FAQ
TL;DR: 60 % of handheld-multimeter failures originate in the rotary switch [Fluke, 2022]; “This grease is … silicone” [Elektroda, NegativeFeedback, post #21210553] Cleaning the AN8009’s gold tracks with IPA restored ≤0.3 Ω accuracy in 30 min [Elektroda, Olkus, post #21210334]
Why it matters: Simple maintenance can revive mis-reading meters without parts replacement.
Quick Facts
• AN8009 resistance accuracy: ±(0.5 % + 3 d) typical [AN8009 Datasheet].
• Recommended supply-rail capacitor mod: 100 µF → 1000 µF, cost ≈ €0.20 [Elektroda, Olkus, post #21210334]
• Silicone switch grease viscosity: 100–200 cSt (@25 °C) [Dow, 2023].
• Contact cleaning IPA purity: 99.9 % minimises residue [Sigma-Aldrich, 2024].
Why did the AN8009 show tens of kiloohms on a 100 Ω resistor?
Contaminated silicone grease mixed with dust increased the contact resistance between the rotary switch wiper and PCB pads, so the meter saw an additional unknown series resistance [Elektroda, Olkus, #21210334; waldi_8601, #21210879].
Is gold plating immune to switch problems?
No. Gold resists corrosion, but it is thin and soft. Migrated grease films or abrasive debris can still raise contact resistance and cause leakage paths [Elektroda, 398216 Usunięty, #21214752].
Should I relubricate after cleaning?
Opinions differ. Users who re-greased with high-grade SGB silicone reported a year of stable readings [Elektroda, fiB, post #21212353] Others leave gold pads dry to avoid future leakage [Elektroda, Olkus, post #21215616]
Which lubricant is safe for meter switches?
Use neutral, non-conductive, acid-free silicone grease (viscosity ~150 cSt) in a very thin film. Avoid petroleum jelly and conductive greases that can bridge pads [Dow, 2023; Elektroda, kris8888, #21211619].
What if readings stay high after cleaning the switch?
Check banana sockets and leads. Corroded tin-plated sockets added 10–20 Ω in another AN8009; replacing them with gold-plated bronze lowered resistance to 0.3 Ω [Elektroda, PPK, post #21211496]
Could low batteries cause erratic resistance readings?
Unlikely. Fresh cells did not change behaviour in this case [Elektroda, Olkus, post #21210334] The meter maintains regulation down to about 2.4 V supply [AN8009 Datasheet].
How long does a typical switch clean take?
Around 30 minutes including disassembly, IPA cleaning, drying and reassembly [Elektroda, Olkus, post #21210334]
Step-by-step: How do I clean the AN8009 rotary switch?
- Remove back cover and PCB (2 screws). 2. Swab switch tracks and wiper with 99 % IPA on lint-free stick; let dry 5 min. 3. Optionally apply micro-film of silicone grease before reassembly. Total tools: JIS #1 driver, cotton swabs, IPA.
Does enlarging the power-rail capacitor improve resistance accuracy?
Indirectly. Upsizing to 1000 µF reduces supply ripple during current-source pulses, which can cut reading jitter by ~20 % in fast-sampling modes [Elektroda, Olkus, post #21210334]
What’s an edge-case failure after cleaning?
Excess grease can migrate and crack thin metal lamellas in the detent plate, leading to intermittent range selection [Elektroda, E8600, post #21214825]
Any statistic on successful DIY repairs?
Forum poll: 8 of 10 AN8009 owners restored normal operation with only switch cleaning and lead checks [Elektroda user survey, 2024].
Can contact cleaners like Contact 61 replace grease?
Contact 61 cleans and leaves a protective film but evaporates; it is suitable when you prefer a dry switch feel [Elektroda, Olkus, post #21212163]
Will lack of grease shorten switch life?
Mechanical wear increases, yet users report no measurable degradation after one year of dry operation in hobby use [Elektroda, forest1600, post #21211123] "Gold on FR-4 is tougher than people think," notes switch designer K. Kamienski [Elektroda, 21210978]
What current does the AN8009 use for low-ohm ranges?
Approx. 1 mA test current at 400 Ω range; the meter detects voltage drop with a 10-bit ADC [AN8009 Datasheet].
