OK, let's start over.
Since the EE savvy among you knows a great deal about the internal workings of the amp, there's a subtle implication that there are things inside the amp that should be checked, which I'm not capable or willing to do myself-this is what I was attempting to get clarity on.
If on the other hand, it's as simple as probing the amp's output terminals, I can do that but do need to know if should check V or I, and can/should I do it with the speakers connected and running or short the terminals without them connected. And of course, what should I be looking for as normal/abnormal?
that said, while plugged in last night but on mute there was an occasional "pop" so its definitely going bad and was replaced by an S800 for now. I'd really like to get it fixed if anyone can recommend a repair shop in Orange County.
I was thinking dc voltmeter on unloaded output, but it sounds like the problem is beyond that now... bummer.
I'm a Soundcraftsmen enthusiast and came across this thread while searching for some information on my MA5002. This thread might hold a record for the longest running active thread on any topic!
I have two Pro-Power Fours, a Pro-Power One (shoebox), an MTX/SC A100 and of course my MA5002. My old SC DX3000 and DX4100 pre-amps both died (sold as-is on Ebay a few years back), and I've been looking for a replacement ever since. I also have a PCR800 with a blown channel that I may eventually try to fix (on the to do list for 5 years so far). I'm currently using a Parasound pre-amp which works ok, but just doesn't match my amps as well, IMHO. For speakers I have a pair of Paisley SPL3000 and SPL4000 monitors and a pair of JBL 2231As running as subs (they are ready for a recone-gulp!). I also have some big Cerwin Vega 15" 3-ways for when I just want to drown out the voices in my head
Anyway, my MA5002 was an ebay find that I put into storage for a few years before implementing it. When I first powered it up it was dead due to a blown 10A fuse. I replaced it with an 8A (all I had) and slowly powered it up with a bulb in series, in case it was shorted. It appeared to be fine so I put it into my man cave (garage) system which is usually played at low to moderate volume to avoid bothering the neighbors. I cranked it a few times without any problem but one day it popped the 8A fuse while only running about a watt per channel output. I replaced the 8A with the specified 10A and it was "fine" again until I cranked it one day at 2 ohms. It still works fine at normal levels and hasn't blown a fuse again with many hours of use, but obviously something is awry. I did a quick test and found 100mV DC at the speaker output of channel A, and only a few mV on channel B. I have some high school electronics training and am very good at soldering, but it has been many years since I've done any component level repair work.
Wondering if I should dare try to dig into this myself and if anyone knows of any technical write ups for the MA5002? I've fixed cars, washers, air conditioners and a well pump with forum help, but can't find too much on this old stuff!
Thanks in advance for any ideas, and I apologize in advance if my intro hijacked the thread in any way.
First, I'd like to thank everyone for the great info posted here. I came into possession of nine S800 Amps and landed on this site while trying to figure out just what I have. The postings really helped with that.
I have not had time to test them all yet, but based on the technician notes that came with them, 2 have issues and 1 has some physical damage to the faceplate (maybe I can use one of the bad ones to rebuild it). This leaves me with roughly 6 units to sell. If there is any interest in them, on this board, please let me know. I'd love to have them go to folks that appreciate them and know how to get the most out of them.
Some pictures would be nice. I may be interested. You say some have issues, what kind of issues? I may want them to see if I can repair.
XPL 200's, XPL 160's, XPL 140's, L7's, L5's, L3's, L1's Homemade L Center, 4412's, 4406, L60T's, L20T's
I apologize for falling off the Earth for a while.... had a huge garage sale and it sucked up a lot of time (especially family time, which must be repaid....), so I didn't get much of a chance to evaluate the amps for a while. I still need to clean up a little adhesive residue off of a few of them and get some photos, but here is what I found. There are a total of 10 (not 9) amps. One is in great shape.... I thought it might be unused, but it has a few marks on it, so it has been used... I would give it a score of 9 out of 10. Then there are 5 or 6 that are in good used shape, the usual case scratches etc, but very good (maybe 7 out of 10). Then a couple that have case dings, and 2 (or maybe 3, I am not sure) that have no faceplate any more, and more extensive case damage. If you know this unit, you know it has a floating trim ring (suspended on black nylon spacers) and then a faceplate (suspended on another set of black nylon spacers).
Here's the great news. I did a quick test on them and all 10 appeared to work without issue. It was not a very sophisticated test, but here is what I did:
Source: Iphone 4S with a 3.5mm to Left and Right RCA 'Y' cable
Speakers: A pair of old Bose 151s, with 12 gauge wire and banana plugs
Test: Using the Iphone, I fed each of the amps (one at a time) a couple of songs with driving beats (I won't embarrass myself with titles) at medium and then nearly full volume, and then took turns pulling the Left or Right connector off and testing at medium and then nearly full volume, so I could ensure both channels were working and of similar volume.
I am no expert, but I did not hear anything unusual, or any one channel that sounded different (and I listened to 20 separate channels one after another). The one thing that was a surprise to me is how long the giant caps take to bleed off. You can shut down any of the amps and it still plays for what seems like about 45 seconds afterwards.
I will have photos by the end of this weekend.... message me with an e-mail address and I'll send them as soon as I have them. The units are in Central Florida and it looks like shipping is about $30 each to get them from here to the Northeast if that gives you some idea. Anyone interested in all 10 ??
So I'm guessing they are these shoebox amps??
Pictures of your actual amps would be helpful ...
2ch: Oppo981, DDE3DAC, JoLida 502CRC, VonSchweikert VR4, JBL L212, MG2Cs
7.1: Oppo103D, B&K, 4x UREI 809A, TF600, JBL 4641
These are 2 of the 10 amps.... one shows the shape of most of them, and one shows the shape of the 2 or 3 that are missing faceplates and have some cover scratches/dents. Better pictures will be coming soon.
I spent a bit of time at my little shop today to work on getting the S800 amps ready to sell. Here is the final tally. 7 Of them are in very good shape ($150 each), 1 case is banged up but nothing missing ($120), and 2 are missing faceplates ($85 each), but all appear to work fine. I cleaned them up and retested today. Took a bunch of photos too if you want to give me an e-mail address to send them to. Price does not include shipping which is approx $30 each (when I checked on shipping 1 from FL to PA). I'd take $1000 for all 10 (plus shipping) if someone was able to do that.... If I don't hear something in the next week, I'll resort to Ebay or the like. If I do, I'll post the link on this thread. - Thanks !
I have a lot more pictures, including photos of all of the serial numbers. There are some really nice units here....
I think you really need to put this in a Marketplace post.
I'm not being bitchy, you'd probably attract more attention to your sale that way since, well, you are just selling, aren't you?
". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers
They look nice.. some of them really nice.
Must resist urge...
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