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Post Pics of tube amps here

Lazybones1222

W9WDX Amateur Radio Club Member
Apr 6, 2005
948
28
28
Tampa Bay Florida
Let's see how many ole' boat anchor pics we can post here.



Me first. Click on thumbnail for big pic of my Varmint XL-250:






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I have some boatanchors around my shack. Here are pics of some of them:





Halicrafters HT-41 (acutally nice amp, but I blew one or both of the tubes)



Ex-Varmit XL 1000 converted to a switch keyed 4 tube box for CW (still works, needs RF keying circuit and new fan, but doesn't put out much weak tubes?)



Bunch of old tubes. Take a look at the pictures, if you see something you are interested in just ask, they are all for sale, but I don't know how many of them work, however I think alot of them are brand spanking new, never been used. Bought out from old TV shop by a friend who gave them to me.







The Halicrafters HT-41 (85 pound plate transformer)



CLICK SMALL PICTURE TO GET BIG PICTURE:































The Ex-Varmit XL 1000













Lot's of Tubes
















</p>Edited by: <A HREF=http://p067.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=443>443</A> at: 2/17/05 10:29 pm
 
WOW!! Tube-R-Us <img src=http://www.ezboard.com/intl/aenglish/images/emoticons/wink.gif ALT=";)"> Thanks for the pics!



Guess people are too scared of uncle charlie to post pics. <img src=http://www.wwdx.org/smilies/donotknow.gif ALT=":donotknow">


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amontheairam8dr.png
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heres one thats older then me,sorry for not having pics of the guts.....if ya wanna come by and slip the cabinet off and get some pics your more then welcome.....hahahaha



sb-220.jpg



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nope......heathkit sb-220......2 3-500z's.....<img src=http://www.wwdx.org/smilies/posticon25.gif ALT=":25">



i love that amp,oh my........





im still a duck tho.......workin these registered hands all over this buckeye..........ahahahaha





cya






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Uh, a "wirewound resistor" ?

Was it mounted on a tie strip parallel to the driver tube where the plate cap's wire connects?

If so, this was the plate choke. An Ohmite type Z-28 works for that one. Don't think there's a specimen here to serve as a "photo model".

And if there is no parasitic choke, made from a wire with a few turns around a 47-ohm resistor, your Skipper may have had a tiny ferrite bead slipped over the wire to the plate cap. If the bead is still there, it will do the job. Until it overheats, cracks in half and disappears.

If yours already did this, there will typically be no trace that it was ever there in the first place. Winding 4 or 5 turns of #22 or #24 wire around a 47-ohm 2-Watt resistor will take its place, and probably last longer.

My experience has been that the driver tube will go nuts and smoke the driver plate choke if it oscillates. If the original ferrite bead is no longer there, the tube is likelier to misbehave this way.

Palomar would use these tiny ferrite beads, slipped over the plate-cap wire in place of the more-typical coil-on-a-resistor choke coil. They worked okay until the first time they got hot, would crack and fall off. Forever.

And it seemed like such a clever idea when they first started doing that around '77 or '78. Until they started falling off the wire and disappearing. The coil-on-a-resistor "parasitic" choke just holds up better.

73


73
 
Ok, 1.YES the Wirewound Resistor was mounted on the tie strip! I can see where i unsoldered it from 15 years ago :)
2. Yes there is a bead on the lead to the cap :)
3. Any idea WHERE the other end of the Wirewound goes ?
I take it a 10 or 100ohm Wirewound would not be correct ?
Guess I'll have to figure out what a Ohmite type Z-28 is :)

Thanks for the info!

nomadradio said:
Uh, a "wirewound resistor" ?

Was it mounted on a tie strip parallel to the driver tube where the plate cap's wire connects?

If so, this was the plate choke. An Ohmite type Z-28 works for that one. Don't think there's a specimen here to serve as a "photo model".

And if there is no parasitic choke, made from a wire with a few turns around a 47-ohm resistor, your Skipper may have had a tiny ferrite bead slipped over the wire to the plate cap. If the bead is still there, it will do the job. Until it overheats, cracks in half and disappears.

If yours already did this, there will typically be no trace that it was ever there in the first place. Winding 4 or 5 turns of #22 or #24 wire around a 47-ohm 2-Watt resistor will take its place, and probably last longer.

My experience has been that the driver tube will go nuts and smoke the driver plate choke if it oscillates. If the original ferrite bead is no longer there, the tube is likelier to misbehave this way.

Palomar would use these tiny ferrite beads, slipped over the plate-cap wire in place of the more-typical coil-on-a-resistor choke coil. They worked okay until the first time they got hot, would crack and fall off. Forever.

And it seemed like such a clever idea when they first started doing that around '77 or '78. Until they started falling off the wire and disappearing. The coil-on-a-resistor "parasitic" choke just holds up better.

73


73
 
On one of the tie points nearest the deck is a disc capacitor. One leg to this tie point, one leg grounded. This tie point will also have a wire on it that disappears into a hole in the deck. That tie point is where one end of the plate choke is attached, where the wire and the disc cap meet.

The part is a coil, not really a resistor. The difference is in the type of wire, mostly. A wirewound resistor is made from wire that has a LOT of resistance per foot. A choke coil is typically would with copper wire.

If you have a junker amplifier handy that used sweep-type tubes like this one, that may be faster than tracking down the part I mentioned. A plate choke found in a junker will probably serve as a substitute.

Ohmite company makes resistors, and was a brand that was stocked by thousands of small, local electronics parts distributors. Those small outfits have nearly all become extinct in the last 15 years as consumer-electronics devices all became throwaways, one by one. It used to be fairly simple to have the local guy order ceramic-body RF chokes made by Ohmite. They look like a resistor, since they are made on the same equipment. The Ohmite part number "Z-28" is a nearly universal part used by thousands of basement "leenyar builders" for decades. What made them so popular is that they are wound from an "in-between" sort of resistance wire. This made them perform a little better than a choke wound with plain copper wire.

Odds are that if you can cannibalize a used RF choke from a junker, that it will be close enough to do the job. Ordering "just one" of any part is an uphill struggle, when there's nobody local to go to.

Oh, and the burned choke is usually caused by one or more problems:

1) Bad (or wrong) driver tube
2) Rear-mounted "Driver tune" knob NOT peaked.
3) Too much radio carrier on AM, or just plain TOO MUCH RADIO. A modern 2-final radio delivers roughly twice what a legal 23-channel would do. And that's what the designers of the Skipper designed it to work with, much smaller radios that rarely got past 20 Watts PEP.

Or all of the above, sometimes.

73
 
nomadradio said:
Oh, and the burned choke is usually caused by one or more problems:

1) Bad (or wrong) driver tube
2) Rear-mounted "Driver tune" knob NOT peaked.
3) Too much radio carrier on AM, or just plain TOO MUCH RADIO. A modern 2-final radio delivers roughly twice what a legal 23-channel would do. And that's what the designers of the Skipper designed it to work with, much smaller radios that rarely got past 20 Watts PEP.

Or all of the above, sometimes.

73
You've been very helpfull! Thank you.
and the correct answer in my case would be #3 Too Much Carrier :)

thanks again!
 

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