• 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

SA-7500 2SC1451 Replacement Question (KSC3503DSTU)

EastPoint said:
Is the writing on the 3503 facing the camera?
Click to expand...

It is hard to see there, but yes, it is.

merlynski said:
As best I can tell, those 2 transistors are correctly installed.
Click to expand...

Which brings me to dilemma of what the hell is wrong now? I am a little unsure of two caps on the volume and input selector board. There is a 100uf cap and a 220uf cap and I am not sure if I put them in the correct spots. I have a feeling they may be switched. It is very hard to make out in the service manual as the board number is different to mine, and the layout is slightly different. Looking in from the front of the amp, I have the 220 on the left and 100 on the right. The 220 is 63v and the original was 25, 63 was the closest I could get.

I need to get the a726 transistors changed, you can see one in the photo there. The legs look kind of corroded, almost rusty. I only have replacements for a725 though.

I also have to work out how the hell to remove the broken phono plug that is inside the input. I don't think I will be able to get it out. It is deep inside and I cannot get to the back to push it through... Looks like I will need to replace them.
 
Last edited:
Both A725 and A726 are replaced with KSA992.

You should be able to push the phono plug piece out through either end.
 
EastPoint said:
Both A725 and A726 are replaced with KSA992.

You should be able to push the phono plug piece out through either end.
Click to expand...

Perfect! You just answered my next question about the A725/726. I think I found what my $265 repair fee got me; ONE of the A726's were changed. So, not only did I get charged a ridiculous price to change one $0.30 transistor, they did not even change what needed to be changed. At the very least all A726, A1313 and the 1451 transistors should have been changed. What's more, the A726 replacement is not even correct... ****ing ripoff, useless dickheads.

I will get these changed today and try and get that phono piece out. I think I will swap that 220uf and 100uf on the AWF-015-B board because I am almost positive they are incorrect.
 
Last edited:
Decided to change the transistors on the eq and the volume board and swap those caps I mentioned around. I also changed some of the caps on the switch board.

I discovered a missing cap so had to put an old one back in until I buy a replacement.

So I tested it and no damn click again. Placed on ths bottom plate and placed the top on it and tried it again. Lucky I had the top on, a few seconds after I switched it on, there was a lound BANG and smoke. I do not know what popped though. Something did, because there is fluid on top of the lid. It was something on the power board cause I saw the sparks, and that is where the liquid is.

No idea where to go from here. What could have caused it? The transistors were all in correctly and so were the caps. If there was a cap in the wrong way, could that cause it? Also, what could have expelled liquid other than a cap? I don't see any popped. I thought it might be one of the power transistors.

Edit: Found the popped cap on the switch board, so I guess I put one in the wrong way around. I have never, ever done that before. I always triple check, I guess I was too tired tonight. Bugger.
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom