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Author Topic: Swan 350 schematics question.  (Read 7244 times)
AA4HA
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Posts: 1418




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« Reply #15 on: October 31, 2011, 08:33:01 AM »

5) Remember this is a 1960s vintage rig and doesn't have the protective devices of modern stuff. Besides the usual high-voltage hazards, it is completely intolerant of operator error. Read The Fancy Manual!

Those were the good old days. When you could make a mistake and blow out a tube or fuse. I learned caution because it cost a few dollars to go down to Walgreens to use the tube tester and to buy a part to replace a screw-up. Also, getting shocked by B+ a bunch of times taught you lessons about what not to go poking around in.

I think I was the only one who still bought 67 1/2 volt batteries every few months. That stockpile on the shelf ended up being all mine until it was finally depleted the the spring of 1979 (the day the music of HCJB died, to me).

Now mistakes are more costly, hidden behind layers of surface mount components and beyond the means of most amateur radio operators to diagnose, much less repair. We become appliance operators because it is a waste of time to even take the screws off the case so you can stare at a few chips.
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
N2EY
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Posts: 3879




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« Reply #16 on: October 31, 2011, 08:56:07 AM »

5) Remember this is a 1960s vintage rig and doesn't have the protective devices of modern stuff. Besides the usual high-voltage hazards, it is completely intolerant of operator error. Read The Fancy Manual!

Those were the good old days. When you could make a mistake and blow out a tube or fuse. I learned caution because it cost a few dollars to go down to Walgreens to use the tube tester and to buy a part to replace a screw-up.

Or a lot more. Some rigs weren't even fused; you could burn up tubes, transformers, chokes and a lot more by not knowing what you are doing.

You could also easily transmit out of band. Dial calibration was often just a suggestion.

Now mistakes are more costly, hidden behind layers of surface mount components and beyond the means of most amateur radio operators to diagnose, much less repair.

OTOH there are fewer mistakes that can be made. Many if not most rigs today will fold back or shut down rather than fry the finals. Many have no tuneup controls at all, and the digital dial is accurate to within a few hundred Hz at worst.

I don't know if any rigmaker actually does this, but it is possible to program a processor-controlled rig so that you cannot transmit outside your license privileges - even to the point that if you try to transmit on 14,349 kHz USB it won't TX because the sideband is outside the band even though the suppressed carrier isn't.

We become appliance operators because it is a waste of time to even take the screws off the case so you can stare at a few chips.

I guess I missed the memo on that. "We" doesn't include "me" in that way. Just look at my profile picture...

The main point is that there's a bit of tribal knowledge that went with old rigs that needs to be passed on. Like the fact that before about 1983 amateur transmitters were rated DC power in, not RF power out. More than once I've heard of hams damaging old rigs by not understanding that.

73 de Jim, N2EY
« Last Edit: October 31, 2011, 09:00:27 AM by N2EY » Logged
KK4CPH
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Posts: 154




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« Reply #17 on: October 31, 2011, 10:20:35 AM »

Jim,
The only calibrator I see is a "Dial Set" next to the VFO and on top of the VFO is a band dial set. (It says to use nylon hex tool)  Of course I don't have any of the equipment mentioned in the manual to do an alignment so I'll have to find someone.  In the meantime I could get a frequency counter.  I know it's off a bit.  I was listening to a rag chew last night and they said QSY to 3946 and my dial was at about 3943.  For the first 30 minutes, I find I have to slightly adjust the VFO to keep their voice normal but after that it seems to stay on frequency.  I guess that's normal (?)
I have found out it won't transmit.  I hooked up my mic (Astatic D-104 and has new battery) keyed up and nothing.  It's still receiving but it's as though the mic isn't plugged in.  The switch is in the "PTT" position and I tried moving the other switch between "Receive" and "Tune/CW"   Both the PA tubes are in and the caps connected.  Also I hooked up my keyer to the rear jack but it doesn't transmit either.   Huh

Eric
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N2EY
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Posts: 3879




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« Reply #18 on: October 31, 2011, 11:37:05 AM »

The only calibrator I see is a "Dial Set" next to the VFO and on top of the VFO is a band dial set. (It says to use nylon hex tool)

DON'T TOUCH ANY ALIGNMENT THINGS until you understand a lot more!


  Of course I don't have any of the equipment mentioned in the manual to do an alignment so I'll have to find someone.  In the meantime I could get a frequency counter.  I know it's off a bit.  I was listening to a rag chew last night and they said QSY to 3946 and my dial was at about 3943. 

That was very good back in the Swan's time. Very good.


For the first 30 minutes, I find I have to slightly adjust the VFO to keep their voice normal but after that it seems to stay on frequency.  I guess that's normal (?)

It's excellent for a Swan 350. Be glad you didn't buy an Eico 753; they never stop drifting.


