I have experienced the same symptoms. The air from the "variable speed" >fan on my UNIX PC 3B1 is warm... but I haven't had any problems with >overheating. (In fact it keeps my room warm :-) ) I know from experience >that if the fan dies, your machine will follow suit rather quickly. Those >chips/power supply heats up real good! I notice the faster speed only when >and lots of noise all the time -- or one variable speed fan and noise only >part of the time? You guys really make me wonder if the UNIX-PC has gone through some revisions that we are not all aware of. My 3B1 has one fan which hums at a steady pitch. The AT&T repairman who came out to change my hard disk out told me that there was a heat sensing circuit in the power supply which would shut the system off in case of overheating. This only makes sense. For a few dollars it would protect the system from a burned out motherboard in case the fan failed. When you say that "you know from experience" do you mean experience with an overheated UNIX-PC or do you mean experience with overheating of computers in general? Also, I suspect that either some of these UNIX-PC's have variable speed fans, or they might have fan or power supply trouble. Marnix ----
richard@islenet.UUCP (Richard Foulk) (11/16/87)
> I have experienced the same symptoms. The air from the "variable speed" > fan on my UNIX PC 3B1 is warm... but I haven't had any problems with > overheating. (In fact it keeps my room warm :-) ) I know from experience > that if the fan dies, your machine will follow suit rather quickly. Those > chips/power supply heats up real good! I notice the faster speed only when > it is real warm. I guess it was a tradeoff for AT&T -- either two fans > and lots of noise all the time -- or one variable speed fan and noise only > part of the time? One solution would seem to be to put two fans in instead of one. But most importantly to use some good quality A/C fans instead of the junko D/C type that comes in the machine. A/C fans are usually quieter and more durable. The existing fan is pretty small though, I'm not sure what's available in that size. -- Richard Foulk ...{dual,vortex,ihnp4}!islenet!richard Honolulu, Hawaii
lenny@icus.UUCP (Lenny Tropiano) (11/18/87)
In article <618@pttesac.UUCP> vanam@pttesac.UUCP (-Root Admin-) writes: | [..two previous articles cut out..] |You guys really make me wonder if the UNIX-PC has gone through some |revisions that we are not all aware of. My 3B1 has one fan which hums |at a steady pitch. The AT&T repairman who came out to change my hard |disk out told me that there was a heat sensing circuit in the power supply |which would shut the system off in case of overheating. This only makes |sense. For a few dollars it would protect the system from a burned out |motherboard in case the fan failed. | I would assume there is some sort of thermostat on the heat sink inside the UNIX PC. When the power supply heats up it kicks the variable speed fan into "overdrive" :-) It might just be that your computer is in a well cooled area and it never overheats. The motherboard is more than I paid for my computer :-( I hope that never goes!! |When you say that "you know from experience" do you mean experience |with an overheated UNIX-PC or do you mean experience with overheating |of computers in general? | I know because a couple of customers have lost their machine (cause was: fan died ... machine overheated and died) I work for an AT&T VAR. |Also, I suspect that either some of these UNIX-PC's have variable speed |fans, or they might have fan or power supply trouble. | I would assume all the UNIX PC's have them? But who knows? -Lenny -- ============================ US MAIL: Lenny Tropiano, ICUS Computer Group IIIII CCC U U SSSS PO Box 1 I C C U U S Islip Terrace, New York 11752 I C U U SSS PHONE: (516) 968-8576 [H] (516) 582-5525 [W] I C C U U S AT&T MAIL: ...attmail!icus!lenny TELEX: 154232428 IIIII CCC UUU SSSS UUCP: ============================ ...{uunet!godfre, mtune!quincy}!\ ...{ihnp4, boulder, harvard!talcott, skeeve, ptsfa}! >icus!lenny "Usenet the final frontier" ...{cmcl2!phri, hoptoad}!dasys1!/
rjk@mrstve.UUCP (Richard Kuhns) (11/19/87)
In article <618@pttesac.UUCP> vanam@pttesac.UUCP (-Root Admin-) writes: >In article <30@icus.UUCP> lenny@icus.UUCP (Lenny Tropiano) writes: >>I have experienced the same symptoms. The air from the "variable speed" >>fan on my UNIX PC 3B1 is warm... but I haven't had any problems with >>overheating. (In fact it keeps my room warm :-) ) I know from experience >>that if the fan dies, your machine will follow suit rather quickly. > >When you say that "you know from experience" do you mean experience >with an overheated UNIX-PC or do you mean experience with overheating >of computers in general? I can't speak for Lenny, but we use a large number of 3B1s (we have over 35 in use), and have had several die from overheating when the fans went out. One got so hot it actually warped the case, causing the monitor to sit at an angle. (The fan apparently went out over the weekend while no one was around). The last few `fan failures' we've had were accompanied by the machines rebooting themselves every 15-30 seconds. The power supply was apparently toggled, not shut down. It didn't really seem to do a lot of good... a litle extra space for the benefit of rnews. -- !pur-ee!pur-phy!mrstve!rjk Rich Kuhns {ihnp4, decvax, etc...} !itivax!mrstve!rjk
robert@pttesac.UUCP (Robert Rodriguez) (11/21/87)
To add a new twist to this discussion, I was having what I thought was a power problem. My screen display seemed to change shapes 'kinda like the power supply was going. So, an AT&T repairman came out with a power supply and was going to replace it, but said he wanted to try something first. He re-seated the ribbon cable connector to the power supply and my screen display seems O.K. now. He said that Convergent hadn't crimped the connector well enough and this was the third 3B1 he'd done this to. Anyway, up until the repairman did this, my fan had *never* changed speeds. But, you guessed it, now it does it about once an hour. Seems to go into overdrive and the air being fanned out is pretty warm. This raises some interesting questions, maybe some AT&T guys can answer. Boy, maybe I should make a ".signature" file, this is my third posting...
