T1 tuner assembly problem

[Rob KK4R]

I had a problem installing the socket for U1.  It would not go flat against
the board, because it was apparently pressing against the row of relays
next to it.  I discovered the problem after 1 pin was soldered, per the
instructions, and I inspected it to see if it was flat.  It took
significant pressure to hold the socket down on the relay side.  Moving the
relays was not an option, so I squeezed the socket down and soldered
another pin.  Now the socket looked a little warped when viewed from the
end, because it still pushed up some where there was no pin soldered.

I got past this point by squeezing and soldering my way down the
socket.  The result was OK, and final assembly did not present a
problem.  So far the tuner works, but I am concerned about the stress on
the relays.  In the manual, there are admonitions about putting stress on
the relay leads or damaging the plastic covers, because this can cause
premature or outright failure.  I sure hope I don't have to try to remove a
relay one day.

Perhaps a manual modification is in order?  I think the relays must have
ended up positioned at the limit toward the socket due to the way that I
held and flipped the board prior to soldering.  Has anyone else had this
problem?  A remedy might be to install (or just tack solder) the socket
prior to installing the relays.

While we are talking about the manual, R1 and R2 in my kit were a bit too
large to mount flush on the board.  They were not in the normal package
(with painted color code), but were blue ceramic-looking things.  There
might be reason to give the kit builder some slack on flush-mounting these
parts.  Bending the leads at extreme right angles at the end of the package
will stress the part.  I left mine just above the board.

Rob


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[Ron D'Eau Claire-2]

Thanks for the feedback, Rob. I wrote the T1 assembly manual, so I keep an
eye out for comments.

>From what I understand, you shouldn't have any trouble with those relays.
The case problems that have caused trouble are when the upper part of the
case is melted or holed by touching it with a soldering iron. That lets dirt
in and, when the deformation is extensive enough it can interfere with the
movement of the mechanism inside.

About those two resistors, they are described on the errata sheet. They were
changed from 1/2 to 1 watt to provide an extra margin of safety when pushing
the T1 at full power. They were changed at the same time T2 was changed from
being wound on a single core to being wound on two stacked cores.

On the bottom of the board, there's about 1/32" (1 mm) excess room with the
1-watt resistor installed at R2. With that little space it seemed best to
keep the resistor against the board and as much out of the way as possible.

On top of the board, the other 1-watt resistor, R1, is nestled between the
dual-core T2 and inductor L5, and one end of the secondary for T2 must be
fitted into a solder pad right next to the resistor. R1 was kept down
against the board where there is more room between the inductors and it
wouldn't obscure the pad T2's secondary.

>From your comments, it sounds like you got the unit together okay so your
resistor positions must have worked for you.  

That's the first instance I've heard reported with trouble fitting the
controller socket in alongside the relays. It bears some further checking.
Thank you!

Ron AC7AC

 
-----Original Message-----

I had a problem installing the socket for U1.  It would not go flat against
the board, because it was apparently pressing against the row of relays
next to it.  I discovered the problem after 1 pin was soldered, per the
instructions, and I inspected it to see if it was flat.  It took
significant pressure to hold the socket down on the relay side.  Moving the
relays was not an option, so I squeezed the socket down and soldered
another pin.  Now the socket looked a little warped when viewed from the
end, because it still pushed up some where there was no pin soldered.

I got past this point by squeezing and soldering my way down the
socket.  The result was OK, and final assembly did not present a
problem.  So far the tuner works, but I am concerned about the stress on
the relays.  In the manual, there are admonitions about putting stress on
the relay leads or damaging the plastic covers, because this can cause
premature or outright failure.  I sure hope I don't have to try to remove a
relay one day....
While we are talking about the manual, R1 and R2 in my kit were a bit too
large to mount flush on the board.  They were not in the normal package
(with painted color code), but were blue ceramic-looking things.  There
might be reason to give the kit builder some slack on flush-mounting these
parts.  Bending the leads at extreme right angles at the end of the package
will stress the part.  I left mine just above the board.

Rob


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