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Tools for alignment

Rule 1, learn on a basic FM radio before you go higher end. And with high end tuners there is certain alignment gear you're expected to own (meaning at least a Sound Technology FM generator in good recent calibration) for starters.
 
fortycoats said:
Regarding tuner alignment, why is it such a black art that nobody is willing to reveal??? Never mind warnings of us students potentially ruining our tuners -- that's our problem. People just don't seem to want to explain it, the information doesn't seem (to me) to be available on the 'net and it seems to me this "art" is going disappear unrecorded into history and be taken to the grave with the seemingly few who know about it.
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The info is out there, in spades, in the archives of the Yahoo FM tuner group. You can download free software to read the archives.
You can take 2 approaches - try to do it cookbook, following the service manual, and have no idea what you are doing. Or try to understand how a tuner works, what the adjustments are doing, and do it that way. To really be successful, you need to do it the 2nd way. If you try to do it cookbook, you can get lost, which is not so bad, because then you may start learning if you persist.
Bob
 
You need to understand how the tuner works, what each adjustment does, and how to perform it correctly. I would start with some simple radios which don't have to be aligned with really precision test equipment or kit tuners which explain alignment concepts well. Bob's points are very good ones. You need to know when to use your tools, when you should not. Even with me knowing my way through many FM stages, I know to not touch some exotic tuners (Meaning don't tinker with the front end on my Marantz 10b at work or my REL Precedent). On those, replacing caps, resistors, and weak tubes are the main things I do for servicing. I know when to align one, when to farm out one.
 
Raccoon1400 said:
For a scope, what brands are good? Some of the ones I see for sale don't have probes. I have a set of probes, but I've heard it can cause problems if they have the wrong ratings. I have no ratings for mine. Does this matter?


Currently looking at this scope. Its a couple hours drive though.
http://montreal.kijiji.ca/c-buy-and...ateur-de-fonction-a-vendre-W0QQAdIdZ291380055
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Tektronix is your best bet for a scope. the 2215 is a nice basic scope that will work for alignment and most trouble shooting. It is useful to have a scope with minimum 100MHz bandwidth so you can troubleshoot problems in the front end rf stages. The 2215 has a bandwidth of 60MHz. That will work for troubleshooting audio and the IF stages, but not the front end of the tuner. However, you can get or make an rf probe, cheaply, that will allow you to probe rf signals at FM broadcast frequencies with a 60MHz scope, by "demodulating" the signal.
 
I got a scope and function generator today. Tektronix 2215A 60MHz scope, HP 3311A function generator. It also came with a bunch of random useful cables and adapters, a 5V ac power supply, and a decent size prototyping board. The scope and function generator were calibrated in 2007. I got it all for $240.

What is a reasonable price for the sencore?
 
Last one sold for over $400 but that's a major aberration. Usually more like $100-$200 max. There's one sitting at $41 as we speak.

John
 
jdurbin1 said:
Last one sold for over $400 but that's a major aberration. Usually more like $100-$200 max. There's one sitting at $41 as we speak.

John
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I saw that. In the add he said it didnt light up and assumed it didnt power up. Guess that could just be light bulbs.
 
Scratching my head but I think they just have a single red power light, don't remember the meters being illuminated though it's been a long time since I had mine out. So, one lamp could be out... or it could be a basket case.

Still trying to figure out why that other one blew up so high, it really didn't have anything special going for it. At one point not too long ago, that kind of money would have bought at least a couple of ST1000A's.



John
 
My thanks to all, for the good questions and good answers. I have 4 Sansuis and a simple Pioneer and all but one are "on the workbench". I would also really like to learn something about FM alignment procedures, and know that the first step is to understand the circuitry and the theory.

I was fortunate enough to find a good TEK 468 scope (and probes) last winter, and have no shortage of multimeters and a good Fluke 8050A. So at least the basics are covered. Now I can focus on the circuits, then the test equipment.

Will certainly appreciate hearing about any of your preferred/favorite reference material, or I will just rely on Google.

Thanks for taking the time to pass on some of your knowledge - - -

.
 
Hey, if anyone is looking for a 2235 Textronix scope 100MHZ (no probes) and a Sencore SG165 (no cables) I know a guy here in KC that has both up for sale on CL. PM me for the details.

I bought his other SG165 without cables and tested the some of the circuits with the frequency counter, most of the settings were fairly accurate, it will need a calibration though.

Would anyone here happen to have a copy of the manual for a Tektronix CMC250 frequency counter out there?
 
I've always been curious about this... why FM tuner alignment is a "black art", as Punker X said. Have circuit designs changed a lot in recent years, whereby alignments either aren't necessary (entirely different architecture that doesn't need it, auto self-adjust mechanisms, etc), leaving the older gear requiring the deeper skills for achieving a proper alignment? And because that gear is vintage, there are far less knowledgeable people around to do it? Is more recent gear susceptible to going out of alignment?
 
Newer gear, if properly aligned at the factory (not always the case) should not need attention for many years. Vintage gear, due to component aging and value drift, often needs not only an alignment but new caps, voltages set, etc. Alignment not only takes special test gear beyond what most techs have, it is an iterative process. Set one voltage and the others go wonky. Takes a great deal of patience and experience to get a 'feel' for what is actually going on. More than one of the better techs here on AK will not work on tuners and sends them along to those that will when required. We are fortunate to have several of the 'known good' tuner techs (Punker X, dr*audio, Terry DeWick, Mark Wilson, Ken ********, etc.) contributing here. Some of the adjustments that are available on vintage tuners are only available on the very best of current tuners (Accuphase, etc.). The use of IC based chipsets for the majority of 'mass market' radios have removed the 'tuneability' of the circuits involved. Generally to the overall detriment of the tuner performance and sonics. Thus, Punker X gets to design and supply mods to the little Sony HD radio, etc.
 
