[GreenKeys] More TU-170 questions

[w9ddd at tapr.org]

Yes I took a short cut and didn't think about there being 2 fuses, especially if the parts list only shows one. Perhaps it's a case of the parts list only showing what's on the PCB.

I'm thinking a 1 or 2 page addendum to the manual would be nice.  We could take the cleanest copy available and have someone  who can edit a PDF insert  the addendum.  

If I were bored with nothing else to do, I'd do a new schematic that combines all in one drawing.  Don't hold your breath.

John, W9DDD


> On Dec 27, 2020, at 9:55 AM, Ralph Mowery <rmowery42 at charter.net> wrote:
> 
> John take a closer look at the schematic.  The .125 fuse is only in the DC
> loop supply side that is normally set for 60 ma max or 20 ma.  It seems to
> be one of the fuses that resembles a resistor and is wired in the circuit
> board.
> 
> 
> There is a much larger fuse that is in the AC line.  Looks like one of the
> 3AG type that is more common to most people.  It is not shown on the
> component schematic, but on the chassis wiring .  I did not see a rating for
> that one, but it should be high enough for the tu170 and the teletype motor
> circuits.
> 
> Ralph ku4pt
> 
> 
> 
> -----Original Message-----
> From: greenkeys-bounces at mailman.qth.net
> [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of w9ddd at tapr.org
> Sent: Sunday, December 27, 2020 2:30 PM
> To: greenkeys at mailman.qth.net
> Subject: [GreenKeys] More TU-170 questions
> 
> The SSR questions got me to looking in the manual again.
> No specs on the motor control SSR.
> They list the fuse as 1/8 amp.  Tracing the circuit diagram shows that the
> switched outlet is fed through that fuse.  I don't think that would work.
> Either the  drawing is in error or the fuse size must be wrong.
> 
> When I return home I'm going to have to take the cover off to replace the
> meter lamp so I may as well investigate then unless some already has the
> answers. 
> 
> John, W9DDD
> 
>