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Old 08-12-2013, 12:46 AM   #1
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Default Air conditioning died.

I have a 95 3200 SCR, today my a/c stopped working. Was working yesterday and for the last 3 years. Its the Marine Air Systems VHT16k-H model. The electronic display in the cabin entrance doesn't power up, and the a/c unit doesn't start. Its simply dead. I pulled the breaker panel off in the cabin, I tested the 30-amp breaker with a line tester, voltage read 115v. I even tried replacing the breaker just in case, still the display is dead, the a/c doesn't start either.

The control box is located under by cabin entry steps. I pulled the cover off the control box, tested the power to the unit by touching the black/white leads, that reads 115v as well, so its getting power. I pulled the display panel off, it has a 8-pin cable connector. Pulled that out of the display as well as the control unit, that looks fine. Still the display is dead as is the a/c.

The manual I have says if the system wont start and the display is not illuminated, it can be

1) circuit breaker off. I tested this, all fine. Duh.

2) Wiring at terminal strip is mis-wired. Well, my a/c has been working for a couple of years, so this isn't it. It doesn't rewire itself in the middle of the day.

3) Metal oxide varister (M.O.V) is blown on control module. Circuit board must be repaired/replaced, call for service. Anyone ever have this experience and any info?

4) Transformer fuse is blown on control module circuit board. Says to replace fuse. I have no idea what this looks like. It just looks like a circuit board to me, nothing "fuse-like" stands out. Anyone know what this is? Manual also says it has solid state fuses, so its kind of ambiguous to me on which one it really is.

5) 8-pin display cable plugs are not making contact (dirty, bent, broken). Says to remove cable ends and inspect. They look fine to me. I unplugged both ends, blew a little air into them, reseated them, jiggled them a bit, nothing. Not sure how to even test for a bad 8-pin cable or why it even would go bad.

6) power button is defective. Press button several times to clear. With power off at the breaker, exchange display panels. How can I test this? I've found only one place online and a new panel is about $500. I must have pressed it a million times. I pressed and held it down for up to a minute. Nothing.

7) Input line voltage is 65 volts or less on 115VAC. Okay, I didn't check this, but this is my normal slip where I keep my boat. I doubt this is it, but I will check tomorrow.

I see Marine sells some retrofit kit but before I go down that road, any help here would be appreciated. Thanks.
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Old 08-12-2013, 11:23 AM   #2
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sounds like low freon pressure, as the unit will not come on if low.

Also, my unit did the same thing and I call a regular A/C guy in who knows how to uses the gauges, and it turn out to be the compressor start switch was just stuck from non-use.

It works fine for 13 years, and limited use, but now I run the A/C every month to exercise it.

I would check the A/C raw water pump in the engine compartment, if that crapped out then that's could be your problem. Sometimes that pumps gets stepped on and the plastic pump cracks.

You can but those drop in replacement A/C units for $1800.00, but how often do you use the a/c?
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Old 08-12-2013, 11:57 AM   #3
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Its not that the a/c compressor or pump doesn't come on, its that the display panel doesn't even power up (this is control panel where power on/off, temp up/down, fan speed, etc are controlled from) . I use the a/c every time I go out, which is weekly (I hook up to shore power though, not generator), and with a wife and 3 kids in it, there just wouldn't be enough beer in the world to keep me sane without any a/c. When in the slip and unattended, the ECU-MAXX control/display unit has a moisture control setting, so it cycles itself on every few hours to keep the cabin dry and somewhat cooler. Its been running great all summer. Last year it did get a recharge though, but that's only because I had bought the boat itself a year prior. I read online yesterday about possibly a blown MOV, but that would be a guess.
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Old 08-12-2013, 12:54 PM   #4
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one last thing to check is the micro filter on the front of the evaporator.

this is a gray mesh 1/8" thick and you really need to look for it, as it is velco onto the unit to keep the coil clean.

if your is solid and black, then the coil is over heating and shutting it self off.

