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DX 60A NO TX




 
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Author Topic: DX 60A NO TX  (Read 10441 times)
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ve6pg
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« on: February 16, 2005, 08:22:20 AM »

HI FROM TIM...PICKED UP  A DX60A AND VF1 VFO AT LOCAL HAMFEST...THE THING LIGHTS UP,I'VE CHANGED ALL THE TUBES,AND WHEN I THROW IT INTO AM TX,THE PLATE METER READS 80MILS,BUT I HAVE MINIMAL RF.PROBABLY ABOUT 50-100mw. VERY LITTLE MOVEMENT ON WATT METER,NO AUDIO OUTPUT AS WELL...GRID READS NOTHING AT ALL. PREVIOUS OWNER HAD A 1/4 INCH JACK INSTALLED IN THE BACK,IN LINE WITH THE OUTPUT VOLTAGE TO PIN 8 OF THE ACC JACK.ASIDE FROM THIS OBVIOUS MOD,ALL APPEARS CORRECT..NO EXTRA HOLES DRILLED,TUBES ADDED,ETC. WHEN I PUT A 80 METER ROCK IN IT,I CAN ONLY KEY THE AM TRANSMIT WITH A CW KEY IN THE KEY JACK...ANY IDEAS?  I'VE LOOKED AT THE PICTORIALS I HAVE,AS WELL AS THE WIRING...DONT SEE ANT FAULTS...ANY HELP ON THIS WOULD BE GREAT...73...TIM...SK...
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...Yes, my name is Tim Smith...sk..
K1MVP
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« Reply #1 on: February 16, 2005, 11:31:55 AM »

Quote from: ve6pg
HI FROM TIM...PICKED UP  A DX60A AND VF1 VFO AT LOCAL HAMFEST...THE THING LIGHTS UP,I'VE CHANGED ALL THE TUBES,AND WHEN I THROW IT INTO AM TX,THE PLATE METER READS 80MILS,BUT I HAVE MINIMAL RF.PROBABLY ABOUT 50-100mw. VERY LITTLE MOVEMENT ON WATT METER,NO AUDIO OUTPUT AS WELL...GRID READS NOTHING AT ALL. PREVIOUS OWNER HAD A 1/4 INCH JACK INSTALLED IN THE BACK,IN LINE WITH THE OUTPUT VOLTAGE TO PIN 8 OF THE ACC JACK.ASIDE FROM THIS OBVIOUS MOD,ALL APPEARS CORRECT..NO EXTRA HOLES DRILLED,TUBES ADDED,ETC. WHEN I PUT A 80 METER ROCK IN IT,I CAN ONLY KEY THE AM TRANSMIT WITH A CW KEY IN THE KEY JACK...ANY IDEAS?  I'VE LOOKED AT THE PICTORIALS I HAVE,AS WELL AS THE WIRING...DONT SEE ANT FAULTS...ANY HELP ON THIS WOULD BE GREAT...73...TIM...SK...


Hi Tim,

 The first thing I would do, is "forget" about the AM function for now.
 Just think about the rig as a straight CW rig, and as such, why are
 you not getting grid drive?
 You should be able to get at least 2 to 3 ma of grid drive indicating
 the oscillator is working,--if not why not?
 You mentioned using a VFO,--forget the VFO for now, es install an
 80 or 40 meter crystal es see if you get proper drive.
 If you do,--you probably have a VFO problem, if not check the oscillator
 with a scope es see if its working, if it is--check the buffer stage.
 You have to find out why ur not gettin "basic grid drive" in the CW
 mode, es get the rig working as a CW xmtr, and then worry about
 the AM function.
 Hope this "helps" as a starter.
                                       
                                     73`s Rene, K1MVP :neutral:
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xe1yzy
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« Reply #2 on: February 16, 2005, 11:32:06 AM »

Hi Tim

What happens when you go to CW? do you have the bias voltage correct? should be -38V at pin 5 in the 6146.

Also make a good clean in the function switch with deoxit, you can download the manual from BAMA ;

http://bama.edebris.com/manuals/heath/dx60b-sch/

Good luck with your DX60!

