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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Jan Sun 21, 2018 5:10 pm 
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Location: Morris Plains, N.J. 07950
I agree with Mike. These are entertaining and educational posts. Keep 'em coming.


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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Jan Fri 26, 2018 3:31 am 
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Joined: Dec Mon 31, 2012 11:09 pm
Posts: 226
Location: Portage le Prairie, Manitoba
Well thanks for the words of encouragement guys!

Over the last few days I have been doing mechanical work rather than electrical. I made some blanking plates for the relay socket and phono...input? I'm still not certain what that terminal strip was for. It is labelled "Phono" in the manuals I have, but I have yet to actually find any reference to it in the text.

Anyway, I don't plan to use those holes for anything, so I thought it best to cover them up. There are still some empty holes for the 6-32 screws that mounted the bathtub caps, but they are not very large, so I'll leave them. I'm also waiting for some SO-329 connectors in the mail to fill the IF output hole.

Here's a pic of the plates:

Image

I made them by hand as usual. My piercing saw makes quick work of cutting curves like that and I enjoy it! Just a little work with various files and they look great!

As well as the blanking plates, I also added some extra braces which double as handles. I had seen such a thing done before here: http://www.boatanchors.org/LearyPix/LearyS3.jpg and that's what gave me the idea. I have always found the SP-600 to be a little flimsy even with the front panel installed. The massive power transformer and chokes are definitely to blame for that it seems. The chassis always wants to sag in that direction a bit.

Hopefully my modifications will help with that a bit, if not, they still serve as handles! For such a large piece of equipment to not have rack handles is absurd to me! When not in a cabinet, there's no real way to carry them aside from the edges of the front panel or having the chassis cut into your fingers. And if the front panel is off for some reason and you want to move it, it's not easy. Now I have a way to carry it right side up and not have to struggle...as much at least! It's still heavy! :P

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I used about nine feet of 1/2x1/8 inch aluminium stock doubled up along the top of the sides and back. Each side has a single vertical section in roughly the center (aligned with the 10-32 screws that attach the chassis to the side panels). This vertical section adds some rigidity and allows the side sections to be used as carrying handles. The whole affair uses 27 6-32 screws tapped into the aluminium as well as two 10-32 screws and two brackets cut from 1/8 inch thick aluminium right angle stock for the rear corners.

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This was the most aluminium hole tapping I've ever done! I don't like tapping aluminium in small sizes like this. Once you've tapped brass, everything else sucks in comparison! Aluminium is very sticky and clogs up the tap almost instantly. It doesn't have the same "crunch" that brass has! :P

Now since I mentioned it, I have to post this:

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That's my only experience working with brass, but it was enough to fall in love with it! It's not too hard, but not too soft and sticky like a lot of aluminium is. I built that shielding for a superhet I was building. Never did finish it though... The variable capacitor and reduction drive I built it around turned out to be highly unstable for some reason.

Anyway, I feel like I've gone on enough for this post.

This may be my last post for a while. I'm looking at buying my own house. My brother, with whom I have been living since 2015, has just had his boyfriend move in and I feel my time here is coming to an end. He's not kicking me out or anything, it's just a little crowded here now and I like my privacy.

I guess I'll keep you all updated in my next post here.

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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Jan Fri 26, 2018 5:08 am 
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Thanks for the informative post, towble.

Very nice metal work.

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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Jan Fri 26, 2018 1:02 pm 
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Location: Liberty, Missorui
Nice looking plates. Another one of those time consuming details that make the job look properly done.

This isn't specific to the SP600, but the "posts" at the rear of the SP-600 chassis side plates gave me an idea I've used for quite some time now.

A couple pieces of half by half aluminum angle from the big box store, that I can attach to the chassis of a receiver or transmitter, so I don't have to worry about crushed or broken transmitter output tank circuits or brass I.F. can adjustment screws, or other parts. Interestingly many receivers and transmitters already have pairs of holes at the front or rear of the side aprons, and some are even tapped. You have four "sides" at the ends of the pieces, where you can drill holes in the angle, and thus far I've not used all four locations. This one, simple, fixture makes handling, and sliding these oldies around on the bench pretty easy and worry free.

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To keep the edges of the wrap around front panel paint, used on some radios, in good condition I put some of those 1" diameter felt, self adhesive feet along the edge as you can see on the Viking Ranger, during it's time on the repair bench.

