Stromberg and Carlson ASR-120 - Replacement transformers?

[txtune]

did your voltage stay about constant during the 5 minute test?

The voltage stayed constant at around 450vdc for five minutes.

I will check this more thoroughly tomorrow, it's been a busy week. Thanks for your patience!

[shooter]

 
I spent 10yrs with '90's teens, patience is a must 

[txtune]

I spent 10yrs with '90's teens, patience is a must 

Hey, I was a '90's' teen ... this should be a walk in the park for you! 

[shooter]

 


I can spot 'em a mile away, NOW, you do your part and you're shakin window's 


think about "the look", it will be a big part of the stereo.  Once it's playing some good grunge, although Nelli (sp?) is playin in my head currently

[txtune]

I can spot 'em a mile away, NOW, you do your part and you're shakin window's 


think about "the look", it will be a big part of the stereo.  Once it's playing some good grunge, although Nelli (sp?) is playin in my head currently

I am probably going to have to learn how to solder as well. 

As soon as I hear some music come out, I will probably go ahead and strip it down to refinish the frame.   Should I be looking for any hard to get parts? Tubes, sockets, etc?

[shooter]

let's get music or noise 1st.


If you don't have a good soldering equipment, start there.  hunt up some junk pcbs, old junk chassis, things that can be burnt up as you learn NOT to burn up.  maybe hunt up an 'ol guy that's in your area that can solder, buy him a 6 pack, or a 1/4 oz, learn 1st hand 

[txtune]

let's get music or noise 1st.


If you don't have a good soldering equipment, start there.  hunt up some junk pcbs, old junk chassis, things that can be burnt up as you learn NOT to burn up.  maybe hunt up an 'ol guy that's in your area that can solder, buy him a 6 pack, or a 1/4 oz, learn 1st hand 

lol ... I think I have some ideas. I know some older traffic signal techs.

[txtune]

Ok. I circled the wrong cap item last time. Take a look at these images, same image actually... one is marked up the other is not. I got ~150 on the device I circled. Then I marked the wires that I OHM'd, chassis ground to pin on socket, and I got 157 or 158 on all four of them.

[shooter]

 


Since you are new at this, I would highly recommend getting the input power "set", holes drilled, chassis cut, stuff.  High voltage is nothing to "play" with. wires, switches, fuses, all dangling is a recipe for disastrous outcomes.


buy, find, or re-purpose an EIA connector, mount it where the original 2 pronger is.  I'm calling that the "back" of the chassis.  Doug has both eia and power cords at his store
https://hoffmanamps.com/MyStore/perlshop.cgi?action=template&thispage=FusesCords&ORDER_ID=743790629


I would mount my power switch and breaker there also. pita having to reach in back to power on/off but taking it to the front gets way to close to the preamp IMO.
maybe others have a better option, maybe you do.  The point is, make it safe to continue.



a power on light is also REAL handy, yours indicates one but my guess is was mounted on the "other chassis"
Doug also has something that will work off the filaments just like your schematic indicates
https://hoffmanamps.com/MyStore/perlshop.cgi?ACTION=enter&template&thispage=Lamps&ORDER_ID=!ORDERID!
the fender 6.3 volt, socket, and bezel.  figure out where you want that mounted.



those parts will give you a good start on soldering, so find someone, make a day of it.
remember the turtle always wins.
take the schematic, some blank paper, your favorite crayon, and draw up all the connections and parts i've listed above, how "you're" gonna connect them to the original

[txtune]

Ok. I suppose it's time to take this down to bare metal and clean it anyhow. I have taken quite a few photos from nearly every angle, I am sure I missed something.

If I do want to connect the stereo input (RCA jacks) and output (speaker wire connections) ... where do those connect?

[shooter]

If you haven't already started;
re-working the power to be safe can all be done on the "back", no need to strip it all down yet to get music.


I would mount the RCA jacks in "front",  there a 2 small tubes, your driver tubes, the RCA's will connect to them, you want short wires  6" or less if possible.  (see the orange square on attachment, that's IN)  Also note I put 2 .1uf caps "in-line"  They may not be needed, but if you plug something In that has DC volts on it, you will be happy they're there


the speaker out's come off the 2 identical looking transformers, the problem there, your AC In will take up some of the "back", you want the speaker wire away from the AC IN, can still be on the back, you just have to think things through so you have a clean layout instead of a spaghetti bowl of wires.




