I just had my McIntosh MR 74 serviced and all the lamps replaced two weeks ago. Last night I noticed some of the lamps are out above the left side knobs… What could be at play here? Bad contacts that need cleaning? Not a very techy guy and of course the tech I used is on vacation for two weeks.
McIntosh MR74 Lamps Out After Replacing
- Thread starter jgduck
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Bad Contacts is a possibility for sure.
I am assuming that the bulbs are the original style (incandescent.) It is possible that the quality of the replacement bulbs is not what it used to be. Another possibility is just the moving of the unit. I have moved recently to a new house and a few of the bulbs, that were working before, went out. I believe this was due to the mechanical strain on the filaments of the bulbs while moving the unit in the car.
I am assuming that the bulbs are the original style (incandescent.) It is possible that the quality of the replacement bulbs is not what it used to be. Another possibility is just the moving of the unit. I have moved recently to a new house and a few of the bulbs, that were working before, went out. I believe this was due to the mechanical strain on the filaments of the bulbs while moving the unit in the car.
Confirming the correct new incandescent lamps were used when replacing. I also did notice the window for the alignment meter was blinking a bit a week ago but that randomly stopped and looks fine now. Excuse me for the dumb question but when people say bad contacts is that just where the female part of where the bulb sits? And is that a fairly simple fix of just cleaning and re soldering? Appreciate the advice!
Pretty easy. I would get some bulbs on hand so you have all you need when you open the unit. I would use some contact cleaner on the bulb socket (probably with a Q-tip) - the ring and the tip in the middle. Don't get the cleaner on the glass or plastic colored gels. I would check that a wire was not broken off of the sockets during servicing. When all bulbs are in and lit then I would turn off the unit and give the bulbs time to cool before moving the unit as the filaments are more susceptible to breaking while hot. Put the unit back together and in place, then turn on and hope all is well.
If you remove the glass, do not take the glass out of the frame - there should be some screws on the top & bottom at the front of the chassis that release the frame that holds the glass - leave the screws on the endcap attached so the glass and frame stay together as one unit. You may be able to do the job without removing the glass - not sure - can't remember.
Be careful - good luck!
If you remove the glass, do not take the glass out of the frame - there should be some screws on the top & bottom at the front of the chassis that release the frame that holds the glass - leave the screws on the endcap attached so the glass and frame stay together as one unit. You may be able to do the job without removing the glass - not sure - can't remember.
Be careful - good luck!
Sorry for the delayed response! Thank you so much for the advice here. I’m going to try to clean the sockets this weekend. Was thinking Deoxit sprayed on a q tip and see if that solves the issue.
Some of those lamps have a holder that has two ears that you squeeze to remove the holder from the chassis. I’ve found that, in addition to the holder contacts being dirty, sometimes those ears don’t make good electrical contact with the chassis. A bit of sandpaper to clean up the tabs that fit into the chassis slots usually clears that up.