Aaaaaahhh!!!!

[Ed/KB1HYS]

Man I just gotta Vent a little.

It's a good thing Valiant are HEAVY else the one here would be flying out the window!! 

I had a problem, no modulation. (yet another minor issue to fix) and for the first time in a month I've had time in the shack to work on it. Get it fixed, and on the air, make contacts YEA! life is good...

UNTIL --  I was in a QSO with Jon/N1MMD up in there in Grey Maine, and with a loud PUFF and flash the mains fuze blows out.  Great. Well. Disconnect everything, pull her off the shelf. Hmm no signs of blackness, molten slobber, nothing.  Ok, maybe the fuze just had a bad day. Stick in a second fuze. Powered up ok. Good. Key the mike and POP, there goes the last fuze rated for the V in the shack.  Crap.  well I unplug it and disconnect the plate xformer HV leads. Figure theres a short to ground (yea, so I always assume the worst possible thing) nothing there (though that does not preclude inter winding shorts).  Looks like I'll be a bit longer on this go around to get it running again. 

When I solid stated the HV supply, I checked and double checked everything while I was there.  I had found that the 5V filament leads for the 866's had arced at one time!!  there was a spot weld and black marks hidded until I pulled the stuff apart.  That explained why the previous owner had put the fuze holders in the front panel for easy access!!  Grrr!   Who know's what abused component has given up the ghost now.

WTF.  This thing is like some British sports car!  I spend more time fixing than talking.

Oh well. On the bright side, I am learning as I go.   It is just so frustrating that the mean time between failures is so SHORT!   

[N3DRB The Derb]

I'm with ya Ed. This stuff can drive you nuts. the only way I've ever found to get it right is to take a meat cleaver to it after taking plenty of hi res digital photos, and build it back up the right way. Even then if the thing was not designed much good to start with, you have problems. 

It takes a lot more time on the front end but saves a lot of crap outs when you want to be operating instead of working on gear this fall and winter. Me, I'd rather do it now when static is bad than when condx are primo and you got 20 people on.

I've had a mixed record getting my stuff ready to say the least but I think the next power up will be the charm. If I can get Maul #1 finished and reliable and get teh W7FG antenna in the air, I'm ON!

I have managed to repair Yeasu #1 and get teh KW matchbox refinished and re built, but it just doesn't come as easy as it used to. But nothing else does either.    Thank heaven for buddies like Slab an JN and everyone else thats helped out. You discover it's not the gear thats special, it's the people that keep it alive and out of landfills.

keep swinging.

[Blaine N1GTU]

thats the problem with solid stating the power supplies on those old boxes.
voltages increase and components start to short.
its like giving a 90 year old man a bottle of viagra and an 18 year old girl 

[WQ9E]

This is actually a common problem with earlier Valiants, Johnson used regular hookup wire for the 866A filaments and over time it would breakdown to the chassis often taking out the LV transformer in the process.  The cure is to replace the wire with proper HV wire if you are using the 866A tubes still or disconnect the wires at the 866A sockets if you have gone to solid state thus removing the HV from the wiring.

If you haven't discovered so already ALWAYS loosen the screws on the flexible coupler on the VFO before turning the Valiant upside down or you are likely to break it since the front panel will flex and the coupler will try to prevent this from happening and it will lose.  If the VFO tuning feels stiff/gritty it means the grease in the ball reduction drive has dried out and you need to clean and relube it; it is fairly simple and results in the original smooth tuning.

If your Valiant was built from a kit is is likely the meter shunts are incorrect so if you find output is low based upon read plate current you probably have incorrect shunt values.  The builder was supposed to cut these from the supplied nichrome wire and end up with the correct length after tinning; generally that didn't happen as the total shunt length was generally off.  You can get correct value modern resistors from Mouser.

If your drive pot goes out, the DX-100 SS replacement shown on the AM website will also work fine in the Valiant.  It is difficult to find correct wattage replacement pots these days and most of the new ones listed by suppliers are only able to run at their stated wattage at very low ambient temperatures which do not apply to life inside the Valiant.  The Valiant does run much cooler than the Ranger given its much larger cabinet but the new small controls would probably not live long inside one.

Minimum clipping occurs with the clipping control at FULL CLOCKWISE!  Before ripping out the clipper make sure that it is not set at the "intuitive" minimum level which is actually maximum.  Hi Fi audio is great IF you have a strong signal; when the signal is weaker a little clipping does bring up the average audio and makes it possible for the other stations to copy you easier. 