 When you DO tear it down, DOCUMENT, and learn the "terms" (your original documents have something like C42 in a circle pointing to a component.  It also has a parts list that references "C42" and gives a discription)
study those sheets til you see circles when you close your eyes, you've quit eating, can't sleep because you're so focused on learning this amp 


example that 150 ohm resistor is the cathode resistor, your notes should say something like "yellow wire from cathode resistor"  always specify where the wire went.  leave all the wires on the board, disconnect at sockets, switches, etc, AND LABEL them.
since you're not soldering yet, clip the wires within a 1/4" of where they're soldered to.  then your 1st soldering job will be to remove that 1/4" wire and clean up all the connections, sockets, etc.

[txtune]

Thanks shooter. Let me chew on all of this and get back to you.

[shooter]

to windy to fly so sketched up a cleaner schematic (CHECK for errors, edit in .sch :)


EDIT missed a resistor 
AND bypass cap
_2 should be correct

[txtune]

to windy to fly so sketched up a cleaner schematic (CHECK for errors, edit in .sch :)


EDIT missed a resistor 

What type of aircraft? My Dad had a '66 V35 Bonanza, that was an awesome machine.

Do you use a specific software to create schematics?

[shooter]

 


I'm learning to fly sUAV's, hoping to get my commercial licence in the spring, but studying maps and rules and and..... is NOT much fun.


some of us here use expessSCH, it's free, pretty intuitive, I've been using it since it came out in 3.5" floppies 

[txtune]

I'm learning to fly sUAV's, hoping to get my commercial licence in the spring, but studying maps and rules and and..... is NOT much fun.


some of us here use expessSCH, it's free, pretty intuitive, I've been using it since it came out in 3.5" floppies 

Ah! I have a Phantom 3 Pro ... you are probably flying something much more complex. The technology is amazing in that arena.

I have another, multi-part, question for you. The schematic says to use Belden 8530 or 8524 wire.

1) Would you suggest stranded or solid?

2) Is the cloth insulation a thing of the past?

3) My local electronics dealer (Allied Electronics) only sells this wire in 100' reels. I would like to get several colors, but that will windup costing me a fortune. Any suggestions for a 'kit' of small reels, rated at 1000V? Or should I bit the bullet and get a couple colors from Allied?

Thanks!

[sluckey]

Click the link below this message for all the wire you need. Sold by the foot.

[shooter]

Ah! I have a Phantom 3 Pro

not there, yet
I just have 2 Hubsan 501SS, FPV, way more fun breaking a $150 drone than a $2,000 one 
hopefully will be flying the P 4 pro + advantage(?) soon.  having a fixed, low-quality camera is cheezy, except it really works well to get "the sense of flight" using FPV


OK, wire;
Sluckey pointed you to where
my personal preference is 22-24 GA Teflon stranded for everything but filaments, and inputs.
filaments I like solid core ~18 ga, in's I typically use RG174 but you gotta have GOOD solder chops so you don't melt the center coating into the shield


some use cloth wire, I've used it, I find it best to put shrink tube at both ends for an "aesthetic" look, but that's extra steps so I quit using it

[txtune]

not there, yet
I just have 2 Hubsan 501SS, FPV, way more fun breaking a $150 drone than a $2,000 one 
hopefully will be flying the P 4 pro + advantage(?) soon.  having a fixed, low-quality camera is cheezy, except it really works well to get "the sense of flight" using FPV

The phantom has been extremely 'forgiving'. I have crashed it twice at the deer lease, one was more of a crash landing... the other one was full on, full speed, drone-meets-tree. If there was a tiny crew on board, they would have walked away both times. I replaced the props and back up she went. I have video if you care to yell at your screen and laugh all at the same time. Perhaps I can send that through a PM.

I have not flown in awhile, I need to brush up on the current rules and regs.

OK, wire;
Sluckey pointed you to where
my personal preference is 22-24 GA Teflon stranded for everything but filaments, and inputs.
filaments I like solid core ~18 ga, in's I typically use RG174 but you gotta have GOOD solder chops so you don't melt the center coating into the shield


some use cloth wire, I've used it, I find it best to put shrink tube at both ends for an "aesthetic" look, but that's extra steps so I quit using it

I have zero solder chops. I bought a decent solder station yesterday, which made me feel like the person buying a good guitar with no idea how to play it. With that being said, can I use 22GA Teflon on everything?? Or should I use 18GA on the ins and filaments, just a different type?