Well, I said that I thought it was a secretive black art and most of the responses have only supported that theory. Really, some steps please! (We are all) asking for advice here, not 'you-pleb' dismissals.

I have the manuals for my tuners and it all seems pretty clear so what about them can be so difficult, assuming the right equipment?

"Try it yourself and see", I can hear you say but would there be so many thousands of FM tuners on the market if they were so difficult to calibrate? FM wouldn't ever have even got off the ground in that case, surely...?

There must be thousands of techs, both from factories and repair shops, who have the know-how and surely now, more than ever, is the time to share it.

As I and others have said, or implied: it's my tuner so no need for you to be worried if I break it!
 
What else do you need to start?

fortycoats said:
Well, I said that I thought it was a secretive black art and most of the responses have only supported that theory. Really, some steps please! (We are all) asking for advice here, not 'you-pleb' dismissals.

I have the manuals for my tuners and it all seems pretty clear so what about them can be so difficult, assuming the right equipment?

"Try it yourself and see", I can hear you say but would there be so many thousands of FM tuners on the market if they were so difficult to calibrate? FM wouldn't ever have even got off the ground in that case, surely...?

There must be thousands of techs, both from factories and repair shops, who have the know-how and surely now, more than ever, is the time to share it.

As I and others have said, or implied: it's my tuner so no need for you to be worried if I break it!
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Nobody is dismissing you.
And Raccon1400 has been asking specific questions and getting answers.

You say you have the service manual and it looks straight forward.

I am not a tech but the Service Manual is what I have gone by.
Without having anyone hold my hand with steps.
And each tuner can have different schematics and adjustments so it can be a lot of work to write a tutorial for you.
Some things you really have to experience to learn.
There are some steps that I won't attempt like the multiplex sections because of lack of proper equipment.

As I said, the basic steps are in the Service Manual. I said that back on 6/17 that you had enough to proceed as long as you knew the cautions.

You say the service manuals seem pretty clear.

Now the only showstopper is you.
Try it and see.

IGNORE THIS IF YOU REFUSE TO LISTEN TO ANY MORE CAUTIONS: It seems clear Punker X and others have been quite straightforward about what is needed and what the cautions are. Adjustments take finesse and may require repeating. Some of the hex cores are fragile and can crumble easily. And it is important to interpret how the circuits react to your adjustments. Easy does it and patience is the rule, if you over adjust you may have a hell of a time recovering where you were. You may not like to hear that but it is worth repeating.
 
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Or, as one of our 'known-good' (there are many pretenders) tuner techs told me when he went through my Sony STR-6200F with the factory service manual at hand, "they missed an entire set of adjustments". Without his experience and knowledge of electronics it could have been a real problem. Not that you can't get there, but it won't happen over-night.
 
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I wouldn't call Tuner alignment a "Black Art". It definitely is made more straightforward by experience though. AM is kink of a a peak this, peak that kind of a thing, where FM is kind of peka this, minimise distortion here, null this, peak that kind of a thing. FM is more of a complex system. The more background you know, and the more you've diddled adjustments, the less Black the "art" is.
 
fortycoats said:
Well, I said that I thought it was a secretive black art and most of the responses have only supported that theory. Really, some steps please! (We are all) asking for advice here, not 'you-pleb' dismissals.

I have the manuals for my tuners and it all seems pretty clear so what about them can be so difficult, assuming the right equipment?

"Try it yourself and see", I can hear you say but would there be so many thousands of FM tuners on the market if they were so difficult to calibrate? FM wouldn't ever have even got off the ground in that case, surely...?
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Black art? Is that what you call learning an advanced skill that can take years of study and practice to develop?
You need to understand test equipment first - what to buy, how to set it up, and check it's rough calibration to make sure it's working OK. Then understand the right probes or impedance match circuits to use. Understand how to convert and use RF levels given in manuals - the manual may say dBu, and your RF Generator says mV - you need to figure out how to convert across the 50ohm to 75 ohm matching circuit.
Then learn what all the adjustment points look like - Those loose "screws" on top of the tuning gang should NOT all be tightened :-)
You need to be able to read a schematic, and perform troubleshooting, so you can tell the difference, when needed, between an alignment problem and a broken tuner.
Next, understand what type of tuner you are trying to align, (tube, analog SS, or digital PLL varicap) as they are all a little different.
Expect someone can put years of experience like this into a post?
Do you also thing someone could tell you how to be an expert car mechanic, or electrician, or plumber in a few paragraphs as well?

If you limit the discussion to one specific tuner, we all can see/share the online manual, and you tell us all the test gear you have, and what you've done so far, post pics, and where you have a specific question, that can be done.

Bob
 
To the OP, you've just heard from one of the top FM tuner 'known-good' tech/FM designers out there. Print it out and post it on your wall and get to work. Every time you become discouraged, read it and get back to work. No free lunch.
 
Just won a sencore on ebay. $105 plus shipping. With cables, from a retired tech. Looked like the best deal I'd see any time soon.
 
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Saw that, looks like a good score... much better than whoever just popped for one at over $300!

Don't post the link though, you'll get this thread bounced to Dollars & Sense.

Once you get it and have a chance to play with it, post back with questions for a specific tuner or receiver project and I am sure you'll get some good input. A number of people around here know the SG-165 even if we've moved on to other devices.

John
 
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