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I think these little "feet" are great and I use them alot. They allow you to slide these big old boxes around on the bench, yet have enough friction to make them "stay put" once in position. Here is an old WWII TCS-13 receiver weighing 30 pounds or so, that I put these on. If any radio has a foot missing, I just use these felt feet. YMMV

Image

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Last edited by Mikeinkcmo on Jan Sun 28, 2018 12:03 pm, edited 1 time in total.

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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Jan Sun 28, 2018 7:03 am 
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Joined: Dec Mon 31, 2012 11:09 pm
Posts: 226
Location: Portage le Prairie, Manitoba
Thanks for your comments, Chuck!

And thanks for yours as well, Mike! Great idea with the metal "stand offs" as well! I've done similar with wood before. Just building a frame from 2x2 and 2x4 scrap to hold the chassis and allow me to place it in various positions. If I ever do get a smooth work bench, I will definitely use little felt pads like that! That's a great idea! I don't think they would work all that well on my plywood bench though. :P

Speaking of work benches, stop posting pictures of yours, Mike! You're making me too envious of how nice it looks! :mrgreen: Maybe when I get my own place I will be able to build one half as nice as yours! But it'll be a little sparse in the test gear department.

I'd like to pick up a better signal generator soon as well as a sweep generator. I've never used a sweep generator before, but the TM11-851 recommends a sweep generator and an oscilloscope to align the IF deck. That'll be something new to learn I suppose. I have plenty of scopes considering I rarely use them. I mostly collect them because I find them to be the most aesthetically interesting of the various pieces of test gear.

Regardless of the fact that I don't have a sweep generator, I did do a quick alignment of the 455kHz IF just to see how far off things were. I didn't even use an output meter, I just did it by ear. It was nothing serious anyway. Most cores were quite close aside from L36. But I remember fiddling with that one in order to remove some corrosion from the screw threads, so that explains that.

Even before the adjustments, the radio was not a bad performer so far as I can tell. I'm using an end fed random wire about 30 feet long running up the side of the house at the moment. In the future, I plan to experiment with large tuned loops. I got the same number station today. "Atencion" from Cuba I've been told. 20 meter CW was pouring in today and the foreign broadcasts above 10mHz were quite good. I even got CRI which I always love hearing. That's what drew me to shortwave from the time I got my first real SW radio when I was 13 (I think), a Grundig S350. I can't afford to travel the world and have hobbies like this. But I can work on my radios and travel the world on them! Maybe not as much now as in the old days. :(

Anyway, I also replaced the final six BBODs in this radio. The ones in the band turret. I've entertained the idea of machining a pair of those fancy pliers shown in the manual. That would make things a little easier. I wonder if anyone who works on these things actually has a pair? :P

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I haven't reinstalled the coil sections that I removed yet, as I plan to remove the RF deck again for at least one reason... They are for band 2.

While working on the band turret, I noticed that the 2nd RF coil sections for band 5 and 6 have each had a 22K resistor installed across their sole fixed capacitors. I'm not sure how much this affects operation. There's not much going on up on band 6 but I did pull in some SW broadcasts and weather stations near the bottom end of band 5.

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The AGC seems to work alright on this receiver. I'm not sure if I'm going to modify it or anything yet. There doesn't seem to be all that much distortion on stronger signals. But I have yet to do a proper alignment and all that anyway, so I guess I'll wait and see.

I have also found yet another switch that has gone bad. The noise limiter switch is kaput. I should order the replacements soon.

When powering this radio up, I have been running it on my variac, turning the voltage up to 120v over a few seconds. I've never done anything to a radio to limit inrush current, but I think that I should consider it from now on. I know that a lot of people use the CL-90 thermistor. I have also been looking at the NTC 120-D15 to put inline with the AC line. Or perhaps a lower resistance, higher amperage thermistor for just the filaments?

Maybe I should use this vintage "tube saver" I found in my junk box:

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Or maybe I should get fancy and use this 51 second thermal delay relay!?

Image

I always thought I could be a writer. I guess these novel length posts will be my legacy! :lol:

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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Jan Sun 28, 2018 1:29 pm 
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Joined: Oct Sun 15, 2006 12:57 pm
Posts: 5719
Location: Liberty, Missorui
Quote:
... limit inrush current, but I think...
To each their own of course, but it's lasted for 60 plus years without such things, and the power transformer has several taps, so you can adjust the primary for whatever your line voltage is.

Quote:
Speaking of work benches...
As you already know, hobbies can easily "cross pollinate" and the benches here are another result that process. Hobbies are by definition Money Pits, and I have always tried to make them at least self supporting as soon as I could, without them becoming WORK. The only one that hasn't ever been revenue neutral, is ham radio. THAT, is a big money pit!

