Lou,
The first thing to try in the situation you describe is to loosen and then
retighten all the screws that hold the boards to the chassis. Many boards
get their ground through these connection points and over time the boards
compress under the constant pressure of the screws and the screws no longer
exert enough pressure to maintain a good ground connection. The connection
becomes erratic and causes intermittent problems to appear. By loosening and
retightening you not only put enough increased tension on these connections
but cause the copper foil to flow a bit more onto the chassis to re-make the
connection secure electrically. It is the easiest thing to do and generally
fixes many of these types of problems after years of service.
If that doesn't correct the problem, the next thing to consider is reheating
every solder connection until the solder flows again, maybe adding a touch
of new solder in the process. Some solder joints may also become
intermittent after years of thermal cycling every time the rig is turned on
and off. The expansion and contraction eventually works some marginal small
connections to become resistive between the component, solder, circuit board
foil interface. I've personally seen this under microscopic examination in
many cases. It generally shows as the lead separation from the solder pool
on the foil.
Finally, on a rig of the age of the Triton IV, it would be wise to replace
every electrolytic capacitor in the rig as they lose their capacity value
over time. This happens to all old electrolytic capacitors whether in use or
sitting on the shelf since it was manufactured. At 15-20 years since
manufacture, more than half the original capacity value is no longer there.
Replacing with new fresh electrolytic capacitors can bring new life to an
aging rig or any electronic device. Follow that with a full alignment and
the rig should operate as it did when it was new. This, of course, is a
final coarse of action, taking the most time and a bit of expense, but if
you intend to keep the rig for awhile yet and neither of the first two
common remedies above do not correct the intermittent condition, it may be
an electrolytic capacitor that has fallen below the critical value for the
circuit it is in. If the intermittent problem gets progressively more
frequent or worse, this is likely a cause on any piece of equipment over
10-15 years of age. Good Luck, and if you change out the electrolytic
capacitors, check that you get the polarity correct. Electrolytics installed
with reverse polarity makes for lots of yellow smoke and shrapnel you can
surely do without.
73, -=Rog-K9RB=- (former First Class Commercial License holder 1967)
----- Original Message -----
From: "Louis Ciotti" <lciotti@twcny.rr.com>
To: <tentec@contesting.com>
Sent: Tuesday, October 16, 2007 9:13 AM
Subject: [TenTec] Triton IV intermittant transmit problem
> Hi all,
>
> I finally am getting a chance to look into a small problem with my Triton
IV analog. When using ssb, I key up and will not get any output. Usually a
light tap on the case would fix it, but is is getting worse. I took the top
cover off and have narrowed the problem to the circuit card that is in the
front center of the rig. I removed the metal cover over the board and found
that if I press on the far right tunable capacitor on the rear of the
circuit card the problem goes away only to return a short while later. I am
wondering if this could be just an intermitant connection or something more
complex. Any help would be great. I had this rig back for other repairs
about 3 months ago, and about three weeks after I got it back this problem
showed up. I really would prefer not to send it in for repairs again...
>
> Thanks,
>
> Lou
> KC2RVD
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
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