05-20-2008, 10:12 PM
Well, aligned her up tonight. While the dial calibration was on, that's all that can be said. The IFs were way out, tuned somewhere around 451/2 kc. Also the primary IF was off from the secondary IF. I suspected this as the selectivity wasn't quite up to my other two 650s. But fidelity was better.....An added plus I guess. After aligning the IFs, selectivity increased as did over all sensitivity, but lost some fidelity.
The 1st IF secondary adjustment was goofy, I didn't like it. This calls for disassembling that IF to see what's up. Anyhow, as usual the dial calibration came almost spot on. I mean within a hair of accuracy. It amazes me how accurate these sets are on the dial. Anyone that knows me, knows I'm an anal prick when it comes to dial calibration Another added plus is the shadow meter is now more responsive.
Last, I mentioned the tuner assembly was sloppy. Trying to fine tune a station was a lesson in futility. The tuner gang moved, but not the dial. The dial disk mount was tight, though I could hold it lightly, and keep it from moving while tunning. The set screw was tight, so I just loosened it, and moved the disk out a fraction of a hair. Problem solved. Plus the dial scale no longer rubs the diffuser hard. Now you can fine tune to your hearts content.
Well, for you gents who are looking for a nice example, might I recommend one of the 36 models. My reasons are this. Easier to service than the 37 series with their RF sub-chassis. Hot performers right down to the 620, they have that great "30s" look. What else can I say
Here are a few pics of the xfmr work
[Image: http://antiqueradios.com/gallery/d/77716-1/xfmr2.JPG]
[Image: http://antiqueradios.com/gallery/d/77714-1/xfmr1.JPG]
The 1st IF secondary adjustment was goofy, I didn't like it. This calls for disassembling that IF to see what's up. Anyhow, as usual the dial calibration came almost spot on. I mean within a hair of accuracy. It amazes me how accurate these sets are on the dial. Anyone that knows me, knows I'm an anal prick when it comes to dial calibration Another added plus is the shadow meter is now more responsive.
Last, I mentioned the tuner assembly was sloppy. Trying to fine tune a station was a lesson in futility. The tuner gang moved, but not the dial. The dial disk mount was tight, though I could hold it lightly, and keep it from moving while tunning. The set screw was tight, so I just loosened it, and moved the disk out a fraction of a hair. Problem solved. Plus the dial scale no longer rubs the diffuser hard. Now you can fine tune to your hearts content.
Well, for you gents who are looking for a nice example, might I recommend one of the 36 models. My reasons are this. Easier to service than the 37 series with their RF sub-chassis. Hot performers right down to the 620, they have that great "30s" look. What else can I say
Here are a few pics of the xfmr work
[Image: http://antiqueradios.com/gallery/d/77716-1/xfmr2.JPG]
[Image: http://antiqueradios.com/gallery/d/77714-1/xfmr1.JPG]
-Brian
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