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Recapping Ranger I




 
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Author Topic: Recapping Ranger I  (Read 5960 times)
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W3UTD
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« on: January 07, 2010, 10:51:04 AM »

I want to get her back in standard operating form, so Step 1: replace the paper caps

Cap  - Original  - Replace with
C51     .1mfd    400V     - 0.1uf 1KV      
C52     .1mfd    400V     - 0.1uf 1KV      
C53     .02mfd  400V     - 0.02uf 1KV    
C60     .005mfd 400V     - 0.005uf 1KV    
C61     .02mfd  1.6KV    -  0.02uf 2KV        
C62     .1mfd    400V     -  0.1uf 1KV    
C63     .05mfd  200V     -  0.05uf 500V  

Did I miss any?

C78 I'll use a 47uF at 450V
C77 is 10uF at 700V. I can't find one of those.

Any suggestions?

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WQ9E
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« Reply #1 on: January 07, 2010, 11:46:56 AM »

For C78, a 47@450V is fine; the value tolerance on older electrolytic caps was really wide.

For the 10@700 I would use two 22@450V in series.  In this application you probably can get away without equalizing resistors since the high voltage on these isn't that high and with two modern production caps the values are going to be pretty similar. 

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Rodger WQ9E
W3UTD
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« Reply #2 on: January 07, 2010, 11:54:55 AM »

for C77, when I series two the 22uF caps at 450, I generally should get a little less than half the capacitance at twice the voltage correct?

I also seem to remember reading I need to connect a resistor across each cap for equalization.  How do I calculate what size resistor I need for that?
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ke7trp
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« Reply #3 on: January 07, 2010, 12:05:51 PM »

I dont think you need the resistors on this application.   Just series the caps and move on. I have done 2 rangers and 4 valiants this way.

Its ok to go larger on the filter caps. Keep in mind they used the min they could as the caps where large and expensive. They are now small and cheap. 

While you are in there, You should take the VFO apart and fix the Dropping resistor issue.  Replace it with a wattage resistor and move out of the VFO box.  Also a good time to check the tubes inside that box since they probably have never been checked before. 

Clark
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W3UTD
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« Reply #4 on: January 07, 2010, 12:28:24 PM »

Yup, those other items are steps 2, 3, 4, .....
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ke7trp
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« Reply #5 on: January 07, 2010, 12:34:56 PM »

Step 5 :  Put a nice 3 wire Power cord on the unit. 
Step 6, Gut an old Xtal can and make a Relay PTT output cable  The Xtal fits right into that two pin plug.
Step 7, Open the accesory jumper plug on the back and make sure the wiring is solid and solder joints are good.

Clark
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W3UTD
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« Reply #6 on: January 07, 2010, 12:40:44 PM »

Step 6, Gut an old Xtal can and make a Relay PTT output cable  The Xtal fits right into that two pin plug.

Got any more info on that one, I don't quite understand...
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ke7trp
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« Reply #7 on: January 07, 2010, 12:44:14 PM »

On the back of the ranger and valiant, There is a two pin female plug. This is for the Relay output.  This switches the Dowkey or antenna relay. 

That johnson plug gets lost and when you buy a ranger, It almost never comes with that plug. So you have a few choices if you lost yours.

1.  A large size radio Xtal plugs in so you can GUT an old Xtal can and use it to make a connector.
2.  Run wires out the back of the ranger.
3. Drill holes and put a terminal strip on the back.

I like to keep things stock and never have that connector so I just make them out of old large Size Xtals.

Clark
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ke7trp
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« Reply #8 on: January 07, 2010, 12:47:29 PM »

I just took a camera phone pic of the connector made out of an xtal can.

Clark


* Photo_010710_001.jpg (342.56 KB, 1280x1024 - viewed 434 times.)
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W3UTD
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« Reply #9 on: January 07, 2010, 12:50:15 PM »

gotcha   thanks very much Grin
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W3UTD
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« Reply #10 on: January 07, 2010, 01:04:11 PM »

Clark,

I don't have the rig here with me to look, but I want to order some parts from Mouser.  For the electrolytic caps, especially C77 and C78, should I get Radial or Axial caps?
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WQ9E
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« Reply #11 on: January 07, 2010, 01:14:58 PM »

for C77, when I series two the 22uF caps at 450, I generally should get a little less than half the capacitance at twice the voltage correct?

