Nouveau Câblage et connecteur PCB plaqués argent
- 386807IMG1416.jpg (126.7 Kio) Vu 1709 fois
- 320929IMG1417.jpg (242.01 Kio) Vu 1709 fois
- 237478IMG1418.jpg (182.46 Kio) Vu 1709 fois
Voici les infos pour le remplacement des condensateur et diode, c'est un extrait du pdf de chez dada electronix, le prix du kit de base est 80 €.
Replace the other components before you replace the Op Amp chip. This way we avoid static discharges.
Remove R4, R6, R7, R8, D1, D2, C2, C3 (from board M12565.5 omitted), C4, C5, C10 and IC1.
o Leave R4, R6 and C4 in place for 0.5V sensitivity
Remove C17 from the board or from the separate clamp circuit on the output terminals,
prior serial 9000 there was no clamp circuit. But some units are converted at a later
stage
Remove the old PCB-connectors
Replace R6 with 100K for 1,5V sensitivity
Replace R4 by 6K8 for 1.5V sensitivity
Replace R6 with 220K for 0.775 V sensitivity
Replace R4 by 15K for 0.775V sensitivity
Replace R7 & R8 with 3K
Replace D1 & D2 with Zener 15V 1,3W (watch the position of the stripe!)
To reduce the switch off noise of the amplifier we decouple D1 with a 220uF electrolyte
capacitor, the plus wire connected to the cathode! The decouple cap is placed at the
copper side. See picture on page 7.
Decouple the Zener-diode D2 on the copper side of the board with a 100nF capacitor.
See the picture on page 7.
Replace C2 with 100μF (watch polarity!)
Replace C4 with 150nF 10mm pin spacing, in combination with R6 is 100K
Replace C4 with 68nF 10mm pin spacing, in combination with R6 is 220K
Replace C5 with 100μF (watch the polarity!)
Replace C10 with 100μF (watch the polarity!)
Replace C17 with 10uF bipolar, on the board or on the separate clamp Pcb, if present
In the 405-2 also replace C18 & C19 with 47μF (watch the polarity!)
Solder the new PCB-connectors to the board. Use a 1cm thick object like a small carton
box to fit them vertically one by one.
Replace the Op Amp with OPA604 (or OPA627). Avoid touching the chips with your
fingers, use pliers.
Replace D1 and D2 with the new zeners first, on a 405-2 board.
By changing the input-circuit feedback we reduced the sensitivity of the input to 1.5 V (Line- voltage) or 0.775 V (0 dBm) which is better suited for modern input-sources. This also reduces noise & distortion with another 9 or 4.5 dB.
We did this by adjusting local feedback and DC feedback.
J'alimente donc mes Studio Monitor 66 avec et le moins que l'on puisse dire c'est que ça envoi.. à coté nous avons des PCM à 15000 € et les 66 non pas grand chose à leur envier 