73's Pedro XE1YZY
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N8ECR
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« Reply #3 on: February 16, 2005, 11:41:55 AM »

It sounds like your fuction switch is dirty or bad. as for output this might explain this as well, or you rock has poor output.  always with these HeathKits  really check over the wire connections and solider joints.  I recall a solider joint in them with several wires back near the overload fuse/bulb.  there might be other points as well.  Check all resistors even if they look good.  I had a DX-60, with a resistor in the modulator was suppose to be 1 Meg.  and had no resistive reading at all; so my  modulator didn't work.  I would check it over real good; with the expectation that a not so skilled builder put it together.  Get in there and move wires and parts near the solider points, and teminals.

Good luck  

Mike/N8ECR and the DX-60 Net......
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w3jn
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« Reply #4 on: February 16, 2005, 01:35:04 PM »

To the subject at hand:  Tim, you say it DOES work on AM with a key in the jack?  If so, do you have to press the key for it to xmit?  If so, someone's replaced the 1/4" jack with a NC switch with just a normal jack - or the switch on the jack is dirty.

Good luck and 73 - John
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Tom W2ILA
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« Reply #5 on: February 16, 2005, 02:15:50 PM »

All the above  info is an excellent start

Looking ahead:
When you do have the oscillator working with a crystal and 2.5ma grid current you will probably see output.
You mentioned a jack installed on the back.  There were lots of mods for PTT and someone may have put a PTT jack on the back and disabled or re-configured the key jack on the front.  Thats something to be aware of so when you have time look to see where the wires go.

The DX60 is a FB transmitter and if you decide to do mods it responds well.  Hope to hear you.

Tom
W2ILA
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W1RKW
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« Reply #6 on: February 16, 2005, 02:54:24 PM »

If you use DeOxIt on the function switch make sure you rinse off the residue otherwise you'll be needing a new switch.  The hi voltage on that switch will cause the DeOxIt residue to burn.  Been there done that.  It ain't a happy thing.
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Bob
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His fear was when I turned it on for the first time life on earth would come to a stand still.
Tom W2ILA
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« Reply #7 on: February 16, 2005, 03:03:12 PM »

does that residue ever evaporate?  I am hearing about deoxit problems a lot lately.
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Paul, K2ORC
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« Reply #8 on: February 16, 2005, 03:13:14 PM »

Sideband Pat's post was deleted as abusive.   Reference AM Forum membership guidelines, found under "The Legal Stuff" on the Forum Index, regarding prohibition against abusive posts.  

Paul, K2ORC
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w3jn
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« Reply #9 on: February 16, 2005, 03:22:52 PM »

TNX, Paul.  I edited my post to reflect that.

73 John
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kc2ifr
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« Reply #10 on: February 16, 2005, 04:17:12 PM »

I think his name says it all.......... :twisted:
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W1RKW
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« Reply #11 on: February 18, 2005, 11:18:57 AM »

Quote from: Tom W2ILA
does that residue ever evaporate?  I am hearing about deoxit problems a lot lately.


Tom,
I don't believe it does evaporate.

I'm not necessarily singling DeOxIt out as a problem.  I think any cleaner that leaves a residue on a hi voltage bakelite switch assembly is asking for trouble if it isn't removed from the bakelite areas.

With Caig's DeOxIt cleaners there's actually a multi stage cleaning and lubing process. The way Caig suggests IIRC is to use the red DeOxIt chemical  to clean, rinse the red stuff off with a non-residue cleaner and lube with their blue stuff called PreServIt. But even the blue stuff leaves a residue that can cause carbon tracking if a high enough voltage is applied to that particular area. Bakelite switches or the bakelite material should be left clean dry of any residue to avoid the carbon tracking and possible burning. I've killed two separate switches on different occasions because of contact cleaner residue.
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Bob
W1RKW
Home of GORT. A buddy of mine named the 813 rig GORT.
His fear was when I turned it on for the first time life on earth would come to a stand still.
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