[HECnet] TK50 issues

[Brian Schenkenberger, VAXman-]

Johnny Billquist <bqt at softjar.se> writes:

On 2014-05-11 05:11, Cory Smelosky wrote:
Evening all,

Got a nice haul of equipment today...aside from the TK50 issues and the
smoking VT340 everything seems to be okay!

However:

                                                                              CARTRIDGE PRESENT
                                                                              HEAD AT TRACK ZERO
                                                                              POSITIONED AT BOT
              TRK NUMBER                       00
                                                                              LOGICAL TRACK NUMBER = 0.
              PHYSICAL BLK#             0000
                                                                              PHYSICAL BLOCK NUMBER = 0.
              LOGICAL BLK#                   00
                                                                              LOGICAL BLOCK NUMBER = 0.
              TAPE POSITION         000EFB
                                                                              TAPE POSITION = 3835.
              DRIVE STATE                 035E
              RD/WRT STATE               1937
              OPERATION FLGS           0201
              CNTRLR STATUS                 0C
                                                                              DRIVE ERROR
              DRIVE ERR CODE               93
                                                                              AMPLITUDE ON HEAD 2 TOO LOW

and an error about it being unable to find calibration track 2 on the
second drive lead me to believe the drives may be faulty.   The leader
isn't broken and I've reattached it to the arm on the one where it had
come off.

How would I do about cleaning one?   Are the drives bad and a cleaning
wouldn't help?

(Yes, I tried multiple cartridges)

Others have replied, but anyway.
Yes, you need to clean the TK50. Almost certain that is your problem.
And cleaning them is easy. Open the box, so that you can see the drive. 
There is a cover plate over the drive, fastened by four screws. Remove 
the cover plate and you'll see the head, the rollers, and the pickup hub.
Use iso-propanol and a swab, and just clean the head.
Reassemble, and you're done.

Try ethanol instead!   "Rubbing" ethanol is available at most drug stores
along side isopropanol.   This is, of course, denatured so that it can not
(or should not) be consumed.   If you want the purest, off to the liquor
store and get yoruself a bottle of grain alcohol (Everclear is one brand
names of pure grain alcohol).   It's what I use simply because I've never
sussed out what is used as the denaturing addative with the drug store's
ethanol.

Isopropanol can oxidize producing a ketone.   The ketone that it oxidizes
into is acetone.   Not what I would prefer to have on the rubber (real or
otherwise) conponents nor to come in contact with my tapes.   Depending on
what is gunked up in your TK50, some of those chemicals may suffice as a
catalyst in the oxidation thereof.   

I do know that the tech wipes (small pouches with alcohol dampened cloth
or paper) we used back in the day were ethanol based.   Perhaps, for this
very reason?

-- 
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