Rodek 275i (ZED Audio) amp

Dr Zeus

Member
2010-10-17 5:12 am
This amp looks like its going to be fun to work with!

IMAG0095.jpg
 

Dr Zeus

Member
2010-10-17 5:12 am
This amp turns on in protect mode. It looks like a real repair company took a stab at replacing all sorts of things; the TL594CN, LM358P, and several small transistors. Taking what I learned from the Hifonics Thor, I'll start tracing back through the parts and hopefully find something other than the proprietary circuits as failed.
 

Dr Zeus

Member
2010-10-17 5:12 am
The KF347 opamp near the RCAs has +13.4vDC on pin 4, and -16.25vDC on Pin 12.

THe outputs are measuring a tad bit funny. For isntance, Q217 (Posted picture, large output on the right in the middle of the heatsync) is easy to measure:

Q217
Leg1: -29.85vDC
Leg2: -30.67vDC
Leg3: -29.32vDC
-All negative

Q114 is on the other side, in the bottom left corner closest to the LEDs:
Leg1: -29.8vDC
Leg2: +33vDC (Positive)
Leg3: -29.13vDC
 

Dr Zeus

Member
2010-10-17 5:12 am
All input and outputs pins of the KF347 opAmp are measureing exactly +1.080vDC

Q101 and Q201 diode check ok. It looks like a previous adventurer replaced these transistors.

Q101:
Leg1: 0.000v
Leg2: -22.52v
Leg3: -21.87v

Q201:
Leg1: 0.000v
Leg2: -13.60v
Leg3: -21.97v
 

Dr Zeus

Member
2010-10-17 5:12 am
I had measured the KF347 inputs and outputs referencing amp ground. Referencing non-bridging terminals all inputs and outputs measure 0.000vDC.

The Q101 and Q201 was referencing non-bridging terminals. Invertently, when referencing amp ground Q101 and Q201 measure just +1vDC higher than before.

Unpowered, from non-bridging speaker terminals to rca shield measures 0.4 ohms.
 

Dr Zeus

Member
2010-10-17 5:12 am
I'm so proud of myself for desoldering this module so cleanly. Check it out

[IMGDEAD]https://i886.photobucket.com/albums/ac65/unclemeat2010/amps/IMAG0098.jpg[/IMGDEAD]

If the 2 end pins are the ones all the way to the right; I only get a resistance reading of 8.2k between just those two pins. Referencing either of those pins, all other pins read as open.

Should I take the other module out for testing?