The Museum of HP Calculators

HP Forum Archive 14

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Tape drive problem
Message #1 Posted by David Ramsey on 1 Aug 2004, 12:27 p.m.

I just acquired a spare 8216A digital cassette drive from eBay. It wasn't advertised as working, but for $30 including 1 used and two new tapes, it was a no-brainer.

The drive works mechanically: that is, tapes spin, it goes throw the NEWM routine, and so forth. Most attempts to read and write from the unit fail with a "medium error" (once or twice I've gotten a good directory listing).

A closeup of the tape head shows the likely problem:

The question is "Is this contamination of some sort, perhaps flaked oxide, that can be removed, or is the head toast?" Medium hard rubbing with a cotton swab has no effect.

      
Re: Tape drive problem
Message #2 Posted by Emmanuel, France on 1 Aug 2004, 1:20 p.m.,
in response to message #1 by David Ramsey

Did you dip the swab of cotton wool in surgical spirit? I used that to clean my Revox AT77and HP82161A Digital Cassette Drive heads.;o)

            
Re: Tape drive problem
Message #3 Posted by David Ramsey on 1 Aug 2004, 3:02 p.m.,
in response to message #2 by Emmanuel, France

Vigorous scrubbing with an alcohol-moistened swab worked. The old tape was discarded. I unwrapped one of the new tapes that came with the unit and it reads and writes perfectly.

So $30 got me two new tapes and a working drive. Not bad!

                  
Re: Tape drive problem
Message #4 Posted by Emmanuel, France on 1 Aug 2004, 6:13 p.m.,
in response to message #3 by David Ramsey

Nice, isn't it?

                        
Re: Tape drive problem
Message #5 Posted by David Ramsey on 1 Aug 2004, 7:59 p.m.,
in response to message #4 by Emmanuel, France

Any suggestions on what to do with the flaking tape? Does anyone rebuild these, or should I just throw it away?

                              
Old Tape
Message #6 Posted by Artur - Brazil on 1 Aug 2004, 8:08 p.m.,
in response to message #5 by David Ramsey

If you have a way to send it to me at reasonable price, I'll try rework it, ok?

Best regards from BRAZIL - Artur!

                                    
Re: Old Tape
Message #7 Posted by David Ramsey on 1 Aug 2004, 9:50 p.m.,
in response to message #6 by Artur - Brazil

Luiz,

You can have the tape if you want it-- I have 4 known good tapes, which is really a lifetime supply for me! What's your mailing address?

                                    
Re: Old Tape
Message #8 Posted by David Ramsey on 2 Aug 2004, 1:09 a.m.,
in response to message #6 by Artur - Brazil

Artur,

Send me your address and I'll send you the tape...

                              
Re: Tape drive problem
Message #9 Posted by Emmanuel, France on 2 Aug 2004, 5:46 a.m.,
in response to message #5 by David Ramsey

You can replace the dead band.
I used audio cassette band when I did not have new sealed HP82176A cassettes.
It was really hard and took several hours.
I wrote somewhere something about that surgical operation.
                  
Metal polisher...
Message #10 Posted by Vieira, Luiz C. (Brazil) on 1 Aug 2004, 8:38 p.m.,
in response to message #3 by David Ramsey

Hi, David;

after seeing the picture, it seems ot me old-tape "leftover" grasped in the head surface. I used to deal with magnetic tape drivers (professional audio devices) and in most cases, when no spare tape head was found, cleaning with non-abrasive, liquid metal polisher was enough. With one side of the swab moistened with the liquid metal polisher you gently rub the head surface. When the liquid dries out, use the other side of the swab (supposing cotton in both edges) and then you rub with a bit of pressure, as if polishing it. You'll see it becomes a mirror-like surface, in most cases. Efficiency usually goes more than satisfactory, and tape surfaces will "thank you" for a non-scratching head...

A very important remark: use this technique only when you have "crusts" or any other material that refuses to be removed with regular cleaning liquids, like alcohol. Metal polishers remove a thin coat of the surface (chemically) and using them constantly will reduce head life. Degaussing may also be usefull.

My 1.

Luiz (Brazil)

      
Re: Tape drive problem
Message #11 Posted by Diego Diaz on 2 Aug 2004, 4:28 p.m.,
in response to message #1 by David Ramsey

Hi David,

Hope this can help you:

http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv009.cgi?read=24257

Please note that when I said: "constant angular speed" it meant: "constant sum of the angular speeds of both rotors", appart from that the description if fairly accurate.

Best wishes

Diego

            
Re: Tape drive problem
Message #12 Posted by David Ramsey on 2 Aug 2004, 5:38 p.m.,
in response to message #11 by Diego Diaz

I'm impressed you managed to respool one of those old tapes! It's more trouble than I'm willing to go to, though, since I have several working tapes now.


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