More actions
| Simco ChargeMaster Medium not turning on repair | |
|---|---|
| Device | Simco ChargeMaster Medium |
| Affects part(s) | Main switching transformer |
| Needs equipment | multimeter, soldering iron, soldering station |
| Difficulty | ◉◉◉◌ Hard |
| Type | Soldering, Teardown, Part replacement |
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Problem description
Fixing the ChargeMaster Medium that doesn't turn on, does not pull any current, and does not react to power. This particular issue is related to the main DC-DC transformer being faulty. This is a rather common issue with this device since the DC-DC circuit does not use any smart IC to reglaute it but rather an analog circuit to drive the switching MOSFETs that switch the transformer.
Symptoms
- Doesn't turn on.
- No reaction to input AC power
- Screen always off
Solution
This issue was rather hard to diagnose since there aren't any ICs that you can check the various pins of. After checking if the MOSFETs are not shorted, the resistors/diodes/caps are within spec, the only thing left to check was the transformer. There's currently no way to buy a replacement transformer, the only way is to open it up, unwind the wires making note of the number of turns, and then replace the windings with a slightly thicker wire. This problem occurs because the transformer heats up beyond its rated specification which cause the enamel on the windings to break and short them.
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