---------- Forwarded message ----------
Date: Sun, 23 Jan 2005 13:43:05 -0500 From: paul daulton <k5wms@...>
To: farhan@...
Cc: farcir@...
Subject: Assembling Far bitx boards
Ashhar, I have nearly finished assembly of the main board I received from
Far Circuits
a couple of weeks ago. I am copying Fred Reimer( FAR CIRCUITS) . I am in
no way
disapointed with the design or quality of the boards. I'll review the
experience I had and
recommend a solution to one problem.
See attachment bitx2.jpeg . Looking at the board from the top view with
the Band pass
filter in the upper left hand corner of the board, the circuit proceeds
left to right through
the first bi amp, diode mixer , 2nd bi amp, filter, 3rd bi amp, then bfo
on right side of picture. Lower edge of board in picture left to
right,has tx amp vfo, and rec audio. Your text stated the transistors in
the bi amps face each other and all other transistors face to the
rightexcept the mic amp. All of this agrees and makes sense as the layout
follows the schematic. The exception is the LM386 stage where the IC
layout is a mirror image. I dont know if I speified the orientation
wrong to Fred or if there is an error on the rx amp layout. There is an
easy solution: I mounted the LM386 IC on the bottom side of the board to
achive the correct pinout for the lm386. You can advise Fred if the
layout was printed as a mirror image or if there is a mistake on the 386
stage. It would be helpful to
add a notation like "viewed from foil side" or "viewed from component
side". Personally I like the board as it is reversed I could translate
the mirror image but it would take more time. Fred has made a quanity of
boards rather than scrap these I would advise him to
ship with a note on correctly installing the audio IC.See attachment bitx1
for Ic placement.
Two other minor descrepancies. 1. there is a trace missing from L1 in the
bandpass filter to the pad where the top of l1 solders in , no problem
just poke the wire through the hole
and run it to the trace going between the 10pf cap and the 2.2pf cap. 2.
there is a diode shown on the schematic from the 12r connection to the
junction of the 100 ohm and 220 ohm resistors that supply the Audio
output IC and the driver, I did not find a place for this
on the circuit board. This shouldn't be a problem and the circuit will
function fine without
it.
Thanks to both of you for your time and efforts on this project. What you
see in the pictures took me about 7 hours time. I dont know the cost as
almost every thiing came from my stock. I bought a few resistors and a
half dozen 2n2222's form local RADIO SHACK store., I usually buy .1uf and
such in bulk.
I am leaving tonight and wont be back until Friday. I have every thing on
board except zener and coils. Testing will have to wait untill next
weekend.