you can buy the stuff in home depot in the window A/C isle.

there is a push button fuse reset, but you got to hunt for it.
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Old 08-12-2013, 02:39 PM   #5
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Mine was showing L-O A-C. Supposed to start with the blower, then the lake water pump, then solenoid, then compressor (blower goes to low speed) and then the blower goes to hi speed. My blower starts, then the code appears. Supposed to be low voltage, but I have 118 volts at the Line In terminals. Cost $800 a year ago to have a dead board replaced. Hope my guy can look at it this week. Thinking of going with another unit for $1,600.
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Old 08-12-2013, 06:27 PM   #6
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Thanks guys, but my problem is that the display shows nothing. The filter is clean (I clean it regularly). There is no clicking or sound or anything coming from any part of the a/c system as the display/control unit itself doesn't illuminate so there is no way to even try to power up the a/c. I'll check for a push button fuse reset, but I haven't been able to find one. The breaker is good. There is power to the control box. I haven't tested the 8-pin cable that leads from the control box to the display panel yet, but that's on my to-do list.
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Old 08-12-2013, 11:44 PM   #7
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Sounds like the actual control panel died. A friend had a 15 year old system with a Passport II control. One day it was off. Nothing just as you describe. He installed a new control panel and everything has been fine for the last 5 years.

Both of my AC systems are the original 1998 units and luckily they still work great. I leave them on year around. When I leave on Sunday I set them at 78 in the summer and 65 in the winter.
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Old 08-13-2013, 02:05 AM   #8
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Went down to my boat today. Line voltage to the breaker and circuit board white/black lead wires reads a solid 115vac, so power is fine. The tech support folks at Dometic/MarineAir gave me some troubleshooting help. Pulled the 8-pin cable out from the back of the display and tested if there is 5vdc to 8vdc across pins 1 and 6, nope, no voltage there. Okay, pulled the 8-pin cable out of the jack on the control board itself, tested for 5vdc to 8vdc across pins 1 and 6 there, nope, no voltage there either. Pins 1 and 6 are the positive/negative wires in the cable, he wasn't sure which side of the cable is pin 1, so I test both ways. I even grounded the tester on one lead, then checked each of the 8 pins for any voltage, none found.

I noticed that right next to the cable jack on the circuit board is a red LED light and on the board it reads "power". The red LED light is NOT lit. Called tech support again, they said if there is red LED light isn't lit, the board is blown, the transformer on the board he said is usually the culprit. Now, why in the world do they place a red LED light inside a control box that cannot be seen without opening up the box itself is anybody's guess.

Tech support told me that a company called Micro Air in Allentown, NJ may still make these circuit boards, I'll be calling them tomorrow. Their site is http://www.microair.net/index.php
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Old 08-13-2013, 03:23 AM   #9
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Thanks, I thought Marine Air was defunct. The board a got a year or so ago was a used one. Please let me know if they still make them.
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Old 08-14-2013, 01:23 AM   #10
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I did call Micro Air, they don't sell to the general public, but they said they may be able to repair the circuit board, I'm sending them some pics of the circuit board I took, will wait to hear what they say. This model I have is from circa 1995/1996 and parts for it are brutally expensive. The circuit board alone is about $900, the display panel about $500. Dometic/MarineAir makes a retrofit kit for the ECU-MAXX to Elite/Passport, http://www.dometic.com/45a56174-06d4...143ee4a0.fodoc , which replaces the control box, the display panel, and comes with a remote air sensor, a starter relay, cable, and mounting plate. The cost for the kit is $600. Tech support is great, they already sent me a wiring diagram on how to convert from the old unit to the new unit. Its not a drop-in replacement, but all the necessary parts are included they say, and just needs some simple rewiring. Depending if MicroAir can repair the board or not, and at what cost, I will probably opt for the retrofit kit. I understand that any future component failure like a circuit board or display panel, the parts are easy to come by and relatively inexpensive.
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