Restoring Apache TX-1

[AB3FL]

Hi all,

I am new to boatanchors.  I am working on an Apache TX-1.  I have a few questions

1) The plate current swings down instead of up on modulation.  The manual says that it should swing up

2) What should the windings on the modulations transformers read in ohms on a DC meter

3) The VFO seems to have a second harmonic on 80M that I would like to get rid of


thanks all

Tom - AB3FL

[Jim KF2SY]

From this recent thread, someone put schizmo up...
http://amfone.net/Amforum/index.php?topic=18411.0

My eyes lie to me sometimes but it looks like 11k on primary and k? on secondary?
Which now begs the questions........., do you have the schematic with your manual?
Whatz the modulated Rf waveform look like on a scope?
Whatz the plate voltage doing? 
?....??.....??.....??
More info needed.  Get your meter out and start pluggin' at it.  Check PS's and bias voltages etc.

G/L

[AB3FL]

I took out the modulation transformer.  The primary is shorted.....from the center tap to one end its 250 ohm from the cetner tap to the other end its 20 ohm

[W1EUJ]

Rewind time for that transformer. Call Gary, WZ1M

[w8khk]

From this recent thread, someone put schizmo up...
http://amfone.net/Amforum/index.php?topic=18411.0

My eyes lie to me sometimes but it looks like 11k on primary and k? on secondary?
Which now begs the questions........., do you have the schematic with your manual?

Yes Jim, you are correct, 11K primary, 3K secondary, with 500 ohm tap for driving external modulator.   The schizzy in that thread is not real clear, but the one I received in the manual PDF is sharp.

Tom, if you need a copy of the manual, let me know and I will email it.  BTW, I picked up an apache last week, it appears to need a good bit of work.  Haven't tested the iron yet.  It is so heavy, I am thinking about pulling all the iron, and making a rack-mounted  exciter, with separate power supply, for my 304TL rig.  If you do not find a replacement mod tranny for your apache, let me know, if mine is good we could work something out.

73, Rick

[AB3FL]

thanks!    I have the manual and schematic.    Let me know about the modulation transformer if you are not going to use it......

Tom - AB3FL

[w8khk]

OK, I will test it within the next couple days, and pull it if it tests good.

[Tim WA1HnyLR]

See my posting on modulator tubes for apache. If fixed up correctly the apache can be a very fine vintage transmitter.
DeTimWA1HnyLR

[AB3FL]

I am planning on doing that mod, but why does the PS have to be solid stated.  I have over 800V on it with the tubes.  My line voltage is high at 125V

Tom - AB3FL

See my posting on modulator tubes for apache. If fixed up correctly the apache can be a very fine vintage transmitter.
DeTimWA1HnyLR

[WD8BIL]

but why does the PS have to be solid stated

One reason is the voltage drop across the rectumfinders is less under load.

[AB3FL]

I do agree there, but I already feel bad that I replaced the selenium rectifiers with silicon ones.  I want to try to keep it as original as possible....except for the audio mods.  The nice part about the tubes is the slow start so the transformers and caps don't get that instead high current draw.......

but why does the PS have to be solid stated

One reason is the voltage drop across the rectumfinders is less under load.

[Steve - WB3HUZ]

Won't matter on the high voltage since it only comes on when the transmitter is keyed. If you are worried about in-rush on the LV supply install a thermistor on the primary of the tranny. Good to go.

[Pete, WA2CWA]

I do agree there, but I already feel bad that I replaced the selenium rectifiers with silicon ones.  I want to try to keep it as original as possible....except for the audio mods.  The nice part about the tubes is the slow start so the transformers and caps don't get that instead high current draw.......

You're already beyond that point, so what's the difference. As long as you don't drill 1/2 holes in the front panel or elsewhere, it's "original" looking.

[The Slab Bacon]

I do agree there, but I already feel bad that I replaced the selenium rectifiers with silicon ones.  I want to try to keep it as original as possible....except for the audio mods.  The nice part about the tubes is the slow start so the transformers and caps don't get that instead high current draw.......

but why does the PS have to be solid stated

One reason is the voltage drop across the rectumfinders is less under load.

