Measured voltage on Q and Q See attached schematics and troubleshooting guide. Union City My Country: I agree that they appear to have been running very hot. R and R are rated for ohm. Not Specified by Manufacturer. I forgot but had one from original amp that still worked. R at 27R sorta matches the listed voltages for about 6.
Typically, shorted power amplifier transistors trip the DC protection circuit. That could cause it. For the diodes, D gives me a reading of 0. Originally Posted by redwire. Be the first to review this item. Im wondering if somewhere within that area is the problem.
See attached schematics and troubleshooting guide. If the output transistors shorted, the fusible emitter resistors 0.
TOA Series II Amplifier Pmk2 w Single Channel | eBay
Note the polarity of the voltage if it is not zero. Originally Posted by redwire Note this amplifier uses a servo circuit op-amps M which work to keep the idling p9-12mk2 at 0VDC. At CN I get a voltage reading of around Find More Posts by Thedoc R at 27R sorta matches the listed voltages for about 6. You can start at the power supply, the amp input, the output, the middle etc. If you can post the schematic you obtained, that would help. In Stock Update Location close.
You may want to remove the pc board and check the solder amplifiwr, if the boards been running hot the solder can break down and cause poor connections, that might be whats wrong. The output transistors, drivers, pre-drivers, emitter resistors I would test. Let’s go with R as 27R sch typo is R and look amplirier trouble elsewhere. I could not find a service manual or schematic for the “P” series, but did for the “W” series wall mount and “A” series, like AMK2 which may be similar.
For the diodes, Amplifidr gives me a reading of 0. The time now is I just cant seem to find it. Typically, shorted power amplifier transistors trip the DC protection circuit. Im wondering if somewhere within that area is the problem.
TOA series ii Amplifier PMK2 I also failed to mention that there is a portion of the board which appears to have possibly overheated. Sometimes DC voltage stored on a capacitor nearby upsets the multimeter reading. For further details see delivery estimates in cart.
If any of the voltages on the drivers were off, the amp offset would be off, and you said you measured 0 volts on L, Just to double check, measure the voltage on the white. Please see attached photo and let me know what you think.
Toa Electronics PMK2 Watt Single-Channel PMK2 UL B&H
I am getting a reading on both at 1. The system also has a direct input so that it may be used without an input module. Or you can take more voltage readings with the amp powered on, carefully at each transistor and write them down. Rated 5 out of 5 by Anonymous from Painless Best price.
Find More Posts by redwire. Module slot accepts a variety of plug-in modules for easy customizability Wide Frequency Response Low Noise and Distortion 25V, 70V, and 8 ohm transformer-isolated outputs Direct input for connection of an audio source Direct low-impedance output mode for non-transformer operation Selectable Input Sensitivity Protection circuitry for overload, short circuit and overheating Turn-on delay disconnects output at power-up Master volume control Status indicators for normal, clip, power, protect, and signal Includes volume control security knob Optional rack mount kits available.
R is R on the schematic but pic looks like 27R installed on this board??? D gives me a reading of 0.
TOA 900 Series II Amplifier P-912mk2 120w Single Channel
Enter new zip code to refresh estimated delivery time. Don’t forget ampplifier order the input module separately if you need one. The PMK2 has a selectable input sensitivity to accommodate high or low inputs levels, a low cut switch to limit low frequency response, a master volume control, indicators for normal, signal, power, protect, and signal, and a turn-on delay which disconnects the output during power-up to prevent shock to the speakers.
TOA series ii Amplifier PMK2 P-912kk2 any of the voltages on the drivers were off, the amp offset seties be off, and you said you measured 0 volts on L, Just to double check, measure the voltage on the white. Have you checked the thermal cutout listed as thermostat Check the voltages on M protection ic it also drives the relay.
The protect light is on and the amplifier will not function.
I tested the transistors which appear to be good. I forgot but had one from original amp that still worked. Normally at idle you have 0V DC at the loudspeaker terminals, unless transistors have failed.