06-11-2011, 06:22 PM
Hi Steve,
I've checked both diodes for Vf and reverse-leakage, but will check them by substitution if all else fails (I'll need to borrow a pair from a working set, as I don't have many germanium diodes in stock). As for the resistors, I did find that RV1 had changed value (track measured 3K6 rather than 1K), so replaced that. I forgot to mention that by turning this control, I can make it null out perfectly - I presume that I'm balancing the detector for maximum AM rejection at this stage?
I also changed C66 and C69, which made no difference. The AGC capacitor had high ESR, and replacing that improved AM, and as it's the same type, I suppose I ought to check C56...
Will attempt line-up once the kids are in bed.
Cheers,
Mark
I've checked both diodes for Vf and reverse-leakage, but will check them by substitution if all else fails (I'll need to borrow a pair from a working set, as I don't have many germanium diodes in stock). As for the resistors, I did find that RV1 had changed value (track measured 3K6 rather than 1K), so replaced that. I forgot to mention that by turning this control, I can make it null out perfectly - I presume that I'm balancing the detector for maximum AM rejection at this stage?
I also changed C66 and C69, which made no difference. The AGC capacitor had high ESR, and replacing that improved AM, and as it's the same type, I suppose I ought to check C56...
Will attempt line-up once the kids are in bed.
Cheers,
Mark
