fluke 289 problem

[anwfeb]

Hello,
i have a problem on a fluke 289 when it is turned on without a probe it cannot state that it is without anything, for example on VDC it displays 0.0758VDC, on mV it displays 91.52mVDC, on ohms it displays 54.1MΩ, on the capacitor menu it displays 28.9nF. is the problem with the internal battery? and if i want to replace it, what part number suits it? and if it is not an internal battery problem maybe you can give me any input to detect this problem,

thanks

[Ugur]

Check your varistors.

[anwfeb]

Check your varistors.

the physical is fine, but for the RT1 i see like there are scratches, does that affect it?

[Ugur]

Have you measured your varistors? You should measure them as open circuit "OL" on the ohm scale.

[anwfeb]

Have you measured your varistors? You should measure them as open circuit "OL" on the ohm scale.

yes, one showed a value of 10 Mohms, but the remaining two showed OL, then i removed the problematic varistor i left it empty, and then i tested, but what was displayed was still the same, the multimeter could not display Zero when not in use.

edit:
even i removed all three varistors and left them blank, when tested, it's still the same, i haven't gotten a zero value on the display screen.

[Ugur]

I suggest you remove all varistors and try.

[anwfeb]

I suggest you remove all varistors and try.

and i removed all three varistors and left them blank, when tested, it's still the same, i haven't gotten a zero value on the display screen.
what other parts should i explore?

[Ugur]

Check the board under high light, is there any problem with the paths?
Check the rotary pins.
Check RT1- RT2- Z1 and R4.

[anwfeb]

Check the board under high light, is there any problem with the paths?
Check the rotary pins.
Check RT1- RT2- Z1 and R4.

i have traced the part of the track and there are no parts that have corrosion or problems.
then the rotary PIN also looks fine, clean, there is not a lot of dust stuck to it or blocking the switch.

RT1, RT2, and R4 value is 1KΩ ±1.024KΩ to 1.026KΩ i measured with fluke 175, but for Z1 i don't understand how to measure it? if it's just a resistance, i get a value closer to 1MΩ.

===============================
Edit:
now i have removed all the components that i think are connected to the red terminal, and i found that when one is removed, namely Z1 or RT1, the multimeter can display zero in voltage menu, and display OL in the Ohm menu, but the problem is not resolved, the damage is not in RT1 or Z1 they are fine, but i have to find again the path that i marked with a red arrow, because i see there is still pseudo resistance on the path marked by the arrow maybe it should be in the resistance measurement that there should not be any value with COM, and i haven't found out what component is problematic there.

[Ugur]

Z1 should be 1 Mohm. RT1 and RT2 should be about 1.1 K ohm. R4 should be 1K ohm. You should measure the varistors as open circuit. That is "OL". If these parts are good, you can check the parts up to U9. However, if I have to comment, since the Fluke 289 device has a lifetime warranty, it would be healthier to send it to an authorized service.

[anwfeb]

Z1 should be 1 Mohm. RT1 and RT2 should be about 1.1 K ohm. R4 should be 1K ohm. You should measure the varistors as open circuit. That is "OL". If these parts are good, you can check the parts up to U9. However, if I have to comment, since the Fluke 289 device has a lifetime warranty, it would be healthier to send it to an authorized service.

Yes, thank you. Because i think problem it was a simple thing, i didn't need to send it to the Fluke office, Besides that the distributor was in my country when i asked and it was charged. i don't understand the meaning of the guarantee, is it free? and if the device had already been disassembled, so i try to fix it yourself, and it did lead to U9, i would consider sending it to the official fluke.

[Ugur]

The device has a warranty, but as with all warranty conditions, this warranty covers manufacturing defects. In your first examination, you said that one of the varistors was broken. This is a part that can be damaged by improper use. Therefore, the service team may interpret this as user error.

[anwfeb]

The device has a warranty, but as with all warranty conditions, this warranty covers manufacturing defects. In your first examination, you said that one of the varistors was broken. This is a part that can be damaged by improper use. Therefore, the service team may interpret this as user error.

yes physically RT1 it looks like there is a crack or peeling, but for measurements i see both have the same value in ohms 1.024Ω
i thought 1K1 was under certain conditions maybe in a higher or lower temperature, whereas in room temperature it displayed 1.024Ω and i had to look for a similar replacement with the same value, and RV1-RV2-RV3 also I tried removing the third one and it didn't solve the problem either. this did not solve the problem when the multimeter was not used it still couldn't work to zero condition. i still think the problem i'm facing is no longer a Z1, R4, RT1, RT2, RV1, RV2, RV3, C3 problem, i think this area is clear because when i try to find a replacement component, it's still the same (i can't get 0.0000V or even in Ohms i can't get OL when the multimeter is not used)

but I'm still curious, before going to the U9, are there any components that could have an impact like pseudo resistance, sometimes I wonder whether there are false barriers on the mainboard at several layers?

sorry if my english is bad.

[Ugur]

If I were you, I would first clean the board with alcohol. Then I would heat the entire board with a hot air station. It may be a cold solder error.
If the problem still persists, I would check the following before U9.
Z2's 1st and 2nd pins are 10M ohms.
Z2's 6th and 3rd pins are 1M ohms.
R27 and R21 are 2Kohhm.
Q13 fet.

[anwfeb]

If I were you, I would first clean the board with alcohol. Then I would heat the entire board with a hot air station. It may be a cold solder error.
If the problem still persists, I would check the following before U9.
Z2's 1st and 2nd pins are 10M ohms.
Z2's 6th and 3rd pins are 1M ohms.
R27 and R21 are 2Kohhm.
Q13 fet.

Z2, Pin 3 to Pin 6 my fluke resistance is 420KΩ, it should be 1.1MΩ
the other pins i check all had the correct values.

[Ugur]

You may see different values ​​on the card. You can put the rotary position in ACV and measure again.

[anwfeb]

You may see different values ​​on the card. You can put the rotary position in ACV and measure again.

and it was still the same, until i turned the switch to the Ohm menu, even to the mA / A menu.

[parawizard]

If removing RT1 fixes it are you sure its not some kind of really high resistance short at the jacks or something? Conductive goo?

[Ugur]

There is a parallel capacitance connected to it so you may measure it differently. I don't think there is a mistake but if you want to be sure you should remove it and try it.
Have you tried heating the card with a hot air station?

[anwfeb]

There is a parallel capacitance connected to it so you may measure it differently. I don't think there is a mistake but if you want to be sure you should remove it and try it.
Have you tried heating the card with a hot air station?

i haven't done that, i just cleaned with a brush, so that no dust sticks, but haven't tried heating with hot air. Maybe this is the last solution if i don't find any damage, i will try washing with alcohol and drying with hot air.