Can't receive when Dentron amp is inline
 

I hope this is just a dumb question and not some complicated problem
that I just bought.

Just picked up a Dentron GLA-1000. Filaments come on in standby, (1100
volts) and the t/r relay seems to be working. However when I put the
amp inline patched with coax between my transceiver and my antenna, I
lose reception as if the receiver can't "see" the antenna anymore.
Even if the amp is turned off. So I won't even try and tune the thing
of course!

Thanks for any suggestions,

Chuck
KB5GC

Unplug it, take it apart, short the relay terminals with a jumper. If
the receive comes back, take the relay apart and try to clean the
contacts with an eraser lightly, try to keep them silver polished. Or
replace the relay.
Good luck, 73 Chris VE3NGW/W4 Florida


Chuck W. wrote:

I hope this is just a dumb question and not some complicated problem
that I just bought.

Just picked up a Dentron GLA-1000. Filaments come on in standby, (1100
volts) and the t/r relay seems to be working. However when I put the
amp inline patched with coax between my transceiver and my antenna, I
lose reception as if the receiver can't "see" the antenna anymore.
Even if the amp is turned off. So I won't even try and tune the thing
of course!

Thanks for any suggestions,

Chuck
KB5GC

Hello, Chuck

Put an Ohmmeter between the center pins of the input and output
coax connectors of the amplifier, and check for continuity.
If open, suspect the "back" contacts of the T/R relay need cleaning.
A bit of rubbing alcohol on an index card, pulled
through the contacts while you carefully hold them shut
should clean the contacts. Don't use an emory board
or sandpaper. A burnishing tool is also good, if you can find one.

Also look at the coax jumper cable you use between your rig
and the amplifier. Look for continuity between center pins,
and no short across the coax. (It is easy for a strand
of the coax shield to short out a connector, if the coax braid
wasn't tinned before assembling the PL-259.) Flex the coax
while you are doing the ohmmeter check, to look for
an intermittant short.

73,
Ed Knobloch

Chuck W. KB5GC wrote:

Just picked up a Dentron GLA-1000. Filaments come on in standby, (1100
volts) and the t/r relay seems to be working. However when I put the
amp inline patched with coax between my transceiver and my antenna, I
lose reception as if the receiver can't "see" the antenna anymore.
Even if the amp is turned off. So I won't even try and tune the thing
of course!

a white business card works well also... I normally cut the card into 1/4 or
3/8 inch wide strips. Then run the card strip back and forth between the
closed contacts (use you finger, but be fairly gentle). Inspect the card
strip when your done. If there is any color on the card from the contacts,
start over from the top, until the card comes out clean. Do not use
sandpaper or an emery board!!!!!!!

Bob in phx
"Edward Knobloch" wrote in message
news:niV5e.8299$Xm3.4622@trndny01...
Hello, Chuck

Put an Ohmmeter between the center pins of the input and output
coax connectors of the amplifier, and check for continuity.
If open, suspect the "back" contacts of the T/R relay need cleaning.
A bit of rubbing alcohol on an index card, pulled
through the contacts while you carefully hold them shut
should clean the contacts. Don't use an emory board
or sandpaper. A burnishing tool is also good, if you can find one.

Also look at the coax jumper cable you use between your rig
and the amplifier. Look for continuity between center pins,
and no short across the coax. (It is easy for a strand
of the coax shield to short out a connector, if the coax braid
wasn't tinned before assembling the PL-259.) Flex the coax
while you are doing the ohmmeter check, to look for
an intermittant short.

73,
Ed Knobloch

Chuck W. KB5GC wrote:

Just picked up a Dentron GLA-1000. Filaments come on in standby, (1100
volts) and the t/r relay seems to be working. However when I put the
amp inline patched with coax between my transceiver and my antenna, I
lose reception as if the receiver can't "see" the antenna anymore.
Even if the amp is turned off. So I won't even try and tune the thing
of course!

Here is a dumb caution -- but:

Don't forget that there are lethal voltages inside that unit. Furthermore,
a good jolt may be present even with the Amp unplugged, since the caps may
be holding a charge.

Phil


"Chuck W." wrote in message
oups.com...
I hope this is just a dumb question and not some complicated problem
that I just bought.

Just picked up a Dentron GLA-1000. Filaments come on in standby, (1100
volts) and the t/r relay seems to be working. However when I put the
amp inline patched with coax between my transceiver and my antenna, I
lose reception as if the receiver can't "see" the antenna anymore.
Even if the amp is turned off. So I won't even try and tune the thing
of course!

Thanks for any suggestions,

Chuck
KB5GC

Thanks to all. Definitely something is up with the relay. Another
"buyer beware" on eBay story.

http://tinyurl.com/66ytl

Hopefully the sweep tubes aren't shot.

73,

Chuck