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New Viking Valiant Project - New guy is at it again




 
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Author Topic: New Viking Valiant Project - New guy is at it again  (Read 2421 times)
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KB2WIG
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« Reply #25 on: May 12, 2017, 11:42:20 AM »


M,

Please define "reasonable care". Do you go to a car wash, or do you have your own pressure wash?

KLC
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What? Me worry?
n1ps
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Zorch!


« Reply #26 on: May 12, 2017, 07:46:49 PM »

for cleaning chassis, I like to use a metal polish.  I tried everything over the years and found the metal polish to work best.   This one works well:

http://www.acehardware.com/product/index.jsp?productId=1420325&KPID=1190443&cid=CAPLA:G:Shopping_-_Catch_All_-_DT&pla=pla_1190443&k_clickid=f88b71b1-1126-4a36-a8ee-fd22fdeaa4e1

peter
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KC3GMQ
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« Reply #27 on: May 24, 2017, 10:26:44 AM »

Update: Cheroble resister replaced with 25K 10 Watt. This size was recommended by W1HLR in his Valiant Mod Section. Tight fit, but it is in there.

Checked all tubes: 3 of the 6146's were bad. So with the odd ball 6146's that were in it already (6146 B's and W's) I guess I am buying 5 new 6146 lol.  Also replace all plate cap wires with HV 20 awg wire.


* IMG_2992.JPG (1886.95 KB, 4032x3024 - viewed 83 times.)
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KC3GMQ
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« Reply #28 on: August 02, 2017, 10:45:58 AM »

Hi all,  I have been working on the Valiant.  Was about to start resistance checks when I noticed these caps on the finals (6146),  Im thinking they are toast?  Any advice...pics included



* IMG_3228.JPG (869.22 KB, 2016x1512 - viewed 74 times.)

* IMG_3227.JPG (930.87 KB, 2016x1512 - viewed 66 times.)
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KA2DZT
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« Reply #29 on: August 02, 2017, 03:05:34 PM »

The chance that those disc ceramics are bad are slim to none.  The micas that are in the first picture maybe.

Fred
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MikeKE0ZUinkcmo
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« Reply #30 on: August 02, 2017, 11:22:29 PM »

Quote
M,

Please define "reasonable care". Do you go to a car wash, or do you have your own pressure wash?

KLC

Holy Cow, sorry for not checking back long ago.   

I have my own little 3000 PSI washer   

"Reasonable care" is just not lingering over transformer openings, or in the case of IF/RF cans, maybe a small piece of masking tape over the top hole.
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KC3GMQ
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« Reply #31 on: August 07, 2017, 09:43:12 PM »

Update.  Got the Valiant Capped, a few tube sockets replaced, Chernobyl Resister replaced,  Tubes checked and bad ones replaced did the initial resistant checks and they were OK.  Plugged it into my light bulb safety rig and flipped on the power.  And now the issues to find Smiley   Indicator lights no poer, Plate switch not activating anything, Does have VFO  about 10 on meter, should be about 25.  Tried a bit of grid and it comes up but not a lot.  I shut things off at this point so as not to burn up anything.  Going back thru the book and making more checks.  I will take the issues one at a time, Guess I will start with the lights, those cant be too hard right Smiley   Advice always welcome.

Thanks All
Dave KC3GMQ
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WD5JKO
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WD5JKO


« Reply #32 on: August 08, 2017, 07:37:39 AM »

  Plugged it into my light bulb safety rig and flipped on the power.  And now the issues to find Smiley   Indicator lights no poer, Plate switch not activating anything,

Dave, The series AC line light incandescent bulb can sure be useful if there is a major circuit fault, but the bulb wattage must be sized to the load. If the bulb lights up a fair amount, then it is dropping too much voltage, and the rig under test isn't seeing enough voltage to run proper. Just guessing, but for a Valiant, I'd start with three 100 watt lamps in parallel. Even with that much bulb wattage, you won't be able to tune up the final such that you get appreciable RF output.

Good Luck,
Jim
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KC3GMQ
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« Reply #33 on: August 08, 2017, 07:56:47 AM »

Thanks for the reply. I had two 100 watts. They lite bright and then dropped to a low glow. I picked 2 100 watt bulbs because the book said idle it would draw 180 watts. I also tried my light bulb system with my working Viking II so I would have a reference. The Viking II worked ok. I will try it without now and see if there is any change. Fist thing I am going to look at is the panel lights. Bulbs checked good and the 6BY5GA filiment is lite, so it will be interesting to see what the problem is. I'm really sweating it, I'm afraid this one will have bad iron.
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KC3GMQ
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« Reply #34 on: August 09, 2017, 07:01:24 AM »

Update 8-9-2017  So tracing the indicator lights, found the + wire loose, re soldered and now the Dial lights work.  Found 2 solder splashes that were shorts and removed them.  Turned on transmitter and looked like all was working and responding per the book.  Then it happened.  So I learned a valuable lesson today.  NEVER trust someone else's work.  When I recapped the 80uf caps I just installed them the way the previous caps were installed.  Bad move, one of them was in backward and of course when I hit the plate switch BANG.  All stop until I get more caps.  I think I will bump up the value  also.  I had installed 80uf 450V, think I will go 100uf 450.  That's all for now, at lease progress.