I also seem to remember reading I need to connect a resistor across each cap for equalization.  How do I calculate what size resistor I need for that?

In the case of the two caps in series you are operating them so far from rated voltage that it is most improbable that you would have enough variance in value between the two to exceed the voltage rating of either cap.  The HV in the Ranger should stay under 600 volts even with no load and in operation will drop to a bit over 500 volts.  So, one cap would need to have over 75% of the total voltage drop to exceed its working rating. 

If you were operating them closer to the rated working voltage or if these were not two new manufacture units (same manufacture, style, etc.) then equalizing resistors would definitely be needed.  In most gear, the equalizing resistors also operate as the "bleeder" and any of the older handbooks will supply information to calculate the value. 

Rodger WQ9E
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Rodger WQ9E
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« Reply #12 on: January 07, 2010, 01:16:54 PM »

I did one for the V II. Get a junker from a CB, or a freq you know you'll never use. I held one of the pins with some needle nose pliers and flashed over the solder joint on the xtal cover with a propane torch a couple times slowly. If you hold the xtal upside down, it will fall to the floor. Snip out the quartz and scrape the pins to be soldered to really good. Solder on the wires good and dab with a little goop to insulate them. If you clean out the ridge good enough to reseat the cover to the bottom half, you can drill a hole in the cover to put in a very small grommet, thread the wires through and tie a knot in them to act as a strain relief. The cover can then be reattached with some solder using a 40 watt iron. Take a small screwdriver and carefully retension the contacts in the socket. Done! Now, you have a keyed 115v line from the tx. I worked mine through a 115 vdc relay using a half wave rectifier; then used the 115 relay to energize a 4PDT 12v relay in my homebrew T/R box. See you guys later. I'm going out in the cold now to see if I can raise the diaperpole up another 30ft. Then, it's off to my OA2's mounted for my Mod screen regulator ckt in the Viking.

Phil
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ke7trp
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« Reply #13 on: January 07, 2010, 01:30:27 PM »

If you dont have an ARRL handbook, You really need one.  I have about 30 of them.  If you dont have one, Send me your address, I will forward you a 50s or 60s book. It has all the information you need.  Just send another AMer on this site a part or book you have in good faith.

I did not use the resistors.  But you can if you want.  I just series them and go on.  The voltage is low enough that I dont think its an issue. If you had multiples or high voltage, I would use the resistors.

 If I find time later today, i will just look up the value for you.

I use this place to order caps

http://www.justradios.com/cokits.html

Also  www.tubesandmore.com   Click around on different manufacturers. There is a big difference in price. I use alot of the ILL caps from them. Never had a bad one. They ship same day. 

Clark
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ke7trp
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« Reply #14 on: January 07, 2010, 01:32:23 PM »

Oh... and you want AXIAL leads. This means there is a lead on each end of the cap. The radial caps mean the leads are on the same end. I never liked this for high voltage applications.  The wires and your work might be to close and you could arc over..

Use AXIAL caps.

Clark
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w4bfs
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« Reply #15 on: January 07, 2010, 01:38:24 PM »

just want to back up what Clark had to say .... I have used 1000's of Illinois electrolytic in repairs over 35 years ....ZERO defects ...73 ...John
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Beefus

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to see ourselves as others see us.
It would from many blunders free us.         Robert Burns
WQ9E
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« Reply #16 on: January 07, 2010, 01:53:07 PM »

just want to back up what Clark had to say .... I have used 1000's of Illinois electrolytic in repairs over 35 years ....ZERO defects ...73 ...John

Too bad the company cannot produce a zero defect Illinois governor for us also...

As to axial or radial, either would work and I would choose them based upon the specific mounting scheme you plan to use in the Ranger.  One of Murphy's laws is whichever style you have the other would be better for the task at hand.  For some reason, it seems the radial caps are often cheaper (at least from Mouser where I get most of my stuff).

Rodger WQ9E
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Rodger WQ9E
W3UTD
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« Reply #17 on: January 09, 2010, 08:46:57 AM »

Thanks to all for the help getting an AM noob up and running.  Hope to be on the air soon.
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