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Tube❄️Time

here is one of the cards. this one is an "MH" card containing 4 PNP driver transistors.

a brown circuit board with around 20 parts on it and some jumper wires. it is about the size of a playing card, and it has an edge connector sticking out the side.
15 comments
Tube❄️Time

if anyone wants to see the back of the card, it looks like this.

the back of the card with just solder joints. the card has gold plated edge fingers. it also seems to have a conformal coating applied to insulate it.
Tube❄️Time

i want to build a breakout system to make it easier to test these cards. they use a 16-pin connector with 0.125" spacing between contacts. at the local electronics store, i could only find this 44-pin connector.

Tube❄️Time

my idea is to remove a few pins and cut the connector down.

Tube❄️Time

the final product. you can barely see the glue seam. bonus points to anyone who knows why the connector pin alphabet is missing a few letters. further bonus points to anyone who knows why each contact has two wires connected to it.

an IBM sms card plugged into my customized socket. the socket pins are wired up to a set of 16 test points marked "A B C D E F G H J K L M N P Q R"
prozacchiwawa

@tubetime the obvious answer with the letters is they're gonna leave out the ones that can be confused with numbers.

i'd imagine one of S or Z or both is left out as well.

oh -- or they're the symmetric ones that don't tell you if you're reading it upside down :-)

William D. Jones

@tubetime I and O too easy to confuse with 1 and 0?

I feel like I've seen this before in e.g. Game Genie codes.

Darryl Ramm

@tubetime

I != 1
O != 0

Two wires? Because you wanted to be able to insert boards either way? But why?

Emily Velasco

@tubetime I have a front panel from some old electronic device that has the same letters removed

JeffG

@tubetime the missing letters can be mistaken for numbers!

Zack Stern

@tubetime I don’t see any traces on top of this card but my entry is: to get continuity on the top and bottom of the card at the same time. The leads go to teeth on one each of the top/bottom?

Henning Paul DC4HP

@tubetime For the same reason they're omitted in MIL connectors, I guess, ambiguity.

Holiday Bill

@tubetime I've done this so many times. I ♥️ epoxy!

Bob Davidson

@tubetime
just stuff a bit of pcb material to block the unused pins rather than cut the connector

root42

@tubetime that one transistor doesn't look healthy...

masukomi

@tubetime i’m having trouble with the fact that this is so chunky looking that I feel like it could just be a standard breadboard

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