** == **¢ INSTALLING A COOLING FAN ON YOUR DISK¢ DRIVE - A DIFFERENT VIEW! (Excerpts¢ from a letter by BEN POEHLAND Editor¢ of ATARI CLASSIC to Ron Fetzer.)¢¢ (Editor, The article BEN refers to¢ was printed before BEN's response was¢ received, but so that both views are¢ given, this is being printed. You are¢ on your own as to what you decide to¢ do. See Jan/Feb 1994 OL' HACKERS¢ newsletter for the original article¢ to which B. P. is reponding.)¢¢ A FAN FOR THE 1050 DRIVE?¢ ...The problems I have with your¢ article (upgrade) are more of a¢ philosphical nature. ... I'm¢ philosophically opposed to the idea¢ of adding fan cooling to disk drives¢ generally. And, although the additon¢ of a fan is conceptually a good idea,¢ you can end up doing more harm than¢ good in the long run if you don't do¢ it right. Let me explain.¢¢ FANS SHOULD RUN COOL.¢ First off, a disk drive¢ (especially a 1050) that runs hot is¢ probably defective. ...I'm rather a¢ staunch believer in curing problems¢ at the source rather than applying¢ band-aids. Some 1050 run abnormally¢ hot because certain repair companies¢ installed underspec'd rectifiers in¢ the charge-pump circuit of the power¢ supply. The cure is to replace the¢ diodes, not carve up the drive to¢ install a fan. Replacing the diodes¢ is a lot cheaper, too (the high-¢ current diodes are available at Radio¢ Shack).¢¢ NORMAL HEAT!¢ It's normal for the heatsinks in¢ the Atari drives to get hot. They¢ serve to keep the voltage regulators¢ at a steady-state temperture. As long¢ as the regulators don't get so hot as¢ to trip their thermal shutdown¢ circuits, the drive is OK.¢ In most Atari drives there's a¢ power transistor attached to the¢ regulator heatsink. This transistor¢ provides current to the drive motor¢ in the mechanism. If there is a fault¢ in the mechanism or a defective disk¢ or someone operating the drive¢ irresponsibly, this transistor will¢ pass excess current and heat up the¢ heatsink. ...¢¢ CURING THE PROBLEM!¢ Again, you cure the problem at¢ the source: don't use crummy disks,¢ repair the mechanism, or correct the¢ operator's sloppy habits (impatient¢ people flipping the latch while the¢ drive light is on is a typical¢ case).¢ ...Cheap disks can cause spindle¢ motors (and heatsinks) to run hot.¢ There's a simple test you can perform¢ to detect one of these nasty buggers,¢ I call it the "two-finger test". You¢ stick your index and middle fingers¢ into the hub hole of the disk. Spread¢ your fingers slightly until the disk¢ is securely held. Then rotate the¢ diskjacket with your other hand. It¢ should turn easily. If it doesn't,¢ trash that disk, it has too much¢ internal friction ... My favorite¢ disks are the Verbatim Datafile Plus.¢ Their jackets are internally coated¢ with teflon, they pass the two-finger¢ test easily and work flawlessly in¢ all drives ...¢¢ WHEN TO USE A FAN!¢ About the only justification I¢ can see for adding fans to drives is¢ if you live in a hot climate and use¢ the drive for more than 3 hours/day,¢ or if you live in an area where¢ chronic overvoltage (above 130VAC) is¢ a problem (very rare!)... Once a fan¢ is installed you are moving massive¢ volumes of air through the case, much¢ more than by ordinary convection.¢ Consequently, you are now moving¢ massive amounts of dirt into the¢ case. The air leaves, but most of the¢ dirt stays behind. Bad news! Dirt¢ does two bad things. First, it coats¢ individual electonic components with¢ an insulating layer that inhibits¢ their ability to dissipate heat, so¢ you actually increase the potential¢ for failure at the component level.¢ Second (and even worse), on damp days¢ dirt conducts electicity. The¢ electronic effects are variable, but¢ typically act to introduce unwanted¢ capacitance, change the value of¢ resistors by providing alternate¢ current paths and distort dynamic¢ signals by partly rectifying then¢ (diode action). Such drives behave as¢ if they were inhabited by demons.¢¢ HOW THE FAN AND A FILTER CAN BE USED!