Rodek 275i (ZED Audio) amp

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Ok i think i found the right ones this time. The only thing is, these transistors are connected to the non-bridging speaker terminals where the two terminals themselves are internally connected on the PCB.

The transisors are Q101 and Q201 and are 2n5458. They both seam to diode check ok while on the PCB. Resistance between Legs 1-2 is ~270 ohms. Leg 1 is directly connected to the non-bridging speaker terminals. Leg 3 are connected to the 3rd from last pin on the right of the NW1.

Aside from these, I cant seem to find any other small transistors directly connected to any speaker terminal + or -.

Im not sure what I should do with what I've found. You think the NW1 has a problem?
 
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Here you can see Q101 (Behind blue pot) and the NW1 (Near RCAs)

IMAG0101.jpg
 
If they're OK, remove Q113 and Q213. Does the amp go into protect mode?

Removed Q113 and Q213 after confirming Leg's 1 directly connect to bridging speaker terminals. Also reinstalled Q2 and Q3 (C2389 SC) transistors.

Powered the amp up and it still goes straight into protection mode.

I've got 100ohms from Q113/Q213 leg pads 1-3. I pulled C111 and C211 for testing and they test out fine.
 
I pulled NW201 (ANW6) and measured alright around the 33k resistor; not leaking from anything around it not connected. Everything is measuring OK except however the two 120ohm resistors. They are measuring 78 ohms instead of what I thought should have been 240 ohms across them. This in an ANW6 9402. I dont find anything else wrong with this module.

About to pull the second one...
 
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Check the diode to confirm that there is no reverse leakage.

Without permanently damaging the module, can you solder it back into the board with the pin for the 33k resistor not connected?

If so, reinstall all of the transistors (and other parts other than the second module) to see if it will go into protect.

The information I have was faxed in January of 93. There may have been revisions or there may simply may have been an errors in the values on the document.
 
Got it. The diodes on the modules are checking out fine. No leakage at all.

I clippe half the pin of the 33k resistor so that when putting it back into the board it does not touch the PCB. If I need to re-connect it I'll just use a thin piece of wire lead with a little extra solder. Both modules are now soldered back in the PCB with the 33k pin detached.

I'm amazed you have the schematics for these things being so proprietary and all.

Testing amp shortly.
 
Hey Steve!!! You rock! But now I'm confused. This amp is using a TL594 although it looks like it may have been replaced at one time. I know they are about the same thing anyways.

[edit] i think you were refering to the first couple of posts anyways. And Yes; at least the ANW7 modules in this amp arent so healthy.
 
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Short Q1 base to emitter and power up the amp then remove the short. You can use a pair of hemostats or needle-nosed pliers to short them. Does that allow the amp to power up and does it remain on after removing the short?

If it remains on, confirm that the capacitor connected across the base and emitter of Q1 is within tolerance.
 
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