The Dark Wob

Re the gauges, apparently the regulator is a 5V one and they do burn out. You should be able to measure a voltage on the back of the gauges with the ignition on.

Phil

Hooli wrote: ↑Mon Dec 07, 2020 12:59 pm

AMCrebel wrote: ↑Mon Dec 07, 2020 12:46 pm

Hooli wrote: ↑Sun Dec 06, 2020 7:02 pm One thing I hate on modern cars is the massively over servoed brakes that need a gentle glance at the pedal to stand it on it's nose & then there is nothing more all the way down the pedal.

Er....that's actually a pretty good description of the AMC braking experience - it's much more pronounced than my Disco or Ms Rebel's CR-V

It's why I couldn't drive my mum's Pony X2 years ago, if I even thought about looking at the brake pedal both front wheels locked. I've no idea how she drove it.

It takes a bit of getting used to but it's OK - I think US cars of the period were all about the power assistance - the power steering is very light - and the steering has no real "feel" in the way we'd understand it these days.
These cars were all about ease of use and relaxed coverage of long distances on sometimes dodgy roads.
Jabbing the brakes causes a big dip in the front suspension - it's soft and has no anti-dive geometry and no anti-roll (or sway as they Americans would have called it) bars.
A lot of AMC lickers in the USA have some killer suspension mods to bring it up to date but I don't have the cash and I think it wouldn't really work for a convertible.

PhilA wrote: ↑Mon Dec 07, 2020 1:15 pm Re the gauges, apparently the regulator is a 5V one and they do burn out. You should be able to measure a voltage on the back of the gauges with the ignition on.

Phil

Thanks Phil, I will take a look.

No, by 68 they were trying to stay afloat so you got simple designs, massive numb power assistance and so long as it stops in a straight line when you stamp the brakes and squats down to go when you stamp the gas, job's a good'un.

Phil

Got some time to investigate today. I am not sure if it’s only the positive supply (via the voltage regulator) - it may be one or both senders as well.

Using the meter showed the voltage reg was getting supply, but not feeding the gauges.

I decided to take the regulator apart to see how it works. It turns out it’s like a fast flasher unit - power heats up a bi metal strip that bends and breaks the contact that feeds the gauges - then it cools then reconnects - and so on. It’s like an early electro -mechanical form of pulse width modulation but probably with a messy waveform compared to a solid state type.

I tried a spare regulator from some a spare AMC speedo I had - no dice.

Now googling the solid-state replacements.

I take it you've done what you can like cleaning the contacts and checking continuity at each stage?

fried onions wrote: ↑Thu Dec 10, 2020 8:32 pm I take it you've done what you can like cleaning the contacts and checking continuity at each stage?

Not yet - I am eliminating stuff a bit at a time. I had power to the 12v supply side of the regulator(s) but no juice to the gauges. I suspect there may be several points of failure.

It is possible the 'sockets' on the round multi-plug have opened out and aren't making good contact. What's the score with the purple wires?

Good point on the multi-plug (Trivia - aren't these based on valve bases?) - the purple was done by a previous owner - it's the feed from temp sender which they've chopped and replaced with a replacement feed.
I have ordered a solid state regulator.