Vintage EF Johnson Invader 200 Ham Tube Transmitter Attempted repair Failed Need Help any advice?

[@mackfisher4487]

All of us run into problems in life, it takes a secure person to ask for help and that’s the kind of person who makes a good technician or a good builder or a good neighbor especially when they’re in the public eye. You’ll get it Terry

[@d-labelectronics]

Thank you my friend, I wont give up

[@Wizardofgosz]

Paging Mr. Carlson... paging Mr. Carlson...

[@d-labelectronics]

Hope he knows, I really want to find the solution

[@coldfinger459sub0]

This makes for a Mr. Carlson movie grab the popcorn and sit back and relax and drink your soda pop

[@TheRadioShop]

When I first heard that music I thought I had clicked on a Stefan Gotteswinter video lol. But in more serious note that is an interesting problem. Time to remove items for process of elimination until the ohm readings are correct. Like the wire going to the switch. Are those tube sockets like the Vikings? I seen them carbon over and show short to ground. I know you can fix it Terry.

[@d-labelectronics]

Thanks man, 1st time I have worked on an Invader. Different... Stepping back to think

[@richardnalisnick462]

You have a leaky mics cap. Common problem with this transmitter. Shows on when voltage is applied to driver tube. Also check to make sure bias is correct on the driver tube grid. It mill make it stay say to much corrent. W3AMT 73's

[@LarryDeSilva64]

Sometimes even when we take a methodical approach we run into an issue that at the time does not seem to make any sense. We just never know when we buy a used rig if someone else had gotten into it and added more wiring that was partially shorting out high voltage. It is good to find someone who has had the same problem and solved it when all else fails. Good luck in your quest Terry.

[@preiter20]

I knew I felt a disturbance in the tube radio force today. I wish I could pay back all of the knowledge you have imparted on me but I know someone in the D-Lab audience will be able to help.

[@jameswood592]

Terry, I agree with The Radio Shop about the tube socket. If it's Phenolic wafer material and the tube has been overheating it could have created a micro crack that has carbonized making the circuit draw more current. Suggest pull all the leads off the socket and check for insulation to ground and between pins. Check with a megg-ohm meter. Change that socket out. I had a similar problem with a Quad Comparator. All the reference levels were OK but it just wouldn't work. Changed the IC- no difference. Changed the phenolic socket and bing-go, it started working.

[@d-labelectronics]

Yes, I agree, I am also concerned with the heating damage on coil L12. It is feeding the plate of V9, plus the junction of the 1K that overheats, I wonder if there is a carbon path within that coil? I plan to inject 300vdc direct to that area and see what heats. I have a hanger queen for spare parts! Will follow up

[@merashallan]

I noticed some of the wafer switch sections might be double-sided. I have seen a carbonized short between two sides of a wafer switch (in my case an old HP voltmeter).

[@TheBoptillyoudrop]

Dance of the Nights by Prokofiev, nice. Good luck with the transmitter. This must be a first of, on your channel? Really exiting how this one ends. Maybe just put it aside and let your brain chew a little on it, sometimes a solution pops up from one of those rarely used shelf’s deep down.👍😀

[@wb8cxo]

A rare moment! Best of luck Terry!

[@wklinger79]

What if you isolate the driver section from the earlier stage of the transmitter? Radio goes into transmit and then when you switch off the push to talk it's still transmits? That internal T/R relay, close contacts. How close is close? Also, is it wired up right? Stuff that is connected on the NC or NO part of the relay, is that all good? Prior owner had everything lifted off that tube socket checking what you just got done checking. Did he assemble it right Finally, what about swapping out the driver tube? Checks okay on your tube tester but maybe falls apart in the radio circuit? Voltages on the socket are correct? That resistor cooking the way it does.... A big beefy resistor at that. Interesting.

[@dandypoint]

I have a Viking Invader and have had it since the late 60’s. Until recently I had only had one problem with it long ago. A spurious signal just below 7.0 MHz. Turned out to be weird harmonic of crystal oscillator. 2nd harmonic of carrier oscillator mixed with 2nd harmonic of first mixer. Ended up with keyed CW signal at 6994 KHz. ( I received a notice from the FCC) I added a trap tuned to second harmonic of one of the crystal oscillators. A few years ago it stopped transmitting. I suspect one of the oscillators. I will soon be going in to see what the issue is. Did you pull the driver tube and check the resistance? I don’t think I heard you say you did. Just a wild thought. I will watch the video again. I am very interested in your Invader project. Don, N4DJ

[@umajunkcollector]

Wow, I must look up Prokofiev Montiques and Capulets aka Dance Of The Knnight from Romeo and Juluet, as you used in the intro.

