Today, a QSD-1 I purchased at a good price showed up. It has some cosmetic issues (scratches, outer volume knob misisng) but what is most interesting is that it appears to be a very early unit, almost like an engineering sample. It has serial number 7407010. That's no typo, only 7 digits. I interpret that as unit 10 , July 1974 on line 7. If anyone has further thoughts on the odd serial number, please chime in here.
Now, where the differences are really evident is per the following list:
1. Absolutely no markings on back panel identifying it by make, model, or voltage input (the typical ID plate present on most Sansui gear). The back panel is screen printed with the markings for all the ins and outs, and shows the fuse rating at 1A 250V at 100V. Those are all the markings present. No UL or other certification stickers, though it has a standard two prong north American plug fitted from the factory.
2. The rear panel has two holes punched where the ID plate would be secured with screws or rivets. Nothing was ever attached there, black paint still present all the way through the holes to the inside surface. The serial number sticker is located here.
3. All internal circuit boards are single sided - including the backplate board - and lack green conformal coating on the foil side. No silk screening at all on either side of any board.
4. On the two front most boards, F-2462 and F-2466 (these markings are present as voids etched in the foil, not screen print) there are several mods added with caps and resistors hand assembled to the solder side of the boards in point to point fashion.
5. Front panel legends are all screen printed in black, including the QS insignia. On my later QSD-1, the front panel is engraved (black fill on all legends) and the QS insignia is a separate silver on matte black badge that attaches to the aluminum panel. Also, the "on" and "off" legends above and below the power toggle are not present, just the word "POWER".
6. The power transformer is marked with the Sansui logo, T-8496 and "43 7" on it top surface. I suspect this is configured for 100V. Interestingly, it has two primary input leads. Orange, soldered to one pole of the power toggle switch, and red which is capped with a rubber boot. Suspect the red may be a 120V in, but not sure. Could be a 220V primary as well.
Anyway, anybody run across one like this before? There aren't many QSD-1 around, but this is the first instance I've seen of this variant. Will try to get some pictures up here in a bit.
Now, where the differences are really evident is per the following list:
1. Absolutely no markings on back panel identifying it by make, model, or voltage input (the typical ID plate present on most Sansui gear). The back panel is screen printed with the markings for all the ins and outs, and shows the fuse rating at 1A 250V at 100V. Those are all the markings present. No UL or other certification stickers, though it has a standard two prong north American plug fitted from the factory.
2. The rear panel has two holes punched where the ID plate would be secured with screws or rivets. Nothing was ever attached there, black paint still present all the way through the holes to the inside surface. The serial number sticker is located here.
3. All internal circuit boards are single sided - including the backplate board - and lack green conformal coating on the foil side. No silk screening at all on either side of any board.
4. On the two front most boards, F-2462 and F-2466 (these markings are present as voids etched in the foil, not screen print) there are several mods added with caps and resistors hand assembled to the solder side of the boards in point to point fashion.
5. Front panel legends are all screen printed in black, including the QS insignia. On my later QSD-1, the front panel is engraved (black fill on all legends) and the QS insignia is a separate silver on matte black badge that attaches to the aluminum panel. Also, the "on" and "off" legends above and below the power toggle are not present, just the word "POWER".
6. The power transformer is marked with the Sansui logo, T-8496 and "43 7" on it top surface. I suspect this is configured for 100V. Interestingly, it has two primary input leads. Orange, soldered to one pole of the power toggle switch, and red which is capped with a rubber boot. Suspect the red may be a 120V in, but not sure. Could be a 220V primary as well.
Anyway, anybody run across one like this before? There aren't many QSD-1 around, but this is the first instance I've seen of this variant. Will try to get some pictures up here in a bit.