Aiwa said:
so what means "verified" manufacturing dates in this case?
either :
sales bill.
brochures.
transformer stamp.
loudspeaker stamp.
moulded date stamps in housing.
back side date tags.mostly in battery case.
service manuals do not count :they could have been printed earlier or later in the total span.
The production spans of early boomboxes :up to 7 years.(so the print date of date of the service manual does not show the exact mfd date)
These are just my opinions:
Sales bill ---- Doesn't mean anything. The box could have been sold years after it was built.
Brochure --- Usually accurate......unless the box was sold for multiple years, and the brochure was printed in one of the later years. Companies do usually change their brochures/catalogs every year to ensure they look "fresh".
Transformer stamp -- Doesn't mean anything. They could have used old transformers from old stock.
Speaker stamp -- Same as above....Doesn't mean anything.
Molded date stamp in the housing -- This would be accurate, UNLESS the model was produced over multiple years, therefore the date wouldn't tell you when it was first introduced.
Battery date tags --- Same as above.
Service manuals -- I suspect these dates are mostly accurate. While it's true that a service manual COULD have been printed (and dated) years after the box was produced, how likely would that happen? Any reputable brand would print the manual as soon as possible after the box began production, so that service techs would have the necessary info to repair them. And once the manual is printed, in say 1980, there would be no reason to change that year on the manual even if they were forced to print a fresh batch 2-3 years later. Publishers don't change the date of a publication unless there have been changes to it. And in the boombox world, if there are changes, they usually print a supplement, not a new manual.