HT-37 CW Break-In Modification
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Hi,
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I recently did the modification for break-in keying as shown in the Hallicrafters Information Bulletin.
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I used a separate 10M pot and mounted it in the 3/8” empty hole in the back of the chassis. I installed the 4.7M fixed resistor in series and I did remove the .005mf cap from pin #8 of SO8.
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The break-in function works as advertised - counterclockwise for shorter delays.
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However, I do have one issue in that the break-in function is always on. I can not return to normal manual CW operation by turning the pot maximum clockwise as stated.
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My 10M pot actually measured 8.6M so I tried going up to a 6.8M fixed resistor and that didn’t fix the issue. I also tried a 10M fixed resistor and still had the same issue.
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I also tried substituting the V14A VOX diode 6AL5 with 3 other spares that I had here and still had the issue.
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The copy of the bulletin that I have here has a sketch that shows someone using a fixed 22M resistor in place of the normal components resulting in a 2 second delay. I find that interesting in that 22M resistance is certainly beyond the factory’s full clockwise “return to normal manual CW operation” resistance.
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Has anyone here successfully performed this modification and had if perform as described in the bulletin? Maybe I’m missing something, so I thought I’d ask here.
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Regards, Alan, W9CG
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