¢ In electronic equipment, you¢ ALWAYS install a fan in such a¢ fashion that is draws outside air¢ into at the fan location and create a¢ positive pressure differential inside¢ the case. The fan intake opening is¢ then covered with a suitable filter¢ to ensure the air entering the case¢ is free of gross particulate matter¢ (submicron particulates exit the case¢ with the exhaust air so aren't¢ usually a problem). ... These filters¢ are sold at most electonic supply¢ houses. I get them for $.95 at¢ American Design Components in New¢ Jersey. You can get them to fit a¢ standard 3.5 muffin fan ... I've¢ developed the trick of deliberately¢ installing the filters backwards.¢ This permits you to snap out the¢ plastic grille so you can remove and¢ wash the filter element without¢ opening up the case.¢ Installing a negative-pressure¢ fan (fan sucking air out of the¢ case)is as bad as installing ¢ positive-pressure fan without a¢ filter... In such condition you have¢ no control over airflow direction,¢ and it's impossible to filter¢ incomming air. Most IBM-type¢ computers are cooled this way. Like¢ most IBM things: Bass-Ackwards.¢¢ THE INDUS DRIVE.¢ Your (RON FETZER's) idea to¢ increase convection cooling in the¢ Indus was more to my liking but not¢ well implemented. Much simpler to¢ just pencil a gird on the case and¢ drill a bunch of closely-spaced #4¢ holes, followed by deburring with a¢ drillstone and covering with a piece¢ of screen held in place on the inside¢ by a bead of silicone adhesive. ... I¢ question whether the rather large¢ hole you described for the Indus is¢ really necessary.¢¢ USE OF OIL---- HORRORS!¢ Finally, I recoil at your advice¢ to apply sewing machine oil to the¢ head rails. NO, NO, NO! Liquid¢ lubricants must NEVER be applied¢ there! Or anywhere inside a drive for¢ that matter.¢ There are two problem with¢ liquid lubricants. First, even¢ assuming you put it where you want¢ it, it doesn't stay there. Liqulid¢ lubricants migrate, especially in the¢ warm invironment of a drive case.¢ Sooner or later it ends up where you¢ don't want it. And second, sooner or¢ later all liquid lubricants¢ evaporate/polymerize, depositing a¢ gummy residue that inhibits head¢ movement. This gummy polymer residue¢ junk is nasty to clean off.¢ The correct type of lubricant to¢ use is a lightweight silicone grease.¢ CSS sells a product called the¢ "Silencer"...My standard, that I use¢ computer/electronic lubricant is¢ "Lube-Gel". It comes in a tube for¢ $6.00 at Radio Shack.(#64-2326--¢ $2.49 -- RON)... one tube will last¢ several liftimes, you can pass it on¢ to your grandchildren as part of¢ their inheritance. It's a chemically¢ stable slilicone-base clear grease¢ containing microparticluate emulsion¢ of teflon.¢¢ HOW TO:¢ The application techingue¢ requires breaking a wooden Q-tip¢ handle so you can get a nice thin¢ sliver of wood (Radio Shack sells¢ wooden - handled Q tips.) Using this¢ sliver, ... apply tiny amounts of the¢ grease to practically any location in¢ the drive. The rails have to be¢ greased on the sides and the bottom¢ as well as the top. The cotton end of¢ the swab is used to remove any¢ excess. The stuff stays where you put¢ it, doesn't migrate, evaporate or¢ polymerize. I also use it on the¢ drive latches and the disk ejection¢ mechanism; some drives turn into¢ "disk cannons" after the treatment.¢ Lube-Gel is also great for printer¢ mechanisms, especially the head bars¢ on the 1027.¢¢ MY OPINIONS.¢ As you can see, this is a¢ subject in which I have quite a bit¢ of experience and, consequently, some¢ rather strong biases. I certainly¢ won't say the advice in your article¢ is incorrect: only that it¢ contradicts so many of my own biases¢ that it would bother my conscience to¢ print it.¢ Warmest regards,¢ Ben Poehland¢¢¢ >> <> <<¢ RON FETZER replies:¢¢ I have used the disk drives as¢ described in the article of the OHAUG¢ NEWSLETTER of JAN/FEB 1994 for over a¢ year without any trouble.¢ The advice BEN gives is¢ wothwhile. I will limit the use of¢ the fans only during long copy¢ sessions. And finally I will use ONLY¢ "LUBE-GEL" inside the drives.¢ The INDUS disk drive¢ modification that BEN suggests is¢ also much easier to do.¢ I thank BEN POEHLAND for the¢ many great suggestions and worthwhile¢ procedures and for reviewing my¢ article. (Ed. Thanks for both views!)¢¢ >>>>>>>>>>>>>>>>END<<<<<<<<<<<<<<<¢