I will give it the old college try before I pack it up and mail it to you. j/k I will order some wire now, the restoration kit won't be here until mid-week next week.

I added a PEM to the 'back' of the frame. I will put the breaker (for now) and the on/off switch in as soon as I get time. I bought some a couple of fuse holders with the same panel mount hole diameter as the breaker, so I can put a fuse in the finished product.

[shooter]

 


I have plenty of my own crash vid's!


re-read my post, tells what i use for filaments. inputs, if they are < 6" and not near any strong signals the small wire works fine.


find a broke boombox, start de-soldering stuff, then when it's clean and pretty, solder stuff back, couple hundred times should make you pretty good.
does your station do both suck solder and solder?  If not you need a solder sucker, some solder wick.  DO NOT start with eco-friendly lead-less solder, buy the good stuff. pick up some flux, look for the tube/syringe dispenser fine tip stuff.

[txtune]

find a broke boombox, start de-soldering stuff, then when it's clean and pretty, solder stuff back, couple hundred times should make you pretty good.
does your station do both suck solder and solder?  If not you need a solder sucker, some solder wick.  DO NOT start with eco-friendly lead-less solder, buy the good stuff. pick up some flux, look for the tube/syringe dispenser fine tip stuff.

The solder station is a Weller Includes: WE1 with WEP70 and PH70.

I bought a separate desolder station on amazon, it has a built in vaccum. Should be here today or Monday.

I also ordered some Chemtronics 80-3-10.

[txtune]

I have not given up on this, very busy lately. I hope to work get back to it soon.

[shooter]

 
I haven't deleted the file i started either 

[txtune]

I have the PEM, fuse holder, and on/off switch installed in the frame.

I started to de-solder the connections of wires that I removed already. The de-solder vacuum tool makes easy work of it, I assume much easier than soldering will be. I *think* I can handle soldering to the 'tabs' that have the holes in them. The ones that I removed solder from had the wires through the holes and bent back around the tab, then covered in solder.

With any luck I will be able to solder the PEM, fuse holder, power switch together and get it energized again so we can proceed to the next step.

Thanks again! 

[shooter]

the wires through the holes and bent back around the tab, then covered in solder.

You want a good mechanical bond before you solder, solder isn't a great conductor.  Pay attention to those solder joints you're un-soldering, yours should be that good or better.


spent some time watching YT vid on "basic soldering"
no, i'm not gonna look for any 

[txtune]

Here is my first attempt at soldering. I know it's not pretty, but will it work for now?

[txtune]

More pics.

[shooter]

not bad for 1st timer 


look at the white wire, you can see 2 "hairs" protruding, nbd there, but if it's a tube socket that "could" be enough to touch the next pin with 2 hairs.


the red wire on switch, looks pretty cold, almost like it's glued.  flux will help, also, "pre tinning" the copper by applying solder just to the tab, then clean off excess, add wire and solder.  when you see the solder start to flow, set off the 2 second timer in your head, so; flow, 1 thousand 1, 1 thousand 2, OFF with solder 1st then iron
you'll be ready for NASA soon   

[1blueheron]

In a certain country you might be promoted to sweat shop supervisor by now with work like that

Your doing a nice job on that relic.  You know people pay extra for relic these days   Don't polish it too much.

[txtune]

Ok, I thought you guys/gals were going to give me a lot more crap than that! I will redo the switch solder, then try firing it up.

IF it does not catch fire when I turn it on, what is the next step?

[sluckey]

That green wire just may save your life one day... ***IF*** it has a proper secure connection to chassis. I would use a ring lug on the wire and bolt it to the chassis using a kep nut.

[shooter]

good catch!

Once you fix the ground, I would suggest printing out the schematic I drew and "highlight" each wire you "changed", that should "lead" you to the rectifier tube AC side  (NO power required :) AND it should make sense, if not ask.


You can figure out your RCA's, mount them and use the schematic to figure out what 2 wires will connect to them.   also figure out where to mount a couple caps like I have in the schematic (they might be just for testing, or they may stay), also NO power required 

[txtune]

That green wire just may save your life one day... ***IF*** it has a proper secure connection to chassis. I would use a ring lug on the wire and bolt it to the chassis using a kep nut.

Got it, I will do that tomorrow as well. Thanks!

[txtune]

I repaired the ground issue per sluckey's advice, bolt and keps nut, fired it up and the fuse blew. Turns out I had the new power switch wired incorrectly... I had to get the fancy illuminated one...    I took the switch back out, removed the solder and wire, tested it, and soldered new wire leads on it.

