today my 1990 cluster LCD decided it wanted to start acting up!
I was driving normally and all of a sudden parts of the numbers stopped being displayed and the MPH was VERY slow to catch up, and sometimes wouldn't even change, while the A/C information display was correct and up to speed. also my information buttons (Trip A/B, inst/ Average MPG, and range) wouldn't register sometimes and be very slow to change the information with missing parts of the numbers as well
I don't know if its just from loose connections that need re soldered or if its the LCD.
if anyone else who had this problem, what did you do to fix it?

I also need to take my cluster apart anyway. my RPMs are way off.
it shows 4000RPM when at 2000, idles around 750, shows 3000 at idle each RPM number goes up in increments of 250
I know how to fix it, but I don't have a way to adjust the Tach with the Batee.com adjustable IC.
has anyone fixed their Tach IC without Batee's $600 out of stock tester?

 

Last time mine (also a '90) did that, which was last Fall, I just took it out and reinstalled it and it started working right.

I didn't tighten it down until I wiggled it around a bit with the key turned to the on position (not the run position)

The connection was probably sketchy.

Once it started displaying properly, I tightened everything down.

Batee does real good work, but I think a lot of times people send em out too arbitrarily when it's just something dumb wrong with it.

 

I dont like sending any thing out for repair for two reasons,
most of the time it's super expensive. Second, I can learn to do it myself, complicated or not.

I had a guitar pedal that broke, no display on the screens and no sound. I took it apart re-soldered the audio connections and any point that looked a little sketchy.
had it fixed within an hour, worked perfectly. It would have cost about $200+ to get it repaired

 

I did end up fixing both problems
I found an old thread for the Tach from about 2010? I think it was

One user soldered a potentiometer (POT) to those pins go on a test drive to adjust the Tach, and to measure the resistance and put in resistors to match the POT, and it made me realize how the Batee.com IC unit works. That's all it is!

Another user found that 300k is the right resistance for #4 to #10 and to cut the pins off the IC unit. Makes the Tach dead on +- 10 rpms
which completely skips the POT step.

Unfortunately, I didn't have a 300k ohm resistor and no one sells them locally, but I did have a 270k, which is what comes on the Batee.com unit, just with the adjustable POT to get it very close. It shows +- 100 which is no biggy.
Went for a test drive matched the RPMs with the A/C #6 trick. it is a much more enjoyable ride to know where my RPMs actually sit, and can see how much power I truly have still when up shifting, and can now effectively start rev matching on the down shift!

for the LCD screen I just resoldered the harness for the screen, and the 38?? pin plugin for the cluster itself. works like it should!
I got it all done in just a couple hours!

 

Good work. It's satisfying to get these jobs done