The AM Forum

One side of the "plate" switch was evidently carboned up. I swapped the HV side for the grounding-the-12by7a cathode side, and it works 100%, both cw and fone, no deoxit or nuthin.

Now I'm on to figuring out why my speech amp isn't happy.

So hear it is a day short of october, I've been futzing with this thing on and off since early May.

Five months of work and I'm ALMOST back to the point of people telling me I have less-than-broadcast quality audio. ;)

Jason,

Hey at least you are making progress! You can always work longer on stupider stuff, become less efficient and get poorer results. I have put a month of work into a 5 Watt grid modulated military rig. I'm hoping for the best - Hi.

Mike Wu2D

I dont mean to sound too hard on this but.............................

5 months?? Come on Jason, you could have completely gutted and rebuilt it in that amount of time. Now that you have the momentum going, dont stop at half done, keep on going until it's right. Do the audio stuff as well and get on the air with it sounding proud!!

                                                  the Slab Bacon

Five months is relatively fast.  I have projects going on years.  They do get done.
Great to hear you are moving forward.

Tom

See my other post where I mention I have a 40+ hr/wk job, a girlfriend, other friends, neighbors, other hobbies, chores and yardwork, learning cw, ...and that motorcycle collection. Occasionally I try to fit some sleeping in there too.

Bear in mind that I also live in California, its still "sorta" summer, we have beaches here. ;)

Figure, If I had to treat the dx100 like I have to treat the computers at my work, knowing that the very next day I HAD to get get back to work on it, I'd have beat it with a sledge hammer long ago.

A great Cheating Way to Have B'Cast audio from a DX100

Do the old "run an outpoot transformer backwards trick" into the control grids of the mod tubes.
Yup use the output tranny from a 6L6 push pull amp. Drive the SECONDARY with your processed hi-fi audio (usually a few watts of audio) and the primary connects to the grids of the mod tubes. The center tap of the primary is used to bring the bias to the pubes. Regulate the bias voltage and the screen volts of the mod pubes and you are there!!! The last sentence is an option. Test equipment would show any improvement, not the ears.
Quit wrestling with the old technology and have fun with more wires and a js..ed transmitter. I would get many compliments on the audio from a DX100 and a Scratchy Apache I owned in the past.
Fred

I built my entire HB rig once all the parts were in place at my crib in less than 3 weeks, having a 9-5 job as well. It took about another 2 weeks to build the speech amp and 2A3 driver deck from scratch. I did have the luxury of having 2 pre assembled HV power supplies 1500 @ 500 Ma ready to go as well.

the results: STRAP!

http://amfone.net/index.php?ind=media&op=file_view&iden=81 (http://amfone.net/index.php?ind=media&op=file_view&iden=81)

Control grids?  Screens?  I tried this going to the (plain ol) GRIDS using an xformer from a push-pull 6v6 amp and it sounded like yellow poop.

I think once I get it working good, back to stock, I'm going to build myself a nice transmitter of my own, and sell this monster...

WOW!! The audio source was prolly not up to hi-fi spec. There's not much in the way to  make it sound like yellow poop. The modulation transformer is good stuff. I've always had good success with the cheating method. I don't want to take the time to re-invent the wheel. There are folks here who have great sounding Dixies with the good ole D104. Beautiful clean audio without the extreme ends boosted.
You might not have enough or toooo much bias voltage OR HUM in the bias supply which would make the audio ratty. The modulator is just a copy of a hi-fi power amplifier from the 60's.
I witnessed the DERBS handy work. The power supplies were BA&L busters and lottsa watts.
Good Luck
Fred

...5 months?...that's nuthin'...still have stuff in the trunk from a hamfest 2 months ago...sk..

It took me close to 10 years to put my  Ranger 2 on da aair  klc

I've had a DX-100 on the bench now, for 10 years! 

  "  I've had a DX-100 on the bench now, for 10 years! "

So, yah wanna play that game ............  i've got a B&W coil , a 6 position switch and GE 300pF variable  cap to build an antenna tuner. All I need to do is to hook em up together.....  got them in 1973,   thats 34 years ago on that project  .... ..    klc

Ahhh GRIEF-KITS!  ;D

Damne...I think we could'a saved you tons of grief. We forgot to give you the THREE (OK, FOUR) RULES OF BOATANCHOR ACQUISITION.

1. DEOXIT = HOLY WATER. Spritz all switches and pots and even tube socket contacts. But especially switches. Wafer switches are notorious for crud buildup.

2. CHERCHEZ LE CAPACITORS. I know, it's "racial profiling", but in almost every situation they are guilty. Waxies, paper, lytics, and beauties...chuck 'em and replace 'em with new ones.

3. CHECK TO SPEC. Check that the HV, LV, Filament, and Biass voltages are to spec according to El Manual. If not, suspect a PREVIOUS MR. QUICK-FIXIT was in there replacing leaky caps but ignoring resulting resistors gone high.

4. BEWARE THE OTHER GUYS MODS. They nearly always suck. Rip and strip and restore to stock.

Ppppfft!  S' nothin'!    I  have had plans to build a "Big Maul" since  before I got my ticket, going back to 1966!  So there!   :P