Jag har köpt nyligen en Yamaha MX1 slutsteg, från Tyska ebay. När jag kopplade upp den med CX1-an och en Yamaha CD allt var fint bra ljud och allting körde riktigt bra. Efter en timme känge jag brännlukt ... det kom från steget. Nu har jag kopplat på flera gånger och samma sak upprepar sig, som att det går att köra fint till en timme sedan går tempen upp gradvis till 40 grader, sedan rusar under ca 2 minuter till 55...60 sedan mäter inte tämpmätaren, men det blir riktigt varm.
Jag laddada ner servicemanualen, och tomgångs ström över mittmotståndet stämmer 14mV efter 10 minuters funktion.
Jag hittade en artikkel om förstärkaren snarare teknisk deskrivning.
LOW IMPEDANCE DRIVE CAPABILITY
The MX-1 Amplifier is rated for continuous output power all the way down to 2 ohms - - impossibe for most amps because lower impedances cause much higher amounts of distortion. This means the MX-1 can be used with low impedance speakers and will function flawlessly even under fluctuating loads caused by variations in the music signal.
HIGH DYNAMIC POWER
Dynamic power levels, or the ability to deliver momentary power levels beyond the RMS power rating, is also exceptionally high. 280/630 W (8/2 ohms) for the MX-1. This is especially important when playing CDs, which have a very wide dynamic range.
HCA (HYPERBOLIC CONVERSION AMPLIFICATION)
The Yamaha developed HCA circuit goes a step beyond the conventional Class A amplification generally used in a high performance amplifier. In a Class A amp, when output exceeds a limit determined by the idling current, operation degrades to Class AB, resulting in increased crossover and switching distortion. With the HCA there's less distortion and less heat generation.
TOP-ART DESIGN
ToP-ART stands for Total Purity Audio Reproduction Technology. It dictates that every factor that could affect performance is analyzed and optimized. From its symmetrical layout, direct signal path, extra thick, gold-plated wiring, to its massive power transformers, with heavy-duty extruded aluminum heat sinks, and large block capacitors - - this component was designed with the finest quality throughout.
HEAVY-DUTY TOP-ART BASE
To support these heavy components and prevent vibration and resonance, Yamaha has a special base inside the chassis. It has a double panel structure, each 1.6mm thick, and the MX-1 adds extra damping material between the two panels. It's all supported by XL-AV (extra large,antiI-vibration) feet.
APS (ADVANCED POWER SUPPLY)
At low power levels, ordinary power supplies are adequate, but at middle and high levels, especially at low impedances, voltage irregularities called ripple are likely to occur. Yamaha's APS circuitry prevents ripple, maintaining precise, constant voltage at all power levels.
REMOTE POWER LINK
Remote power link with Yamaha CX-1 and CX-2 Preamps for custom installation applications.
A/B SPEAKER SELECTOR
Allows use of one or both sets of speakers.
3-WAY BINDING POST SPEAKER TERMINALS
Banana plug compatible on all channels. Permits the use of a variety of speaker wires and connectors.
GOLD-PLATED SOLID BRASS INPUT JACKS
Solid brass input jacks are gold-plated for optimum signal conductance and corrosion prevention.
LINEAR DAMPING FACTOR CIRCUIT
An extremely high, stable linear damping factor of 350 into 8 ohms, 20 - 20,000 Hz, means plenty of ability to stop the speaker cone from vibrating when the signal stops. It also cancels the effect of level variations due to high amp impedance. The result is clear, crisp, pure sound and significantly improved frequency response.
L/R LEVEL CONTROLS
Llocated on rear panel, this feature allows independent level control of left and right channels.
Jag tror att HCA kretslösningen har fått problem, istället för att sänka strömmen till slutsteget, så ökar den, med kraftig värmeutveckling.
Tar emot all hjälp jag kan få.
