CR 2040 No Lights, No Relay Click

[absolve2525]

Grrr.... I was attempting to replace some dimming lamps in the meters, and accidentally tapped the long skinny board, with the four top lamps, against the main heat sink. Saw a spark, now no bulbs light or meters work. I replaced and checked bulbs. Perhaps a transistor blew? I only see a main fuse in the back. Are there others? The amp section is still working, as I can measure DC offset and bias, which aren't too high for the relay to not engage. Thanks for suggestions!

 

[petehall347]

follow orange and yellow wires from transformer and look for the fuses .

 

[petehall347]

if they are both good there is a resistor ladder . all 1k .

 

[petehall347]

look at the schematic it isnt hard to follow as i can do it easily .

 

[avionic]

Inside are two fuses F901 and F902 ( 3A / 250v).

 

[avionic]

Located on the power supply board right next to the Bridged rectifier. The same board has the loudness control and headphone jacks mounted to it. The protect relay is also on that board.

 

[petehall347]

has to be those fuses .

 

[absolve2525]

Thanks guys! Found the blown fuse!

 

[absolve2525]

Well crap. It's still burning up the left fuse. I used lamps that I bought years ago for a big Kenwood KR model. I assumed the voltage was the same, but perhaps they were not? I cut off all the dial lamps, disconnected the four top lamps. Now it's just the tuner lamp, which I replaced also with the Kenwood lamp. Still slowly blows the fuse.

 

[petehall347]

check the wiring first . and diodes to be sure . then put old lamps back if they were working but i guess not .. the sparking bit stands out to me .
or best disconnect the lamps completely to save chasing in the wrong direction .

 

[avionic]

Still slowly blows the fuse.

D912 perhaps.

Just in case............................
UF4004

 

[absolve2525]

I disconnected all the lamps, and the left fuse still slowly heats up. Sooo I will try checking the diodes. Thanks!

 

[absolve2525]

Do you know if there's a parts list to show what diodes I would need? I haven't replaced many diodes before. Thanks!

 

[avionic]

Do you know if there's a parts list to show what diodes I would need?

Yes. The manual calls it a schematic.

 

[absolve2525]

Cool, I didn't know for sure if type was shown. I'll check and come back with an update. Thanks!

 

[absolve2525]

Finally got some time to work on the 2040. Good call! D912 is bad. I ordered a pack of suggested BAV21 for replacements. I've read resistors before, but I'm trying to figure out how to read diode values. I understand the polarity, but I'll have to read up on the colors. Thanks guys, I'll keep you updated!!

D912 perhaps.

Just in case............................
BAV21 or equivalent.

 

[jbailey930]

good luck. it is a great receiver. I know since I have two although one needs a bit of work too. I have schematics but they are large, so i could take a pic as needed. Post an update....

 

[avionic]

Finally got some time to work on the 2040. Good call! D912 is bad. I ordered a pack of suggested BAV21 for replacements. I've read resistors before, but I'm trying to figure out how to read diode values. I understand the polarity, but I'll have to read up on the colors. Thanks guys, I'll keep you updated!!

D912 1S1885 (green and violet band) 100v 1 amp switching diode

 

[absolve2525]

Oooo okay. Is BAV21 too high of voltage? I can order BAV 20 if that's what I need.

 

[avionic]

Yamaha uses 1S1885's in everything.