I have found out it won't transmit.  I hooked up my mic (Astatic D-104 and has new battery) keyed up and nothing.  It's still receiving but it's as though the mic isn't plugged in.  The switch is in the "PTT" position and I tried moving the other switch between "Receive" and "Tune/CW"   Both the PA tubes are in and the caps connected.  Also I hooked up my keyer to the rear jack but it doesn't transmit either.   Huh

I will have to research the TR system in the manual and get back to you. Often rigs like the '350 have some trick to them (such as jumpers in odd places or having/not having a key plugged in). See the manual and schematic.

If they were simple, everybody would use them.

73 de Jim, N2EY
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WB6BYU
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Posts: 13231




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« Reply #19 on: October 31, 2011, 03:55:22 PM »

I remember working on a Drake TR-4 that would transmit only when upside down on
on the bench, not when it was right-side-up.

Turned out that, if there was a key plugged into the key jack, it had to be closed
to transmit on SSB.  Whenever I turned it right-side-up I'd also plug in my key - the
lead was too short to reach when it as turned over.

So, yes there are quirks in some of the old equipment.  Be sure to Read the Full Manual.

Only 3kHz off is good for that era.  Many of the dials were only calibrated to the nearest
5 kHz, and those could be off 15kHz or more if you were only calibrated at each end
of the band.  The general method was to adjust the calibration (with the Dial Set, which
probably just moves the hairline) to where the 100kHz markers from your crystal calibrator
lined up as well as possible on either side of the frequency you were using.  When you
told someone to meet you on 3945, you would get somewhere close and tune around
listening for the other station, giving a call when you found an open spot, until you found
each other.  None of this "dial the exact frequency" stuff.


I do remember being told about a Swan users' net on the air.  You didn't have to know
what frequency it was on - you just listened somewhere in the middle of the band and
they were sure to drift by sooner or later...
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N2EY
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Posts: 3879




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« Reply #20 on: October 31, 2011, 05:47:00 PM »

I have found out it won't transmit.  I hooked up my mic (Astatic D-104 and has new battery) keyed up and nothing.  It's still receiving but it's as though the mic isn't plugged in.  The switch is in the "PTT" position and I tried moving the other switch between "Receive" and "Tune/CW"   Both the PA tubes are in and the caps connected. 

OK. I looked in the manual and found some info.

I presume that what's happening is that you push the PTT or turn the switch to TUNE/CW and nothing happens - no relay click; the thing still receives. Is that correct?

If so, the problem is pretty basic.

The TR relays in the 350 are 12 volt DC relays (they used DC relays so it would work in mobile apps). The power supply generates 12 volts DC by rectifying some of the 12 volts AC for the heater circuit, passing it through a simple filter and then through Pin 5 of the power cable. The 12 volts DC then goes to one side of the TR relay coils. The PTT switch grounds the other side to transmit.

If there is any problem or brek in the 12 volt DC supply line, the set will receive normally but won't go into transmit. As far as I can see, all the 12 volt DC does is power the TR relays, so it could be open or have a bad diode and it would still receive OK.

Note that there is a diode across the relay coils to absorb the inductive kick when the circuit is opened.

Do NOT attempt to align the set yet. It is probably doesn't need it, and even if it does, you need to get a lot more of it working first.

73 de jim, N2EY
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KK4CPH
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Posts: 154




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« Reply #21 on: October 31, 2011, 08:10:58 PM »

Correct.  No click, nothing... as though there was no mix.  So I should check pin 5 to serif there is 12v?  And if there is, you suspect a diode has gone bad?  Is it possible the relay is stuck?  I don't know how long this thing has been laying around.  BTW; don't worry about me messing with the alignment.  I don't have the necessary equipment to do it and if +/- 3khz is good for a 46 year old radio then I'll leave well enough alone. 

Eric
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N2EY
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Posts: 3879




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« Reply #22 on: November 01, 2011, 03:37:59 AM »

Correct.  No click, nothing... as though there was no mix. 

No "mix"?

So I should check pin 5 to serif there is 12v?

Yes. 12 volts DC, positive to ground.

there is, you suspect a diode has gone bad?  Is it possible the relay is stuck? 

Anything could be bad - diode, resistor, capacitor,. But the most probable is an open circuit someplace, just like with the heater circuit.

73 de Jim, N2Ey
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KK4CPH
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Posts: 154




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« Reply #23 on: November 01, 2011, 07:48:10 PM »

Correct.  No click, nothing... as though there was no mix. 

No "mix"?

So I should check pin 5 to serif there is 12v?

Yes. 12 volts DC, positive to ground.

there is, you suspect a diode has gone bad?  Is it possible the relay is stuck? 

Anything could be bad - diode, resistor, capacitor,. But the most probable is an open circuit someplace, just like with the heater circuit.

