Amp Repair Grade: F

In 1978 my father brought home a new McIntosh MC2125 and C28 pre and a pair of ADS 910 speakers. Years of fun. Fast forward 2012 on a trip north my dad brought me the amp and pre. He’d had them cleaned in around 2006 and were used by him for a few more years.
A couple of weeks ago I brought the amp and pre in to be tested and cleaned by a certified McIntosh repair center in MA. I didn’t want to hook it up without being sure it would operate without any problems. I asked them to bring it back to spec, change any bulbs, check meters, and run the amp under stress to make sure it had no problems.
Got it home...about 5 hours of back and forth travel for the whole project and $400 all in. The pre seems to work fine-all controls, and there are many, are quiet and do what they should.
Hooked it up to some old speakers to test the combo and the amp has a mild popping sound in both channels that makes the meters dance to around 1/4 of the way up at full gain on the amp with or without the pre connected. With the "meter range" on "0db" it does not make the sound and on "hold" it isn’t noticeable. With music playing at regular volume it isn’t apparent on any of the "mter range" setting unless there is a quiet passage.
In addition, there is a higher than normal level of hiss coming from the speakers (with or without the pre hooked up), audible from across the room. I always remember there being this white noise, static, hiss, etc, but I suspect it is louder than it should be. When the tech took the glass off to touch up the faceplate he introduced large amounts of dust- looks like fine sawdust into the meters, one of which has a bulb out.
Both peices came back with dust and fingerprints all over everything. When I called and explained my findings the person that answered the phone seemed surprised, apologetic, and willing to have me drive two hours round trip to look at it again. I feel like I don’t want to let them near it again. I feel like they will never figure it out, waste more of my time, and in the end probably tell me the amp is old and I should lessen my expectations. I just say this because I’ve been down this road before with other "certified experts".
This set has some nastalgic value, plus it holds one of the main sounds of repoduced music that I grew up with. I would like to place it into any system I own freely but currently would not play it on anything other than flea market speakers.
Any ideas on the amp or a tech solution? As it stands I have no problem paying for the work done to the C28, but I feel like the amp came back worse off and don’t feel like I should pay for hack service.  I should add that I have no problem spending some money to have this work done right.