Just discovered it was D303 that was smoking....not the capacitor. D302 looks fine...what's the deal??
Using non-matching caps in McIntosh 2125 repair? Or will it destroy amp/burn down house?
Hi all,
Please take 5 minutes to read and let me know if what I am going to attempt poses any physical danger (fire, broken McIntosh amp, etc.)
today is my last day off before I start an 8 week rotation of working 7 days a week from 4am-8pm (the joys of med school) so I am scrambling to replace the caps on my old McIntosh 2125 amp. I didn't consider it until I would hear an occasional crackle from time to time, and also BOTH meters have never worked (although the light up fine).
I already cleaned all connections with DeOxit, replaced all 6 IC's on the meter PC board, as well as all of the electrolytic caps. Which offered no change. My plan today is to correct a few signal diodes on that same board which have their polarities reversed, according to the service manual at least, but they are reversed in a symmetric fashion so I don't even know if it matters since the culprits are in pairs, never solo or at a point of termination, so overall the phase output shouldnt be changed by their configuration (I'm guessing).
with that said, I'm working on to the Power Supply PC Board today while I still have the time.
First major issue I discovered when looking closely between the big parallel axial caps were 2 signal diodes that looked obliterated. I have enough silicone signal diodes and zener diodes to do the whole board, as well as the caps, well almost all the caps. I DONT have exact replacements for the 2 big electrolytic caps (C307, C308) that are rated to "85c, 2200MFD-16v". They don't appear to be In bad shape, but I will have to take them off anyways to get to the busted diodes inbetween them.
So option #1, remove them from the circuit board and test them with a digital multimeter (Klein Tools model MM2000) if that's possibly? I wouldn't know what readings would equate to "bad" though?
option #2: I have 2 Kimber Kaps .22+/-10% @ 600V. I'm assuming the .22 is micro (u) units, because it's not stated on the cap wrapper.....obviously this is pretty far off from the originals, but just so I'm prepared - when I remove/test the originals if I find they are bad will these Kimber Kaps suffice for a few months until I have time to install a proper replacement? Or would I run the risk of them blowing up/starting a fire/breaking my amp?
any input would be greatly apprefiated! I am damned and determined to get these meters working today...
thanks!)
Please take 5 minutes to read and let me know if what I am going to attempt poses any physical danger (fire, broken McIntosh amp, etc.)
today is my last day off before I start an 8 week rotation of working 7 days a week from 4am-8pm (the joys of med school) so I am scrambling to replace the caps on my old McIntosh 2125 amp. I didn't consider it until I would hear an occasional crackle from time to time, and also BOTH meters have never worked (although the light up fine).
I already cleaned all connections with DeOxit, replaced all 6 IC's on the meter PC board, as well as all of the electrolytic caps. Which offered no change. My plan today is to correct a few signal diodes on that same board which have their polarities reversed, according to the service manual at least, but they are reversed in a symmetric fashion so I don't even know if it matters since the culprits are in pairs, never solo or at a point of termination, so overall the phase output shouldnt be changed by their configuration (I'm guessing).
with that said, I'm working on to the Power Supply PC Board today while I still have the time.
First major issue I discovered when looking closely between the big parallel axial caps were 2 signal diodes that looked obliterated. I have enough silicone signal diodes and zener diodes to do the whole board, as well as the caps, well almost all the caps. I DONT have exact replacements for the 2 big electrolytic caps (C307, C308) that are rated to "85c, 2200MFD-16v". They don't appear to be In bad shape, but I will have to take them off anyways to get to the busted diodes inbetween them.
So option #1, remove them from the circuit board and test them with a digital multimeter (Klein Tools model MM2000) if that's possibly? I wouldn't know what readings would equate to "bad" though?
option #2: I have 2 Kimber Kaps .22+/-10% @ 600V. I'm assuming the .22 is micro (u) units, because it's not stated on the cap wrapper.....obviously this is pretty far off from the originals, but just so I'm prepared - when I remove/test the originals if I find they are bad will these Kimber Kaps suffice for a few months until I have time to install a proper replacement? Or would I run the risk of them blowing up/starting a fire/breaking my amp?
any input would be greatly apprefiated! I am damned and determined to get these meters working today...
thanks!)
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- 17 posts total
http://s1096.photobucket.com/user/hockey4496/library/New%20discovery%20McIntosh There is a tiny drop of solder on C307 that happens to be right above a pin hole on the circuit board, which on the other side (back) has solder over the hole. Does this mean anything? Should that C307 be tilted a little to make a connection?? |
I also just found a few of these transistors (2N3904-A06) seen here: https://www.fairchildsemi.com/datasheets/2N/2N3904.pdf are these usuable able anywhere on the Power Supply PC board? |
Post removed |
- 17 posts total