ken@maxepr.UUCP (Ken Brassler) (11/22/87)
In article <624@pttesac.UUCP> robert@pttesac.UUCP (Robert Rodriguez) writes: >up until the repairman did this, my fan had *never* changed speeds. >now it does it about once an hour. Just to shed a slightly different light on this subject.... My 3b1 has run continuously for 2+ years. About every other month, the fan starts switching to high blower. This is my signal to get the vacuum cleaner and suck out the dust from the air input louvre, which is mainly the front half of the horizontal grill under the right side of the monitor. Then I suck the dust that has accumulated on and around the fan blade(s). This proceedure has always returned the fan operation to normal speed - except about once a year, when it's necessary to remove the top cover and suck the dust from the motherboard & power supply. I suppose if I cleaned my house, this wouldn't be necessary :-) -- Ken Brassler {ihnp4|qantel|pyramid|lll-crg}!ptsfa!maxepr!ken ....ethos!gladys!ptsfa!maxepr!ken
alex@umbc3.UMD.EDU (Alex S. Crain) (11/22/87)
Not to deviate too far from the subject at hand -- My fan rarily puts out hot air because my house lacks a central heating system and is entirely heated by portable kerosine heaters (2). For obvious reasons, the heaters are only run when the room is occupied by an awake person, and we don't run the heaters all the time then because of the possible problem of carbon-monoxide poisoning. The result is a room tempreture that varies radicaly from as low as 10 deg to 65 deg F. on a daily basis. while I don't think that the situation will change any time soon, Is there any reason I should worry about my machine (3b1)? will sub-freezing tempretures hurt my machine? I doubt that the temp will ever drop below 0. :alex. alex@umbc3.umd.edu
netnews@erc3bb.UUCP (11/22/87)
In article <624@pttesac.UUCP> robert@pttesac.UUCP (Robert Rodriguez) writes: > >To add a new twist to this discussion, I was having what I thought was >a power problem. My screen display seemed to change shapes 'kinda like >the power supply was going. So, an AT&T repairman came out with a power >supply and was going to replace it, but said he wanted to try something >first. He re-seated the ribbon cable connector to the power supply and >my screen display seems O.K. now. Along similar lines, I just had to have my motherboard replaced. While I was talking with the repairman, he told me of a job he had done recently. A customers machine kept going down and he couldn't figuare out what it was. He had swapped just about every part that he could think of. He then noticed that one of the internal cables was not the original CT one, the system had been purchased through a VAR that had msde up their own cables. Sure enough, as soon as he replaced the cable, the machine started humming along fine and he hasn't had to go back there since. Avi Feldblum
vanam@pttesac.UUCP (Marnix van Ammers) (11/22/87)
In article <624@pttesac.UUCP> robert@pttesac.UUCP (Robert Rodriguez) writes: >Anyway, up until the repairman did this, my fan had *never* changed speeds. >But, you guessed it, now it does it about once an hour. Seems to go into >overdrive and the air being fanned out is pretty warm. > >This raises some interesting questions, maybe some AT&T guys can answer. > Yes, it does raise very interesting questions. You and I got our 3B1's at the same time. I've added a EIA/COMBO board with 1.5 Meg on it and a DOS73 board. My far has only been at one speed since day one. If we have dual speed fans, I would expect mine to have changed speeds after adding those two boards. Maybe I somehow have a newer issue fan which runs only at the single, higher speed? I would like to know for sure that my 3B1 will shutdown safely if my fan stops. Someone in the know please enlighten us. Marnix ---- -- Marnix (ain't unix!) A. van\ Ammers Work: (415) 545-8334 Home: (707) 644-9781 CEO: MAVANAMMERS:UNIX WORK UUCP: {ihnp4|ptsfa}!pttesac!vanam CIS: 70027,70 HOME UUCP: pttesac!Marnix!vanam
amir@ms.uky.edu (Amir Sadr) (11/28/87)
