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Tuner alignment gear question, for Pioneer Tuners

merlynski

merlynski

Curmudgeon Electronicist
Question for those of you who do Pioneer FM tuner alignments. What equipment do you use? Is it modern gear, or vintage? If you can/will, quote what you paid for it and when. Did you repair the test equipment before you used it?
How often or how many have you done?
I am thinking about doing this myself, as I have at least four that I can do, three in Receivers (SX-1050, SX-780, SX-650) and one stand alone Pioneer Tuner I cannot remember the model, just now. I will have to acquire the test equipment. (I have a scope).
Thanks for your input!
 
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Here's what I do for a simple alignment using no additional equipment.
  • For frequency reference in setting dial tracking I just use known stations at each end of the dial.
  • I peak the RF coils and RF trimmers using the receiver's signal strength meter.
  • The IF transformers seldom need adjustment, but you could use the signal strength meter for those too.
  • I have adjusted the 19 kHz stereo circuit by tuning to a weaker station known to be broadcasting in stereo and adjusting so the stereo light turns on when the station is tuned in exactly.
  • I don't touch the discriminator primary and secondary.
I almost never see any improvement except for dial tracking. ( As an aside: I have a lowly Kenwood KT-5500 tuner that tracks absolutely perfectly across the full dial, AM and FM. Better than some much more expensive analog tuners I have. )
 
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adowns said:
Here's what I do for a simple alignment using no additional equipment.
  • For frequency reference in setting dial tracking I just use known stations at each end of the dial.
  • I peak the RF coils and RF trimmers using the receiver's signal strength meter.
  • The IF transformers seldom need adjustment, but you could use the signal strength meter for those too.
  • I have adjusted the 19 kHz stereo circuit by tuning to a weaker station known to be broadcasting in stereo and adjusting so the stereo light turns on when the station is tuned in exactly.
  • I don't touch the discriminator primary and secondary.
I almost never see any improvement except for dial tracking. ( As an aside: I have a lowly Kenwood KT-5500 tuner that tracks absolutely perfectly across the full dial, AM and FM. Better than some much more expensive analog tuners I have. )
Click to expand...

Thank you for your response, I am looking to (possibly) acquire the equipment to do the alignment with measurable results. Where I live there are no strong FM stations to use for a reference. I live in a low spot, with higher ground all around, especially between me and the cities with FM transmitters. It takes an outdoor antenna to receive FM. My OCD Perfectionist nature says I must do it correctly. It is probably going to take a very well adjusted tuner to get a stereo signal with any separation. I have to turn the Mute off to hear any FM.
 
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As long as you know which station you are using to set the dial tracking you can take its frequency to be exact. The FCC requires them to be extremely accurate in their frequency, more accurate than most signal generators you could use for alignment.

If the received station will move the signal strength meter at all then it's strong enough to peak your RF adjustments using the receiver's signal strength meter. In fact, instructions for alignment usually say to use as weak a signal as possible.

If you want to make the IF frequency exact, then almost any signal generator is ok. IF frequencies are usually 455 kHz for AM and 10.7 MHz for FM. More modern tuners now use ceramic or crystal filters instead of adjustable IF transformers so there may be no adjustment here to make.

To adjust the discriminator and the stereo detector final part of the FM circuit you would need a sweep generator and oscilloscope or I think there are stereo signal generators on eBay for big $.

That's about the extent of my knowledge. I'm just an electronics hobbyist, not a technician. Perhaps a real expert will chime in.
 
For general purposes, something like a "lowly" Sencore SG165 will work. It may not be as elegant and digitally precise as some other options, but if set up correctly it can be just as effective. The output of the SG165 can fall off at higher frequencies, but that's the nature of RF anyway. It's still sufficient. I also always check the accuracy of the vernier output indication with a 'scope to make sure the frequencies are right where I want them. I had to trade about half a dozen portraits of U.S. Grant for that one. I rarely use it for power testing, but it CAN do that as well, to a point. It also has a somewhat crude but effective IF marker generator and rocker for setting up adjustable IF transformers/sections if you're in an older receiver. I still use the SG165 on occasion.

I later picked up a Panasonic VP-8121 as a more precise generator. It cost quite a bit more, even though it was a "bargain" compared to similar types, and it also needed attention (low RF output). It was a rack-type unit and I needed to convert it to a bench style, bringing all the BNCs out to the front. That added some time and material, but made it a less expensive alternate to a fully functional out-of-the-box bench unit that likely would have cost three times as much or more. It is not as intuitive as the analog controls of the Sencore, but is easy enough to learn and understand. It also offers a lot more control over the outputs' frequencies and levels, as well as input options. That's usually the go-to unit for tougher work, like something that somehow got whacked completely out, like after replacing critical components or getting a unit where someone had diddled with adjustment haphazardly.

I later found another SG165 and went through repair and update of that, and off-loaded that to another AK member who expressed a desire to get into the RF end of receivers. It was an "as-is" unit and as was expected, it also needed the common repairs, alignment, and TLC.

Both types appear in auctions and surplus sales occasionally.
 
