Alignment Tools?

Pilot lamp means as an indicator, indicating that power is "on" and if B+ is too low, or not present, the lamp extingishes.
Yup, shock treatment has been used for a while to fix bad thoughts, so are lobotomies :) only for the ones drugs can not fix, of course.
I remember one day (hard to forget) I got a shock, fixing a Tek scope, hopefully first and last time, sent me flying into the parts cabinet behind me, lucky me, know one (esp. the boss) saw it happen.
 
The stabilization lamp has two modes- open and working. If you get a reasonable resistance, don't light it up or do anything else, just use it. It's good.
 
Sounds good Conrad. I was afraid of that being the case as well as it possibly being un-obtanium. Zaps = bad :) Ive been hit twice once by 220v on an AC condensing unit. Another I got across the Alt B+ on my old Stingray with it idling with a 200 Amp alt. My metal watch band + wrench + header bolt + me + 1200CCA gel cell battery = exploded watch, 4 holes through my left wrist, glowing red wrench and one horrible odor. Hey it was only DC right... pfft.
 
FIXED IT!!!
Traced out a broken solid core wire inside the insulator. Repaired and now have the 1st 2 sections in spec. Oscillating and voltages in spec.
Now to finish the calibration... hopefully no more snags.
 
I think I have it calibrated fairly well. Was finally able to get a decent Lissajou pattern. Voltages are in spec. 2-3 deoxit treatments on all the pots and VR's inside it.
 

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So it flaked out again and I finally nailed down the reason the power light would go out and only portions of the generator would work. The light is in good shape turned out the smaller of the 2 resistors across the power supply was intermittent.

Once replaced it has been stable.

However during my first attempt to use it to align the 5000x last night I realized... I forgot to buy a Demodulator Probe! I was looking at my waveforms and checking against the pictures in the service manual again and again thinking well.. perhaps I am on the incorrect input? What am I doing wrong, is my scope incorrectly setup. Then it dawns on me...

Beginner....
 
The IG-37 does not contain a 10.7MHz IF sweeper, which is what is required to tune the response of the IF filter L/C stages and to adjust the discriminator for that famous "S" curve as they show on page 10 of the service manual.
I recall mentioning this earlier, if you want to adjust older receivers that use L/C tuned circuits for the IF strip, before ceramic IF filters became common place.
I think you can also adjust the discriminator, using a low THD RF SG and a THD analyzer, which I think is more accurate than using your eye to determine the discriminator linearity, however I have never done this and this only theory speaking and not hands on experience with this or a similar tuner.
I do not believe IG-37 is a very low THD modulator, since its modulated THD maybe much higher(>1%) than the 5000X, so unsure of the results and if you can find a null.
I have actually wanted to make a 10.7MHz IF sweeper. It involves a ramp generator and a 10.7MHz oscillator, which the ramp is DC coupled to a varactor diode placed in parallel with the L in the tank.
Check out
http://www.audiokarma.org/forums/showthread.php?t=541419
The semiconductors can be substituted esp the varactor BA163 which I doubt that you can find these days, just get a varaqctor which has the highest capacity. If you are interested, I can help you do this on a perf board, probably best to start a new thread.
 
I have never tried a big die diode as a varactor, it certainly is something to try in a pinch, something like 50-100pF should do.
Going to
http://www.1728.org/resfreq.htm
Choosing 10.7MHz, 100pF, you get 2.2uH
and
http://ca.mouser.com/ProductDetail/...=sGAEpiMZZMtQ8nqTKtFS/CJn0lckxLPo7kK8mzqJNOc=
with 3V reverse bias, so cap is 40pF, if you have 2 in parallel = 80pF, calculate L= 2.77uH
2.7uH a standard value,
http://ca.mouser.com/ProductDetail/...EpiMZZMsg%2by3WlYCkU69%2bjvm3I6Pyh1lEcd/Eoic=
To bad only smt varactors these days, leaded varactors are obsolete these days, sot-23 is easy to use.

And for his rf detector, use the exact same thing as Sansui did,
a 1N60 Ge diode, see the signal level detector circuit, output of ic201-7, through the 4.7pF(C219?) cap, to 1N60(D202), and (output) 3.9K(R121?),20nF(C220?) to ground.
 
Well this would explain why this IG-37 wont help me much. I wondered what the RF Sweep feature was.. just took for granted it was a 10.7.

Now wishing I won the auction the other night on that ST-1000

-R
 
Got me too, on the RF sweeper, i guess they mean the 2MHz variation of the 100MHZ oscillator, that is why the var cap is on the front panel.
A 20MHZ DDS would probably do the job if you can program it so that you can set the sweep width and rate. If it has FM modulation capabilities, even better.
AD9851 part seems to be used a lot.
Just what you need is more test equipment.
This looks like what you need
http://www.ebay.com/itm/NEWTRONICS-...957?pt=LH_DefaultDomain_0&hash=item2a3a852205
Actually IIRC, these are the folks I bought my HP 8656B spares unit for $100.00
 
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This Boonton 102F does not have a 10.7MHz IF sweeper function that you require for your Sansui 5000x tuner adjustment procedure.
It also does not have any stereo modulation but you can use the IG-37, if it working, apply to the external modulation input BNC.
Other than that, it looks to be a decent general purpose RF signal generator from yester-year. Beware this unit is 30+ years old, if something breaks, it is not that easy to fix or un-repairable unless you have the knowledge,service manual and spare parts.
How many receivers do you need to align? Buying a RF SG may not be the most economical means to tune up one receiver.
 
