[1000mp] Mark V turn-on, power-up issue

[Glenn Rattmann]

Phil,

Thanks but I'm afraid it is totally dead-- no functions.  I wish it 
was just the display! ;-)
See my additional post to answer Mike's questions....

--Glenn K6NA

At 03:41 PM 2/16/2009, you wrote:
>Perhaps the rig lights up but the display is dead......
>
>Try using the rig from a computer connection.
>
>I have some personal experience from this  perspective
>in that I thought I had a dead unit but it was probably
>only the hv unit powering the  display...there is a separate
>hv unit for the front display..
>
>good luck, 73,
>Phil
>W5BVB
>
>
>----- Original Message -----
>From: "Glenn Rattmann" <k6na at cts.com>
>To: <1000mp at mailman.qth.net>
>Sent: Monday, February 16, 2009 3:21 PM
>Subject: [1000mp] Mark V turn-on, power-up issue
>
>
> > List,
> >
> > I've had an intermittent turn-on issue with one of my Mark V 200-Watt
> > radios, where it won't light up at all.  I have two rigs and two
> > FP-29 (and two cables), so I have definitely isolated the problem to
> > the one radio.  The radio also more than once has just gone black
> > unexpectedly while in use, and won't restart when this happens.  If
> > it sits cold for a week or two, it might come back up normally, only
> > to fail again later.  Lots of wiggling around with the DC cable/FP-29
> > hasn't fixed it.  I searched the 1000mp archives for FP-29 or other
> > power-up issues and didn't see anything exactly like this.
> >
> > I've got this radio spread all over the bench now.  The DC cable
> > comes to the rear apron and meets a Molex-type bulkhead mount 6-pin
> > connector there.  I've removed the connector from the rear
> > apron.  The six conductors in the harness go almost to the front of
> > the radio, under the fan, where four of them curve back to the power
> > input board accessible by removing the fan and the heatsink/amplifier
> > module.  The other two conductors (light gauge) terminate in a little
> > connector mounted to a bracket near the power-on switch, but
> > interestingly there is no mate to that connector-- it's just floating
> > there.
> >
> > The four other wires terminate on the DC power board in lugs bolted
> > to the board.  The board has a few capacitors and a couple of relays,
> > and the heavy output wires then lead from the board into the RF power
> > amp module.
> >
> > I'm thinking of replacing the relays on the board as a shot in the
> > dark.  Or, the intermittent may be caused by either poorly crimped
> > lugs on the high current leads (at least one looks insufficiently
> > crimped, but it's a guess), OR poorly mated pins inside the
> > Molex-type connector (I assume it is not a true USA Molex-- it's not
> > marked).
> >
> > Before putting the radio back together, I will improve the crimping
> > on all the DC lugs, and add solder to them so I can rule out this as
> > a possible problem source.
> >
> > Second, I want to pull the pins out of the DC connector, examine the
> > pin-crimping, and perhaps solder them, too.  I know Molex has a
> > series of pin-removal/install tools for their various connectors, but
> > has anyone identified the correct tool for this particular Molex-like
> > connector?  FYI the pins are not round, they are hollow square, or
> > perhaps rectangular, in section.  I want to obtain the tool if
> > possible (have not started a search with vendors yet, because the
> > connector mfr. is unknown).
> >
> > I will also go into the amp module to inspect how the DC voltage
> > leads terminate in there, and inspect everything.
> >
> > When this radio lights up, it works perfectly in all respects,
> > usually for hours at a time, so I don't really suspect the amp-output
> > devices-- but I am open-minded.
> >
> > By the way, I know of two people who after difficult troubleshooting
> > did eventually learn that they suffered from improperly crimped pins
> > in the Molex connectors of the power supply leads in their kw RF
> > amplifiers (the connector between the removable power transformer and
> > the amp wiring harness).  This led to intermittent filament
> > voltage.  So, these types of connectors are not always perfect, and
> > if intermittent, can be a bear to discover and fix!
> >
> > Any ideas on this issue are appreciated... thanks!
> >
> > --Glenn K6NA
> >
> >
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