> Looks like there is a line switch for selecting the current loop. Would
> verify that it is in DC Line.
>

Yes, I have had it set to DC Line.  I was very glad to find that manual online and have been using it a lot!  Thank you, Nick!   I "think", but do not know for certain, that the machine may have been in a 20ma set-up before and so that's why I wondered if it had been hardwired for 20ma.  I have tried the various set-ups shown in the manual but still haven't been able to get it to print ITTY.  It is possible it is geared for 100wpm so I will try that channel of ITTY but I would have thought it would at least print garbage.  There is no "chatter" from the magnets at all.

73

Kevin
> According to a TT-4 manual on this site.
> https://rattrig.com/manuals/tm's.htm
>
> (2) Set the LINE switch of the TT-4(*)/TG and TT-335/TG (fig. 1-7) to Dc
> line for 60-ma signal circuit operation (operation in a dc system) (fig.
> 1-3) or to VOICE FREQ LINE for 20-ma signal circuit operation (operation
> in
> a voice- frequency system).
>
>
> On Tue, Oct 4, 2022 at 9:11 PM Kevin H. Phillips <kh-phillips@9-5usa.org>
> wrote:
>
>> To follow up on this message I posted: I have finally gotten the
>> machine back to printing from the keyboard. The problem probably was
>> oil somewhere it shouldn't have been but the fix took some time.
>>
>>
>> I tried inserting pieces of paper between the armature and magnets to
>> absorb any oil. This did not help (at least at first or as far as I
>> could tell).
>>
>>
>> I eventually tried spraying Contact Cleaner (WD-40 brand; it dries dry)
>> between the magnets and armature. This did not help. This evening I
>> started spraying the Contact Cleaner more liberally all over the magnet
>> area as well as on the electrical/electronic components behind the front
>> panel. This began to help. I kept typing RY's
>> (one-handed/two-fingered) while adjusting the Range and Armature
>> controls back and forth. I spent a lot of time doing this. All I can
>> say is that it finally started working properly. I was typing many lines
>> of RY's as absolutely fast as I could without a single character
>> dropped.
>>
>>
>> Another thing I tried was reducing the line current via the rheostat on
>> the front panel. I turned it down as far as it would go but the meter
>> would not read below 30ma. I tried slightly increasing it in stages up
>> to about 45ma but the magnets seemed happiest at 30. I may try a TU
>> with an adjustable loop and see if I can get it lower and see if that
>> helps . . . or hurts.
>>
>>
>> It still will not print ITTY. The loop locks up and I can type on the
>> keyboard but there is no print from ITTY. I am going to try reducing
>> the audio output and see if that does any good. It is the only thing I
>> can think to try at the moment. Maybe the loop current is too high
>> and/or the signal strength is just higher than these magnets can handle
>> (??)
>>
>>
>> 73
>>
>> Kevin
>>
>> W5TTY
>>
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