RPM Gauge is flickering

[mburshtain]

Not sure what started it, but recently I noticed my RPM gauge needle is flickering.

https://youtu.be/bQWzqxWQEi4

My car is working well, this is clearly not representing the true values

[Bitsyncmaster]

Probably the IC in the gauge has gone bad.

[mburshtain]

Probably the IC in the gauge has gone bad.

Oh so I need a new instrument cluster printed circuit?

[Bitsyncmaster]

Oh so I need a new instrument cluster printed circuit?

IC is short for integrated circuit. Also known as a chip. It is soldered on the circuit board inside the RPM gauge.

[Rich]

That's a failure I hadn't heard of before.

So it calls for removing the old tachometer from the instrument cluster (https://store.delorean.com/parts/electrical/3-6-6-instrument-cluster.html)?

And replacing the tachometer (https://store.delorean.com/105868-tachometer.html)?

[mburshtain]

IC is short for integrated circuit. Also known as a chip. It is soldered on the circuit board inside the RPM gauge.

Thanks Dave, I will try to get a hold of a replacement


Sent from my iPhone using Tapatalk

[David T]

Before ordering parts just try plugging and unplugging the connector to the flexible PCB. It could just be a bad connection and plugging and unplugging the connector will clean the connections up and maybe fix the problem.

[mburshtain]

Before ordering parts just try plugging and unplugging the connector to the flexible PCB. It could just be a bad connection and plugging and unplugging the connector will clean the connections up and maybe fix the problem.

Great advice David, I will give it a try.

[Ron]

I have a tachometer that reads off due to a bad precision resistor. Since I haven't had any luck sourcing a replacement resistor, I'd be interested in your old unit if you have to replace it. Or, maybe we could work something out where Dave M could rob the IC out of mine.
PM me.

[Bitsyncmaster]

I have a tachometer that reads off due to a bad precision resistor. Since I haven't had any luck sourcing a replacement resistor, I'd be interested in your old unit if you have to replace it. Or, maybe we could work something out where Dave M could rob the IC out of mine.
PM me.

What resistor do you need?

[Ron]

What resistor do you need? Been a while so I would have to dig to get the number. You may recall, I PMed you about it being made with a cut/gap down through the center of it?

...Just remembered it was 160 MPH.

[Bitsyncmaster]

Been a while so I would have to dig to get the number. You may recall, I PMed you about it being made with a cut/gap down through the center of it?

...Just remembered it was 160 MPH.

You could always use a few resistors to get an exact value you want. Or even use a trim pot. Most of the metal film resistors are 1% tolerance and are stocked in many values. You can probably calibrate it on the bench. It depends what the threshold of the tach signal is. I have built a signal generator for testing the idle ECUs that has two calibrated values 700 RPM and 850 RPM with a 400 volt signal level.

[Ron]

You could always use a few resistors to get an exact value you want. Or even use a trim pot. Most of the metal film resistors are 1% tolerance and are stocked in many values. You can probably calibrate it on the bench. It depends what the threshold of the tach signal is. I have built a signal generator for testing the idle ECUs that has two calibrated values 700 RPM and 850 RPM with a 400 volt signal level....it is so touchy that I could run a moist finger along the cut and make it read correctly.

65743
PM me your address if you want to play with it.

[mburshtain]

Before ordering parts just try plugging and unplugging the connector to the flexible PCB. It could just be a bad connection and plugging and unplugging the connector will clean the connections up and maybe fix the problem.

David, you were right !
I removed the binnacle cleaned all the connectors and tested it while driving. Working great, no more flickering.

Unfortunately, I broke the trip reset shaft during the binnacle removal. [emoji2959]
How hard is to replace it? I ordered one from DeloreanGo.

https://uploads.tapatalk-cdn.com/20210309/9d7aae10ac31fbcc6b8df4612ae9a868.jpg
https://uploads.tapatalk-cdn.com/20210309/27b3cd0ca44d0e0f0f4c6ec7bd018c4c.jpg
https://uploads.tapatalk-cdn.com/20210309/7ba8d9ffde519a50cb6520f3102eb06d.jpg
https://uploads.tapatalk-cdn.com/20210309/4011dfef617ab60c2798a1ba7fc167ca.jpg

[mburshtain]

Thanks to Christian Williams I replaced the trip reset shaft.
It’s a nice project, going really deep in the gauge...[emoji28]

https://uploads.tapatalk-cdn.com/20210321/953df40a016fc890006bc5e1ca25e9fe.jpg

https://uploads.tapatalk-cdn.com/20210321/39c212c13ca685ec0bfe4818d4301600.jpg

[Mark D]

Thanks to Christian Williams I replaced the trip reset shaft.
It’s a nice project, going really deep in the gauge...[emoji28]


My car's had a broken trip reset shaft since I bought it back in 2008 and it even came with a new replacement. I just never seem to get around to fixing it.

It looks like a fun project though. I actually kind of enjoy working on detailed/intricate projects like that vs. the rusty knuckle busting bolts I've been dealing with on my daily driver.

After seeing your pics I think I might dive into it this spring.

[Jonathan]

My car's had a broken trip reset shaft since I bought it back in 2008 and it even came with a new replacement. I just never seem to get around to fixing it.

It looks like a fun project though. I actually kind of enjoy working on detailed/intricate projects like that vs. the rusty knuckle busting bolts I've been dealing with on my daily driver.

After seeing your pics I think I might dive into it this spring.

You already have a copy of the DMCH instructions?

65820

[David T]

While you are inside make sure none of the plastic posts have broken off. On more than one car I found at least one broken and because there is a metal clip on it, it got attracted to and jammed up the speedometer causing several angle drives to fail. Glad to hear the tach fix was cheap and easy. Replace all of the bulbs while you are in there too.

[Mark D]

You already have a copy of the DMCH instructions?

65820

I think I have a paper copy buried in a binder somewhere, but the PDF will be helpful, Thanks :)