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</head><body><p>Relays are a switch. They use low power to operate an electromagnet which closes the contacts for a higher powered circuit, thus saving the smaller switch you used to energize the relay. Here's the Wikipedia explanation: <a href="https://en.wikipedia.org/wiki/Relay">https://en.wikipedia.org/wiki/Relay</a><br></p><p><br></p><p>Cars built back when your TR3 was don't have diodes anywhere in them. Heck, even the radios were tube-type not the new-fangled transistor kind.<br></p><p> <br></p><blockquote type="cite">On July 23, 2017 at 5:38 PM TERRY SMITH <terryrs@comcast.net> wrote:<br><br><p><span style="color: #333333; font-family: helvetica,arial,sans-serif; font-size: 12pt; background-color: #ffffff;">So the overdrive worked great on the day after I adjusted the linkage. The next day, slipped in and out. Fluid is topped off and am using Redline MT-90 per all recommendations. The fuse is NOT blown, but when I test, I get no clunk of engagement nor snap from disengagement. I've checked and rechecked all the wires leading in the system. Joints are soldered, solid and insulated (shrink tubing). </span><br></p><p><span style="color: #333333; font-family: helvetica,arial,sans-serif; font-size: 12pt; background-color: #ffffff;"><br></span></p><p><span style="color: #333333; font-family: helvetica,arial,sans-serif; font-size: 12pt; background-color: #ffffff;">Except.<br></span></p><p><span style="color: #333333; font-family: helvetica,arial,sans-serif; font-size: 12pt; background-color: #ffffff;"><br></span></p><p><span style="color: #333333; font-family: helvetica,arial,sans-serif; font-size: 12pt; background-color: #ffffff;">The relay. I didn't even know I had one. Leastwise, I'd forgotten since I first wired the thing a dozen years ago. <br></span></p><p><span style="color: #333333; font-family: helvetica,arial,sans-serif; font-size: 12pt; background-color: #ffffff;"><br></span></p><p><span style="color: #333333; font-family: helvetica,arial,sans-serif; font-size: 12pt; background-color: #ffffff;">Relays are simple mechanisms. Looks like a resister, maybe a diode in there. But diodes blow and resisters can die. <br></span></p><p><span style="color: #333333; font-family: helvetica,arial,sans-serif; font-size: 12pt; background-color: #ffffff;"><br></span></p><p><span style="color: #333333; font-family: helvetica,arial,sans-serif; font-size: 12pt; background-color: #ffffff;">Just curious, though. It's been 50 years since I was working on comm/nav electronics on F4-Phantom jets so am not clueless, but definitely rusty, about electronics. Are simple relays more or less bullet-proof, or do they have some sort of reputation I'm not aware of....????<br></span></p><p><span style="color: #333333; font-family: helvetica,arial,sans-serif; font-size: 12pt; background-color: #ffffff;"><br></span></p><p><span style="color: #333333; font-family: helvetica,arial,sans-serif; font-size: 12pt; background-color: #ffffff;">Thank you, everyone,<br></span></p><p><span style="color: #333333; font-family: helvetica,arial,sans-serif; font-size: 12pt; background-color: #ffffff;">Terry Smith, '59 TR3A, A-Type OD, TS 58667<br></span></p><p><span style="color: #333333; font-family: helvetica,arial,sans-serif; font-size: 12pt; background-color: #ffffff;">New Hampshire<br></span></p></blockquote><p><br> </p><blockquote type="cite"><br>** triumphs@autox.team.net **<br><br>Donate: http://www.team.net/donate.html<br>Archive: http://www.team.net/archive<br>Forums: http://www.team.net/forums<br>Unsubscribe/Manage: http://autox.team.net/mailman/options/triumphs/pdqtr6@comcast.net<br></blockquote></body></html>