Johnson Navigator Ham transmitter repair D-Lab stumped need help no transmit difficult problem
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- Опубліковано 7 вер 2024
- Well, yep, I'm stumped. Normally performing an UN-Mod solves the problems. Not the case here. I do not know if this issue was always there, or if I induced it. Need to get this repair off the bench. If anyone has a good idea, have you seen this before? I'm all ears. Thank you
UPDATE: I found the issue. The VFO switch underneath is not in proper position. I manually adjusted it to match the band and boom! Transmits full power! Thanks everyone
I admire your humility. I used to be a robotics field engineer, and as brilliant as I thought I was, I was never too proud to reach out. Intelligence and humbleness are great qualities in a man.
Thank you my friend. I am always looking into the knowledge pool. Good to get input from others
It sounded like the mod he was going for was that voltage regulator in the VFO. Since you said there was a diode, a voltage divider and a wire going to the VFO. But it appears that didn't have much to do with your problem. Glad you figured it out!
glad to see you found the issue.
I had a Navigator that was beautifully built from a kit….it only worked on 20m. The vfo worked fine on all bands and all the voltages were correct. I finally figured out that the tank circuit bandswitch wafer was riveted together backwards by the factory. This meant that the tank ciircuit was only correct in the center (20m) position. I am sure the original kit builder and subsequent owners went nuts on this one, I nearly did.
I have another one on the shelf that you have insired me to investigate.
k7yoo
Hi Terry, in addition to the last comment I left below, I thought of another possible problem. About 5 minutes and 11 seconds into your video, I paused the video to get a better close up of the band switch ( I believe it's the band switch) it's the 3 pole ceramic switch. From what I can see from the video, those contact surfaces look to me to be "pitch black". I'd suggest cleaning all those contacts using "TARNX" with a cotton swab. TARNX will polish up those contact surfaces better than anything I ever used including DEOXIT. DEOXIT is expensive and doesn't do as good a job as TARNX and bottle of it will last a life time. I'm not suggesting that this will solve the problem but, we all know that this vintage equipment comes with a lot of corroded switch contacts etc. As a general rule, when I get a piece of this vintage equipment, one of the first things I do - in addition to replacing the filter caps - is to clean all those switch contacts. This also helps to get a better view of any possible arching that may have been going on in that switch that all that black crude is covering up along with any possible cold solder joints, broken wires etc;. This helps eliminate a lot of those "phantom" problems we sometimes just can't see. JUST A SUGGESTION ! Bill
Hi Bill, Yes Sir, cleaned the switches Yes the were tarnished. Hey, I'm building your VFO PS right now! abt time huh?
Another cobble job from the Kobbler.. I knew you'd sort it out once you waked away for a bit but asking for community input is what makes this my favorite YT channel.
Good stuff as usual Terry !!!!!!
Appreciate the desperation and the frustration. Familiar to anyone who sets out on the journey, I suspect. Thanks for your honesty, and a glimpse at the real challenges of repairing olde equp't.
Better than a ‘who done it.’ When I read the title, i said to myself that you would have it figured out before you published the video then read the description after watching. Great video. Thanks for another good one.
Hi Terry,
I can't find my navigator manual but will look some more.
Things to think about.
1) all voltages are good, sounds like you did that.
2) If there is an issue with the VFO???? Try a FT 243 xtal. 40 meter is what I'd try first.
3) Xtal / VFO switch ???? exercise and try again.
I can tell you the Navigator is a stable xmitter but you have had others, so, you know.
4) do you see the VFO output on a scope?? Do you see an Xtal oscillator ??
5) Two glasses of wine and go to bed...
73 de WA4AOS Glenn
Is RF being passed through C37 and present on the final's control grid? Check this with the scope. Once I had a brand new Valliant with that capacitor totally missing! Talk about QC!
I wish I still had my Navigator I used when I was a novice in 1972.....
This is why Im afraid to plug in my NC - 300 until I watch more of your videos. Cheers and thanks for posting!
The switch was kinda similar to trying to drive somewhere with the gear shifter in N.
Check for B+ on the antenna connector just to insure the blocking cap isn't shorted. Also do you have driver RF on the grid of the 6146?
Great! Another ham rig repair. Dont feel defeated, when someone else has created so many mods there is no telling what could have been done. Just one connection out of place could be a game stopper. With all the circuits working as should and all the voltages correct, perhaps there is a problem in band select and VFO? Reason I say that is there is not but just so much that goes on in this transmitter. Thanks for the video Terry and Happy New year.
Yes Sir, Turned out to be the VFO switch not engaging with the proper band select position. Took some time to align it, Lots of lube later, it works as it should. Navigator is transmitting again!
Something that heavily modded, I would copy out the schematic and go through every node, checking the wiring and marking it on the copy.. There's just no other way to verify one has found all of the little cobblers.
Cheers,
I applaud removing Mods and putting the circuit back to original. Drawing out the mod ( schematic) lets you see what they were doing. -> A receiver on the workbench is a very useful tool. You can then hear the oscillator and know it's frequency and strength, and quality ! I keep 75 m and 40m crystal handy and usually will begin to test a transmitter using a known good xtal.
Did you have the correct wine? Good luck Terry. Don’t give up.