As an alternate for simply setting up the RF sections, it is possible to use a low-power FM transmitter fed by an external source for tracking and span adjustment of an RF section, and also for limmited adjustment of a discriminator. The RF output level can be adjusted in steps on some of those units (down to 100mW), and careful positioning of the transmitting antenna and isolation from the receiver can make it work. Such a device can be set up well away from the workbench and fed by either an AF generator or PC with a sound card and playing an audio (wav) file in a loop. The audio file(s) can be set up to alternate channels left and right, and the level can be set roughly via volume control.

Before having any sort of FM generator I tweaked in quite a few receivers that way. some of which I have gone back and checked with a "real" generator and needed to make no adjustment. The first "fine China" transmitter I used was a CZH-5C, and variants of that are still available brand new. The up-side of that is that I can also short-range transmit FM all over the house with whatever programing I decide to feed into it. Well, it goes a little farther than that, but we don't need to wake up Friendly Cousin Charlie.
 
This question was asked recently on the tuner section, Bob who is a test equipment expert answered it very well.
For me I own a HP 8656B, 11715A, 8904A. I had to service the 8656 as it had dead AM modulation not like I use AM but I fixed it anyways
I saw a St 1000a on eBay for sale, if you can get one of these for a decent $ you should be happy.
If you plan to do detector linearity then you need to measure or display the recovered signal to minimize the harmonics
It been a while, iirc the 8656 was around 300, 11715 was a 100 but it was with no chassis, 8904 ~$200?
For the few units you have to do have to wonder if the investment is worth it or not.
 
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rcs16 said:
...For the few units you have to do have to wonder if the investment is worth it or not.
Click to expand...

I pondered that as well, especially since the units listed are all IC and ceramic filter. That's the reason for posting up the "alternate" method of peaking the front end and decoder with a simple local transmitter.
 
I always use broadcast stations for oscillator and antenna trimmer peaking. Accuracy is way better than anything I own. I do that on AM and shortwave too whenever possible for the same reason.
 
I am basically in the same ROI boat, as you, so as Bob suggested, the ST1000A or the Panasonic VP's unless you go with my choices.
 
rcs16 said:
This question was asked recently on the tuner section, Bob who is a test equipment expert answered it very well.
For me I own a HP 8656B, 11715A, 8904A. I had to service the 8656 as it had dead AM modulation not like I use AM but I fixed it anyways
I saw a St 1000a on eBay for sale, if you can get one of these for a decent $ you should be happy.
If you plan to do detector linearity then you need to measure or display the recovered signal to minimize the harmonics
It been a while, iirc the 8656 was around 300, 11715 was a 100 but it was with no chassis, 8904 ~$200?
For the few units you have to do have to wonder if the investment is worth it or not.
Click to expand...
Pardon the length of this message but I am just getting back into electronics after 40 years and have a lot of questions, so be patient with me, I am really excited to have found this forum and everyone in it.

I am setting up my lab for this great hobby, now that I am retired and have the time. Purchased the HP8657A, HP8904A based on a lot of reading in this forum. I am trying to learn what I would like to have and have made acquisitions as opportunities and budget have allowed. I have not seen any information about the HP 11715A, which appears to be an attenuator. Any information or instruction would be helpful. My current focus has been on how to use the HP8904A with the HP8657A, I did get the newer version with the stereo options in the menu.

I just got a non-functioning SX-780 from a friend who put it away in his closet several years ago (working at that time) but when he pulled it out a few weeks ago and turned it on the lights came on, but no sound. It will be my first project and I am still working on getting my dim bulb set up (in California the sale of incandescent is not allowed), my brother lives in Texas and will be getting some 100 and 200 watt incandescent for me. I plan to wait and study until I get the dim bulb up and running before plugging it in. It is in mint condition, I opened it up and everything seems original, so I am very excited.

When I read the manual on FM tuner adjustment's it really scared me since they do adjustments at 90Mhz by "spreading the plates" with some kind of spatula (Part GGK-066). Hopefully I won't need to adjust this part, but what is that tool, I have not been able to find any pictures or information about it.
 
That tool is long since obsolete. It is essentially a flat-bladed stick made of an insulating material. I've used a generic trimmer tool which is often found in TV alignment tool sets. They were long, flat, and insulator to permit adjustment of the focus on CRT flyback transformers - Something you wouldn't want to get anywhere near with a conductive tool. Look at the Aven 13502A tool or GC/Waldom 2520 tool and that will give you a visual.

Adjusting the tuner VC plate spread is not at all a fun job. It is ONLY necessary if the linearity of the tuner is not reasonably close. Usually that problem is solves if the VC gets properly cleaned and lubricated. In those rare remaining cases where the linearity needs adjustment, bending the plates is the only way since there are no trimmer cores in the transformers for low-end adjustment. The upper end of the scale is still adjustable sicne the trimmer caps are present, but that tends to push or pull the lower end out as well. I've found that it isn't just bending the plates in one position, but having a varying gap at different points of engagement may be necessary to really get it indicating correctly.

Frankly, it sucks. I hope that you will be able to get it correct by simply cleaning, replacing any damaged components, and using the LO and provided trimmer to get it close enough to use.
 
