HELP! Rotel RA-1062

[kchu1377]

My Rotel RA-1062 stoped working and all the fuse blew. I took it in to Rotel service centre and they told me the Power Driver is the cause and they must be changed in pair. They also told me something else needs changing but I forget what it was and that had to be replaced in pairs as well. Since they wanted to charge me an arm and a leg, therefore I ended up buying a new amp.

Now as I have no used of the amp I want to rebuild it or at least getting it to work. If I get it working then I may do more mod on it. Please if anyone have this amp or know what I should replace please help me out. I circled a few parts, are those the power drivers? And where can I buy them? There are 3 pairs and have part number as follow:

1) C3902
S 2F

2) A1507
S 4C

3) D600K
E 3K

Also do I need to change the 8 ic mounted on the heatsink? 4 of them are

D1047
E 3A4

and the other 4 are

B817
E 3A3

I did plenty of solding before, but I'm don't know much about amps. Please help!

[kchu1377]

More Pictures

[Bill Fuss]

Hi k,
First, you need the service manual, do a Google search for it.

Most of the parts you list are transistors, just put 2S in front of what you read, such as 2s plus c3902 equals 2sc3902, a common transistor. Work on one channel at a time and if its already broke you have no worries, just be patient.

Bill

[kchu1377]

Thanks Bill,


I tried to find the service manual for a long time but all I can find is the owner's maual.

So would the two boards in the bottom picture be the Power Drivers?

As I remember the service guy told me I need to replace a pair of Matched Power Drivers and a pair of transistors.


Thanks,

Kevin

[Bill Fuss]

Send John at {analogalley@sunflower.com} a request for the service manual, he can probably find one for you.
Bill

[Bill Fuss]

Send John at {analogalley@sunflower.com} a request for the service manual, he can probably find one for you.
Bill

[Bill Fuss]

Looking at your previous post, everything on the heatsink is just transistors. Just unsolder all of them and check them with a meter on the diode setting. If you dont know how to do that then you have some homework to do. Use Google searches for info, everything you need to know is out there.

Bill

[homemodder]

Hi kchu

I have repaired a lot of Rotel gear, i dont have the service manual for this one but if youd like i can send you for a diffrent model but that uses basically same topology and transistors. The main diffrence in these amps is the compensation scheme only and that should be ok.
I can guess what happened is that capacitor zobel network at the output failed causing oscilation and distruction of power transistors and with it most probably the drivers. Weak point in these models.
Can you do electronic soldering???
Can you do basic transistor testing?
First try and find a supplier for those transistors 2sd1047 2sb817 complementary pair and 2sa1507 2sc3902, rotel only use about the best transistors *sanyo* and very hard to find, maybe from a dealer of theirs. There are equivalents i could recommend.
The 2sd600 is usually used as vbe multiplier and should be ok. It is excellent replacement for 2sa1507 2sc3902 with its compliment 2sb631.

Alex

[kchu1377]

Hi Alex,

Thank you very much for your help. I can do electronic soldering as I worked on some PCB and batteries for my R/C hobby. However, I don't know how to test the transistors. I do have the meter.

It would be great if you can send me a copy of service manual for similar product. My e-mail kchu1377@hotmail.com

BTW is Power Driver same as Transistors?


Many thanks,

Kevin

[john blackburn]

KCHU1377

If you want to start learning about what things do this is a good site...

http://www.allaboutcircuits.com/

Theres a lot to read but it is a good starting point

John