Hello,
Im trying to fix an Alpine 3554. its blowing fuses and even melt the sockets of the fuse.
I checked some of the transistor, for each channel it uses, 2sc4387 and 2sa1672. On one channel, repair has been made and it uses 2sc3182 and 2sb827.
While the transistor is intact, the previously replaced 2sb827 has shorted legs. So am i correct that this is defective?
Where can I get the replacement parts for the 2sc4387 and 2sa1672. I want to restore it back to them its they are still available.
I noticed some capacitors are getting bulged a bit, should I replace them while I fix the transistors?
How do I remove the caps which has been epoxied?
What other things should I pay attention to an amp this old. I really like to fix this.
Thanks much for the pointers.
Kind regards,
Ben
Im trying to fix an Alpine 3554. its blowing fuses and even melt the sockets of the fuse.
I checked some of the transistor, for each channel it uses, 2sc4387 and 2sa1672. On one channel, repair has been made and it uses 2sc3182 and 2sb827.
While the transistor is intact, the previously replaced 2sb827 has shorted legs. So am i correct that this is defective?
Where can I get the replacement parts for the 2sc4387 and 2sa1672. I want to restore it back to them its they are still available.
I noticed some capacitors are getting bulged a bit, should I replace them while I fix the transistors?
How do I remove the caps which has been epoxied?
What other things should I pay attention to an amp this old. I really like to fix this.
Thanks much for the pointers.
Kind regards,
Ben
Any amp this old needs all of the caps replaced just because they are way past any shelf live they were ever were rated at. It's simple good practice to do this as most caps only have a 5 year lifespans by their respective makers I might add. Wet caps are the weakest component inside ANY electronic device. Just use a exacto knife to gently cut around the caps base so the old cap can be removed. I use electronics grade Silicone sealant to replace the seal when I replace them.
As for your mismatched output devices, well I use only original parts so as to remove any guess work engineering you may create when putting in whatever you have laying around. Seen this a lot lately, and its just more work to put the unit back to original. But IMO it must be done unless you want to reverse engineer the whole device.
As for where to get the parts well I am lucky here in Cali. we have PAC parts in So-Cal and they usually have most any transistor used in Alpine in their stock. They are online just google them.
And when replacing 2SA and 2SC parts you usually use 2SA and 2SC parts or if you must use lower grade devices then look for 2SB and 2SD matched pairs . A & C or B & D is how they match up sets overseas.
If you pull the bad outputs and test the amp on a current limited supply you will be able to diagnose weather or not if there are power supply issues other then bad caps that caused the amp to melt its fuse holder. Once the bad outputs are removed this amp should turn and idle properly if no other problems exist.....
Also be prepared to replace the driver IC in the bad channel. I have seen bad outputs toast the driver IC many times. And in your case where a device has been subbed improperly well its a best guess the driver is also bad at this point. They don't like to operate into dead short conditions usually
Hope this helps, I am familiar with your Alpine amp from back in the day, and have successfully repaired many of them over the years, good luck on your restoration work
Hello,
Thanks for the tips everyone.
I found pac parts website but they dont carry the transistors. Also im having trouble sourcing the 8 power supply caps, its 40v 2200uf 18x25mm. Mouser only have 2 types, and both are 35v. Digikey doesnt even have any.
Pac parts has some capacitor for alpine 3554, but it doesnt say which one or value, and the price is $8 each.
As far as the replaced outputs, it was working fine, but I didnt know that it was replaced by other type, and that channel was bridged. It works for about a week though. I guess normal use should be fine, but not bridged.
Any hints to where I can source the transistors?
Thanks again,
Ben
Thanks for the tips everyone.
I found pac parts website but they dont carry the transistors. Also im having trouble sourcing the 8 power supply caps, its 40v 2200uf 18x25mm. Mouser only have 2 types, and both are 35v. Digikey doesnt even have any.
Pac parts has some capacitor for alpine 3554, but it doesnt say which one or value, and the price is $8 each.
As far as the replaced outputs, it was working fine, but I didnt know that it was replaced by other type, and that channel was bridged. It works for about a week though. I guess normal use should be fine, but not bridged.
Any hints to where I can source the transistors?
Thanks again,
Ben
I would agree with 1moreamp. Have to replace all electrolytics inside, especially the bigger ones. Like 12VDC cap and +/-rail caps. They all have turn bad, usually corroded the PCB tracks too.
If you can't find the exact replacement, any audio output transistor (with the same size, voltage and current rating) will do.
Coba anda pakai TIP35C-TIP36C, tipe ini biasanya bandel, kuat.
If you can't find the exact replacement, any audio output transistor (with the same size, voltage and current rating) will do.
Coba anda pakai TIP35C-TIP36C, tipe ini biasanya bandel, kuat.
B&D Enterprises: Part #2SA1672
B&D Enterprises: Part #2SC4387
If you remove the shorted transistors, will the amp power up? If so, measure the DC voltage on the center leg of the output transistors (one probe on center leg, other probe on a non-bridging speaker terminal). If the voltage is 35v or less, you should be able to use the 35v caps. I don't know if this power supply is regulated so you should measure the voltage with a relatively high input voltage (~14v DC).
If the rail voltage is greater than 35v and the original capacitors haven't vented or leaked, they are probably OK. Heat the terminals of several of the capacitors that are bulging. If you don't smell anything that smells like vinegar or antifreeze, the caps are probably not leaking. If the caps are leaking, they must be replaced. If you can't find any with the same capacitance with sufficient voltage, you may have to use caps with less capacitance. It's not an ideal situation but if the required parts are not available, there's not much you can do.
