• 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-6300 repair, fuses blowing, both channels working

KingKung

KingKung

New Member
Hi!

Long time ago I got this beauty and it played wonderfully. But one day the fuses blew, I got new ones and they blew as well.

At that time I upgraded my entire setup and let the Pioneer take a rest in the closet.

Now I'm looking for projects to finish and this tickles my fancy.
I don't have too much knowledge in electronics other than knowing what not to touch when it's live. I googled around and I've found a lot of results on this site, but none seemed to have come across my issue from what I can tell.

With the help from the other thread I disconnected the protection circuitry board and the fuses stopped blowing up, the ones next to the 42 mark on the mainboard.
It was suggested to check the output transistors, but they were all working and the two channels are playing sound, with the protection circuitry board disconnected.

I'm currently on the last pair of fuses and I wanted to doublecheck with your guys help before I connect it all back together for another test.
 
Register to hide this ad
looks like a crowbar protection circuit . it could be that its working as intended . measure dc volts at the speaker outs .
 
is that both left and right channels ? if so that looks good . i suspect D101 first . check if its shorted .whilst you are at it test Q101 and Q102
 
Waiting on the iron to heat up. I have to desolder them to test them properly, correct?

Cant tell which are the gate/drain/source on this one, the SM2B41
 
Last edited:
It's giving me a beep when I put Positive on A1 and Negative to A2, vice versa.

Positive on Gate and Negative on A1 and A2 doesn't give me a beep, but a readout of about 320ish.
 
Keeps beeping after shorting the pins together between A1 and A2.
Setting the multimeter to 200k and 2k resistance(?) gave 0 readout between A1 and A2.

Edit:
The Q151 does not beep from the A1 and A2 pins(left to right)
Neither does the TQ247.
These were the two smaller transistors next to the SMB241.
 
Last edited:
the small transistors have ECB pin outs emitter collector and base . the TRIAC isnt a transistor .its a switch . anyway it looks the triac is shorted . if you remove it the fuses wont blow if that is correct . i do believe some people remove the protect circuit and install one with a relay instead .
 
So I'll put back the smaller ones and leave the SMB241 out and connect the protection circuitry board back to test if fuses blow?
 
The pin 4 and 5 tests 0 reading at board and the disconnected cables themselves.
Also reading 0 when connected to the board.
 
thats strange as i cant see a path with the triac removed .it should not be possible to get less than 0.5 ohms even if the triac was shorted and installed .
touch your meters leads together and see what it reads ,
 
4 is ground and i expect it to be black . 3 should be at -22v and expect it to be orange .5 should be at =22v and i expect it should be red . thats if the colour codes were followed correctly in the first place . i have seen it where colours dont match what you expect . it would be best to find a pic of an untouched one .or follow the wires back . service schematic is on hi-fi engine .
 
You must log in or register to reply here.
Back
Top Bottom