When I started out fitting my bench 1 1/2 years ago I bought a Sencore SG-165 AM/FM Generator. It was supposed to be fully functional but.....
After finding out the outputs were completely dead I put it on the shelf to fix later. Recently I found the time to pull it down to take a look. I have an orginal manual. The manual is exceptional. Great circuit descriptions. The schematic has "oscope to test point" pictorials to aid in troubleshooting. Looks to be easy until you open it up to access those test point. Test points are not easy to access without lots of difficult disassembly.
I quickly found the first problem. A leaking electrolytc cap on the output. I happen to have a replacement in my stock. Now I have all AM outputs and most of the FM outputs except the RF and 19khz. The 19khz turned out to be another leaky cap in the 19khz multivibrator. Moving on to the FM RF circuits. This will require a very difficult disassembly to access the foil side of the PCB.
So I am at an impasse whether to continue. I suspect that many if not all of the electrolytics need replacing. I should replace all the ceramics while I am at with at least MLLC caps. I suppose I could also replace the old carbon resisters with modern metal oxide 1% resisters which would also reduce noise.
I intend to use this to perform alignments on solid state stereo tuners not tubes.
My questions:
Is this generator worth the effort of a complete rebuild? I am up to the task and expense but I have my concerns as to the usefulness for my intended needs.
Would I be better off cutting my losses and buying a better AM/FM Generator suitable for more modern FM tuners and receivers?
.
After finding out the outputs were completely dead I put it on the shelf to fix later. Recently I found the time to pull it down to take a look. I have an orginal manual. The manual is exceptional. Great circuit descriptions. The schematic has "oscope to test point" pictorials to aid in troubleshooting. Looks to be easy until you open it up to access those test point. Test points are not easy to access without lots of difficult disassembly.
I quickly found the first problem. A leaking electrolytc cap on the output. I happen to have a replacement in my stock. Now I have all AM outputs and most of the FM outputs except the RF and 19khz. The 19khz turned out to be another leaky cap in the 19khz multivibrator. Moving on to the FM RF circuits. This will require a very difficult disassembly to access the foil side of the PCB.
So I am at an impasse whether to continue. I suspect that many if not all of the electrolytics need replacing. I should replace all the ceramics while I am at with at least MLLC caps. I suppose I could also replace the old carbon resisters with modern metal oxide 1% resisters which would also reduce noise.
I intend to use this to perform alignments on solid state stereo tuners not tubes.
My questions:
Is this generator worth the effort of a complete rebuild? I am up to the task and expense but I have my concerns as to the usefulness for my intended needs.
Would I be better off cutting my losses and buying a better AM/FM Generator suitable for more modern FM tuners and receivers?
.
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I played with one of these way back in to 70s; seems like it was kind of a combination unit for testing audio amplifiers as well as tuners. Seemed like a handy general purpose unit just to have around and I'd think it'd be worth shotgunning the electrolytic capacitors and resistors in the audio sections at the least.
Do the specifications and functions meet your expected needs? Low enough distortion, useful test frequencies, separation, S/N? Good features for RF/IF alignment, multiplex?
Sencore had a much better FM generator, SG80, but it's pricey. Might want to compare its features with the Sound Technology 1000A, which is the standard. I've certainly wanted some sort of FM generator myself.
Do the specifications and functions meet your expected needs? Low enough distortion, useful test frequencies, separation, S/N? Good features for RF/IF alignment, multiplex?
Sencore had a much better FM generator, SG80, but it's pricey. Might want to compare its features with the Sound Technology 1000A, which is the standard. I've certainly wanted some sort of FM generator myself.
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You can find it here: http://bama.edebris.com/manuals/
(I know this is an old thread but this may help someone someday...)
(I know this is an old thread but this may help someone someday...)
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