What equipment do I need to Align FM tuners

Perkinsman

"I've never met a fixer that I couldn't break"
I'm a student of tube audio repair and would like to also learn how to properly align tube fm tuners but I don't have a clue how where to start. What special tools and equipment do i need? A signal generator or function generator? How many Hz does the generator need to go to?
 
FM mono, or FM stereo? Stereo needs extra stuff.

You need an oscilloscope to do it the preferred way, and a sweep generator to sweep the IF strip for proper response. Something like a Sencore SG-165 would do it for you if its in working order, and you have a scope to pair with it. Failing that, there is the old way using a fixed frequency signal generator and a voltmeter to set things up. That doesn't work so well, and really isn't recommended if you want reasonable stereo.

I just recently got a decent signal generator myself, so I haven't gotten any practice with doing it the non-crap way. I have used fixed frequency generators and a VTVM to do the job. It works, but not ideal by any stretch.
 
Also, higher end tube tuners need more advanced test equipment to do properly. Especially in Stereo. Mono tuners except for advanced stuff like the REL Precedent and the early McIntosh to MR 71, the Fisher, HH Scott, and similar will need much better than TV shop generators to do. If you do those, and similar, the Sound Technology is good to own.
 
which is sort of amusing if you consider the gear those were probably aligned with originally. Much of it was pretty awful though. I have a sweep generator from the late 1950s. Its useless unless I just need a heavy object to prop open a door or something though.
 
IMO the minimum requirement is a Sencore SG-165 and a quality oscilloscope. Always follow the equipment manufacture's alignment procedures.
 
Some of the Macs required a distortion analyzer, and the HP 330B being the suggested one.

The scope the MAC 1500 requires is laughable.
 
Collect the alignment procedures for the things you think you might need to align. Read down the list and ask yourself what signal generator (and other stuff) you'll need for each instruction. Almost any scope will work. You may find that alignment procedures contain errors or omissions, assume various bits of knowledge that you may not have, and may not be the best way to do the job. That was then and this is now. Figure 0.5-2 years of aligning junkers (depends on how often you can do it) before you have enough knowledge and confidence to tackle the better units.
 
Unless you have a lot of coin, time and knowledge you are better off paying someone to do it for you.
 
I appreciate the responses here and I think reading thru a few of the alignment procedures (are they on the schematics?) is a great idea to determine what equipment is needed. I do have an oscilloscope, what about an RF generator, I'm looking at an old but recently upgraded and calibrated Triplett.
 
I'm a student of tube audio repair and would like to also learn how to properly align tube fm tuners but I don't have a clue how where to start. What special tools and equipment do i need? A signal generator or function generator? How many Hz does the generator need to go to?
Join here https://groups.yahoo.com/neo/groups/FMtuners/info and ask. Some very knowledgeable FM folks hang out on this group and are more than happy to help. You might even find some inexpensive spare test gear to help you along. Any number of the members are FM engineers of various ilk and some serious hobbiests as well.
 
How stable is the Triplett? I've had a number of oldies and they just floated so horribly as to make them almost useless. If its not a sweep generator, I'd probably pass in favor of one.
 
Hello

This is a black art that few can do at all, much less very well. You don't know what you ask! I belong to a radio club with 125 retired guys who have been doing this for decades and only know of 1 who can align FM properly(and he doesn't like to do it). I hope you can figure it out! Inner Sound in Portland does a good job at alignment for about $85.
 
I was going to say that nothing really old is suited to the task, but then it occurred to me that the Sencore 165 and ST 1000A are really a bit elderly. It really comes down to those two, the couple that Leader made and the higher end lesser known units from Kikusui, Panasonic, Kenwood & Meguro. eBay will usually turn up something, but it may take some waiting to get what you want at a price you can afford. There are also some potentially good units, but no available documentation. IMO, equipment without docs and the ability to service it isn't worth much.

They all have different features. I use an HP8640B for general purpose modulated signals, and a Leader SG-231 for lower distortion stereo signals, with a Sencore as backup.
 
I use these (there's significantly more, but these are the heavy hitters):

Leader 3216
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HP 8903A
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Tektronix DSA 602A w/ appropriate plug-ins
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I put that up so you can begin to count the cost, before you begin to build the tower. You are going to have to come big, or stay home.

