#151
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I started going through the alignment procedure tonight. The video IF barely needed any tweaking which didn't surprise me since the picture was quite good already.
The audio IF on the other hand were off quite a bit. Now I have plenty of volume and FM stations aren't leaking in but there is some background hiss. That's after performing the VTVM type alignment. Next, I'll try the visual approach and get an S curve up on the scope. That was all with channel #3. The sound on channel #4 is identical to 3, but the video has snow. Tweaking the channel oscillator helped but nowhere near enough |
#152
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Here's what I have for the S curve. Background hiss is unchanged using the OTA converter box I use on the workbench. I tried a different brand and it had much lower volume. I'll try a blonder tongue modulator next.
The bandwidth is around 4 MHZ. That's the 2nd from left section where I can make out vertical strips. The last bar is 4.5 MHz. Vertical linearity needs a slight tweak, but the horizontal looks great. |
#153
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I decided to cheat a little for the time being and stick this chassis into a cabinet from another set that's in better shape. I'll continue working on the original cabinet when I can.
It also a somewhat later production (C61036 vs C29885) that used a plastic channel plate versus a brass one. Here's a better look at the stand. Last edited by bandersen; 08-30-2013 at 09:22 PM. |
#154
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Low volume using DTV converter.
I've had trouble with low volume, even on newer sets, with the Magnavox converters. The other makes seem to be a little better with the volume.
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#155
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I too had low volume with a Magnavox converter. An Access DTA1010 was noticeable better. Once I get the set back together, I'll try a Blonder Tongue modulator.
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Audiokarma |
#156
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I don't know what is up with these low volume modulators. A few of the DVD players that I have are low volume as well. It was mentioned in another thread a few years ago that the RF may be down somewhat to keep these things from too much radiation and causing interference back when RF analog was still happening. I don't know. But I have to agree, low volume seems to be the "norm".
Now the Blonder Tongue seems to have none of those problems. Cool... |
#157
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The nicer BT modulator models have separate controls for video, audio and RF levels so you can tailor them for your set.
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#158
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Yes exactly. I bought a BT CATV system amplifier. But I found that I didn't need it. The output from the modulators was quite adequate.
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#159
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I'm making good progress touching up the cabinet. My goal is to fill in any voids in the lacquer (mostly from aligatoring) and touch up and finish loss.
I'm doing the main panels first, then the trim. After a light sanding with 320 grit, I give it a couple coats of lacquer then more sanding. Any pits or cracks are filled in with a small brush then sanded flush. Finally, a couple more coats sprayed on. I figure I'll touch up the trim with Mohawk brown mahogany for the medium trim and deep red mahogany for the very dark trim. |
#160
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How long after you apply the lacquer do you wait before you can sand?
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Audiokarma |
#161
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It depend on the temp and humidity and also the type of lacquer used. With Deft lacquer sanding sealer, usually a couple hours is enough but it's not as hard as gloss nitro cellulose based lacquer. The gloss I'll let sit least 12 hours or maybe less on a hot dry day.
If you don't wait long enough, it may be a little gummy or shrink after you've leveled it and you'll need to apply more lacquer and sand it again. Last edited by bandersen; 09-06-2013 at 10:17 PM. |
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