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1254pbigelow [2007/03/27 16:43] n5na |
1254pbigelow [2007/03/27 16:44] n5na |
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| - Reduced sensitivity on the lower half of the AM broadcast band. | - Reduced sensitivity on the lower half of the AM broadcast band. | ||
| * Remedy: Put a jumper across R72, eliminating that input filter. | * Remedy: Put a jumper across R72, eliminating that input filter. | ||
| - | 3.) FM intermod from strong FM stations. Just add 90 (2* 1st IF) to the received frequency | + | - FM intermod from strong FM stations. Just add 90 (2* 1st IF) to the received frequency |
| to detetmine offending frequency. | to detetmine offending frequency. | ||
| Remedy: Have tried with some success (but none totally satisfactory): | Remedy: Have tried with some success (but none totally satisfactory): | ||
| - | a) Snap-on RF choke on power cable | + | * Snap-on RF choke on power cable |
| - | b) Soldered on a shield on trace side of the board around the 1st Mixer section | + | * Soldered on a shield on trace side of the board around the 1st Mixer section |
| - | c) Incorporated FM trap (from Radio Shack) in the antenna lead | + | * Incorporated FM trap (from Radio Shack) in the antenna lead |
| - | 4.) The rotary Encoder loosens up with use causing the frequencies to jump around (sometimes) when tuning from one step to another. | + | - The rotary Encoder loosens up with use causing the frequencies to jump around (sometimes) when tuning from one step to another. |
| - | Possible Remedy (have not tried yet): Sandwiching a large, black, felt washer between the tuning knob and the tuning knob recess to reduce play. | + | * Possible Remedy (have not tried yet): Sandwiching a large, black, felt washer between the tuning knob and the tuning knob recess to reduce play. |
| - | 5. ) Hum from the power supply. | + | - Hum from the power supply. |
| - | Possible Remedy (have not tried yet): Install a 15V IC regulator in the power supply. | + | * Possible Remedy (have not tried yet): Install a 15V IC regulator in the power supply. |
| - | 6.) Deafening thump upon turning on the 1254 when using headphones. REALLY LOUD. | + | - Deafening thump upon turning on the 1254 when using headphones. REALLY LOUD. |
| - | Remedy: None yet although I suspect a large capactior may resolve this one. | + | * Remedy: None yet although I suspect a large capactior may resolve this one. |
| - | 7.) A little bit of "thumping" due to slow synthesizer lock. Not too bad, really, considering | + | - A little bit of "thumping" due to slow synthesizer lock. Not too bad, really, considering |
| the price. | the price. | ||
| Paul | Paul | ||
