The AM Forum

Well, Late last night I finally got the problems with my Valiant worked out. 

I gots RF comming out and it's getting Modulated!!   ;D

 Seems I was my own worst enemey and when I removed and required the accessory socket, I had some things wrong.  The colors on the Mod tranny are verrrry faded (is that an old red wire or an old brown wire, blue or green??)  Finally got the time on the bench and sat down with a schematic, pencil, paper and meter and traced things and made NOTES. (quite the concept  :-[)

Anyway, just felt so good about finally getting it fixed that I had to share.

Now should I be bold enough to actaully put it back into the cabinet???  :)

Fantastic.
That is always a great feeling

Carl

/KPD

Wahooooo!

YUP sometimes the old stuff needs a few more steps to get it back to working order.
Victory should taste real nice. Enjoy!1
Fred

It is of critical importance to never ever put all the screws back in!!

Of course, YMMV!

                _-_-bear

That's great news, Ed.  I know what you are going thru; I am working on my Valiant while I "read the mail" on AMfone.  (Haven't even started on the Ranger or the Viking II.) 

I traced all the wires to the switches, mod tranny, and accessory socket on the Valiant that followed me home from Huntsville.  The guy I bought it from said it was recapped and ready to go, even had the tubes packed separately for safety.  When I got it home and opened it up, I found parts missing, and it had been dropped, damaging the vfo coupler and severely denting in the chassis where all the heavy metal was mounted.  The recap looked like it had been done with a blowtorch. 

I started disassembling to perform the necessary repairs, and read all the mods and info available about updating the Valiant.  As I disassembled, I took lots of notes and diagrammed the wiring with color codes.  I decided to replace the little mod tranny with a UTC S21, and rearrange lots of stuff on the chassis.  The new mod tranny is where the LV power tranny used to be.  It is now sitting where the 866s used to live.  I blasted holes to mount four 1625s in push-pull parallel, and redesigned the entire speech amp. 

"Body work" is completed, and wiring is now about half done.  There is no longer a 9-pin accessory jack carrying any HV.  Now I have an octal socket for accessory connections, primarily for the receiver muting, TR switching, and balanced audio (high level) in.  No mic input, the audio chain will be external.  I ran tests on the Valiant mod tranny vs the UTC, and found the UTC much flatter at the top and bottom end, even with dc current thru the secondary. 

I thought of adding meters, etc, but I decided to keep it looking original from the outside.  Inside, well, that's a different story!!!  Only the RF sections look like a Valiant!  In a couple weeks, it should be on the air and sounding nice.  I'll share pics later.  Congrats on getting yours working fine!!!  Hope to exchange sigs real soon.

Way to go Ed!  It really is the little things that get you!!  I can remember when the stupid clamper pot was almost my undoing with my Viker 2.  For the life of me, no matter what I did (replace filter caps, bias caps, clamper tube, etc.), the plate current was up in the stratosphere (350-400mA). Finally one night Rodger, WQ9E and I (via a phone call), went through the radio.  I started adjusting the clamper pot.  Rodger asked me, "what's the plate current at?".  I said that it was still over 300 mA.  Rodger then said "that doesn't seem right, those pots only have a turn of travel on them, and you have to be close to the end of that pot's travel."  I responded that I was actually past 1 turn.  "Rodger said, "that's weird, keep on going."  So I kept on going.  Finally at 2 turns of the clamper pot, the plate current settled down to where it was supposed to be (240 mA), and the last of my Viking II's problems was solved.  All because somebody in the past replaced the standard 1 turn clamper pot with a multiturn audio pot, my Viking II restoration efforts were stalled out.  Geez!!

So True!  Assume nothing, check everything!  I had assumed that I had wired things correctly, and I was going nuts trying to figure out why I had soooo much plate current and NO output, and a host of other oddball behavior. 

I'm mostly glad that I didn't bust anything when I miswired it.  I've had six or so QSO's since she's been fixed.

Funny, but now that I've got that rig fixed, I've been more interested in the shack lately. Even to the point of giving it a thorough going through and cleaning :o   

I guess staring at the dead carcass was just too demotivational.

Now the question is what will go next? :-\

Glad ya got it going Ed, I meant to get in here but we had a wedding today to get ready for...and I wouldn't put it in yet....let her run and did you solid state any of the supplies...I don't remember if you said anything about that...or not...

yes, I did Solid State the B+ supply. 
In the end it's like this:

SS B+ supply
Modded the audio by changeing couplling caps to larger polyester types.
increased the mic amp input bias resistor to ~6.6megohms.
removed /bypassed the Clipper and the audio filter
Replaced the small plate choke and associated caps.
installed a 3 wire line with fuze in the back panel. (fuze holder is in the SSB input hole)
Reconfigured the mains bypass disk caps to go from hot to neutral instead of from each line to ground.
Removed the 9pin "accessory" socket and associated filters

Signal reports are mostly Good, with a few "Golden Ears" reporting restricted audio.

It looks really good on the scope with 100% modulation and no flat topping, and sounds ok to me on the monitor. 

I suppose that if I wanted to go all the way I would make the changes to the audio chain that Tim Tron recomended and go with a phase splitter instead of the interstage tranny they use for driving the modulator tubes.

First I'm going to enjoy using it for a while before the soldering Iron touches it again...

...ed...you got time to look at at dx100?...all kinds of whacked-out mods, no documentation...real nightmare...gotta try to get into the guy's head who did mods fer ssb... geeeez...

.sk..

Bummer on the DX 100, but I would be glad to help out. 
How would you convert a DX100 to SSB? Seems like that would require a lot more work than just getting a conveter (H-10?).

At least the Valiant was almost stock when I started, except for some really DUMB mods to the mains input. It must have kept blowing fuzes, so he drilled to holes in the front panel and put two fuzeholder in and ran the Mans power line up to them and then back to the terminal strip on the back. Right up under the band switch!  Amazing that they never caught up in it.  I found the reason for the shorts in the 5volt filament line for the 866's. There was a Zorch at some time that left the bare wire exposted. It must have occasionally shorted and popped the fuzes.

 I've kept the mods I've done on paper and in a binder with the operating manual, so if I ever part company (not likely) I'll be able to give the buyer something to work to.