Need some help/advice

Go down

Need some help/advice

Post by frank1956 on Thu Nov 06, 2014 12:20 pm

I figured while I had some down time while waiting on my volume control for the Crosley, I would try my hand at IF transformer re-built. Rule #1 take your time, I overlooked this rule as I was use to the inner of the IF transformer being incased. Not so with this one. Before I knew it all of the wires had broken off, except one it eventually gave way. I was luck (I guess) enough to have seen were this one wire went to. I have attached picture. Is there any way to make sure the wires go back in the same place once this mistake was made????








Frank
avatar
frank1956
Member
Member

Number of posts : 410
Registration date : 2014-06-12

Back to top Go down

Re: Need some help/advice

Post by Wildcat445 on Thu Nov 06, 2014 12:26 pm

I have had the worst results imaginable trying to repair SMD. I wish you all the luck in the world with your efforts, but somebody besides me will have to chime in to help you.

WC

Wildcat445
Member
Member

Number of posts : 5164
Registration date : 2011-09-19

Back to top Go down

Re: Need some help/advice

Post by willy3486 on Thu Nov 06, 2014 3:56 pm

If you know one was connected to a certain terminal then look at the diagram and see where the other coil wire connects to. connect it to the lead you think it goes to and then ohm it out. That way you know its soldered to the lead.  

There is a site out there a fellow made that escapes me. Its a great site and the web page has green in its background. The fellow died or something and folks are trying to get the info saved before it goes down. It has a really good pictorial on how to do this. Usually I do as it said and just remove the mica from the caps and add new fixed value caps.

I am like wildcat, I hate to do this, too much can go wrong. But I have done it. I mostly work on mine and unless I will use it all the time and its really bad or if it can't be listened too because it sounds like a constant barrage of lightning I leave it. I hear some talk about almost every one they redo has it but for me I don't often see it. And I have restored 50 to 100 in the last couple of years. Maybe 2 had it bad enough to fix.

willy3486
Member
Member

Number of posts : 1424
Registration date : 2011-07-02

Back to top Go down

Re: Need some help/advice

Post by 75X11 on Thu Nov 06, 2014 4:14 pm

I can offer you help in wire prep to get things reconnected, but can't offhand say where the wires will go. You will have to get a good magnifier, possibly a visor type, a good light to work with, some decent forceps a good razor (x-acto) knife and a assortment pack of automotive sandpaper.
avatar
75X11
Member
Member

Number of posts : 4894
Age : 61
Registration date : 2013-03-10

Back to top Go down

Re: Need some help/advice

Post by 75X11 on Thu Nov 06, 2014 4:15 pm

And some rosin flux.
avatar
75X11
Member
Member

Number of posts : 4894
Age : 61
Registration date : 2013-03-10

Back to top Go down

Re: Need some help/advice

Post by frank1956 on Thu Nov 06, 2014 4:26 pm

Ok. So this is not just remove the old mica cap, replace with a new one. Solder wires back to terminal and life is good?

This is a junker IF Transformer I picked up, so I could see if I could do one, so there is no diagram
avatar
frank1956
Member
Member

Number of posts : 410
Registration date : 2014-06-12

Back to top Go down

Re: Need some help/advice

Post by 75X11 on Thu Nov 06, 2014 4:35 pm

It should be, if there are only 2 leads coming from each of the coils and 2 terminals on each side of the base. You meed to know how the cap was incorporated into the circuit to know how to wire your replacements. The tricky part is that you need to know how each coil was oriented to each other. Do the wires come only out one end of each bobbin, ot do they come out the top and bottom? Then you need to know which wire went to each terminal.
avatar
75X11
Member
Member

Number of posts : 4894
Age : 61
Registration date : 2013-03-10

Back to top Go down

Re: Need some help/advice

Post by frank1956 on Thu Nov 06, 2014 4:47 pm

I have four wires, 1 long 1 short from the top and 1 long 1 short from the bottom. I know where only one went prior to it breaking off, so I assume the one next to it go the terminal next to it???

Frank
avatar
frank1956
Member
Member

Number of posts : 410
Registration date : 2014-06-12

Back to top Go down

Re: Need some help/advice

Post by 75X11 on Thu Nov 06, 2014 5:26 pm

Okay, each coil on the form is called a bobbin. Each are wound in a specific direction with a specific number of turns. They must be wired so that each bobbin is oriented the same. It must be this way for the transfer of the full signal from one bobbin to the other. It would be difficult for me to say even which terminal is the other in the pair. One way to tell would to find any terminal numbers on the base and find a schematic reference to the numbers. That would give you the proper layout.
avatar
75X11
Member
Member

Number of posts : 4894
Age : 61
Registration date : 2013-03-10

Back to top Go down

Re: Need some help/advice

Post by 75X11 on Thu Nov 06, 2014 5:29 pm

Be patient with me. I am also trying to work my job while responding.
avatar
75X11
Member
Member

Number of posts : 4894
Age : 61
Registration date : 2013-03-10

Back to top Go down

Re: Need some help/advice

Post by 75X11 on Thu Nov 06, 2014 10:45 pm

The reason I responded with the basics was so you would be able to understand how the transformer functioned and so you would know what to look for in setting up the connections. Not to aggravate you. If I did, I didn't mean to.
avatar
75X11
Member
Member

Number of posts : 4894
Age : 61
Registration date : 2013-03-10

Back to top Go down

Re: Need some help/advice

Post by frank1956 on Fri Nov 07, 2014 12:09 am

Oh no problem. There was no terminal number on the base, so I guess finding a schematic for that might be hard.

Frank
avatar
frank1956
Member
Member

Number of posts : 410
Registration date : 2014-06-12

Back to top Go down

Re: Need some help/advice

Post by 75X11 on Fri Nov 07, 2014 12:15 am

Is there a wire coming out the top and bottom of each bobbin?
avatar
75X11
Member
Member

Number of posts : 4894
Age : 61
Registration date : 2013-03-10

Back to top Go down

Re: Need some help/advice

Post by frank1956 on Fri Nov 07, 2014 10:24 am

Yes
avatar
frank1956
Member
Member

Number of posts : 410
Registration date : 2014-06-12

Back to top Go down

Re: Need some help/advice

Post by 75X11 on Fri Nov 07, 2014 1:39 pm

Okay, find a schematic diagram of a transformer and imagine instead of the two coils (bobbins) side by side, they are one above the other as you have on the form. re- connect it so the two upper leads are connected in the manner shown. the same level and opposite sides. and the lowers in the same manner. You don't want to reverse the leads on either side, or it will change the amount of transfer between the two bobbins.. Dr. radio or WC will have to advise you on how to connect the replacement capacitors in the can. Don't remove the capacitor assembly in the base of your transformer yet. they may want to see how it is set up. It is difficult to get the lacquer coating off the wire leads. I would advise using a piece of automotive sandpaper of maybe 600 grit to remove it for tinning and soldering.
avatar
75X11
Member
Member

Number of posts : 4894
Age : 61
Registration date : 2013-03-10

Back to top Go down

Re: Need some help/advice

Post by Sponsored content


Sponsored content


Back to top Go down

Back to top

- Similar topics

 
Permissions in this forum:
You cannot reply to topics in this forum