Bob,
That was a great suggestion about cleaning the controls in the bias
circuit. Most times I use a fine line marker and place a line on the body
and shaft of a critical control adjustment. In that way I get closest to
the original setting when finished with the cleaning. As for intermittent
connections, as a boy when changing the channel on the TV ( mechanical
tuners ) I was hollered at many times.... " Don't spin the dial so fast,
you are going to tear the TV up. " You can imagine how confused I was when
my TV Repair Elmer sprayed stuff into one and Spun the thing for all it was
worth. Some here may be too young to remember when a person had to get off
the couch and go over to the TV and turn a big knob to change channels. I
was Dad's remote control for 18 years or longer. Kids and parents just
don't interact like they used too. I vote that we bring back the Vertical
Hold Control on All TV Sets !!! Our TV never looked good unless there was a
paper Matchbook wedged behind the Tuner Knob. Have I triggered some
memories?
73 to all de
Wade/KJ4WS
On Sat, Jul 14, 2012 at 9:23 PM, Bob McGraw - K4TAX <RMcGraw@blomand.net>wrote:
> I'll chime in here.,
>
> Likely the driver bias pot or PA bias was open due to it sitting in one
> place for years. Not unusual. No bias, maximum PA current. Then moving
> things around caused it to make contact and all started working.
>
> I suggest noting the physical positions of the pot adjustments and then
> exercising the pots to the extremes several times. Apply a very small
> amount of contact cleaner and then exercise again. Set them to the
> original
> physical position and then with an amp meter in the red lead, adjust for
> the
> correct current draw. I do recall the procedure and current values are in
> the manual. {mine is at the shop}
>
> The clue to no bias was the test at about 4.5 volts when the supply went
> into current limit.
>
> 73
> Bob, K4TAX
>
>
>
> ----- Original Message -----
> From: "wade staggs" <tvman1954@gmail.com>
> To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
> Sent: Saturday, July 14, 2012 12:51 PM
> Subject: Re: [TenTec] Paragon Problem gets very odd
>
>
> > *Amazing,*
> > * That cap could have been breaking down under load. You
> > could have bad connections. I would look at ALL of the connections very
> > closely. Maybe, it saw you Armed with the proper service info and you
> > scared it into working ;) I am really glad that you are on the air. If,
> it
> > fails again, shake the service manual at it and give it a good cursing.
> > You
> > may need to scare it some more.. Just Joking...*
> > * 73 de Wade/KJ4WS*
> >
> > On Sat, Jul 14, 2012 at 12:43 PM, Ben Hall <kd5byb@kd5byb.net> wrote:
> >
> >> Morning all,
> >>
> >> An update. So I got the power amp out of the Paragon, took it all
> >> apart, and inspected it. I found no obvious damage - no swollen caps,
> >> no burn marks, etc...
> >>
> >> I did remove C25 (which was a 33uF, 35V, 105 deg C unit) and couldn't
> >> find a replacement in my supply. C25 tested fine. I ran it up to
> >> nearly 30 VDC and it did not short, did not leak, etc...
> >>
> >> But I could find nothing wrong, so I put it back together minus C25.
> >> With just the power amp on the bench, I hooked up 13.8VDC to the red
> >> lead.
> >>
> >> Everything was fine. No power draw. (insert head scratching here)
> >>
> >> So I put it back into the radio, hook up the RF output. Apply power.
> >> No power draw on the red wire into the power amp.
> >>
> >> So I reattached the blue "11" plug and repeat. No power draw.
> >>
> >> So I reattached the RF Input and repeat. No power draw.
> >>
> >> So at this point, everything is hooked up minus the red power wire. So
> >> I resolder it to the power board and apply power to the radio.
> >>
> >> It POWERS UP FINE. Hooked it up to the dummy load, hooked up my mic,
> >> and it makes output power just fine. Voice peaks into the dummy load
> >> easily hit nearly 100W.
> >>
> >> SoooOOOOooo! I am now totally confused as to what's going on. Best I
> >> can figure was maybe a loose connection from the bias board to the power
> >> amp? VERY ODD.
> >>
> >> I am ordering some replacement caps from Mouser - will replace that 33uF
> >> and the 10uF ones with 50VDC, 105 deg C replacements...
> >>
> >> thanks much and 73,
> >> ben, kd5byb
> >> _______________________________________________
> >> TenTec mailing list
> >> TenTec@contesting.com
> >> http://lists.contesting.com/mailman/listinfo/tentec
> >>
> > _______________________________________________
> > TenTec mailing list
> > TenTec@contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
> >
>
>
> _______________________________________________
> TenTec mailing list
> TenTec@contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
>
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|