I have 3 Sansui's in the pile at the moment but only 1 I am working on. I have it sounding really nice and tuning strong/centered. Not 100% certain though without scientific proof that its "perfectly aligned". Whatever I do buy I will use at least a few times per year.
 
Alrighty, spurred on to acquire some nicer RF gens than my SG-165, I got a Panasonic VP-8131A. Actually I got a second parts unit as well.

I found the first one to be dead on acurate frequency wise and the amplitude seems to be fairly close but all I have to go on for that is my o-scope. This is a very easy to use front panel and I did not need to dig into the user manual to run it. You can arrow over to the digit you wish to modify when using the scroll wheels. The modulation readout has multiple modes depending on what function you have just selected to modify; kHz for FM deviation and % for AM modulation for example. I really like it!

I borrowed a spectrum analyzer from work to check the RF spectral purity and found it to be always better than -45dB on any harmonic at any frequency I dialed up. The spec varies for different frequency bands but the best ranges call for better than -40dB so this unit is fine.
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The parts unit was an interesting deal. I saw an ad on eBay with a stock photo and asked for real pictures - this was before buying the one I got from another source. I got back a picture of a unit with a bashed in front and the seller mentioned that he tested it and found it "dead", would I be interested in an as-is deal. Of course! So after a bit we came to terms and I got it thinking parts unit. Here it is as I got it.
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At least the back was intact although I later found a trashed BNC on RF Out #2. I had also cleaned off some melted black goo from the inner rubber feet having melted / decomposed on the top inner cover. I brought it up on the variac and found a somewhat incorrect display. Enough OK that I thought the micro was running.

I took off the top inner cover to see how that looked inside. It looked fine.
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The I thought I'd see how badly the front pc board (for the display and buttons) was messed up so I unscrewed the assembly and pulled it out and the board away from the bracket. I didn't see any damage other than it was kind of tweaked because the aluminum bracket was so bent up. When I fired it up it worked fine!
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After some putzing around I got the bracket pretty straight and gave it a light sanding.
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I peeled off the front sticker that says "VP-8131A" and the original labelling was "VP-8121A". Hmmmm, I'll have to go find out what the difference is. It could be that it was upgraded later to an 8131. That would be the optimistic way to look at things! :D

I haven't reassembled it, I want to measure it all out and get it drawn up so I can design a new front laminate (sticker). We make our own at work for our products so I have a shot at talking the engineer in charge of that area into helping me out. I'm thinking of doing it in black with white lettering as I have to repair the front plastic bezel and paint it. Black is easy to do! I'll post that if it happens.
 
Ah! I forgot to mention the main thing! I hooked it up and found that indeed there was no output. For grins I put it on the spectrum analyzer and could see a blip was dow about -50dB from where it should be. I also found that I could change the frequency around and it would change on the output. Very hopeful!

I tried out the "RF off" button which indeed shut it off. When I hit the button for switching the output to jack #2, the signal popped right up to where it should be! In an 'aha' moment I remember that jack #2 was damaged and wondered if someone had actually damaged it while it was in the jack #1 spot and the swapped them around to make the connection point the same. I need to get a replacement jack in and get them swapped back and see if both work. Not totally necessary but it would be nice!
 
In the picture with the HP spectrum analyzer sitting on top of the VP-8xxx, I see a bnc tee, with what I suspect to be a 50 termination. Why, the S/A should have a internal 50 termination? thus the ext termination should not be needed for accurate measurements.
I can see the above set-up for a scope that does not have a 50 ohm input, but most good scopes have a 50 ohm DC coupled input.
According to the spec sheet, the VP-8121 does not have the electronic "ATT".
 
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Thanks for your input Rick!

Son-of-a-gun, I bet you're right on the analyzer's input being 50 ohms already! I just didn't think of it. I did want it for use on the o-scope which is a nice Agilent 2 + 16 MSO but doesn't have 50 ohms as an input option. It was under $2K and is verrrrry nice for a piece of home gear. AT any rate I'll bet the extra load didn't change the spectral purity check but I'll give it a try and report back.

You're correct on the electronic attenuator thing. It's not alledgedly in the VP-8121. I wonder if later models had them after all. Maybe there was a factory upgrade kit that came with the new sticker for the right side panel? It has an "Option J" sticker on the back, maybe it's the attenuator upgrade option? I'll listen for relays!! :scratch2:
 
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