Restoration President Zachary T. (Uniden)
I will try to get this tranceiver from 1978 to work 100%.
Post by lbcomms » Sunday 17th Feb 2013, 0:48
"The most common problem with these 80's / 90's Unidens (except for the golden screwdriver syndrome) is the "10 volt blues".
There will be 15 to 30 light grey 10V electrolytic capacitors, these fail (start to conduct DC, something an electrolytic must not do) after 10 to 20 years.
Replacing ALL of them - a process known as "recapping" - is the only way to make these sets reliable.
Usual symptoms of bad caps: no TX/RX but PA works. Trying to transmit gives faint audio on the internal speaker.
Other caps cause different failures: no TX, no Tx audio, low or distorted Rx, or no / very dim channel display."
The radio will look perfect inside (i.e. nothing looks burned out).
Hope this helps...
was simpel te verhelpen, de twee dikke 473k condensatoren wijzigen in twee c,tjes van 10nf en de dev instelling wat meer open draaien, op de fm unit pc -743AA
doffe modulatie oplossen
All gathered docs
Block diagram Zachary T (pdf)
Parts list Zachary T (pdf)
Schematics Zachary T (pdf)
Frequencies (80) Zachary T (xls)
Below you can see some images from my own Zachary T.
extra 40 channels print (pc-686AA added in 1981 by company "DX Corner" Netherlands)
FM print (PC 743AA added in 1981 by company "DX Corner" Netherlands)
Advert company "DX Corner" Delft, The Netherlands: extra channels/FM module