Anyhow, since I am cleaning up my wiring a bit... would it be best practice to land the power supply AC neutral, switch lamp neutral, and power transformer neutral all in one place? That's how I had it and it was not pretty. Just wondering if I should land all three together on an empty terminal strip tab? 

[sluckey]

I just connect everything to the switch. Nice and neat. Look at this pdf...

     http://sluckeyamps.com/dual_lite/dual_lite.pdf

And here's an actual pic...

     http://sluckeyamps.com/dual_lite/big_guts.jpg

[txtune]

I just connect everything to the switch. Nice and neat. Look at this

Wow! That is slick. I really like the 'nice and neat' look. Have you been at this awhile?

I have a long ways to go, hopefully you kind folks have as much patience as I do determination. 

There is a seller on ebay who auctions off one very nice amp every couple of weeks, mostly single ended 45 triode amps with Tamura transformers. One of you may very well know who that person is, or be that person. The overall 'simplicity' of his builds falls into the same category of nice and neat like your work. 

[shooter]

If you want to get good, study Sluckey's page, those are the "standards" you want to shoot for.


There's a member in your state that has produced some great "original works" schematics and amps.
so IF you put in the effort, you can't help but get better.

[txtune]

Interesting. Do you know where in TX that member is located?

[txtune]

good catch!

Once you fix the ground, I would suggest printing out the schematic I drew and "highlight" each wire you "changed", that should "lead" you to the rectifier tube AC side  (NO power required :) AND it should make sense, if not ask.


You can figure out your RCA's, mount them and use the schematic to figure out what 2 wires will connect to them.   also figure out where to mount a couple caps like I have in the schematic (they might be just for testing, or they may stay), also NO power required 

Unfortunately I am at a dead end. I am looking around for other folks who have restored this amp with a 'how to' guide. I will let you know how it goes.

[shooter]

once you have a way to connect an audio source and speakers, the initial testing says it should play, then maybe figure out what it looks like 

[txtune]

once you have a way to connect an audio source and speakers, the initial testing says it should play, then maybe figure out what it looks like 

I got the speaker terminals on, just used some cheap ones for now... I will use some good ones on the final. I planed to connect the RCA today, but realized I did not have all the proper caps and resistors... hence the earlier post. Fingers crossed I will get music to play out of this old amp tomorrow.

[txtune]

once you have a way to connect an audio source and speakers, the initial testing says it should play, then maybe figure out what it looks like 

Finally got around to adding some inputs. As I mentioned in the 'cap' post, I found a blog online where someone (actually two people) were both rebuilding this exact model. The individual writing the blog took possession of the amp with some mods already done, though he plans to do much more. First two pictures are from blog.

I was running out of time this evening and finished up with a only a few minutes to connect it to some speakers. All I got was a constant hum, after the tubes warmed up, so clearly something ain't right. The speakers are tiny little samsung rear surround speakers from who knows where... I hated to plug this into anything nice... but I need to get something better than those. Could it be those speakers are not the right impedance for this amp? Or do you see something obviously wrong with my contraption? I forgot to get good pictures of the speaker hookup, but they are connected just as his are. I plan to use some better ones later, so I did not mount these.

EDIT: I see what I did, man it was a long day.  What are those tabs on the RCA inputs actually for?

[sluckey]

I bet the one with the yellow caps does not work.   

[txtune]

 

I started to delete my post, but decided to let it stand.

What are the little tabs on the RCA inputs actually for?

[sluckey]

They are ground tabs. Your yellow caps should be connected to the center pin on those phono jacks.

[txtune]

Thanks Sluckey. I hope to get down there tomorrow and fix that. Did anything else jump out at you as 'danger' or 'won't work like that?'

[sluckey]

My only concern is that you are completely out of your element with this stuff. Just as I would be under the hood of my 2018 Highlander.

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My only concern is that you are completely out of your element with this stuff. Just as I would be under the hood of my 2018 Highlander.

I cannot argue with that assessment.

[txtune]

Got the inputs connected to the center pins. I went ahead and connected some bookshelf size Klipsch speakers. Music came out!

The AM/FM tuner I am using for input only has line out volume control on the 3.5 headphone out. I found a 3.5 to dual rca and connected that in order to control volume. It is playing audio out of both left and right speakers, but there a loud humming noise coming from both speakers. 

[sluckey]

That's progress.