I have 4 TR7As, one of them I purchased new and none of them have
anything glued to the top of the? PTO can. I also currently have 3
TR7s with serial numbers in the 9000s and none of them have any thing
glued to the PTO. On the DR7 the LEDs are multiplexed, all of the
segments of each digit are in parallel with the segments of all of the
other digits, all the A segments are connected to all of the other A
segments etc. If a single digit segment is missing then it's either the
connection or a bad LED itself.
73, Joe Pyles KC9LAD
At 12:00 PM 3/21/2021, you wrote:
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Did you check that there is an
insulting strip loin top of the PTO mechanism? There is a very close fit
between the bottom of the DR7 solder? and the grounded metal below
the DR7 just below the display elements. This often results in dead
segments.
Drake,? in later radios, glued a grey piece of high voltage
cardboard on top the PTO assembly. Your radio looks like a pretty early
one so may not have this.
Also, the notion suggested by another, a bad foil, makes sense because
the same segments are dead on both the MHz displays.
Gary
W0DVN
On Mar 21, 2021, at 7:19 AM,
Steve Wedge, W1ES/4 via
<
w1es@...> wrote:
The second digit is missing two segments. It looks like a display or
driver issue to me (assuming the etches and soldering are okay).
I can?€?t remember if the display drivers are open collector or not.
Check the output of the display driver for each digit.
73,
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
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On Sun, Mar 21, 2021 at 06:34, Mike Davidsohn G3ZCC
<mike@...>
wrote:
Hi Everyone, hope you are safe and well.
I have fitted the rebuilt DR7 and the up/down and jumper works just
fine.
The first two digits seen to be missing the same part of the display
which is a lovely blue colour.
I have also knocked the PTO calibration so I will have to fix
that.
The fact that the first two digits are missing the same segments leads me
to believe that it is not the display itself.
I have attached a picture of the TR7 on 28.888
Any thoughts
Kind Regards
Mike
G3ZCC
