akai gx-620, shorted, need help/assistence

[Gangmania]

Hello,

I was changing the TIP47 on my akai gx-620 (power off) But when i wanted to use the multimeter with power on, I accidentally had the power switch come into contact with the housing. Then everything fell silent and the T5 fuse blown. I inserted new ones and every time I power it, it burns out again after 5 seconds. If I put a bigger fuse, it will stay on, but the pause, play, stop, ffd, fwd buttons will not work. Can someone help me?

 

[Gangmania]

here a picture where T5 is located, and its connected with the operation block. it goes trough a few transistors, capacitor and IC's. which one should i check first?

 

[JediDude]

Do the VU meter lamps light up? If not the bridge rectifier is probably defective. There is probably more than one component that got fried in your mishap....

 

[Gangmania]

thanks for you quick response, the vu lights light up, but the moment the fuse blows, the lights go out. Should i best start with the parts closest to F5?

I have an AKAI GX-215D for parts. There are some bridge rectifiers in there too. Can i use those as replacement?

 

[Gangmania]

And is it possible that other circuits are damaged too? Or should i only be worried about the circuit where F5 is in

 

[JediDude]

There is something else powered by that part of the power supply that is overloading and blowing the fuse. Is there any way you can temporarily disconnect the output of that section of the power supply to isolate the overload?

I have no idea if the bridge rectifiers would be interchangeable. There might be a part number on the compoment. If the part numbers match up, you're good. Sometimes a web search of the part numbers will turn up specs.

 

[Gangmania]

I can isolate the circuit of T5 but i don’t have another power supply.
I tested the bridge rectifier out of the board. And it seems okay.

Black lead of meter on the + of the rectifier.
+ (pin 1) -> ~ (pin 2) = 650
+ (pin 1) > ~ (pin 3) = 650
~ (pin 3) -> - (pin 4) = 650
~ (pin 2) -> (pin 3) = 0
+ (pin 1) -> (pin 4) = 1550


red lead of meter on + of the rectifier
= no readings

 

[JediDude]

Can you isolate the outputs from the power supply? If you can isolate all of them, check the outputs from the supply, and reconnect the loads one at a time. This might narrow down the source of the overload which keeps blowing the fuse.
BTW, make any changes with the deck unplugged from the AC source.