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STK433-240 pinout?

In a Yamaha TRS MS02 for a Yamaha Tyros 2 keyboard

3 ch , 19 pin hybrid chip. I cannot find the pinning . A 27MB SM out there has full component level schema for the Tyros but not the powered speaker add on . Strange use of screened signal lead carying the 2ch input signals, to take 1ch back to the keyboard, separate lead for the other ch and woofer in the box. I'm particularly after the standby or mute pin. The STK433-240E is a different pinning, this one no suffix , ie not "A" either. Cold tracing so maybe erroneous

-power p2

+power p3 ch A, p4+5 o/p ch B, p6+7 op gnd p9+10 p11 an input, assumed , as capacitor feed p15 an i/p same C p17 an i/p, same C p18+19 chC, op leaving 1,8,12,13,14,16 unplaced so far, LV supplies ? , FB ? etc
Reply to
N_Cook
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How about

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and look at page 6, which has a pinout for an "STK433-240A-E" (3 channel, class AB, 40 W). It seems to match what you've traced:

Sanyo N_Cook What I think it means 1 -PRE Preamp negative supply? 2 -VCC -power Main negative supply 3 +VCC +power Main positive supply 4 OUT/CH1+ Ch A out Channel 1 output + 5 OUT/CH1- Ch A out Channel 1 output - 6 OUT/CH2+ Ch B out Channel 2 output + 7 OUT/CH2- Ch B out Channel 2 output - 8 +PRE Preamp positive supply? 9 SUB.GND Gnd Substrate ground (connect to ground)

10 GND Gnd Ground 11 IN/CH1 input Channel 1 input 12 NF/CH1 Channel 1 negative feedback? 13 STAND-BY Standby 14 NV/CH2 Channel 2 negative feedback? 15 IN/CH2 input Channel 2 input 16 IN/CH3 Channel 3 input 17 NF/CH3 input Channel 3 negative feedback? 18 OUT/CH3+ Ch C out Channel 3 output + 19 OUT/CH3- Ch C out Channel 3 output -

Elsewhere in the datasheet, it looks like you tie pin 13 to ground (or less than +0.6 V) for standby, and connect it to something between +2.5 and +5.5 V for operation.

Matt Roberds

Reply to
mroberds

A useful tabulation in that pdf, thanks . I'd wondered why there were what looked like disc ceramics at the 3 inputs, in fact for feedback, and had not noticed the 3x load sensing W/W dropper 0.22Rs were connected between the output pin pairings

Reply to
N_Cook

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