IF alignment, What is your prefered equipment for the job?

[Red Raster]

This question may belong in the Diagnostic & Test Equipment but seeing as my collection of color sets is growing I am seeking input from the early color
Gurus on what gear you like using?
I have a Sencore VA 62 video analyzer, B&K 1077B television analyst with a B&K sweep marker generator and a good analog 100meg Tektronics scope.

[Electronic M]

I've yet to test my Heathkit gear to see if it is in good enough shape to use to try my hand at alignment with (so take my advice with as many grains of salt as you like), but from what I've read the VA-62 is one of the better alignment generators out there. I think there was a thread here where somebody de-complied the programming on one of the chips of the VA-62 and made some modifications to it so the unit would have extra functionality/features. In that thread they explained the mod and offered to reprogram peoples' chips....It might be worth your time to look it up if you did not see it when it was active.

I think the 1077 was an IF(and all other circuits) trouble shooting instrument and not meant for serious alignment work, but I may be wrong.

[Phil Nelson]

Here is that thread about reprogramming the VA-62 EPROM to cover the lower IF frequencies used in older TVs:

http://www.videokarma.org/showthread.php?t=253433

Also included are links to some VA-62 manuals if those are of any interest.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

[bandersen]

I've been using a modified VA62 for a while now with great results I don't think you need the mod for color sets though. Aren't they all 44 MHz IFs ?

[Phil Nelson]

Yah, the early color sets use frequencies above 40 MHz. The standard VA-62 range of 35-50 MHz should cover them.

Phil Nelson

[miniman82]

B&K 415 is what I use, gives you everything you need to do a color chassis alignment right there- just add your scope.

[Kevin Kuehn]

Originally Posted by bandersen

I've been using a modified VA62 for a while now with great results I don't think you need the mod for color sets though. Aren't they all 44 MHz IFs ?

I didn't think a VA-62 had provisions to do a visual sweep alignment while viewing the response on an oscilloscope? As far as I know they can only do frequency bar sweeps. Apparently those bar sweeps allow you to align while watching the sets CRT. Does that feature work correctly with the lower frequency mods? Would love to watch a video of someone doing an alignment using that process.

[Zenith6S321]

I'm the guy that did the VA62 mod EPROM. The VA62 does not need the mod to do the 45MHz IF color sets. The mod expands the range of the 35-50 MHz signal generator function to about 10-99 MHz. The VA62 does not have a sweep generator. I use it as a digital marker generator while using a Wavetek 1002 sweep generator and Tektronics scope for IF and RF alignments. I learned aligning from watching bandersen video, THANKS Bob! The mod also modifies channel 42 to the 25 MHz IF frequency for use in doing early TV alignments. This lets you drive the IF stages with the VA62 video test patterns and audio tone which can help when IF aligning and finding tuner problems. I found the VA62 Multiburst frequency sweep useful during alignment of my 21CT55 (very touchy, difficult to align) because you can see the signal amplitude on your scope (and on the CRT face) of frequencies from 0-4.5 MHz in .5 MHz steps. I also used a Heathkit IG-57A marker/sweep generator to see multiple markers on the Wavetek sweep on my Oscope. I can still supply/burn EPROMs for those interested.

[Penthode]

I use an HP8601a sweep generator with an 8600a marker frequency counter. It provides the best sweep with variable and absolutely accurate markers which do not interfere with the sweep.

It can be used to sweep align from AM BC radios to TV VHF tuners using harmonics and it is dead accurate and easy to use. The set up cost about $10K when new and I bought it for less than $100 on Ebay.

[Kevin Kuehn]

I think for color sets, that you'd want something with built in sweep capabilities, and also supports multiple markers simultaneously. You really want to see the bigger picture and have the ability to switch on all pertinent markers as needed. Something like the B&K 415, Heathkit IG-57 series, or the HP8601a and 8600a combo would be the ultimate.

The Sencore VA-62 is a fine and very advanced piece of modern gear. However, for the older color sets it does not support the classic visual alignment process for viewing the sets response curve on an oscilloscope. IMO the Sencore bar burst method would seem very confusing for someone learning alignment on older sets.

BTW, I most certainly do not qualify as an "early color
Guru"

[bandersen]

The Wavetek 100x series of sweep generators are pretty sweet too and cover from about 10MHz - 1 GHz. Both internal and external post sweep markers like the 8601 too. The nice ones show them at 1, 10 and 100 MHz increments in different intensities. You can also vary the angle of the 'birdy' markers. Handy when the marker falls on a steep portion of the response curve.

[Red Raster]

Thank you all for your input, I will verify that the equipment is up to spec for the task and try it on some of my sets from the sixties.

[Ralph S]

Has anyone used a Sencore VG 91 for RF, IF and general setup on a color set? I have one, but haven't given it any serious use yet. It's fairly obvious that it wouldn't do for early B&W sets. Thoughts?