"Dave Plowman (News)" wrote:

In article ,
Michael A. Terrell wrote:
Delco used a very thin double sided PC board at the input as a "Spark
plate", followed by a large filter choke. Anything over the voltage
rating of the gap arced over from the input lead, directly to the
radio's case.

And this was used to protect against voltages of 50 or so? I really can't
see that being a reliable method in the hostile environment of a car.


It was paper thin phenolic PC board, and Delco claimed that it would
arc over below 50 volts when I went to the factory school. I asked the
engineers so many questions that they stopped answering. They thought
that I was after their jobs. ;-)


BTW, the first transistor car radio I had was a hybrid kit where only the
AF was handled by transistors. Early '60s.


Delco was building hybrids in the late '50s with a DS501/2N441
doorknob germanium output transistor:

Industry Number : DS501
NTE Device Number: NTE105
T-PNP, GERMANIUM AUDIO PO, TO-36 Case

Other companies used tubes designed for 12 volts on the plates in the
aerly '60s while Delco was building all transistor units.


No sign of anything like that
on it. Perhaps Lucas electrics couldn't produce much over 14 volts. ;-)


From what I've heard about Lucas you were lucky it didn't go up in
flames the first time it was turned on.



--
*On the other hand, you have different fingers*

Dave Plowman London SW
To e-mail, change noise into sound.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida