icom 736 and al811h hookup

[KM5PS]

I have recently bought a icom 736 for a backup rig and I am trying to hook it up to an AL811h amp.  I have hooked up the send line from rig to amp but when I key the rig in FM mode or CW mode my plate voltage meter reads abt 140 mA and the Grid meter does not move.  I have also tried hooking up the ALC line also and get the same reading.  I never have used the amp with an Icom rig before.  I works fine with my K3 using the send line only. The icom manual says to use both send and ALC connections.  I thought before I do that and mess with the ALC adj. on amp I would ask here first.  i have the icom set at about 40 watts of drive.   

TIA
John

[WB2WIK]

Sounds like it's keying just fine but not getting any drive.

Do you have a wattmeter in line after the amp?

If so, switch the amp to STBY or turn it OFF, key the rig again, see what the meter reads.  I have a feeling it might be "nothing."

[N4JTE]

Same advice from here, is the 736 showing anything out bypassing the amp? I use a 751a icom with a modified 811h and never use the alc connection.
Bob

[KM5PS]

I have the amp off and key the 736 and shows pwr coming out abt 50 watts.  Radio read 50w and so does the watt meter that I have inline with the amp. 

John

[K4RVN]

Have you tried plugging in a straight CW key to key the Ameritron amp with the 736 in the CW position using the send outlet on the 736?  The ALC is not required for this driving at 50 watts. I know these seem dumb questions but I would like to hear how you were keying the amp in the cw mode with your transceiver. Do you have a dummy load to check your 736 for 100 watts out? I use an ARB 704 on my little Icom 7200, but your relay is good for 16 volts and 2 amps listed in the manual.

Frank

[KM5PS]

Frank
I have now put a straight key in 736 and get the same results as before.  I was using FM mode before to get solid carrier for tuning.  When I key the 736 with straight key (cw mode)or FM Mode the  amp still shows abt 140mA in plate meter and barely moves on Grid meter.  It does this with straight key or when I use FM mode.  My watt meter shows that I am putting out 50 watts.  Yes I do have a dummy load and the 736 does put out 100 watts. 

John

[K4RVN]

I would suggest unplugging the send key cable from the amp and check it with an ohm meter for gound when keyed
with the transceiver going into your dummy load. Sure sounds like a relay problem on the send circuit since your other transceiver works OK with the amp. I don't know if like some other makes whether you have a menu item to turn on or not for a non Icom amp. I doubt it.

Frank

[W1QJ]

UM, do you have the coax cables connected the right way?  Coax from the radio to amp RF INPUT and antenna to RF OUTPUT?  Leave out ALC line for testing.  The radio is keying the amp just fine because your readings are correct for just being keyed with no drive.  CHECK THOSE COAX CONNECTIONS AGAIN.  OH. Make sure both radio and amp are on the same band.

[WB2WIK]

I would suggest unplugging the send key cable from the amp and check it with an ohm meter for gound when keyed
with the transceiver going into your dummy load. Sure sounds like a relay problem on the send circuit since your other transceiver works OK with the amp. I don't know if like some other makes whether you have a menu item to turn on or not for a non Icom amp. I doubt it.

Frank

It can't be that.  He's getting 140mA Ip.  If the amp was not keying, his Ip would be zero and stay that way.

[K4RVN]

Yep you are right, Lou already told us that. He did say he was getting 50 watts on the watt meter in line with the amp,
not nothing like you suspected so that threw me in addition to being a little dumb here. I really don't know what the poster meant " in line with the amp." Could be backwards like Lou mentioned for him to check his coax connections. I've done that at least once myself.
 I will be anxious to see what the problem is.

Frank

[KM5PS]

Well the problem is solved.  I hate to say that stupidity on my part is to blame.  The way I had my K3 hooked up and the Icom 736 were different.  I thought everything went threw my coax switches but the k3 was the only rig that was hooked directly to the amp. I took a day off of trying to figure it out and just happen to think that maybe the K3 was the only thing that was hooked up right, and sure enough it was.  Now that I have changed my cables on my coax switches, both rigs now go directly to the amp.  I guess that is a problem with two rigs, TWO many cables.  Thanks for help, I feel pretty stupid for not checking that first.  Thanks again guys for the information.   Hopefully this post might help someone else out before they do what I did. 

73's
John

[W1QJ]

Maybe my CHECK THOSE COAX CONNECTIONS AGAIN   helped?

[K4RVN]

Lou,
You done good, to coin a phrase, as well as some others but you pretty well nailed it. I did no good whatever.

Frank

[AD6KA]

Well the problem is solved.

Glad to hear it, and super glad it wasn't something
serious or expensive!

I feel pretty stupid for not checking that first.

Don't beat yourself up. We all have made (or make) those kinds
of mistakes during some point in our careers.

What you might do is label your cables if you have
more than one rig, or antenna, so this won't happen again. One way
is to hand laminate (only needs pressure) a small tag between
two layers of clear Dupont "Mylar D" tape.
(The "D" is important)
You can find this at a good art store or library supply store
It is pressure sensitive (sticky) tape with an aggressive
acrylic adhesive,  so it is easily used to hand laminate labels.
Two Mil thick tape works FB.

Tape a label tag to both ends of rig coax cables
and the indoor end of every antenna and rotor control cable.
And it's not a bad idea to also label stuff like amp PTT
cables, RTTY Keying cables,  Audio Out and Audio In cables
that go to the rig's rear panels, etc. Don'tcha just hate having a loose
cable with a connector and having to pull the radio forward
or sideways and figure out what it is?

It's not much work and you'll be glad you did it,
especially when some piece of gear craps out in the
middle of a contest and you are tired, sleep deprived,
PO'd, and hurrying to patch in a replacement.
THAT'S when Mr. Murphy likes to show himself!  

73, Ken  AD6KA

[W1QJ]

Lou,
You done good, to coin a phrase, as well as some others but you pretty well nailed it. I did no good whatever.

Frank

Who said that Frank?  I'll split it with ya