Is it possible that the polarity was wrong on one coil of the DVC woofer?
There doesn't seem to be any internal fault that can cause the symptoms that you described.
There doesn't seem to be any internal fault that can cause the symptoms that you described.
I didn't even see the second question.
I agree. Replacing 15 amp transistors with 6 amp transistors isn't a good idea.
I agree. Replacing 15 amp transistors with 6 amp transistors isn't a good idea.
Well I got a whole mess now
I had flames shoot out at me today. So now my question is what all do I need to replace when I blow the power supply. I'm going to use the transistors suggested IRF 3205's. Now what else goes out when this happens? ( besides the outputs)
Now do all the transistors have to be matched? And if I replace one side do I need to replace the other? The other half seems to be ok.
I had flames shoot out at me today. So now my question is what all do I need to replace when I blow the power supply. I'm going to use the transistors suggested IRF 3205's. Now what else goes out when this happens? ( besides the outputs)Now do all the transistors have to be matched? And if I replace one side do I need to replace the other? The other half seems to be ok.
In the power supply, you should replace...
all of the power supply FETs
2 MPSA56 drivers
2 MPSA06 drivers (probably survived but replace them anyway)
Check the following...
10 ohm resistors between the collector of the MPSA56 drivers and ground
all of the gate resistors (after the blown FETs are out of the circuit)
12v zeners connected between the gate driver's emitters and ground
The power supply transistors must be matched in each bank of transistors. In my opinion, it's best for all of them to match but it's mandatory that all in each bank match. If you order FETs, order extras in case you don't get matched components. If you order by phone, tell the salesman that you need matching date codes.
In each channel, the 2N6488s have to match and the 2N6491s have to match. You don't have to replace the transistors in the other channel but they're inexpensive and really easy to change so you should. The amp is relatively old and the outputs could begin to fail due to age. If they fail, they may cause the supply to fail again.
all of the power supply FETs
2 MPSA56 drivers
2 MPSA06 drivers (probably survived but replace them anyway)
Check the following...
10 ohm resistors between the collector of the MPSA56 drivers and ground
all of the gate resistors (after the blown FETs are out of the circuit)
12v zeners connected between the gate driver's emitters and ground
The power supply transistors must be matched in each bank of transistors. In my opinion, it's best for all of them to match but it's mandatory that all in each bank match. If you order FETs, order extras in case you don't get matched components. If you order by phone, tell the salesman that you need matching date codes.
In each channel, the 2N6488s have to match and the 2N6491s have to match. You don't have to replace the transistors in the other channel but they're inexpensive and really easy to change so you should. The amp is relatively old and the outputs could begin to fail due to age. If they fail, they may cause the supply to fail again.
Um. Mine doesn't have those. It has the spots for them but they are not there.
Where do you buy your parts from?
Where do you buy your parts from?
They are not critical. Don't add them if none were installed when the amp was originally assembled.
Ok. you had me worried there for a second. Now the Cap leads are melted apart should I replace them with higher value ones or the same ones?
One other thing. Does it matter what brand parts I buy?
One other thing. Does it matter what brand parts I buy?
The same ones if you can find them. If you can't find the exact replacements, Radio Shack has 4700uF axial lead caps that should fit. I don't usually recommend RS for parts but the 4700uF caps I purchased there were all within tolerance.
For the FETs, I'd recommend International Rectifier. For the outputs, I'd recommend On-Semi.
For the FETs, I'd recommend International Rectifier. For the outputs, I'd recommend On-Semi.
These are the numbers at digikey. Mouser is generally a good source but they don't stock the IRF3205s.
IRF3205PBF
2N6488GOS
2N6491GOS
MPSA06GOS
MPSA56GOS
IRF3205PBF
2N6488GOS
2N6491GOS
MPSA06GOS
MPSA56GOS
... dont forget the 2.2uf 25volt tantulums
btw the 'PBF' after the IRF3205 simply means 'lead free'...so dont freak if they dont have the same suffix. 😉
the european market doesnt allow lead anymore.
you might want to inspect the insulating tape since you had a blowout and possibly order some...even a extremely small sliver of metal chard between the fets and heatsink can cause it too short... i learned the hard way 😡
btw the 'PBF' after the IRF3205 simply means 'lead free'...so dont freak if they dont have the same suffix. 😉
the european market doesnt allow lead anymore.
you might want to inspect the insulating tape since you had a blowout and possibly order some...even a extremely small sliver of metal chard between the fets and heatsink can cause it too short... i learned the hard way 😡
10-4 I'm gonna try my local electronics store tomorrow and hope they have everything I need.
I already have some tape. So I'm good to go.
I already have some tape. So I'm good to go.
one more thing, its easier and better for the fets if you mount them under the securing rails before you solder them...unless you can get them level with each other during soldering.
you can use a clothes pin with two pennies inbetween to draw some heat away from them while soldering.
you can use a clothes pin with two pennies inbetween to draw some heat away from them while soldering.
Well i got my parts toady. It was about $3 each for the irf3205's. I only had enough cash on me for one side so it will have to do for now.
The outputs are two different brands will that hurt anything?
The outputs are two different brands will that hurt anything?
Different brands won't be a problem as long as all of the 6488s are the same and all of the 6491s are the same.
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