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Discussion Starter · #1 ·
I have a problem w/ my Ampro 4600. It worked fine last night-I came in this morning to crank it up for the Sunday Ticket and...nothing. I unplugged it, pulled the main fuse. The fuse was fine, re-plugged and checked all the power cables. When I turned it back on, it worked, but then shut down after about 1/2 hr. I pulled the main fuse again- the voltage selection card that holds the fuse(s) had a bit of burn at the metal contacts, but the fuse was fine.. Re-powered, and it activated, but it shut off right away. The voltage selection card seemed to have a bit more discolor. Next try- nothing. I was thinking that the voltage selection card is kinduva relay switch that could be bad; but after reading several posts concerning Ampros and power, I'm more concerned than ever. Could anybody out there lend me some sage advice as to what I'm possibly dealing with, and any solutions? Any help is greatly appreciated.
 

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When you say it powers down, do you also loose the remote control display? Can you read any diagnostic error codes on the remote display?


If you don't have a remote display, it could be something up front in the switch mode power supply. I seem to recall that the power for the remote comes on immediately, so that two way communications between the remote and projector can be set up right away.


At power on the CPU board run some diagnostics and checks for missing interlocks and the like. If all is in order, the CPU will send a "turn on" signal to the switch mode power supply to enable the various + and - power supply voltages to turn on.


If the remote display goes blank, it could give a clue as to where to start looking.


Ray
 

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Discussion Starter · #3 ·
Thanks for the info, Ray. You are correct-When it ceases, everything ceases. No remote read, no nothing. Any idea as to if the voltage selector card (at the main fuse box) could be a problem-Can it go bad, or be fried without burning the fuse? Isn't it essentially a switch? I'll check out the switch mode power supply. I apologize if these are stupid questions, but that kind of indicates my electrical / CRT expertise. One other thing- there was no noise, smell or visual that accompanied this problem, if that would matter.

Thanks again,

Rick
 

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Rick,


The plug problem you described is definitely possible, but unlikely. I've never taken the fuse plug out of mine, but you might try to clean the connections well with something like a rubber eraser. You may have a cold solder connection inside the unit.


I don't have any schematics for anything as new as a 4600. I have an eight year old 4200, and the prints I'm looking at are for the even older 2000/4000 series. Yours could be totally different.


The prints show the voltage coming thru plug you describe at the back of the projector. Next are some capacitor filters. The voltage gets applied to a small transformer called T1 in the switch mode power supply. Two wires out of T1 go to a full wave diode bridge with a capacitor filter.


The unregulated dc voltage at this point is refered to as "v+ always" and is the main voltage source used to wake up the projector. From the smps it is applied to the main mother board.


At the mother board it goes across to the CPU board where (among other things) it is applied to "host" connector on the back of the projector where it next goes out to the remote to power the display.


If the projector is powered on, you should be able to read +22 volts between pins 11 and 7 (or 12 and 6) at the host port connector all the time, if you are getting ac through to the primary side of the switch mode power supply main transformer.


If you don't have dc voltage, you could pull out the switch mode power supply and test for continuity thru the power plug at the back of the projector to the connector on the main mother board (runs across bottom of projector) that the smps plugs into.


If you are not familiar with basic troubleshooting procedures, you probably shouldn't try to get into the unit. You could easily get yourself killed in there. The box in front of the smps puts out 35,000 volts. There are places you can get hurt even with power disconnected.


Ray
 

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Rick,


Where are you located. I have a 4300 and am kinda familiar with the power supply after repairing it with the help of Ray and others on the forum here. If you are nearby, I could come over and help you out.
 
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