RX01 missing felt pad, repair advice

Tim McNerney mc at media.mit.edu
Wed Nov 26 12:18:57 CST 2008


The felt pad that presses the floppy disk into the r/w head fell off my 
RX01 (or whatever dual floppy drive is actually inside a DECmate model 
III (a late edition of 6120-based PDP-8).
Has anyone tried to do that repair?  What did you use for replacement, 
self-adhesive felt material?

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> Today's Topics:
>
>    1. Re: 5" floppy?. (Jules Richardson)
>    2. Re: 5" floppy?. (Sridhar Ayengar)
>    3. Re: 5" floppy?. (Sridhar Ayengar)
>    4. HP3000 (Mike Loewen)
>    5. Re: HP3000 (William Donzelli)
>    6. Re: HP3000 (Mark Davidson)
>    7. Re: HP3000 (William Donzelli)
>    8. Re: Help with Shugart SA801 8" floppy with 230v 50 cycle
>       (feldman.r at comcast.net)
>    9. Re: 5" floppy?. (David Griffith)
>   10. Re: 5" floppy?. (William Donzelli)
>   11. Screwheads; was  5 floppy?. (Chuck Guzis)
>   12. RE: Help with Shugart SA801 8" floppy with 230v 50 cycle
>       (dwight elvey)
>   13. Re: 5" floppy?. (Dave McGuire)
>   14. RE: Help with Shugart SA801 8" floppy with 230v 50 cycle
>       (Chuck Guzis)
>   15. RE: 5" floppy?. (dwight elvey)
>   16. Re:Screwheads, was:  5" floppy?. (Chuck Guzis)
>   17. Re: AT&T 7300/3B1's (was: Re: Who is vintagecomputermuseum?)
>       (micheladam at theedge.ca)
>   18. Re: AT&T 7300/3B1's (was: Re: Who is vintagecomputermuseum?)
>       (Gordon JC Pearce MM3YEQ)
>   19. Re: AT&T 7300/3B1's (was: Re: Who is vintagecomputermuseum?)
>       (Lance Lyon)
>   20. IDE <-> MFM, was > Re: AT&T 7300/3B1's (was: Re: Who is
>       vintagecomputermuseum?) (emu at e-bbes.com)
>   21. Re: The Day the Infant Internet Uttered its First Words
>       (Steve Maddison)
>   22. RE: Help with Shugart SA801 8" floppy with 230v 50 cycle
>       motor... (ROBO5.8)
>   23. Re: AT&T 7300/3B1's (was: Re: Who is vintagecomputermuseum?)
>       (Jules Richardson)
>   24. Re: Help with Shugart SA801 8" floppy with 230v 50 cycle
>       motor... (Jules Richardson)
>   25. Mystery paper tape reader (Tobias Russell)
>   26. MITS Disk Boot Loader manual (Richard A. Cini)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 25 Nov 2008 17:25:48 -0600
> From: Jules Richardson <jules.richardson99 at gmail.com>
> Subject: Re: 5" floppy?.
> To: General Discussion: On-Topic and Off-Topic Posts
> 	<cctalk at classiccmp.org>
> Message-ID: <492C897C.1080407 at gmail.com>
> Content-Type: text/plain; charset=ISO-8859-15; format=flowed
>
> Fred Cisin wrote:
>   
>> It sure is easy to slip into off-topic mechanical griping.
>>     
>
> Yeah, funny how there's a lot of interest overlap between vintage computing, 
> old cars, and engineering (and that it says in the "to" field of this message 
> that the list is for "General Discussion: On-Topic and Off-Topic Posts") - but 
> let's not go there, huh? ;-)
>
>
> J.
>
>
> ------------------------------
>
> Message: 2
> Date: Tue, 25 Nov 2008 19:04:06 -0500
> From: Sridhar Ayengar <ploopster at gmail.com>
> Subject: Re: 5" floppy?.
> To: General Discussion: On-Topic and Off-Topic Posts
> 	<cctalk at classiccmp.org>
> Message-ID: <492C9276.8000809 at gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Tony Duell wrote:
>   
>>> Even computer companies - people that should know better, make 
>>> mistakes when talking about floppy disks. Last week I was in a Staples 
>>> store (American office supply store chain), and saw a Memorex 3 1/2" USB 
>>> floppy drive, the package stating clearly that it supported "1.44mb 
>>> double sided and 720k single sided diskettes". > 
>>>       
>> Well, calling it mb (millibyte) is clearly wrong. And the value of 
>> 1.44Mbytes assumes you take 1Mbyte as 1000*1024 bytes, which is downright 
>> crazy.