One other advantage of solid stating the power supplies that everyone else overlooks is that if done properly (disconnecting and capping off the rectumfryer filament leads) it helps reduce the chances of the LV / fil transformer from failing due to an internal zorch over from the rectumfryer winding to one of the other windings due to a HV breakdown. It also leaves you free to use that winding to use for something else if necessary.

I actually had to do this to save the oddball transfoma in my G-76 base station power supply. It had developed an internal short from the HV rectumfryer to one of the other filament windings. It has now worked for years that way.

                                                                          The Slab Bacon

[AB3FL]

OK.....that is a good reson for me!    I want no Zorches!

I do agree there, but I already feel bad that I replaced the selenium rectifiers with silicon ones.  I want to try to keep it as original as possible....except for the audio mods.  The nice part about the tubes is the slow start so the transformers and caps don't get that instead high current draw.......

but why does the PS have to be solid stated

One reason is the voltage drop across the rectumfinders is less under load.

One other advantage of solid stating the power supplies that everyone else overlooks is that if done properly (disconnecting and capping off the rectumfryer filament leads) it helps reduce the chances of the LV / fil transformer from failing due to an internal zorch over from the rectumfryer winding to one of the other windings due to a HV breakdown. It also leaves you free to use that winding to use for something else if necessary.

I actually had to do this to save the oddball transfoma in my G-76 base station power supply. It had developed an internal short from the HV rectumfryer to one of the other filament windings. It has now worked for years that way.

                                                                          The Slab Bacon

[Steve - WB3HUZ]

Yea, what's more original:

A) A rig with a couple of solid state diode rectifiers and the power transformers intact?


B) A rig with tube rectifiers and a crapped out power tranny?


For extra credit, explain why keeping somethingl is important in a hobby where we're supposed to experiment, modify and tinker.

[AB3FL]

I chose (A)

 

[Steve - WB3HUZ]

Enjoy your Apache. It's a nice rig. Catch you on the air.

[w8khk]

I pulled the tranny from my beater apache, and tested it.  Checked out fine, so I sent it to Tom.  I will list the measurement info here, in case it might help someone else troubleshooting an old injun in the future......

Resistance measurements:

Plate to Plate 359 ohms, plate to B+  187 ohms, 172 ohms
While the turns on each side of B+ are the same, the diameter of the core is greater for the outside winding section, hence the resistance is higher by 15 ohms on the blue side of the primary.

Yellow to green 57 ohms  green to black 41 ohms, yellow to black (full secondary) 97 ohms.

Voltage measurements with 100 volts 60 cycles applied plate to plate:

Plate to B+ (red)  50 volts on each side, indicating balance.  Secondary voltages: yellow to green 31 v, green to black 21.7 v, yellow to black 53.2 v. 

100 volts full primary to 53.2 volts full secondary is is a turns ratio of 1.88 to 1.  Squaring this to 3.53 gives the impedance ratio.  Assuming 11000 ohms primary, divided by 3.53 equals 3112 ohms secondary.  Rating is 3000 ohms.  This test indicates impedance ratio is correct.   

I ran the transformer with 200 volts plate to plate for 15 minutes, no sound, no heating, therefore no shorted turns.

[w1vtp]

Won't matter on the high voltage since it only comes on when the transmitter is keyed. If you are worried about in-rush on the LV supply install a thermistor on the primary of the tranny. Good to go.

Steve -- I've always liked that concept. Any suggestions on thermistor type, PN source?

Al

[AB3FL]

The only problem that I see with solid stating the PS is that the voltages will be way too high


Tom - AB3FL

[Steve - WB3HUZ]

Pick out the one(s) you need at the link below. Then click on the free samples link. 

http://www.ametherm.com/

[Steve - WB3HUZ]

There is no correct answer. It was a trick question. It's all up to the individual. In reality, if one was really concerned about originality, they wouldn't even use the equipment, for fear of blowing/burning something.

[AB3FL]

I still like the "slow start" aspect of the tubes....

WB3HUZ:  Thanks for the link!

Tom - AB3FL

[W1EUJ]

Collins didn't care about instant-on in the PM-2 supply for the KWM-2.

Lives depended on the PM-2 / KWM-2 combination. American lives.

You saying Art Collins didn't know what he was doing?

:-)