SB-104 display board update

[MIKE BRYCE]

boys and girls...

after some conversations with several guys here on the reflector about the
possibility of using the original heathkit display driver IC on the new LED
display board..

the original driver ICs sink current. in the original version they sink the
current from the +180 volt supply.

in my updated LED version the 7447 sink current from the +5 supply via 180
ohm current limiting resistors

In the "why not give it a try" column I put in the original high voltage
driver and low and behold they work!

The display is not as bright and the limiting resistors would have to be
changed.. did not compute the values ... a good starting point would be 100
or 75 ohms...

now having said that, I will be offering the LED update PC board, displays,
IC sockets and original 180 resistors for $32 +$4 shipping.. Bare PC boards
are still $15+$4 shipping

this offer is only for the guys on this list, nothing will be placed on the
web site.

and there will be no warranty that the old driver ICs will withstand the
current.. it's a experiment.

Will be out of the office this weekend, going to the toledo hamfest..

anyone interested in this project, drop me a email..

parts in stock..



Mike Bryce, WB8VGE
SunLight Energy Systems

http://www.seslogic.com
http://www.theheathkitshop.com

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