Don't think all this stuff is the result of a week end shopping spree, or, it fell off the south end of a north bound delivery truck, or Santa makin a special delivery in his eighteen wheeler!! :wink:

I just try to do things with the least "outta pocket", long term. It took a few years of buying test equipment "lookers" that didn't work, then fixing and reselling them for a profit. Inexpensive quick turn pieces at first, and as my test equipment slush fund :roll: grew, I moved to more expensive stuff. I will admit I played with everything as I went along, but only kept the ones I could afford without killing the golden Goose. The secret to the "profit" part is, very clear, big pics, showing operation if possible, and good text descriptions.

I've been retired for 20+ years so I've been playing for a while now.

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Last edited by Mikeinkcmo on Jan Sun 28, 2018 1:54 pm, edited 2 times in total.

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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Jan Sun 28, 2018 1:29 pm 
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Joined: Oct Sun 15, 2006 12:57 pm
Posts: 5719
Location: Liberty, Missorui
Quote:
...don't have a sweep generator, I did do a quick alignment...
The actual "need" for a sweep generator isn't often, but it is INTERESTING TO SEE the various band pass shapes of some radios.

Quote:
I wonder if anyone who works on these things actually has a pair? :P
Maybe Les, but I've never heard of anyone confessing yet.

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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Jan Sun 28, 2018 5:29 pm 
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I aligned my JX-17 without a sweep generator and from middle GA I can pick up Radio Havana Cuba on 6MHz loud and clear with just a short 3" piece of wire in the antenna jack.

That said given I have more accurate stuff I may realign it.


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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Jan Sun 28, 2018 9:04 pm 
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Location: Gulfport, MS
Mikeinkcmo wrote:
Quote:
...don't have a sweep generator, I did do a quick alignment...
The actual "need" for a sweep generator isn't often, but it is INTERESTING TO SEE the various band pass shapes of some radios.

Quote:
I wonder if anyone who works on these things actually has a pair? :P
Maybe Les, but I've never heard of anyone confessing yet.


I've never seen a pair of those special pliers. I always used needle nose pliers and was very careful to not launch the spring clips into never-never land...
The depots probably had those along with various Hammarlund Dealers and Military organisations.

Incidentally, I owned that John Leary MK.IV receiver Towbie mentioned in his previous post It is now in another owners possession. I still have No. 32 (another Leary SP-600) in the shack. I've owned 25 SP-600's over the years and they are great receivers.

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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Feb Thu 15, 2018 5:45 am 
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Joined: Dec Mon 31, 2012 11:09 pm
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Location: Portage le Prairie, Manitoba
Sorry for the late reply, everyone! I would say I've been busy as an excuse, and I suppose that's somewhat correct, but I've mostly been really lazy lately. My father is endlessly finding things for me to fix for various people that he knows. A record player and a handheld CB radio have been the most recent.

Anyway, I did buy some thermistors, Mike. I'm not sure if I will use one on this radio, but I'll play around with them and see how I feel about them. They are 120 ohms rated for 1.8 amps.

Also, I know what you mean about acquiring gear over time and buying and selling and fixing, then keeping what you want or like best. When I think back, there are plenty of pieces of equipment that I wish I had kept. For instance, I once had a nice HP marker generator with a nixie tube counter in it.

As for the SP-600, not much to say really. I did buy the replacement switches but I have not received them yet. After I replace them, I plan to reinstall the front panel and align the controls a bit. With the radio apart like this, it's difficult to tell what position the controls are in so I feel as if I'm not able to appreciate how well the radio is working. Or perhaps poorly! :P I really don't know. I fear I do not have much of a base line to work from.

I did buy a sweep generator. It's nothing fancy. I was thinking of getting an HP-3336A or a 3325A or even a 3335A, but I'm not sure how much I would actually use such a thing. Like you said, Mike, it's probably not necessary, but would be interesting to see the band pass shape. I figured that I best not rush into buying such a complex piece of equipment. There's a reason I like tubes, they make me feel like I have some rudimentary understanding of how things work. I have little confidence in my ability to repair a fancy new-fangled synthesised function generator. At least, not without you fine folks.

Anyway, I bought an HP-3312A. I read a few long threads about various sweep generators and their usability for IF alignments. The biggest thing seemed to be accuracy. That is, knowing what frequencies you are seeing on your scope or spectrum analyser. I figure that I would more likely do an old fashioned alignment and then just use a sweep generator to visualise the band pass curve if I were curious.

