Phoenix Gold Phorum

Hey guys I am helping a buddy of mine recap his ms 275 and I broke one of the transistors taking it apart I didn't have the right size allen wrench at first it was to big and didn't seat all the way flush (dumbassme) and I broke the corner off of it . I have pics just wondering if it should be replaced I am almost positive it does. I have a parts amp I can use or will buy him another. (If anyone knows the part # for it that would be greatly appreciated) I would also like to know the best way of replacing it. I have seen a thread about this here somewhere haven't found it yet. Thanks in advance guys
Tommy

Pic

I wouldn't replace it if it's properly working, which am pretty sure it is. The transistors die is placed a bit below the center of the device case. So that chipped piece is no where near the die, therefore it shouldn't have any ill effects on the performance of the device. If you are worried regarding cosmetic conditions then you can replace it, just make sure the transistor you use has the "O" right above the "J" on JAPAN which am pretty sure all MS amps them.

Ok thanks Ricky I wasn't sure. He isn't worried about the cosmetics.
Thank you!
Tommy

Ok guys need some more help my buddy powered the amp up using a 5 amp fuse the amp isn't blowing the fuse but he said that the green power light is flashing and the leds inside the amp are not on. He did say that when he powered the amp he heard a small pop noise. Any ideas
Thanks guys
Tommy

He needs to monitor the current draw (obviously is not drawing any excessive current since it is not blowing up the 5 amp fuse) and the voltage (could be getting a voltage drop, so probe inside the amplifier directly onto the board as the terminal block screws may be loose on the nulling toroid side.

Ok will give that a shot.

Also the amp was never tested before changing a he caps out. He bought it from a guy that lives around here the guy is a little shady also. Would changing out the caps make the amplifier act like this?
Thanks again
Tommy

No replacing the caps will not cause it to go into protect or blow fuses unless one or all are backwards.

I have seen an instance where someone used bad solder and it would t piwer up at all. I recapper again and it worked fine.

Can you put up a picture of the solder used? Or as Ricky said, any caps backwards would cause issues. Also, what caps were used?

I don't have a pic of the solder he used. I am not around his amp at this time just to be sure the caps where installed correctly I took a couple pics of my 275 and the caps I have which are the same that he has. What is the + and- on the amp and what is the + and - on the cap.
Thanks again guys

The square pad is positive. If the caps were reversed you would have known it by now. The power supply caps are directly across the 12V supply and as soon as you applied power with reversed caps they would have failed violently.

He absolutely needs to monitor supply voltage. Power light flashing is not normal behavior. It sounds to me like maybe the power supply is trying to start up and maybe when the rail caps charge the supply voltage sags enough to shutdown the amp and restarts. How large of a supply is he trying to power this with? It might simply be way undersized. Were the rail caps done when the PS caps were? Maybe a shorted rail cap??? But really, probably more likely that there are shorted or leaky output transistors than shorted rail caps... He could try to lift the main rectifiers to separate the PS from the power amp and see if it will start. That will narrow things down. Other possibilities are that there is a damaged insulator anywhere in the amp or even a shorted rectifier in the power supply. Does it behave the same way if it is powered up outside of the sink?

There are many possibilities. We require more information to further narrow it down.

Good luck,
Jason

Thanks guys we where working on tha amp during a hurricane late night drinking captain morgan. So the shortest lead off the cap is + I hope because if not the caps are in wrong. I wasn't at his house when he powered up the amp. He said he used a trolling motor battery off his sons lill boat not sure if he had a charger hooked to the battery.
Thanks again
Tommy

yes the short lead is the negative. It is also easy to distinguish with the stripe running down the side, with the "-" symbol inside of it running down the same side as the negative lead.