I asked twice about the date from the yanwu 406 http://www.boomboxery.com/forum/viewtopic.php?f=2&t=4091&st=0&sk=t&sd=a in the leowood forum -the date is verified .They have got brochures from 1978.They found it also on the housing,mould stamp and on speaker printings.
This "LED -APPEARING"theme has been discussed several times.
It`s quite a neighborhood legend and a hearsey that led`s(led rows) appeared so late in boomboxes.There are more than 150 boxes (in bbdb)with verified manufacturing date BEFORE 1980.so:Unfounded rumors say that these kind of led`s appeared after 1980.
------------------------------------------------------------
------------------------------------------------------------
__________________________________
single led -meter rows :
asahi-rd802 :1979
g.e.-3-5257 :1976
hitachi-trk8000 :1979
hitachi-trk8005: 1979
hitachi-trk8110 : 1979 (included lcd timer!)
panasonic-rx5090 :1979
sharp-gf6363 :1979
sony-cfs-v2 :1978
................................
.........................
double led-meter rows:
examples:
aiko-atpr550:1979
graetz-src400:1978
hitachi-trk8020
included 7 segment led)-1978
panasonic-rq4050:1978
panasonic-rq4370 :1978
pioneer-sk71:1978
sony-cfs65,cfs67,cfs81:1978
wilco1047:1978
.......................................
...................................
so what means "verified" manufacturing dates in this case?
either :
sales bill.
brochures.
transformer stamp.
loudspeaker stamp.
moulded date stamps in/on 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 have to show the exact mfd date)
Single LED`s appeared often in boxes bfore 1980 as well (like aiwa tpr950:1978-1984).
special knowledge about led`s:
http://ledmuseum.candlepower.us/led/ledleft.htm
This "LED -APPEARING"theme has been discussed several times.
It`s quite a neighborhood legend and a hearsey that led`s(led rows) appeared so late in boomboxes.There are more than 150 boxes (in bbdb)with verified manufacturing date BEFORE 1980.so:Unfounded rumors say that these kind of led`s appeared after 1980.
------------------------------------------------------------
------------------------------------------------------------
__________________________________
single led -meter rows :
asahi-rd802 :1979
g.e.-3-5257 :1976
hitachi-trk8000 :1979
hitachi-trk8005: 1979
hitachi-trk8110 : 1979 (included lcd timer!)
panasonic-rx5090 :1979
sharp-gf6363 :1979
sony-cfs-v2 :1978
................................
.........................
double led-meter rows:
examples:
aiko-atpr550:1979
graetz-src400:1978
hitachi-trk8020
included 7 segment led)-1978panasonic-rq4050:1978
panasonic-rq4370 :1978
pioneer-sk71:1978
sony-cfs65,cfs67,cfs81:1978
wilco1047:1978
.......................................
...................................
so what means "verified" manufacturing dates in this case?
either :
sales bill.
brochures.
transformer stamp.
loudspeaker stamp.
moulded date stamps in/on 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 have to show the exact mfd date)
Single LED`s appeared often in boxes bfore 1980 as well (like aiwa tpr950:1978-1984).
special knowledge about led`s:
http://ledmuseum.candlepower.us/led/ledleft.htm