Dave
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K4RT
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« Reply #35 on: August 09, 2017, 09:22:58 AM »

I'm afraid this one will have bad iron.

Dave,

I am not familiar with the Valiant, but in my opinion the first thing you should do is make sure all power supplies are working to Johnson specs. Otherwise, you may end up chasing your tail while troubleshooting the transmitter if the voltages are not to spec or in the neighborhood of spec.  If any iron is bad you might as well find out now because you will have to replace bad iron anyway.

You probably already know this, but I will just mention that you should make sure you learn how to safely confirm that the electrolytic filter caps are discharged after the transmitter is powered off and do it each and every time since working on the transmitter out of its cabinet presents a shock hazard. Any time you are checking voltages plan your work, take your time, and be extremely careful.

For each power supply in the transmitter, I suggest carefully checking the wiring against the schematic diagram and correct any wiring problems and replace any out of spec resistors, shorted disc caps, damaged leads, etc. Check for shorts to transformer case & ground, and with the rectifier tubes removed, carefully check the output voltages of the secondary windings. Get in the habit of keeping one hand behind your back! 

There are various opinions on this, but in the two tube transmitters I have worked on I chose to replace old high voltage electrolytic caps with new components rather than trying to reform the old caps.

The guys who know Valiants will have better advice.  Take your time and good luck!

73,
Brad K4RT
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Brad K4RT
KC3GMQ
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« Reply #36 on: August 09, 2017, 09:37:59 AM »

Thanks Brad, Iron looks good checked it all last night.  Always welcome safety tips.  I have a shorting probe I use to discharge caps, and yes, I work with one had often.  Also my work area has rubber flooring, and wood benches, also keep chassis grounded all the time. I do not want to be a statistic. 
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DMOD
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« Reply #37 on: August 09, 2017, 01:36:08 PM »

If you decide to do some upgrading here are some upgrades I did on a friends Valiant last year.


Phil - AC0OB

* Viking Valiant Upgrade Schematics for AMFONE.pdf (162.27 KB - downloaded 24 times.)
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"What kind of Koolaid do they make you drink in the Physics Department?" Charlie Epps to Dr. Larry Fleinhardt, NUMB3RS   Smiley
KC3GMQ
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« Reply #38 on: August 12, 2017, 10:27:05 AM »

Ok  Valiant is re capped and here are my initial readings from the set up procedure at 40M,  I need to find the issue: So I am trying to neutralize because  at 8 ma grid the meter plate is pegged past 500ma.  So far the best I can get is 3 ma grid and 450 ms plate.



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N1BCG
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« Reply #39 on: August 12, 2017, 10:55:19 AM »

The grid and plate readings are read as follows:

Grid Current: 7mA (bottom scale)

Plate Current: 300mA * (top scale)

* The manual suggests a higher current, but keep in mind that this was determined based on 1950s line voltage of 117vac. A lower current will compensate for today's typical 120-125vac and create less work for the modulator.

What band are you checking the neutralization on? 20M is recommended. You should be able to get a solid plate I dip on 20 but it will be sharp so careful plate tuning is needed. If you're not getting a dip and only seeing 3mA of grid I then you may have a drive issue on 20M, which by the way, I found to be the case on the majority of el Valiente's I've come across. The solution is a simple mod to the driver tank coil.
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KC3GMQ
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« Reply #40 on: August 12, 2017, 10:59:47 AM »

Hi Clark,  Just found the issue and corrected it,  the coupling switch was jumpered out for some reason.  I removed the jumper and at the moment, things look pretty good.  I am going to load it on phone here in a few after my dummy load cools down lol, and then test out the modulation.  if all goes well I should be on the air soon.

Dave
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N1BCG
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« Reply #41 on: August 12, 2017, 11:02:12 AM »

Even better!  Hollar at me if you want to try 40M...
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KC3GMQ
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« Reply #42 on: August 12, 2017, 11:52:51 AM »

And the Valiant is tuned up and on the AIR 7.290 for the moment

Dave
KC3GMQ
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