Jamesvintage said:
When I read the manual on FM tuner adjustment's it really scared me since they do adjustments at 90Mhz by "spreading the plates" with some kind of spatula (Part GGK-066). Hopefully I won't need to adjust this part, but what is that tool, I have not been able to find any pictures or information about it.
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Those don't have adjustable coils (inductors) for the lower end. 99% of the time, they are fine and best left alone. Tuning them in with a twiddle stick is frustrating as hell, and a very delicate procedure.

As noted before, lining up the dial will be most accurately accomplished by using known radio stations. They are far more accurate than any generator the average schmuck can afford.
Peaking the trimmer caps and coils in the front end can be done with the signal meter in the unit.
Setting the center point in the unit can be done with dead air (between stations, preferably near the center of the dial).
I use a Sencore SG-165 to set separation, and the 107MHz IF. It's only good to 40dB, but that's good enough for most tuners, and all but the most dedicated DX'ers.
19kHz can be set with the frequency counter in a Fluke meter.
Leader LSG-231 and Meguro distortion meter to set the distortion component of the discriminator.
That will get most tuners to 90% or so of the maximum performance. In my world, not enough people care about FM enough to make it worth it to me to spring big $$ for better tuner equipment.
Most tuners made after the early '70s don't have an adjustable IF, so it's generally not something to worry about.
 
tarior said:
Those don't have adjustable coils (inductors) for the lower end. 99% of the time, they are fine and best left alone. Tuning them in with a twiddle stick is frustrating as hell, and a very delicate procedure.

As noted before, lining up the dial will be most accurately accomplished by using known radio stations. They are far more accurate than any generator the average schmuck can afford.
Peaking the trimmer caps and coils in the front end can be done with the signal meter in the unit.
Setting the center point in the unit can be done with dead air (between stations, preferably near the center of the dial).
I use a Sencore SG-165 to set separation, and the 107MHz IF. It's only good to 40dB, but that's good enough for most tuners, and all but the most dedicated DX'ers.
19kHz can be set with the frequency counter in a Fluke meter.
Leader LSG-231 and Meguro distortion meter to set the distortion component of the discriminator.
That will get most tuners to 90% or so of the maximum performance. In my world, not enough people care about FM enough to make it worth it to me to spring big $$ for better tuner equipment.
Most tuners made after the early '70s don't have an adjustable IF, so it's generally not something to worry about.
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Thanks, that is what I am hoping. Since it has only had one owner and not has tried to "fix it" I am hoping it will be close enough if not already accurate.
 
merlynski said:
Question for those of you who do Pioneer FM tuner alignments. What equipment do you use? Is it modern gear, or vintage? If you can/will, quote what you paid for it and when. Did you repair the test equipment before you used it?
How often or how many have you done?
I am thinking about doing this myself, as I have at least four that I can do, three in Receivers (SX-1050, SX-780, SX-650) and one stand alone Pioneer Tuner I cannot remember the model, just now. I will have to acquire the test equipment. (I have a scope).
Thanks for your input!
Click to expand...
i own a kenwood sg5115. i used to have a national vp-8177 that gave up the ghost. i dont have the buying opportunities you have so my choices are limited. this is offset by the fact that i also cant find anyone who can do alignments here,so the only way was open the wallet,trial and error, with no adult supervision available save the service manual. the kenwood was advertised as N.O.S. and was bought on ebay and it was 800$ (us). theres some grifters here in manila that sell on the bay out of manila. i got my first vp-8177 from them for 60$. it worked well though and did last for over 20 front end alignments so i got my money back. the next 8178 i took a bath on from the same folks. so i dont recommend you buy from them as it looks like a bunch of used and played out crap from korea or malaysia. the generators i mention are not stereo so no adjustments to the mpx can be made. i'm out of this now as ebay for old receivers is SKY HIGH and their once reasonable global shipping program (for larger items only) is now also for the rich and famous. i like the kenwood but i prefer the national as its lab grade. the kenwood is just fine though. the 8177's i took apart when they died the previously burned and bypassed solder runs on the main board were enough to condemn it . they look to be multi layer boards and the damage was in the interior solder runs. its my opinion that most gain to be had is aligning the front end's so that doesn t require a stereo generator. however i only say that from not having a stereo generator and limited experience. i hope this helps. it also is helpful sometimes to be able to use a 400hz tone to trouble shoot.
 
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I bought an HP 5657B that was guaranteed for $800 and a Sencore SG 165 that was guaranteed for $300. I am able to align tuners with these and my scope. I follow xraytonyb directions (he aligns Pioneers) and it works very well. He also runs through the sound technology 1000a and other generators to.

In these cases more often than not it is not the tools necessarily but the technician who wields them that determines the results. I read a text book on radio theory and bought the Elenco am/fm radio kit and went through those exercises first so that I would understand what the adjustments were doing. You are in the right place and asking the right questions!
 
To align my TX-9500II I used:
Tektronox TDS3032
Panasonic VP-8132A
Keithley 2015 (to measure distortion)
 
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