[GreenKeys] ASR33 Manual Reader

[B M]

I am a little further getting the tape reader to work on my ASR33.

It turns out that the fuse was the cause of the problem.  The original
fuse (1/2A) was burnt out, but  I only had 1/4A fuses on hand.  It
turns out 1/4A is not heavy enough.  The power pack apparently needs a
heavier fuse.  The schematics indicate that the fuse is 3/4A for newer
units.  Older units could have 1/2A, but should be replaced with 3/4A.
 Once the fuse was replaced with the proper rating, the reader now
generates data and advances the paper tape.

At the moment, I know the printer and tape punch is working correctly.
 In local mode, the tape has the correct ASCII values for the keys I
pressed.

The reader seems to be generating a constant hex value 5 for the most
significant 4 bits.  The least significant 4 bits are correct.

For example, a space (hex 20) when read from tape gives a 'P' (hex
50).  A 'T' (hex 54) gives a 'T' (hex 54), but a 'H'  (hex 48) gives a
'X' (hex 58).

I am now looking into the contact wires in the reader.

Thanks to all who have provided information to get me to this point.

--barrym

On Wed, Aug 11, 2010 at 8:01 PM, B M <iamvirtual at gmail.com> wrote:
> I am looking into why the paper tape is not working on my ASR33.  I am
> having a little trouble following the schematic.  Since the reader is
> manual, the reader power pack has a part number of 183087.  On the
> connector, there is a switch described as the 'Reader Feed Contact".
> The switch is connected between Pin 3 and Pin 9 on the connector.  I
> was assuming this would be the 'Start/Free' switch on the reader.  Pin
> 3 is a Brown/Green wire and Pin 9 is White/Black wire.  I can see the
> White/Black wire on the reader, but I don't see where the Brown/Green
> wire goes.  Putting the Start/Free switch in 'Start' does not give
> continuity between Pin 3 and Pin 9.  I do have tape in the reader
> (just in case the feed switch is the paper tape out switch).
>
> When plugged in, putting the reader switch in 'Start' mode immediately
> causes the fuse on the reader power pack to blow.  I am wondering if
> the mechanism is jammed leading to increased current draw.  I did not
> remove the reader to clean it, but I did oil & grease the best I
> could.  I am looking through the reader maintenance documentation to
> figure out the mechanical mechanism.  Any hints on how the reader
> advances the drive wheel?
>
> Thanks for any information!
>
> --barrym
>