Asking what you need reveals you don't have the most essential ingredient: "product-specific" knowledge and understanding. This stuff requires it, more than most other types of gear. There are tricks to the trade, and specific tools for specific tasks and stages. DIY? Not likely. Serious? Then go for it, but do so with your eyes open. It is not magic, but it does require a bit more knowledge. Conrad is right...alot of the job comes only with experience, and lots of it. RF guys use the term, "______ magic" alot. You'll find out why.

Before spending the green on gear, acquire and absorb the following text: Clarence R. Green & Robert M. Bourque, "Troubleshooting, Servicing and Theory of AM, FM, & FM Stereo Recievers, 2nd Edition" (Prentice-Hall, Inc., 1987), ISBN 0-13-931114-9 025
http://www.amazon.com/Troubleshooti...g+and+Theory+of+AM,+FM,+&+FM+Stereo+Recievers The text is as vintage as the gear, but you won't find better.

Good luck,
Rich P
 
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Wonderful gear, but the bar doesn't need to be that high. Most of the tuners we need to align are limited in the precision of their adjustments. Certainly there are some TOTL tuners where something like an ST1000A is inadequate, but I'd never discourage somebody from learning how to do this because they couldn't acquire TOTL test gear. IMO, you also have to start somewhere, with something, to begin learning at all.
 
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Wonderful gear, but the bar doesn't need to be that high. Most of the tuners we need to align are limited in the precision of their adjustments. Certainly there are some TOTL tuners where something like an ST1000A is inadequate, but I'd never discourage somebody from learning how to do this because they couldn't acquire TOTL test gear. IMO, you also have to start somewhere, with something, to begin learning at all.
My post was not intended to discourage, but to apprise. The gear shown was to reveal that you need more than a screwdriver & desire. You need a good AM/FM/Stereo signal generator, distortion analyzer & a GOOD scope. You just do. For RF work, your stuff should be calibratible & at least reasonably calibrated.

My real recomendation was the book. It includes info on tubed gear, as well as sollid state. ST test gear is a bit long in the tooth and likely in need of restoration and calibration itself, before it can be used to align tuners. I know. I have an ST-1700B in my gear complement. They made good stuff, but there are alot of switch contacts to clean up, and solder joints to refresh, etc. Again, your gear should be at least reasonably calibrated.

It would be unfortunate to start buying alot of gear and to get stuck in the RF mud. As you know, there is more to know, and to be careful and aware of, when dealing with RF, especially with that which is to produce hi-fi output. Regardless of what gear you choose, you will need to spend significant green. When I started doing tuners, my test gear complement more than doubled, over what was needed for amps & tape decks.

Buy and absorb the book. You won't be sorry. THEN, start buying test gear. Come on in. The water is fine. But do it with your eyes OPEN. A split tuning slug would be pretty hard to find, as a culprit, without the knowledge you'll get from the book. You could very easily split one yourself, or someone could have split it for you. Ham-hands are quite common out here in the field. You can get the book much cheaper than the link I posted, if you are patient. I just wanted you to see what it looked like, and read some reviews. Your most necessary and affordable piece of test gear is between your ears. If that is tuned up sufficiently, many useful test signals are being broadcast over the airwaves for free.

Good luck,
Rich P
 
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Don't forget, you need to use plastic or ceramic tools when adjust the slugs of a tuner, as metal ones will throw the measurements off.
 
This question comes up frequently, and I used to try to answer, to no avail.

The bottom line is, if you're asking how to do it, you're probably not ready. Sincerely, there are very, very few tasks as complex as properly aligning a stereo FM MPX tuner circuit.

Here's my suggestion: Start by learning how to align an AM radio. If you can understand what you're doing, meaning you're not simply following a checklist, but you actually understand how AM receiver circuits and their block diagram functionality works, then you're ready to tackle FM.

Mono FM. The MPX Stereo comes last.
 
Hey, and don't forget a good frequency counter! IMO, the best candidate to learn this is somebody who already has all the basic equipment for other service on their bench. That would be the scope, counter, THD analyzer and meters and such. Only at that point does it make sense to start collecting the RF and stereo signal generators. At that point it's not such a big leap. I'd also suggest starting with the simpler ceramic filter tuners, rather than an IF system with six or so slugs to adjust. Fortunately, that's nearly all the mid-range solid state stuff except Sansui and a few others.
 
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