Dear people of EEVblog,
You are my last hope! Obviously, I have a problem with the meter in the subject and I need help. Here's an intro. I am a proud owner of HT Instrument device shown here:
https://www.ht-instruments.com/en/products/digital-multimeters/trms-multimeters/ht64/It's top of the line unit, it has all the bells and whistles including dedicated 4-20mA loop measurement range and rogowski coil range. Heavy and bulky unit with big fat fuses and perfect display with trend representation and data logging.
Well, it seems that the perfect screen is not so perfect. Unit is several years old, and in total it was used less than 5 hours (protection film is still on the front of the LCD). It was working normally at that time, and was used only in lab, only measuring some resistors and low voltages. Two years ago it was stashed away in basement in its carry bag. It was recently pulled out of the storage and it doesn't work anymore.
My first guess was the battery, but the battery is ok and charged, both fuses are ok, no moisture entered the casing. When the switch is moved into any position other than off, meter responds with a clear beep after pressing any button, but there is absolutely nothing on the screen, so my best guess is that the screen (or the backlight) died and the rest of the instrument is ok. I've opened it up and brought to work, guys at work checked it under a microscope (we are in electronics business), there was no visible corrosion or short circuits anywhere on the PCB, including LCD pins. Guys were clueless what to do next and so am I. I could not find a new LCD with the code that is on the original one. Also, the unit has an exposed JTAG connector inside, but I'm not sure if I can do anything with it. I have bunch of pictures made during disassembly that I can dump here, maybe it's a generic PCB that can be easily replaced. Please help me with my meter, thanks in advance!
Home
Help
Search
Login
Register