[@rciancia]

Terry, I would look at R61... just a gut feel.

[@andrewwaud3407]

You mentioned driver tube stays on after turning switch to standby..perhaps feedback situation keeping the driver tube on with high current RF where you are noticing the tube getting hot? Love your channel btw.. Always interesting problems to root cause!

[@bmh67wa]

Possibly a hairline crack or carbon short in a tube socket? In all of my years of working on radios I have never had the pleasure of working on one of those. It is quite a nice looking unit. I have faith that you will figure it out.

[@plumbersnightmare2354]

Terry, I'm looking at picking one of these up. It has been three years, have you had any luck in finding the culprit?

[@willrobbinson]

12by7 tubes used as drivers can & do get shorts being run hard , did u pull tube ?

[@PeopleAlreadyDidThis]

I’ll have to confirm this, but I did my first research on Invader 200/2000 a couple of weeks ago because one came up for sale nearby. This “sticks in transmit despite the relay” issue rings a strong bell in my mind. I read a lot of threads, but I’d bet this was on a QRZ forum, and my recollection is that people said this is a neutralization problem. The circuit heating would be from the RF oscillation, not a DC overcurrent condition caused by a short or faulty component. Are you seeing VHF on the scope at the driver stage, or final grids? I’ll try to find this again, assuming my memory is correct. Meantime, you might try searching the boat anchor and general technical forums on QRZ.

[@d-labelectronics]

Yes, I agree, I had the RF oscillation, I could stop the transmit latch by detuning the plate or exciter variable caps. This was before I discovered the open 1K resistor. With the new one in, no transmit, but overheating of the resistor

[@prabhakarratnagiri7265]

Please try it sir. I am sure you will fix the problem.

[@2packs4sure]

Did you ever measure it with that tube out?

[@d-labelectronics]

Yes, same issue, Tube is fine

[@kaidenlem]

How does one match up new capacitors to replace the main filter cap? I’m having a hard time finding a 40-30-30 for my old Montgomery Ward Airline. Thanks! Just discovered your channel after getting this radio, and I dig the content! Great work!

[@VintageElectronicsGeek]

3 separate caps, a 40, a 30 and a 30, ensure volts are at a min the same, modern uf's values will be close to old values, tie at neutral. ~Jack, VEG

[@kaidenlem]

@@VintageElectronicsGeek Sounds good! So just a 40mFD, and 2-30mFD?

[@VintageElectronicsGeek]

@@kaidenlem Yes, that is correct, remember to keep the voltage at the same level or higher. Oh, if there is any supporting components on the old legs, insure to install them as well. ~Jack, VEG

[@johnlenz282]

Check relay ? wire going to screen NC on the relay.

[@MrRadioGypsy]

Did you check the tubes for shorts? You do have a tester - I've seen it . . .

[@srtamplification]

Terry, were you making all of those measurements with the driver tube in circuit? If so could it be offering the parallel resistance to ground making the value lower than it should be. Another words, is there something wrong with the tube?

[@d-labelectronics]

I tested with and without the tube, Problem remains

[@srtamplification]

@@d-labelectronics I figured you did, but just throwing stuff out there.

[@Masterkill45588]

Wonder what mr Carlson would say.

[@dhpbear2]

7:11 - That 2k may be the result of shorted element(s) in V9.

[@d-labelectronics]

Problem remains even with the tube removed

[@timka880057]

I know ✋ Commander. Listen, we found some beryllium on a nearby planet. And we might be able to get there if we reconfigure the solar matrix in parallel for endothermic propulsion. And hopefully no engines heating up Cap'n! Lol. Its sounds like you need a thermo meter and follow the trail to the excessive heat.

[@chris5pens]

I'd have thumped it repeatedly on the side and got my wife to stand on the roof waving the aerial about.

[@geoepi321975]

Check ceramic caps

[@minibikemadman]

I would call k1tli. Ol chuck could help ya.

[@MidnightVisions]

@4:48 That middle cap to your fingers left has a bulge on the left side of the lead. Replace those time expired wax capacitors. Don't break your own rules, replace them! There's more than one damaged component from shorting.

[@Lee-NN7X]

I made @3 on the thumbs up button

[@srtamplification]

I was unlucky number 13.