>>     
>
> Actually, doesn't mb imply "millibit", and mB is "millibyte", with Mb as 
> "megabit" and MB as "megabyte"?
>
> Peace...  Sridhar
>
>
> ------------------------------
>
> Message: 3
> Date: Tue, 25 Nov 2008 19:06:26 -0500
> From: Sridhar Ayengar <ploopster at gmail.com>
> Subject: Re: 5" floppy?.
> To: General Discussion: On-Topic and Off-Topic Posts
> 	<cctalk at classiccmp.org>
> Message-ID: <492C9302.40404 at gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Gordon JC Pearce MM3YEQ wrote:
>   
>> (once again, sorry Jay)
>>
>>     
>>> My favourite has to be Torx. I have never had any problems with those.
>>>       
>> Oh I have... <grumble>Bloody Volkswagens with their stupid 5-lobed 
>> Torx-like brake caliper bolts, that you can't even get drivers for from 
>> VW without ordering them from Germany...
>>     
>
> My Audi uses triple-square for that kind of stuff.
>
> Peace...  Sridhar
>
>
> ------------------------------
>
> Message: 4
> Date: Tue, 25 Nov 2008 20:01:42 -0500 (EST)
> From: Mike Loewen <mloewen at cpumagic.scol.pa.us>
> Subject: HP3000
> To: "General Discussion: On-Topic and Off-Topic Posts"
> 	<cctalk at classiccmp.org>
> Message-ID: <Pine.LNX.4.64.0811251950490.22596 at cpumagic.scol.pa.us>
> Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
>
>
>     Where have all the HP3000 systems gone?
>
>     Between 1986 and 1988, I worked on a whole slew of HP3000s, from the 
> Series III to the Series 70.  They were popular in the business 
> environment, especially in COBOL shops.  Where did they end up?  You can 
> find loads of DEC equipment on Ebay, even IBM System 34, 36 and AS/400s, 
> the occasional HP1000, but the only HP3000 I recall seeing in recent years 
> was a single Model 37.
>
>
> Mike Loewen				mloewen at cpumagic.scol.pa.us
> Old Technology	http://sturgeon.css.psu.edu/~mloewen/Oldtech/
>
>
> ------------------------------
>
> Message: 5
> Date: Tue, 25 Nov 2008 20:16:45 -0500
> From: "William Donzelli" <wdonzelli at gmail.com>
> Subject: Re: HP3000
> To: "General Discussion: On-Topic and Off-Topic Posts"
> 	<cctalk at classiccmp.org>
> Message-ID:
> 	<e1d20d630811251716q468c96f4s9ab6b8a98cecdd43 at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
>   
>>    Between 1986 and 1988, I worked on a whole slew of HP3000s, from the
>> Series III to the Series 70.  They were popular in the business environment,
>> especially in COBOL shops.  Where did they end up?  You can find loads of
>> DEC equipment on Ebay, even IBM System 34, 36 and AS/400s, the occasional
>> HP1000, but the only HP3000 I recall seeing in recent years was a single
>> Model 37.
>>     
>
> You answered your own question.
>
> DEC made loads of minis (PDP and VAX).
> IBM made loads of minis (S/34 and S/36).
> IBM made extra sized loads of AS/400 minis (more than any other minicomputer).
> HP did not make loads of 3000s.
>
> I think it is a simple population thing.
>
> --
> Will
>
>
> ------------------------------
>
> Message: 6
> Date: Tue, 25 Nov 2008 17:27:42 -0800
> From: "Mark Davidson" <mdavidson1963 at gmail.com>
> Subject: Re: HP3000
> To: "General Discussion: On-Topic and Off-Topic Posts"
> 	<cctalk at classiccmp.org>
> Message-ID:
> 	<d17c35610811251727u5ec8860ayd6474c43da58e5f3 at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> On Tue, Nov 25, 2008 at 5:16 PM, William Donzelli <wdonzelli at gmail.com> wrote:
>   
>>>    Between 1986 and 1988, I worked on a whole slew of HP3000s, from the
>>> Series III to the Series 70.  They were popular in the business environment,
>>> especially in COBOL shops.  Where did they end up?  You can find loads of
>>> DEC equipment on Ebay, even IBM System 34, 36 and AS/400s, the occasional
>>> HP1000, but the only HP3000 I recall seeing in recent years was a single
>>> Model 37.