Don't forget to replace the dropping resistor for the VR tube in the VFO if you have not done so already; the existing one is under rated wattage wise.  You can do the replacement from the side of the VFO through removal of the side cover without removing the entire VFO.

The Valiant was my novice rig back in 1974 and I have two of them.  One was my main AM rig for years until I added the Desk KW and Viking 500 to my station and I still use it a lot on AM.  Since replacing the 866A rectifiers in both rigs the only failure I experienced was the plate relay went out in one of them.  Enjoy your "new" Valiant.

73, Rodger WQ9E

[WQ9E]

P.S. If you want to get rid of the "Valiant Bong" sound when you turn on the plate voltage, an inrush current limiter in the primary to the plate transformer will take care of this issue.

Rodger

[Ed/KB1HYS]

Thanks for the tips guys.

I solidstated the HV PS. and pulled the 866's and sockets. It's very robust now, as I use Microwave oven diodes to replace the 866s in there and modern oversized electrolytics.  The B+ supply components all check out ok. ( I was worried that I'd be replacing the Plate Tranny)  So it has to be something down line.  IF I can get the "Honey Do" list knocked down a bit, I'll get it up on the bench and dig in... again.
 
I DID NOT know about the VFO Coupler.  I man handle that Valiant alot. I guess that will probably be the next item to break!     I've done a lot of the mods that are recomended for the valiant audio section and when it runs, it runs well.   Yesterday we had a power failure, before the power went out, it "Flickered" and the lights got very bright for the half second or so before the power went off.   I have no Idea how high the voltage was on the Flick. I was operating at the time and shut down the switches after the power went out.
The Valiant failed later on that day, so I'm thinking it's not the rigs fault this time.

That "Valiant BONG" sound scared me silly the first time I fired it up...  After I figured out what it was, I thought it was kinda cool.   

[The Slab Bacon]

ED,
      2 things to check: First check the tie point strip where the mod tranny leads come through the chassis and tie into the wiring harness. I burned the phenolic on mine. Also I lost a bunch of the bypass caps on the antenna relay connections and the accessory plug after taking a lightning strike a couple years ago.

                                                          The Slab Bacon

[kb3qay]

Hi Folks - Sure is helpful to glean all this great information from hams familiar with the Valiant!  I'ts kept this OM pointed in the right direction with my Valiant 1. I was changing the old brittle plate cap leads to the modulators and noticed that only one had a 22 ohm resistor in series with the cap. The schematic indicates both leads should have it. I wonder if there might be a method to the madness, or just an oversight by someone in one of the rig's earlier lives?    73's JIM

[WQ9E]

Jim,

Both leads should have them, later production models had the resistor attached to the plate cap and sealed in translucent plastic.

Someone probably (incorrectly) thought removing the resistor would increase the positive peaks, you should install a new one.

Rodger

[kb3qay]

     Thanks Rodger! - Already replaced the resistors, mounted a new 18K on the outside of the VFO box, replaced some shunts and just recieved a full compliment of tubes.(now I'll have some spares) I'll see if it passes the smoke test as early as this evening. Can't Wait!!!!!  JIM

[W1EUJ]

>Ok, maybe the fuze just had a bad day.

Sadly, this has never been true for me.

David Goncalves
W1EUJ

[WQ9E]

Jim,

Good luck and I hope everything works OK!  If you are using the 866A MV rectifiers for the first start do let them run filament only for at least 10 minutes before applying plate voltage; after that a few minutes warm-up is fine.  Enjoy your "new" Valiant.

73, Rodger WQ9E

[WU2D]

Jim - Bad News

I run half of my station on Dynamotors stock - and that stuff blows up from time to time too. I just lost a receiver and am putting off digging in to it. It is a constant battle with these old rigs.

Mike WU2D

[kb3qay]

Thanks again guys. This Valiant came with a set of HV rectifier tubes much larger than the stock 866's. I plugged in the originals so I could marvel at the cool blue glow. I also pulled the diode strings in the bias and LV supplies and will go with the tubes instead. I'll see if it makes aarrff on 75 meters later this morning. So far - so good! This rig does not seem to get as hot as my ranger but I like to use a muffin fan on top anyway.  Boat anchor fever is alive in Kingsville Maryland!!! JIM

[WQ9E]

Jim,

You will find the Valiant runs much cooler than your Ranger since it is in a much bigger box.  I was surprised how hot the Ranger gets and I probably should mount a fan somewhere to cool it a bit-since it is driving the Desk KW a little more fan noise will not be noticed.