I also bought not one, but two HP-8640B RF generators. I've been meaning to upgrade my RF generator for a while now. The little one I have works quite well for my alignments when paired with a frequency counter, but it has its limitations. Both 8640s should be here tomorrow.

I did a little playing around with my HP-8557A today. (Remember when I said I liked HP equipment, Mike?! :P The collection is growing!!!) I just got an HP-1120 active probe and spent some time replacing some connectors on it. I figured it would come in handy for use with the 8557. Well while playing around with the 8557, I thought I would try using it as a panoramic adapter with my SP-600.

I didn't use the active probe for that as the SP-600 has a cathode follower. I found that a small 1pf capacitor coupling the IF output to the spectrum analyser dragged down the receiver quite a bit and also offered more than enough level for the 8557, so I ended up just placing the leads beside each other on the bench. It was a lot of fun to see what I was listening to! I enjoyed cruising the bands for half an hour or so.

But I felt like something was wrong. I knew something was wrong. I was seeing what I was listening to, but not much else. And the band width control affected the display. The SP-600 manual states that the IF output can be used for a panoramic adaptor, yet the IF takeoff point is after the two IF stages and hence the crystal filter and bandwidth controls. As far as I've come to learn, panoramic adaptors are usually wired into the plate of the mixer allowing them to see signals outside of the IF pass band.

I thought I'd try taking the IF signal from the plate of the 1st mixer instead. I tried the 1120 probe, but it's response seems to drop off dramatically at such a low frequency. I could barely get the signal above the noise floor of the 8557. I opted instead to use a 1pf coupling capacitor with some success. When tuned to a particular signal, the 8557 would drag the mixer down letting me know what I was tuned to. Still, the drift of the 8557 is terrible, so half the time I was seeing all these signals but had no idea where I was among them.

Here's a pic of the setup:

Image

I still don't have tube extenders, so I'm using thin buss wire twisted around the tube pin before inserting it into its socket. Electrical tape is a must to keep it from shorting to the socket collar. I learned that one from the sparks! :oops:

I feel like I have broken new ground today. I'm delving deeper into things than I ever have before. Just trying things out that I have never considered up to this point. I've been enjoying myself so far. I hope you're all enjoying this thread still. Even if I take the occasional two weeks off! :P

-Eric

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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Feb Thu 15, 2018 2:17 pm 
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Put me down as one who's enjoying being in the peanut gallery on this one, Eric.

Thanks for posting your exploits. It lets me be in the lab even though I'm away from mine for a month or so.

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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Feb Thu 15, 2018 3:05 pm 
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Location: SW WA state
towble wrote:
Anyway, I did buy some thermistors, Mike. I'm not sure if I will use one on this radio, but I'll play around with them and see how I feel about them. They are 120 ohms rated for 1.8 amps.
-Eric


Eric, You did well on the thermistors! The trick is to match them as close as possible to the current draw of the piece of equipment, without going over the current rating.
I put inrush current limiting on all of my equipment.
Nice job on the restoration... I need to redo my "daily driver" SP-600 one of these days.

-Tom


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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Feb Thu 15, 2018 3:19 pm 
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towble wrote:
I figured now was as good a time as any to replace the bathtub caps. I did things the same as the power supply caps. I made up a turret board and mounted it in the original location of the bathtub caps. I'm sure I will use turret boards for most if not all of my future recap jobs. They may be more work than simply using turret strips, but they look so tidy and fit the rest of the radio well.


Eric,

Nice job on the capacitor replacements, but I personally would have left the bathtub caps in place and restuffed them. Just my preference!
There's two ways to do this: If the bottom is just easily soldered on, it can be soldered off... Then gut and wire in a new cap. Replacing the bottom is optional.
Method two is if the bottom is also crimped and soldered: The cure to this is to razor knife or Dremel the bottom of the can, pull out the bad cap, and replace.
I do all my work so that the cap can be reattached by screws, and no one knows the unit has been restuffed unless you write it on the cap, or physically pull it and look underneath.
Just my two cents worth.
Again, awesome work on bringing back a great receiver!