B&D Enterprises: Part #2SC4387
If you remove the shorted transistors, will the amp power up? If so, measure the DC voltage on the center leg of the output transistors (one probe on center leg, other probe on a non-bridging speaker terminal). If the voltage is 35v or less, you should be able to use the 35v caps. I don't know if this power supply is regulated so you should measure the voltage with a relatively high input voltage (~14v DC).
If the rail voltage is greater than 35v and the original capacitors haven't vented or leaked, they are probably OK. Heat the terminals of several of the capacitors that are bulging. If you don't smell anything that smells like vinegar or antifreeze, the caps are probably not leaking. If the caps are leaking, they must be replaced. If you can't find any with the same capacitance with sufficient voltage, you may have to use caps with less capacitance. It's not an ideal situation but if the required parts are not available, there's not much you can do.
Hi Perry,
Thanks for the links. Will get them from that site.
Attached is the suspected caps. I will try to remove the shorted transistor. I havent opened up the amp yet.
Just to be sure, so test the voltage on the working channel output transistors, center leg, and what do you mean by non-bridging terminal? a (-) output of a terminal that do is not used when we bridge the amp?
Btw, 1 of the 2 fuse sockets are melted and 1 connector is missing, is there a 40 amp blade fuse? Can i short the fuse, and fuse the B+ just before the amp? or its not a good practice to do so.
Thanks and regards,
Ben
Thanks for the links. Will get them from that site.
Attached is the suspected caps. I will try to remove the shorted transistor. I havent opened up the amp yet.
Just to be sure, so test the voltage on the working channel output transistors, center leg, and what do you mean by non-bridging terminal? a (-) output of a terminal that do is not used when we bridge the amp?
Btw, 1 of the 2 fuse sockets are melted and 1 connector is missing, is there a 40 amp blade fuse? Can i short the fuse, and fuse the B+ just before the amp? or its not a good practice to do so.
Thanks and regards,
Ben
Attached is the suspected caps. I will try to remove the shorted transistor. I havent opened up the amp yet.
**** There is no attached file.
Just to be sure, so test the voltage on the working channel output transistors, center leg, and what do you mean by non-bridging terminal? a (-) output of a terminal that do is not used when we bridge the amp?
**** Yes but it's not necessarily going to be a negative terminal.
Btw, 1 of the 2 fuse sockets are melted and 1 connector is missing, is there a 40 amp blade fuse?
**** Yes but the single fuse holder will likely overheat if you try to pass 100% of the current through it. You can try it. If it doesn't overheat, you can use the single fuse.
Can i short the fuse, and fuse the B+ just before the amp? or its not a good practice to do so.
**** If the fuse holder overheats using a single fuse, yes, bypass the internal fuse and use an external fuse.
**** There is no attached file.
Just to be sure, so test the voltage on the working channel output transistors, center leg, and what do you mean by non-bridging terminal? a (-) output of a terminal that do is not used when we bridge the amp?
**** Yes but it's not necessarily going to be a negative terminal.
Btw, 1 of the 2 fuse sockets are melted and 1 connector is missing, is there a 40 amp blade fuse?
**** Yes but the single fuse holder will likely overheat if you try to pass 100% of the current through it. You can try it. If it doesn't overheat, you can use the single fuse.
Can i short the fuse, and fuse the B+ just before the amp? or its not a good practice to do so.
**** If the fuse holder overheats using a single fuse, yes, bypass the internal fuse and use an external fuse.
To minimize the chance of damaging other components, you need to screw all of the transistors back to the sink. Without clamping them, the transistors can fail within seconds if there is a problem.
Use a 10 amp fuse in the B+ line to provide additional protection.
If you have a jeweler's screwdriver, it won't take more than a few minutes to screw the transistors down. Don't use power tools, you will risk breaking the screws.
Use a 10 amp fuse in the B+ line to provide additional protection.
If you have a jeweler's screwdriver, it won't take more than a few minutes to screw the transistors down. Don't use power tools, you will risk breaking the screws.
Hello,
Havent test run it yet. But the overheated power supply caps are out, I checked by charging with +6vdc, and measuring the voltage across. 1 is slowly declining in voltage, the other one is much faster. So will replace both of these.
Can the failure of this cap somehow blown the output transistors?
Ordered the transistor hopefully getting here in a week ;(
Regards,
Ben
Havent test run it yet. But the overheated power supply caps are out, I checked by charging with +6vdc, and measuring the voltage across. 1 is slowly declining in voltage, the other one is much faster. So will replace both of these.
Can the failure of this cap somehow blown the output transistors?
Ordered the transistor hopefully getting here in a week ;(
Regards,
Ben
I know of no way that the primary filter caps could cause the failure of the output transistors.
If the two small caps near the rectifiers have one leg connected to the center leg of the rectifier and their other leg directly connected
(~0 ohms) to the secondary ground (non-bridging speaker terminal), you're probably correct and you could use 35v 2200uf caps but you need to confirm that the rail voltage is no more than ±35v. You should reinstall the primary filter caps (the two you removed) before applying power.
If the two small caps near the rectifiers have one leg connected to the center leg of the rectifier and their other leg directly connected
(~0 ohms) to the secondary ground (non-bridging speaker terminal), you're probably correct and you could use 35v 2200uf caps but you need to confirm that the rail voltage is no more than ±35v. You should reinstall the primary filter caps (the two you removed) before applying power.
Hello,
You are correct. The 2 caps are connected to center legs of the duals, and the other leg of the caps is connected to the non-bridging terminals.
Will measure the rail voltage later to check if its more than 35v.
Can an output transistor blow without blowing other component?
Thanks much,
Ben
You are correct. The 2 caps are connected to center legs of the duals, and the other leg of the caps is connected to the non-bridging terminals.
Will measure the rail voltage later to check if its more than 35v.
Can an output transistor blow without blowing other component?
Thanks much,
Ben
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