Rodger

[N3DRB The Derb]

hay Jim, where's Kingsville from Harpers Ferry WV? Not too far?

[Ed/KB1HYS]

Found a ZORCH on the Valiant.  On the base of the B+ PI wound (L11) choke there are two 0.01uf bypass caps (C47 & 48) . Between these two caps is an encapsulated choke (looks like a long 1/2 watt resistor) identified as a 4.7 uH choke (odd value?) from the parts list.  The bottom of the choke has a small blackened crater and there is the typical burn mark on the ceramic center post of the big pi choke. Seems that it arced through to small aluminum band that one of the two caps is mounted to.

The caps don't look to swell either, one is down right ugly, blistered looking (pox) the other doesn't look as bad but I'll drop in two new ones anyway. Prolly have to cast around for a choke, I've got one good size Millen type pi-wound that looks like a likely replacement too. It's big but I don't know what value it is.  I'll get out the grid dipper and find out.

Acording to the schematic, the B+ passes right through this encapsulated choke...  Isn't that a bit much for that type of component???

So think the small choke was there to tame some odd resonant behavior? or?? 

[Ed/KB1HYS]

Well, Mouser has 4.7uH choke rated for 9.5amps at 2500volts max for only two bucks! I figure I'll get .01 uF at 2kv caps too while I'm at it!   Neat, I can get brandy new replacement parts for under $4 (well plus shipping).

Now to just pull it apart and scrub off the carbon   

I may even put the rig back into the cabinet now... or is that tempting fate???

[kb3qay]

Hi Derb!           I'm only about 9 miles northeast of Frank (AHE). I worked him on 75 a couple of months ago. I lived on the west side of town when I was a kid and we used to take joy rides out to Harpers Ferry all the time. Also used to pass thru regularly when I came home to visit my folks when I worked in SW Virginia back in the roaring 70's. Had my general back then (WA3LLY) but never had the QTH or the time so I gave away my stuff and let my license lapse. It's been really cool to re-visit the hobby again after all this time...Lots of great memories!!  73's JIM

[The Slab Bacon]

Hi Derb!           I'm only about 9 miles northeast of Frank (AHE). I worked him on 75 a couple of months ago. I lived on the west side of town when I was a kid and we used to take joy rides out to Harpers Ferry all the time. Also used to pass thru regularly when I came home to visit my folks when I worked in SW Virginia back in the roaring 70's. Had my general back then (WA3LLY) but never had the QTH or the time so I gave away my stuff and let my license lapse. It's been really cool to re-visit the hobby again after all this time...Lots of great memories!!  73's JIM

Jim,
     We've definately worked before. Since you're that close why dont ya stop in for a coffee on friday nights!!

Ed,
    If you are changing those caps out at the base of the plate choke, change them to something like .001 or .002s @2kv that will help improve the high frequency audio response.
Also, check the caps at the nasty rats nest that usually grows around the accessory plug.

                                                                 The Slab Bacon

[Ed/KB1HYS]

Will do Slab!!

[w4bfs]

Hi Ed ... I had the same problem with one of my V2's ... has the same deal for a plate choke ... the smaller choke zorched just as you described ... I'm not sure why but as Bacon suggested have gone to .001 uFd bypasses as part of overall rebuild ... I will test with neon bulb to see if there is parasitic activity ... that small choke is wound with very fine wire, iffy at even 250 mA ... not a good place for a wimpy part ... when this opens no plate V but screens still fed ... it may kill the 6146's ...73...John

[kb3qay]

  Frank - Coffee's about the only thing that would keep me awake after the second half of my split shift on a Friday night, but my beverage of choice usually ends up coming from a brown bottle. Might take you up on the offer sometime soon! I just might stop by Baynesville Electronics on the way home this morning and pick up those bypass caps for my Valiant - A little more hi-freq response would be welcome. Otherwise the rig seems to be working FB but seems like every time I put it back in the box, there's another item I want to touch up. (Truely, a labor of love!) - Seeya - Jim

[N3DRB The Derb]

cool jim, I may have to come down to franks myself on a upcoming fri nite to meet ya.

ed, i bet if you found one zorch you got more. now is the time to go thru that tx with a microscope and fix anything that looks even remotely questionable. When the T storms clear out of town, you'll be ready to

 GeT dOWn!

[kb3qay]

Derb - Sounds like a good plan to me! Looking forward to it - keep me posted.....JIM