Quote:
Originally Posted by Penthode
Don't lose confidence! You just have to apply logic and patience. To apply logic, you need to know how it works and what you are doing.
With regards to T-103, you will not be able to leave it as is as circuit variances will affect tuning.
Let us return to the procedure. Since you impatiently began to adjust things before we logically analysed, it means going thru the procedure once again and stopping after the completion of each stage to discuss and not jumping forward prematurely.
In this way you will have a near perfect alignment on this set and you will have gained the knowledge and experience to apply to future alignments.
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Thanks for that advice. Yes, when I reached the step where the top of T-103 needed to be adjusted by monitoring the voltage on the VTVM, I got very heavy handed (literally, I broke the damn thing!). Part of this was, yet again, another piece of faulty equipment...my VTVM. I wasn't getting anything more than a weak swing of the needle even in the 1.5V range and subsequently, began moving the upper slug all over on T-103. I have since acquired another one that was restored, calibrated and tested. It has much greater sensitivity than the brick I was using.
I think you had mentioned it might be useful to look at the overall response curve to check where tweaks are needed. I guess these adjustments may be so far off now that what you said below isn't an option anymore?
"I should have said on the outset of this adventure, normally the alignment is fairly close. The sound IF is narrower bandwidth and is best gone over more concisely. The traps too need a little adjustment but they should be fairly close.
Because the video IF stagger tuned stages are pretty tuned for a broad response, there was really no need to perform the steps to spot align each stage. All that needed to be done was first sweep the overall video IF and only perform a few touch ups to get the response in the manual. I would only resort to deeper investigation if the response is bad and not easily corrected."