[GreenKeys] ASR33 tape reader

[gil smith]

Hi folks:

I am forwarding this on behalf of Charles <charlesmorris@direcway.com> on
the classic computer list.  Anyone with words of advice on his 33 reader
problem?

(sending this for the fourth time -- has anyone seen more than one?  Keeps
bouncing on me).

thanks,

gil


>From: Charles <charlesmorris@direcway.com>
>To: cctech@classiccmp.org
>Subject: Need help with ASR33 tape reader - major frustration!
>Date: Sun, 06 Apr 2003 21:09:30 -0500
>Reply-To: cctalk@classiccmp.org
>
>I can't get my ASR33's tape reader to stop missing occasional
>characters! I have lubed it and tried setting it according to the
>procedures in the manual but that is very frustrating since many
>of the adjustments interact.
>
>Using a test tape punched on the same TTY with 72 printable
>characters per line (incrementing from space through Z and
>punctuation, then LF + CR at end of each line), if I carefully
>adjust the detent position I can achieve one (and occasionally 3
>or 4 in a row) "skipped" characters about every 10-20 lines which
>is roughly once every 1000 characters on average. 
>
>I can load short tapes like the BIN loader and then the second
>short section of 4K FOCAL successfully, but the long first section
>of FOCAL (which takes over 10 mins. to read in) invariably gives a
>checksum error. In other words, not good enough.
>
>The missing characters are not being read into the data stream at
>all, nor are the previous or next characters duplicated. I wrote a
>program to just read the characters into the AC and halt if a NUL
>(000) is read. All 0's are indeed being read on the missed
>character and I think this is because the contact pins are all
>held down if there is a "misfeed" where the tape moves just enough
>to put the pins between rows of holes, but not far enough to skip
>to the next.
>
>Anyone with experience "tuning" this beast, please give me a hint!
>thanks
>Charles


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