Quote:
Originally Posted by Penthode
Hi and happy aligning. I have had experience successfully aligning this chassis for more than 50 years. It can be a challenge if you do not keep various factors in mind.
First you must have accurate marker frequencies. This is a split sound set and to achieve optimum picture quality with best sound, the marker accuracy is utmost. I use an HP5245L frequency counter with an HP 606B signal generator. Plus my favorite alignment combo is the HP8601a Sweep generator with HP8600 Digital Marker. The total net cost for all of this equipment combined was $150 and it was top of the line. There are many solutions available and all are now pretty cheap. It would be wise to review what equipment you have before you begin. Remember this set has more trap circuits than any other set! Two adjacent sound, two adjacent video, two co-channel sound, a baseband trap and an RF trap, each if misadjusted can adversely affect the video quality.
Second as this is a split sound receiver, the fine tuning control is adjusted for best sound, not best picture. If the alignment is not correct, when fine tune for best sound, the video will not look good. So it is essential as the manual advises to first proceed with the sound IF and descriminator alignment before proceeding with the video alignment.
Third, be aware the quality of the video IF amplifier tubes will affect the end result. Make sure you have fresh tubes in place you can trust. Because changing a tube in the video IF will affect the response curve.
Lastly before you start, the set uses an over coupled transformer between the tuner and first video IF stage. This is a broadly coupled link and it is essential to sweep align it. You must follow the instructions in the manual to get the curve depicted. I found it pointless to proceed unless I can get the proper response at this point because the subsequent video IF sweep adjustment will not be right.
I would suggest following the step by step process to the letter and if/when you reach a stumbling block, simply post it on the forum.
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Thank you so much for all of that information. I was looking at the HP606B generators on eBay but since they are analog, I thought they probably wouldn't be stable enough. At this stage, I'm probably going to need to purchase better equipment to do this right, at least from the generator/sweep end. I have a modern digital scope purchased last year and an HP scope that's about 30 years old both of which will do X-Y traces and are very accurate. I might try the Eico 369 I have just for practice until I can get better equipment. I'd be thrilled just to see a trace similar to the sound IF curve depicted. I have all NOS tubes in the TV
I'd like to treat this as an education journey and not a means to an end to get this particular TV perfectly aligned. How to feed in signals...set up scopes...interpret what changes in response curves mean etc... Other than adjusting coils for peak or minimum response on a VTVM is about all I have done in this realm! Believe me, I will ask questions but some of them may elicit an initial reaction of "He said what?...You're kidding me?"!!!!!