• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Yamaha CR-2020 Stuck in Protection Mode

S

SharkBait07

New Member
I am lost trying to figure out why this Yamaha CR-2020 will not come out of protection mode and can use some help and encouragement.

As a noob hobbyist, I have replaced recapped the unit and replaced the ecap and relay boards. The triac mode and Secant's FR riser board is all added. Some transistors on the ecap, output, and preamp daughter boards A and B have been replaced due to failure.

With everything back together both channels the unit was working although there was some screeching and popping coming out of the left output. For this I had disassembled and cleaned the pre-amp coupler switch but there was still popping and screeching on the left side. This happens with the coupler switch in both positions.

After removing and checking almost all the transistors hfe and continuity in the relay board (TR707 was installed backwards), and output boards the behavior changed. All fuses have been checked.

As it stands, the relay does not click to come out of protection when powering up the unit. I can get the unit to come out of protection only by removing the B+ fuse (FR601) on the right output board (with the brown wire).

Here are the DC readings.
Relay Board Readings
AC (BE) 7.11
AC (BE) 7.11
TB (YE) 12.49
MB (OR) 12.51
E (BL) -0.005
-13 -10
LB (OR) 19.28
LB 19.29
LC 9.16
E -0.002
E -0.002
DL 7.46
PL 1.947
+25 (BR) 27.65
-25 (VI) -27.33
E (BL) 0
LL (WH) 0
R (RE) 0.004
E (BL) 0
B (BR) 24.21
r (VI) 0.009
I (GY) 0.009
HL (WH) 0
HR (RE) 0
SR (OR) 0
RI (YE) -0.004
E (BL) 0
LI (BR) 41.2
SL (BE) 0

Cap Board to Relay Board (L to R)
PIN 1 34.01 NB+
PIN 2 33.79 NB+
PIN 3 0 E
PIN 4 0 E
PIN 5 -34.64 NB-
PIN 6 -34.3 NB-

Cap Board
B+ 58
B- -58

Secant's Riser Board
R801 43.1 36.5
FR801 36.5 33.63
R802 -44.7 -38.4
FR802 -38.4 -34.36

Output Right
gy -109.5
wh -58.5
re 58.4
bl 0
br 41.1
rear trans. col. -58.3
front trans. col. 58.2

Output Left
gy -110
wh -58.5
re -58.5
bl 0
ye -0.005

rear trans. col. -58.3
front trans. col. 58.3

Any help is most appreciated.
 
Register to hide this ad
Welcome aboard.
After I re-capped my 2020's main cap. and relay board, and replaced all the transistors on the relay board, along with the relay itself - I had the same problem. Come to find out, the issue was on the main cap board. Two of the solder traces had become disconnected (mainly due to the heat), and had to be re-fabricated. I used small filiments of copper wire twisted together to reconnect the circuits.
Double check and reflow (if needed) any soldered connections on that board (main cap PCB). Do the same on any other PCB's if necessary.
 
I will recheck the solder connection again today on the new ecap (Niclafs) and relay boards (Secant). We also tried the chopstick test tapping around the back and front of the different pcb's and wire connections to see if we could hear any effect but didn't have any luck. Thank you.
 
Still no luck after re-flowing the solder on all the joints of the eCap board. However, the behavior has changes slightly. Now instead of playing audio out of the right channel with the B+ fuse (FR601) on the right output board, audio is only faintly heard with the volume cranked up.
 
SharkBait07 said:
br 41.1
Click to expand...

With 41 vdc on the output of the left channel .. The protect circuit is doing what it is suppose to do....
Either TR613 is shorted C - E. Or TR611 is shorted C-E.. Or Something else in the front end of that amplifier is holding and output to rail.
 
avionic said:
With 41 vdc on the output of the left channel .. The protect circuit is doing what it is suppose to do....
Either TR613 is shorted C - E. Or TR611 is shorted C-E.. Or Something else in the front end of that amplifier is holding and output to rail.
Click to expand...
Thank you. Tested both TR611 and TR613 and did not find any continuity between C - E. The transistor diodes tested in good working order. I will look for something on the front end of the amplifier that may be holding the output to the rail.
 
Check for solder bridging around C615 and C616.. Make sure C615 is installed correctly..
 
SharkBait07 said:
I am looking for the location of FR601…
Click to expand...
Close to D607.. tan/brown resistor on the lower left side edge..

index.php
 
You must log in or register to reply here.
Back
Top Bottom