Hello everyone

Sorry I started a new thread.

My RT-200 analyzer has been in use till now.Recently I found that the "HELP-0" error occasionally appears.I read the service manual but could not troubleshoot the problem.
If anyone knows how to fix this problem or has encountered a similar error, please tell me how to fix it, thanks

Fault phenomenon and description:

Turn on the power switch and enter the RT-203 module?For example: Enter "Low Range", enter "31", press Enter, and then into the 5LPM O2/N2 range.The screen will display "0000 0".Usually you will choose to press the "ZERO" button, and the screen will display zero.
However, after my RT-200 is reset to zero, the zero on the screen will always change as the power is on for a longer time. If I want to keep the zero display, I have to keep pressing "zero" to keep the display at zero.
Read the Service Manual, page 10-6.Enter "30" to enter the V/F converter interface, and find that the number cannot be displayed stably.
I tried to adjust the voltage values ??of R1102, TP4 and TP2, that is, the HI-LO voltage value can be adjusted to ±0.005VDC, and the screen can also display 387.
But as long as I restart the host,The V/F converter value will exceed the range of 250-500,It will take a long time to get back to the 250-500 range again.In other words, the value I adjusted cannot be saved.
(If it is not in the range of 250-500, I force the user interface to be used, and after pressing the reset button, "HELP-0" will be displayed.)

I compared the test videos of "10", "20" and "30" V/F converters, please see the video below

[Linked Image]

service manual->https://archive.org/details/manual_Timeter_RT-200_Calibration_Analyzer_Operator_and_Service_Manual/mode/2up

https://mega.nz/file/sMYVDYCS#Uezoi3J0ui5RHs7EFoCrBJ3jXdoJ0x2UB1VggLn92Lw

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