In article <30@icus.UUCP> lenny@icus.UUCP (Lenny Tropiano) writes: >In article <21740@ucbvax.BERKELEY.EDU>, maddox@renoir.Berkeley.EDU >(William Maddox) writes: >| >| The 3b1 apparently uses a variable-speed fan. On mine, the speed varies >| rather erratically. Not only are the speed changes annoying to the ear, >| but the fan seems to be running slowly most of the time, such that the air >| leaving the fan is warm enough that I am concerned that the machine may >| not be adequately cooled. I have noticed the same problem with my newly purchased 3b1 also. However, the problem has recently gone away. I'm sure it is not because I have got use to it. It really bothered me to the point where I had to compare the sond of my fan to several other 3b1's to make sure everything was okay. Be that as it may, even now if I tap on the fan's grille it causes the fan to run at a noticeably slower speed. After a few minutes the fan returns to it's (I suppose) normal speed. Unless the air leaving your fan is REALY hot, I do not think there is anything wrong with your machine. However if your machine reaches a specified high temperature, it will automatically do a shutdown. Best wishes Amir-
nic@marque.UUCP (11/30/87)
In article <626@pttesac.UUCP> vanam@pttesac.UUCP (Marnix van Ammers) writes: >In article <624@pttesac.UUCP> robert@pttesac.UUCP (Robert Rodriguez) writes: >>Anyway, up until the repairman did this, my fan had *never* changed speeds. >>But, you guessed it, now it does it about once an hour. Seems to go into >>overdrive and the air being fanned out is pretty warm. >> >>This raises some interesting questions, maybe some AT&T guys can answer. >> >Yes, it does raise very interesting questions. You and I got >our 3B1's at the same time. I've added a EIA/COMBO board with >1.5 Meg on it and a DOS73 board. My far has only been at one >speed since day one. If we have dual speed fans, I would expect >mine to have changed speeds after adding those two boards. > >Maybe I somehow have a newer issue fan which runs only at the >single, higher speed? > >I would like to know for sure that my 3B1 will shutdown safely >if my fan stops. Someone in the know please enlighten us. > >Marnix >---- >-- >Marnix (ain't unix!) A. van\ Ammers Work: (415) 545-8334 >Home: (707) 644-9781 CEO: MAVANAMMERS:UNIX >WORK UUCP: {ihnp4|ptsfa}!pttesac!vanam CIS: 70027,70 >HOME UUCP: pttesac!Marnix!vanam Well this has gotten out of hand in my mind so, just to add to the confusion, and maybe a possible solution... I have had, for some time, a friend with an original PC7300, and yes he paid the original retail ( less about 10% ). This unit has TWO fans, one on the right side of the case in the rear, and one on the left side. For about the first year, or so, the fans ran at the same slow speed. After that, they started running faster occasionally. My friend removed the case and cleaned out the accumulated dirt. He was very precicse about this (anal retentive) and removed all accessory boards (memory) and used pure spray freon (tuner wash) to remove all traces of dirt and grime, returning the unit to factory new condition. He ALSO CLEANED OUT THE FANS! This unit returned to factory new quiteness. However, he has to repeat this cleaning every 6 months or so ( he does this for obvious reasons, not to quite the fans ) or the fan speed up returns. Neither he nor I have tried to figure out if the speed change takes place in the power supply or if the fans themselves are two speed. It might pay to see if both fans speed up, be he hasn't paid any attention and thats pretty subjective. The service manual mentions only constant voltages of +5, +12 and -12 volts. This seems to imply that the fan speed up is, in fact a quality of the fans themselves. The manual also mentions that the supply is both overvoltage and overcurrent protected and will shut down totally in case of a short, etc. The service manual also reccommends using the fans as a trouble shooting tool as they will not run if the supply is down. You can disconnect everything, and if the fans run, then there is a shorted device in the system (wait a few seconds for the supply to come up as there are delay circuits built in that will remain engaged after a short). This brings up a possible solution. Is it possible, or practical, to add a second fan ala the PC7300? The service manual lists a "Fan Assembly Spares Kit" Com Code 403865272. - Nic