Re: "liquid crystal driver" sighting

Glenn Little

On 12/10/2019 10:28 PM, Glenn Little WB4UIV wrote:
I will try and get hi res pix posted this weekend.
Hope to have schematic drawn early next year.
This appears to fit a TM-500 series frame.
The unit appears to have two channels.
The main board id very good quality.
There are two "proto" type boards in the unit.
One is for fuses.
The other has a pair of 74121 ics on it.
When I got it the edge card connector was damaged, thankfully if a place where there are no used pins.
There was one power transistor missing and I can replace it with one like in the other channel.
There is also a ground binding post missing, this is easily replaced.
The pictures will be of the unit as I received it.
This has controls for PW UPPER and PW LOWER for both channels.
There is also a DELAY and AMPLITUDE control for each channel.
There is a BNC for the top channel only INPUT.
There is a BNC for SYNC.
The SYNC appears to go to both channels.
There is a label on the front REL 11, so, maybe there are others out there.
The front binding posts are UPPER OUTPUT, LOWER OUTPUT and GROUND for each channel.
The active backplane pins are 2A, 3A, 6A, 7A, 8A, 9A, 10A, 12A, and 7B.
8B, 11B and 8A are connected.
12A and 12B are connected together.
All of these pins are power related, so the only inputs and outputs are via the front panel.
There is a keyway between pins 6 and 7.
There are "flying" jumpers between some IC pins with some of these pins lifted from the sockets.
Probably still a work in progress.
The front panel is thin aluminum with, what looks like, photo etching for the labeling and shading.
Harmonica connectors are used to connect to the board.

More to follow

On 12/10/2019 12:50 PM, p mc wrote:
(seeing this a few weeks later)


Like DaveD says, lots of people here can help with TekWiki. Or you can ask  kurt.harlem@... for a TekWiki account if you want to get into that yourself.

Back in October I made a stub page with  crops from the pictures from the eBay listing:

A first question might be what type of mainframe the plugin plugs into. If you haven't already sussed that, a picture of the edge connector cut-outs will help.

Curious to see what you've got...

Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"

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