Quote:
Originally Posted by jhalphen
Hi to all,
Hi Etype2,
Video input mod will not yield "spectacular" resolution increase except if the tuner and especially the IF chain has drifted badly out of optimum bandpass.
I suppose your Golden Restorer will do a full RF/IF sweep on your set.
As a personal experience, on my CT-100 i purchased Pete Deksnis's video input kit - derived from RCA's studio monitor mod (about 20 years ago). The seller of my CT-100 warned me that the TV was not performing very well on upper VHF (Band III) channels.
As the CT-100 requires IF alignment of no less than 5 IF stages, i chickened out. It is one of the most difficult sets to align and you need a full Lab of gear to do it.
The CT-100 video input module works well, but as you know from your Westinghouse, the 12" picture of a 15GP22 is nothing to brag about resolution-wise.
Oh well, it's IN COLOR ! (1954).
Best Regards
jhalphen
Paris/France
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I not only had to align my CT-100, mine had a mouse nest in the video IF area and I had to fully diassemble the video IF stages, use an electrolysis bath to remove the corrosion and fully rebuild it.
The equipment I used was the HP8601a Sweeper Generator I bought for $40 (I just picked up anpther one last week for less). Plus an HP8600a Digital Marker. The HP combo was designed specifically for this sort of work and provides five absolutely accurate markers. Plus I needed my trusty 40 year old Hitachi scope (which I got for free). I made the input jig RCA specified and used a genuine RCA bias box I found in a pile of electronic garbage years ago.
The alignment was pretty easy and ultimately the results matched exactly the RCA notes. The only issue I had was alignment of the 1st IF tuner link. An open decoupling capacitor in the tuner fixed that. I believe the decoupling capacitor is a common problem and overlooked. Once fixed the process was easy and results exactly as described. The resultant pictures on the 15GP22 are phenomenal... that was before the convergence transformer failed. I will have time to return to that again this autumn. It is all explained in the link below.
You don't need special laboratory equipment. Simply a good nose for a bargain and there are literally plenty of equipment bargains about. I still highly recommend the HP8600a/HP8601a combo because they are relatively cheap and produce the highest quality alignment results.
Here is the link which includes the process of my CT-100 using the HP equipment. Look at page three where the Video IF section of the CT-100 is in the bucket of water indergoing electrolysis rust removal. If this CT-100 can yield a perfect IF response, then any CT-100 can.
https://videokarma.org/showthread.php?t=274959