It is MECHANICAL, not electrical. Read the 28ASR manual. Read the 28ASR training documents. Watch my 28ASR video. In T mode the keyboard signal generator clutch is supposed to be NOT TRIPPED, meaning the generator stays marking while the keyboard/perforator is triggered and reset mechanically. 

I may be crazy but this is not my first rodeo. 

And karma being what it is, I am sure I will have to eat all or some of my words…….

Nick England K4NYW
www.navy-radio.com


On Thu, Feb 29, 2024 at 6:50 PM W2HX <w2hx@w2hx.com> wrote:

I am really not familiar with this stuff, but I do recall there is a micro/limit switch on the K/KT/T mechanical knob shaft. I wonder if that is involved in this (ie to short the keyboard)? Have you checked that switch?

 

 

73 Eugene W2HX
My Youtube Channel: https://www.youtube.com/@w2hx/videos

 

From: greenkeys-bounces@mailman.qth.net <greenkeys-bounces@mailman.qth.net> On Behalf Of Nick England
Sent: Thursday, February 29, 2024 5:43 PM
To: Greenkeys <greenkeys@mailman.qth.net>
Subject: Re: [GreenKeys] 28ASR "T" mode problem

 

Several people have asked if T mode just shorted out the keyboard signal generator instead of mechanically not tripping it.

No - this is mechanical and not electrical. The perf will cycle MUCH faster than the printer, so you are not restricted to 60wpm when cutting tape in T mode like you are in KT mode.

I just made a video of my other 28ASR punching tape in KT and in T modes so you can see and hear the difference.

It looks like YouTube now does some weird scheduling thing so this may not be visible until midnight.

 

BTW, that switch is for controlling an indicator lamp.

 

Nick England K4NYW
www.navy-radio.com

 

 

On Thu, Feb 29, 2024 at 2:55 PM Nick England <navy.radio@gmail.com> wrote:

In "T" mode, the keyboard signal generator clutch is not supposed to engage, meaning that the keyboard mechanically activates the perf but does NOT transmit a signal on the line. This allows you to cut a reply tape without interference while the page printer is printing an incoming message.

 

My problem is that the perf is getting activated/reset fine in T mode, but unfortunately the keyboard signal generator clutch is also getting tripped, causing the keyboard signal generator to interrupt the signal line. This means I can cut a tape OK, but that printing of an incoming message gets garbled.

 

I can't figure out how to adjust  the keyboard control selection lever so it does not trip that clutch. The control cam is causing the perf to activate/punch/reset correctly in T mode, and I can see that the keyboard control selection lever is rotated, but that dang clutch trip lever is still tripping.

 

 Note - I can't actually see the end of the clutch trip lever as it is buried in there somewhere.

 - reference position C on Figure 21 of 573-117-100 - (diagram attached)

 

Any suggestions? I swear this thing used to work properly but something has happened and I can't figure out what.....

Nick