|Re: 82161A Mini cassettes|
Message #4 Posted by Diego Diaz on 23 Nov 2002, 10:16 a.m.,
in response to message #3 by Tony Duell (UK)
Thanks a lot David and Tony for your comments/suggestions. BTW Tony, it'll be very interesting to read your previous experiences and comments about the issue, pls e-mail me when you can.
As I promised, here comes the results of my "Tape experiments":
Regarding the length of the tape, I used my audio tape recorder timer to count the 8min 44sec. needed for the task.
This is the result of calculating how much time a standar tape recorder needs to run 24'384m (80feet) between the holes, plus 2 x 25cm extra tape to reach the leaders at both ends.
I've also wound the old defective HP tape into a standard audio tape shell... and of course played it!! The saturation is farily high >+8dB!!
(I'm sure that my neibourghs' son is still wondering where the hell have I got this amazing new beat!!!! ;-)
Then conected an oscilloscope to the phones output and took a look... It's a 1'85Khz. (approx.) carrier with phase/amplitude modulation, as stated in the 82161 manual, separated in brusts and silences of 1'16s/0'6s ratio (approx.).
Translating this into 82161's read/write speed of 9inches (22'86cm) it results in a 8'9KHz (approx.) carrier. Those are "approx." due to the 82161's constant ANGULAR speed while standard audio tapes runs at 4'75cm. constant LINEAR speed.
I decided to made my first attempt with a CrO2 TDK tape as I assumed a standard FeOxide tape would have some difficulties in handling the required saturation level and Metal tapes trend to be highly abbrassive.
Cutted the tape, made the holes in their corresponding places with a 0'8mm drill bit, taped the leaders, wound it back into the HP Mini Cassette shell and insert it into the drive.
NEWM 256.... and... IT WORKS!!!!!!!!!! ;-)
Some WRTP's, DIR's and READP's to make a first reliability test and everything seems to be OK.
Hope this help someone to recover his/her old (and unusable up to now) Mini Cassettes.
Thanks again and bye for now.