73 de Jim, N2Ey

I meant "no mic"  Sorry, I was sending that from my phone.  Embarrassed
While messing around with it tonight, I moved the cable and the power cut out. I moved it back and forth and the power came back on.  So while holding down the mic key, I moved the cable a bit and it clicked (S meter went all the way to the left)  So it does transmit.  I only held it there for about 2 seconds because obviously I haven't done the "tune up" procedure yet. 
So you were right.  There appears to be a short somewhere in or near the plug.  I have a new Jones plug so when I get time (probably this weekend) I will  cut the old one off and solder on the new.... making sure that the wires are in their correct place!!
Thanks again for guiding me thru this!  I'll post once I get it done and hopefully it's the plug otherwise I'll have to look at the connections inside the unit.
73

Eric
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N2EY
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Posts: 3879




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« Reply #24 on: November 02, 2011, 06:16:38 AM »


While messing around with it tonight, I moved the cable and the power cut out. I moved it back and forth and the power came back on.  So while holding down the mic key, I moved the cable a bit and it clicked (S meter went all the way to the left)  So it does transmit.  I only held it there for about 2 seconds because obviously I haven't done the "tune up" procedure yet. 
So you were right.  There appears to be a short somewhere in or near the plug. 

Not a short. An open circuit. Maybe the plug is bad, maybe the connections. In any event the heater circuit failure and 12 volt DC failure are proof.

I have a new Jones plug so when I get time (probably this weekend) I will  cut the old one off and solder on the new.... making sure that the wires are in their correct place!!

Couple of things:

1) Cut off the old plug a few inches back so you start with a fresh cable end. That way you have the old plug as a guide for how to connect the new one.

2) Put the plug cover on the cable end FIRST. Double check that it is facing the right way.

3) Make sure the new plug is exactly like the old one.

4) Put the plug cover on the cable end. Double check that it is facing the right way.

5) Strip the outer cable jacket carefully and fan out the wires. Strip just enough insulation from each wire to make the connection.

6) Put the plug cover on the cable end. Double check that it is facing the right way.

7) If you have heat-shrink tubing, slide short pieces on each wire.

Cool Before you solder any connections, check that the plug cover is on the cable end and facing the right way.

9) Make the wire connections one by one. Start at the center of the connector and work your way out. Double check each one to be sure.

10) Slide the heat shrink tubing over the connections and shrink with heat gun or similar.

11) Put the plug cover on.

12) Test each wire in the cable for shorts with all other wires. This can be sped up by doing it this way:

A) Check Pin 1 for shorts to all other pins.

B) Check Pin 2 for shorts to all pins with higher numbers.

C) Check Pin 3 for shorts to all pins with higher numbers.

(repeat until you get to the next-to-the-last pin.)

Unplug the power supply from the wall, install the repaired cable, and test for proper operation.

73 de Jim, N2EY
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M0HCN
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Posts: 473




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« Reply #25 on: November 02, 2011, 11:14:03 AM »

I get the feeling Jim is someone else who has crimped a 160 pin plug onto the end of a cable, only to see the back shell sitting on the bench!
Bloody annoying it is.

Regards, Dan.
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KK4CPH
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Posts: 154




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« Reply #26 on: November 05, 2011, 08:15:07 PM »

It's Alive!!!   Grin  Cool
And I got lots of practice on soldering!  Cheesy  Now the speaker works too.  I had a rough time tuning up at first.  I couldn't get over 200ma.  I noticed one of the driver tubes (6GK6) in the left rear wasn't glowing.  I shut it off and took the tube out and noticed the pins were bent (as if the tube was pushed to the side)  I put in a "new" one, powered up, and it lit up.  I followed the tuning procedure and got the load to 500ma which, according to the manual, is where it should be. I found a net and even though there was QSB, I threw my call sign out hoping for the best.  He almost got my call right (off by one letter) and said for me to try back but I got interrupted by a phone call.  So at least I know I can transmit.  I'm thinking next I'll go thru the tubes and see if any are weak.  If the frequency being off by 3khz is OK, then I'll leave it alone.  Otherwise, I'll have to put a "want-ad" out for someone locally that has the equipment to align it.  The only frustrating part is tuning up when I change bands.  Guess that's part of the hobby. 
Thanks again Jim!!  Glad I took a chance on this old rig and feels great to have it working!
73
Eric
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KK4CPH
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Posts: 154




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« Reply #27 on: November 06, 2011, 10:22:30 AM »

I do remember being told about a Swan users' net on the air.  You didn't have to know
what frequency it was on - you just listened somewhere in the middle of the band and
they were sure to drift by sooner or later...

Found it:
Quote
Swan User Net organizers also support the retention of electron tube technology and provide on-the-air associated technical discussions at scheduled net meetings. Current Swan Net schedules: Swan User Net - NOTE CHANGE: Sunday 2100GMT on 14250Khz. Swan Technical Nets - Monday 2300GMT on 14252Khz. Saturday 2-4PM eastern time on 7235Khz.

Eric
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KC7MF
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Posts: 47




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« Reply #28 on: November 14, 2011, 10:26:11 PM »

Call John Bruchey in Tucson.  He was THE Swan tech for over 30 years.  He has worked on all of my Swans and his knowledge of these machines is a joy to behold.  He is also a great gentleman and all around nice person.  (520) 574-0247.
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KE4VBG
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Posts: 220




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« Reply #29 on: November 19, 2011, 09:15:19 PM »

Great reading! Another new Ham who isn't afraid to get his hands dirty, and a lot of help guiding him. Kudos to all.

 73, Doug
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