MC252 Output Meters Access

[jayvis1]

Not sure how many MC252 owners are out there, but hopefully someone can help me fix this. There looks to be some dirt either behind the front glass panels in front of the meters or on the meters themselves. Are the individual meters enclosed by clear glass or plastic? How do I access the meters and/or back of the front glass panels to clean those areas? The MC252 has 3D front glass panels. I've been putting this off for quite awhile and would greatly appreciate any help.

[Chubba]

I am not sure about access.When I had the 252 upside down some black specs appeared in front of the meters.Once back on the amp stand I was able to dislodge them by tapping on the glass.You can remove the front cover and try tapping on the meters.Looks pretty cool in there when the amp is on.

[elshout]

I might be able to help. I bought a pair of MC601s brand new and once set up both of the meters were not at Zero. This bugged the heck out of me, especially for a brand new pair of $14,000 amps!!! The MC 252 looks similar so this may work for you.

1. Just behind the front panel, remove the 2 screws from the top and the 2 screws on each side - 6 total. This will allow you to lift the shield off. The piece I am talking about is that black shield between the front panel and the transformers. It has the MC252 Power Amplifier writing on it.

2. Remove the plastic knobs from the front - just pull strait off - away from the front panel.

3. Now there will be some screws accessible on the front panel that should be exposed now that you removed the shield that was hiding them. I then removed 4 screws toward the bottom rear of the front panel - they were attaching some L type brackets that attached the front panel to the chassis.

4. Then I was able to see some nuts on the rear of the front panel that were holding the front panel together. It was a 3 piece sandwich. Glass, rear, and the meter was in the middle. I was able to separate these and get access to the screw that adjusted the meter. This will allow you to clean the rear of the glass and the front of the meter. I doubt the dirt/specs are inside the meter.

You may have to remove some wires/ribbon cable connections.

I was very nervous working on these amps, but I just took a deep breath, and took it a few screws at a time. It was actually very simple. If you don't think you can do it, you can always stop and reassemble from whatever step stumps you.

Just make a note of each set of screws you remove so you reassemble in the correct order with the correct screws.

I almost took pictures and made a tutorial of this, but did not think many people wound need it. I wish I would have now.

Good luck.

[jayvis1]

Thanks elshout.

[wje]

The MC252 appears to have a very similar front panel to that of the MC402. Remove the 6 screws on the black shroud that indicates MC252 and the specs. Then, remove 2 screws from the bottom front of the amplifier. With the black shroud removed, you may then see approximately 4 more screws (2 on each side). Carefully remove your front two knobs and the felt pieces behind them. Ensure you have your amplifier placed on a soft towel, or similar. You should then be able to remove the front panel. It's a bit heavy (maybe 4 or 5 Lbs.) since the front glass panels are nearly 1/2" thick. Carefully, lie your panel face down on the soft towel. You should be able to see where the blue filters are installed into the front panel - as well as your meters - enclosed in clear plastic housings. I've found that using camera or eyeglass wipes work best as they truly are dust free. Since you have the knobs off, soak them in a bowl of warm water and liquid dish detergent for a few hours. Then, scrub the grooves on the knobs with a toothbrush and thoroughly dry them off. Then, re-assemble the pieces in the reverse order. You should be good to go. Also, the MC252, like the MC402 has 4 pots that you can with the black metal shroud removed. Two pots are for the left meter and two for the right. Of those two pots, the left pot adjusts the color brightness and the right pot adjusts the color temperature. Just thought I'd toss that out there in the event you need to make any adjustments on the color or brightness.