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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Feb Thu 15, 2018 7:53 pm 
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Well I'm glad to hear you're enjoying it, Chuck! I hope you're not getting too lab-sick. :P

I guess I could have been a little closer to the current draw, Tom. This radio draws about an amp, but I'm not sure how accurate that is. I'm just going by the meter on my General Radio variac. I've never used inrush limiting before, but I suppose it's never to late to start. I would like to get a current probe and storage scope and do some tests. One on the filament lines and one on the main AC line. That would give me a better idea of what was happening. Or maybe I can find some obscure, vintage, graphing amp meter somewhere! :D

I used to be a capacitor re-stuffer as well. Mostly because I didn't find the usual terminal strip replacement jobs very attractive. I would still re-stuff them if I were doing a vintage Philco or something, but I find that a nicely built turret board fits in well enough in this military-esque beast of a radio. Also, for me, I find it less of a pain. It's not that I've ever struggled with re-stuffing cans and bathtubs, it's just that I've always found it quite laborious and sometimes messy.

I understand your approach though. I love the look of bathtub caps!

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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Feb Fri 16, 2018 1:16 am 
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...Or maybe I can find some obscure, vintage, graphing amp meter somewhere!...

Now you're talkin' !

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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Feb Fri 16, 2018 2:37 am 
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WoodchuckTN wrote:
...Or maybe I can find some obscure, vintage, graphing amp meter somewhere!...

Now you're talkin' !


I remember seeing pictures of graphing meters in some old heating, air conditioning, and refrigeration books that my dad has. It seems they're pretty hard to come by these days.

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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Feb Sat 17, 2018 4:20 am 
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Not a radio update, but I got my two HP-8640B signal generators yesterday. I'm glad I bought two of them. Neither of them work perfectly, but I suppose I should have expected that.

The first one I checked out was in a much larger than necessary box and rattled around a bit. I received it with a broken handle on the left hand side as well as a missing button for the counter and a damaged AM modulation knob. There are also cracks in two of the plastic gears. But they are not falling apart yet.

Image

I powered it up and it works quite well. The AM modulation is intermittent, but that seems to be a dirty switch. Below you can see it putting out a signal.

Image

The second unit has more issues. It is in better shape superficially. The missing knob cap on the output vernier knob is the only issue with the front panel. However, the inside is a different story. For starters, the plastic mount for board A11 is broken, so it's kind of just flapping in the breeze, hanging on its connector. Secondly, there are six cracked gears. The worst of which having cracked into two pieces (although still functioning! :P ) and the one behind it looking as if it will soon follow suit. The two really bad ones are both in the gears that link the FM peak deviation control to the range switch. It appears that the range switch does not rely on those gears. They seem to be for the FM deviation control only, so even if that drive mechanism failed completely, I would still be able to use the signal generator for most of what I plan to use it for.

Here's a pic of that mess:

Image

As well as the mechanical problems, there does seem to be an electrical problem as well. Everything tested fine when I powered the unit up aside from the modulation. In both AM and FM, 1000 and 400Hz tone, the modulation is not steady, it pulses. If I wiggle the switches or switch various ones in the right sequence, I can get the tone to go steady. But it only lasts so long as the unit is powered on and the switches left alone. As soon as I power it off and back on again or fiddle with the controls, it goes back to pulsing. Doesn't seem to me like a dirty switch.

Anyway, here's a pic of the second unit functioning putting a FM signal at 20kHz deviation into my 8557A spectrum analyser:

Image

I have some work ahead of me. I figure I can make a solid, working unit from these two. And I'll have various spares if need be. The first unit has a higher serial number and has the newer style knobs without the fragile little levers on them. It also has the 50 watt reverse power protection option installed. I think it will be the unit I choose to repair and the other will be for parts.

Fixing those gears is gonna be fun...

I really need to stop derailing my thread!

And I almost forgot to mention, I plan to download the Koch method again and see if I can't stick with it this time. In my 15 or so years in the radio hobby, I've tried to learn CW a dozen times, but I've never gotten far. What can I say?! Maybe all that talk about millennial is true! I would surely regret not becoming fluent at the end of my life. I'm not a licenced ham on HF (just basic qualification), but I'd love to be able to understand code when I hear it. So please feel free to badger me about that. It seems I need to be forced to do it. :lol:

I'd also like to build my own straight key from brass stock. I have the machine tools anyway. I don't think it would be too hard.

-Eric

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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Feb Sat 17, 2018 11:54 pm 
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Doesn't someone make replacement gears for those?


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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Feb Sun 18, 2018 12:08 am 
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Seems to me there was one fellow making those gears. Maybe someone ought go to the HP board on yahoo or where ever it went to, and ask.

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 Post subject: Re: Hammarlund SP-600 JX-7 Restoration
PostPosted: Feb Sun 18, 2018 3:13 am 
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I did read somewhere about a guy in Italy who made replacements. I'm not sure if that's still happening though.

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