When I heard the word "mod,", I was expecting 6 relays riveted to a soup can pounded flat
Hey Terry, don't feel bad man - I have the EXACT same problem with my Heathkit DX-60B - and I can't figure it out either. I beginning to believe it may be in the Function switch. I already had to replace the XTAL switch because it was toast -- it actually sparked and smoked. I know that these Heathkit swithes have been know to go flakey - especially the phenolic ones. Good Luck. Bill
Did you check the mica capacitors was just reading an article earlier today about them going open instead of shorting out just a thought good luck
Haven't worked on a Johnson in decades & it was a different model. But I worked at Heathkit for a couple years. No 'Ah-hah, I know what that is', just thoughts after looking at a Navigator manual online...
0) The sheared off screw head might not be a big deal...unless it indicates the thing was dropped. Anything ceramic switch wafers traumatized?
1) Where was the scope probe connected when you showed VFO signal? V3 plate? V6 grid?
2) Did you look at Tune switch position functionality vs. Transmit? Maybe an alternative view of where the signal chain might be broken.
3) Open or badly out of tolerance (high) carbon composition resistors? V4 as 'keyer' has my interest. It obviously (?) allows the VFO to oscillate, but the 2nd triode (6-7-8) has a lot of dependence on SW2A/B & SW3A/B. Conversely, a lot connected to those switches to depend on V4 function.
4) Any open RFC's or wire-wound R's?
5) Meter wasn't open, but DMM mV across meter to sanity check meter?
6) Hate to ask about continuity through switches...I wouldn't want to try to map the switch paths with just a manual. You may not want to do it either for time reasons...make that the last question after you have an idea what isn't working.
7) The mods may never have been successful. You may be looking at the 'work' of a Neander-tech.
Hmmm...you sound like a Midwesterner on either side of Lake Michigan, and you were in Kalamazoo a couple months ago...maybe you are.
I hate when people modify the original design and butcher the unit to the point a complete rewire has to be done. That happened to me on a Collins 75-A3 Receiver I shelved that one after seeing the mess that was made. Then after that it was a DX100 Transmitter that someone modified and had to put it back to stock I fixed that one so it works fine. So you have grid voltage but its low not 80 volts like it should be and have you also opened up the vfo to check for any mods in there that could be shorting out the switch? It could be a lot of things really I am glad you are persistent.
Oh May
I've been thinking of sending you five NOS 6197s I received in a bin full of good tubes i got from the estate of WA0TYN. I personally have no use for them and I figured they might be more useful to you since they're an industrial version of the 6CL6 used in the VFOs in these Johnson radios. Five of them are GE and one is an RCA.
*SOLVED! VFO switch was wrong! Read the Update in the video description.*
Knew you could find it, Terry. As it often happens, there's a fine line between setting them aside completely and just stepping back for a bit to come back with a clearer head. Especially in the case of a modified unit, no telling what gets taken apart and put back wrong.
I'm reminded of a recent problem I fought with an intermittent rear taillight on my van. It would quit, I could thump it and it would start working so I couldn't find it. Later it would do the same thing. Swapped the bulb, it acted the same. Even priced out taillight assemblies. Worked on it a bit now and then, no luck. Finally dug up another totally different bulb, popped it in, worked great. _Two identically intermittent bulbs?_ Yup! Obvious after the fact, drove me nuts fighting it because I assumed the replacement should have changed the symptoms.
Glad you could close out 2021 with a win, Terry! Here's hoping we all have a better 2022!
Hi Terry, Check for everything that doesn't move and use WD-40, then check for everything that does move and use duct tape for that.
Maybe something shorted to ground somewhere. Can you trace the signal all the way to the driver and output? I'm also assuming you checked the tubes... Best of luck Terry, don't give up!
Terry, take a look at the meter movement. An open meter is a common fault. 73 WC4G
Hi Don, Yep checked it, there is also slight movement in the grid position.
Found the issue, Misalignment of the VFO switch underneath. The linkage is stiff, does not engage properly, so there was a mismatch of VFO freq vrs band switch setting, I have it transmitting, but some lube & alignment is required.
Maybe, the modder didn't think the manufacturer knew what they were doing, so he rebuilt it the way he thinks it should be. I know a local ham that thought that way, and one day he got a brand new Drake TR4, and the next day he was in the radio changing parts and rewiring the underside the way he thought it should be. He did that to his Swan rig, too.
This happens to ALL of us at one time or another. No shame in asking the community for suggestions.
Did you check the cathode resistors?
Is the VFO aligned?
Hi Terry! Buddy (The Radio Shop) has a nice repair video of a Johnson Navigator that may give some clues or insight to the problem that your rig has. His Navigator had mods too and it's original meter had been replaced! See: #212 Johnson Viking Navigator Repair. Happy New Year! Dr. Stan KZ8G
6146 is toast, or scocket? wafer switch?
Id like to hear how good it sounds on ssb! lol
don't get why people mod things
Hi Terry, I have the exact same problem with my Heathkit DX-60B. I can't figure out the problem either. Enough to drive you crazt.
Bil
Some mods can be cool if designed and implemented well. Documented well is also nice.
Maybe A Components Missing, If it was Modded ETC some one may have Ommitted some thing thats needed for it to work As it used to, Did u try it before Unmodding it? ,might need schematic to see if any critical component was missing before u got it, never know what some one does when they mod stuff.Hopefully u can Figure it out.
Did you check the "Flux capacitor, huh?" I'd start there,because this is no way to start 2022!
Did you try turning it off and turning it back on again? I'm joking. If I had a Nickle for every time my bosses have said that I'd have about a Buck 45.