Not sure if you are aware: the 4400 was designed along side the 4000 series amps. The XLR pin-outs at the amp are different between the 4000 and 5000 amps. Pay attention! I actually caught an XLR cable on fire once trying to run a 5450 bridged with a cable built according to the 4000 series pin-out diagrams. The 5000 pin-out diagrams are harder to find!
Re-capping your 5450: be very careful removing the big "snap-in" caps. They are near impossible to get out without pulling the vias out with them. I learned the hard way to leave them alone unless they test bad.
Re-capping your 5450: be very careful removing the big "snap-in" caps. They are near impossible to get out without pulling the vias out with them. I learned the hard way to leave them alone unless they test bad.
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Thanks for the heads up, I will double check the pin/outs/ins. The 4400 is labeled on the board, no mystery there. I also have the pdfs for the 5450 from adcom so it shouldn't be a problem verifying things, and I've made sure of the polarities of the 5450 which has been running in my car for a while now. I am pretty legit at soldering as well, even picked up a hot air desoldering station a while back that will be getting tested soon. There are tons of new caps awaiting an easy life.
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Very cool! I am fascinated by you guys that can successfully re-cap these old gems. I have tried. I am not good at it. I have a hard time removing them. I think a HAKKO 808 will be in my future if I decide to try again. Unfortunately, there is only one way to practice. And, I don't own "practice amps". Just me sweet ADCOMs, and a few SoundStreams. I stopped practicing on them after I ruined a 4304.
I replaced the caps in the 4400 like cake today, but the adcom and ppi amps will be more difficult, especially the snap ins. The ones that will be installed won't be snap in, just some epcos 5600uf 105c. I'm a little worried about pulling the adcom from the car and finding out I need one more capacitor after getting knee deep into it, don't want to go without music for very long. :lol:
Oh, the hot air desoldering tool didn't help. It was very hot and you can control the temp and air independently, but all I managed to do was start scorching the pcb. When that started happening, I grabbed the iron instead, which worked perfectly.
Oh, the hot air desoldering tool didn't help. It was very hot and you can control the temp and air independently, but all I managed to do was start scorching the pcb. When that started happening, I grabbed the iron instead, which worked perfectly.
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My advide, you can do what you like:
Test the snap-ins, and if they pass, leave them alone. They are not in the audio path. And, if they are good, they are good.
These boards are very-very fragile.
Also, regular through-hole caps do not work well in the large snap-in holes.
It is really hard to get a good flow from the bottom to the top of the board without that fat leg in the hole.
Test the snap-ins, and if they pass, leave them alone. They are not in the audio path. And, if they are good, they are good.
These boards are very-very fragile.
Also, regular through-hole caps do not work well in the large snap-in holes.
It is really hard to get a good flow from the bottom to the top of the board without that fat leg in the hole.
Not difficult to fold the legs if that's the case, and I don't want to risk them leaking being such an old amp. I'd rather attempt to give them a new lease on life than risk them dying in this southern heat. I may be able to drill out the old cap leads with a random dremel bit if they prove to be a hassle. Will update
The hot-air is generally only used to add heat to the board (not to the point of damaging it) so that the board doesn't soak the heat from the solder connection. A 300° board will soak less heat than a room temperature board. The soldering iron is used as it would be normally.
You also have to be sure that the leg is parallel with the sides of the hole. When installed, the snap feature pushes it against the side of the hole. If you don't straighten the leg before pulling it, you're likely to damage the via.
You also have to be sure that the leg is parallel with the sides of the hole. When installed, the snap feature pushes it against the side of the hole. If you don't straighten the leg before pulling it, you're likely to damage the via.
Thanks for the advice. I've watched vids of people using the hot air to remove components without an iron but they were smd which is probably why they came right off. I guess it may be possible for me to coordinate not toasting the pcb with the air and also using the normal iron to get a better removal, maybe I can adjust the hot air to be just below the pcb heat tolerance. It seems to have an accurate adjustment range.
I need to repair my little two channel phoenix gold and install it temporarily in the place of the adcom to be able to work on the recap but have been too lazy, even have the parts already. :/
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