>>>       
>> You answered your own question.
>>
>> DEC made loads of minis (PDP and VAX).
>> IBM made loads of minis (S/34 and S/36).
>> IBM made extra sized loads of AS/400 minis (more than any other minicomputer).
>> HP did not make loads of 3000s.
>>
>> I think it is a simple population thing.
>>
>> --
>> Will
>>     
>
> I subscribe to the 3000 mailing list, and there seems to be one other
> complaint... licensing the OS.  I am no expert on the matter, but I've
> gotten the impression that HP can be a real bear to deal with when it
> comes to licensing the OS for users.  It simply can get too expensive
> for a hobbyist to run MPE...
>
> Trust me, I'd love to have a small 3000 at home and if one ever shows
> up, I'll snap it up if I can.  They just seem to be pretty rare on the
> used market.
>
> Mark
>
>
> ------------------------------
>
> Message: 7
> Date: Tue, 25 Nov 2008 20:52:06 -0500
> From: "William Donzelli" <wdonzelli at gmail.com>
> Subject: Re: HP3000
> To: "General Discussion: On-Topic and Off-Topic Posts"
> 	<cctalk at classiccmp.org>
> Message-ID:
> 	<e1d20d630811251752r7c21a151ge4ceec709310254c at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
>   
>> I subscribe to the 3000 mailing list, and there seems to be one other
>>  complaint... licensing the OS.  I am no expert on the matter, but I've
>>  gotten the impression that HP can be a real bear to deal with when it
>>  comes to licensing the OS for users.  It simply can get too expensive
>>  for a hobbyist to run MPE...
>>     
>
> A complaint, yes, but really has nothing to do with why 3000s are so
> scarce. Really, it is hard to beat the IBM AS/400 group for being
> disagreeable when it comes to licenses.
>
> I think DEC spoiled us.
>
> --
> Will
>
>
> ------------------------------
>
> Message: 8
> Date: Wed, 26 Nov 2008 02:41:19 +0000
> From: feldman.r at comcast.net
> Subject: Re: Help with Shugart SA801 8" floppy with 230v 50 cycle
> To: cctalk at classiccmp.org
> Message-ID:
> 	<112620080241.25527.492CB74F00042AA6000063B722007621949DD2020E030B040A00 at comcast.net>
> 	
> Content-Type: text/plain
>
> For small pulleys, check out a hobby shop that deals in radio controlled model airplanes and cars. For small gears, try www.nwsl.com. They also have small drills, bolts, and metal rods (e.g., 1.5mm x 6"). In England, try http://www.ultrascale.co.uk/ for small gears.
>
> Bob
>
> ------------------------------
>
> Message: 9
> Date: Tue, 25 Nov 2008 18:45:30 -0800 (PST)
> From: David Griffith <dgriffi at cs.csubak.edu>
> Subject: Re: 5" floppy?.
> To: "General Discussion: On-Topic and Off-Topic Posts"
> 	<cctalk at classiccmp.org>
> Message-ID: <Pine.GSO.4.55.0811251843380.22711 at helios.cs.csubak.edu>
> Content-Type: TEXT/PLAIN; charset=US-ASCII
>
> On Tue, 25 Nov 2008, Chuck Guzis wrote:
>
>   
>> I once read an interview with the son of inventor Henry Phillips (an
>> Oregon native) and he maintained that it wasn't the original design
>> (US Patent 2046343) that was at fault, it was primarily the fault of
>> ASC for cheapening the manufacturing process by relaxing
>> specifications--and the propagation of inferior tools. Indeed, the
>> screwdrivers I have that are labeled "Genuine Phillips" do seem to be
>> quite a bit better than the generic variety.  One aspect of the
>> Phillips head not shared by Torx or Robertson/square is that it will
>> automatically center the driving bit.
>>     
>
> I don't follow on the automatic centering.  Yes, a slotted screwdriver can
> slide out, but torx or robertsons?
>
>   
>> The "slipping out", I believe is referred to as "camming out".
>>
>> While rebuilding a deck this summer, I found that even square-drive
>> screws are easy to strip when power is used to drive them.
>>     
>
> That's why you're supposed to use a drill with a slipper clutch.
>
>   
>> Fortunately, deck screws are being manufactured with the Torx head
>> (mine were T25s) and allow for much better driving performance.
>>     
>
>
>
>   



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