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fuse question

D

Dire McCain

Well-Known Member
I have been working on my pioneer a77x and along the line was diddling with the fuses.

The spec fuse was a 'T3.15amp 125 volt' which worked fine in the circuit.

I replaced it with a radio shack 3amp 250 volt fuse and it blows every time..
Is there that much difference between 3.15 amp and 3 amps? Or does the
'T' designation have some sort of meaning I don't understand??

Still learning...


Thanks
 
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Only try the slow blow fuse if the original was a slow blow fuse.

Was the original fuse just a thin wire, or is there more inside the fuse than just a plain thin wire?

If the wire inside the fuse is wrapped around something, or looks like a spring at one end, it's almost certainly a slow blow fuse.
 
No, the original fuse is just a tiny thin wire...3.15 amp...RS has a 3.15 slo blo but I am hesitant to use it...can't believe .15amps makes that much difference!!
 
Why did you replace the fuse in the first place? Was it blown? Maybe the question to ask is what is causing the fuse to blow?
 
Does the Pioneer still work OK with the original fuse.Or is the original fuse bad?
 
I took a look at the service manual and I have a couple of questions what is the full model number of the amp you said A77X what is the rest of the model number probably A77X/S.

Are there 4 of these 3.15A fuses?

Should be. What fuse is blowing F1, F2 F3 or F4? Or more than one?

Provide a history of what has happened. Was this amp working before you diddled with the fuses? etc....
 
I was 'troubleshooting'a board checking voltages and I hit the wrong thing at the wrong time...I replaced all the power transistors and the amp works great...but it can't handle the 3 amp fuse..let me explain, this particular fuse in question comes off one of the three power transformers...it was a fix made many years ago by a professional tech in tampa...I found this amp in a pawn shop with one dead channel...the tech fooled with it, jumped a few connections on the power supply... put a fuse between those connections...and the amp has worked fine for more than 14 years...except that it goes through power transistors every 4 years or so...
 
Dire McCain said:
I was 'troubleshooting'a board checking voltages and I hit the wrong thing at the wrong time...I replaced all the power transistors and the amp works great...but it can't handle the 3 amp fuse..let me explain, this particular fuse in question comes off one of the three power transformers...it was a fix made many years ago by a professional tech in tampa...I found this amp in a pawn shop with one dead channel...the tech fooled with it, jumped a few connections on the power supply... put a fuse between those connections...and the amp has worked fine for more than 14 years...except that it goes through power transistors every 4 years or so...
Click to expand...

I was 'troubleshooting'a board checking voltages and I hit the wrong thing at the wrong time...I replaced all the power transistors and the amp works great...

How can you say this works great.

but it can't handle the 3 amp fuse. Does the fuse blow right away or after a while?

Do you have the service manual? What changes have been made by the "tech".

How many fuses are in this amp 2 or 4. Not really clear on what we are dealing with.

Answer my question on the full model number also.

Can you take any pictures of the mods made by the tech?
 
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