[HECnet] TK50 issues

[Johnny Billquist]

On 2014-05-17 18:59, Brian Schenkenberger, VAXman- wrote:
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?

I have bottles from DEC saying "Tape cleaning fluid", and it's Isopropanol. All my manuals for various hardware also always say to clean using Isopropanol, so I think Isopropanol is a safe bet to use. :-)

However, pure ethanol should not be a problem either, unless it actually might be to aggressive in dissolving things.

My main concerns with ethanol would be how aggressive it might be, and secondly any possible residue left behind id it wasn't pure. I would like to have something that is at least 96% ethanol if I were to use that for cleaning. (You won't find that in normal stores in Sweden at least, since it's dangerous to consume as it is, and diluting it with water would mean you'd get a lot of alcohol without going through the state monopoly. :-) Denatured it's available at special stores, but still not my first choice then, since the denaturing is also additives that I do not want left as residue.)

	Johnny

-- 
Johnny Billquist                                   || "I'm on a bus
                                                                  ||   on a psychedelic trip
email: bqt at softjar.se                         ||   Reading murder books
pdp is alive!                                         ||   tryin' to stay hip" - B. Idol