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Post by mastertech on Dec 15, 2016 20:14:00 GMT -5
Well maybe the hissing noise has something to do with the problem. Lets continue and see. Leave ic202 out for now. Find resistor R214. I need you to test for DC voltage on one side of it so the projector will have to be running. So if you cannot get to it when running, solder a wire to it for testing. Now 1 side of it is to ground. I need you to test on the other side of it. I am sure I don't have to explain to you how to determine this. You have been doing this long enough now to know, LOL. Also, check your messages here.  |
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Post by jeremy on Dec 15, 2016 21:11:26 GMT -5
In standby the voltage reads 3.8vdc, when powered on it drops to about 2.8vdc (with the PJ & lamp running as normal), power it off, voltage goes back up to 3.8vdc. Also I replied to your PM |
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Post by jeremy on Dec 15, 2016 21:21:16 GMT -5
I should add, I left it on after getting those readings and the lamp/ballast shut off but the fans stayed running and the standby LED went back to standby mode. When I pressed power again it came back on, stayed on, lamp tried to light, but then the whole projector lost power for less than a second, and when it did, made a weird noise that sounded like a pencil being put into one of the running fans. It was in standby after that, I powered it on and it powered up and ran as normal again...
May mean nothing, thought I should include.
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Post by mastertech on Dec 15, 2016 21:31:04 GMT -5
Is there a part number on that ic202?
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Post by jeremy on Dec 15, 2016 21:48:43 GMT -5
Yep, its either A532 or 4532
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Post by mastertech on Dec 15, 2016 22:04:59 GMT -5
What does it look like?
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Post by mastertech on Dec 15, 2016 22:13:06 GMT -5
Also, the buzzing sound and the recent fan type noise, did it sound like they are coming from the lamp area? Or a transformer on the PS?
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Post by jeremy on Dec 15, 2016 22:15:11 GMT -5
Looks like the pic below,  |
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Post by jeremy on Dec 15, 2016 22:18:04 GMT -5
Also, the buzzing sound and the recent fan type noise, did it sound like they are coming from the lamp area? Or a transformer on the PS? Was more like a steady hissing/sizzle sound, its not coming from the lamp or ballast (makes the noise with ballast unplugged), I would assume a transformer on the PS but the Ballast and PS are sandwhiched so it's hard to tell exactly where on the PS it is coming from. It also makes that hiss/sizzle while in standby, doesnt change pitch or anything either when powered up, just the same steady sound as soon as the PJ is plugged in. |
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Post by mastertech on Dec 15, 2016 23:07:05 GMT -5
I was thinking that maybe the hissing was the temp sensor at the lamp which plugs in the PS at connector CN201 which is in play for your problem. Now I know you said the other projector PS worked ok in this projector but maybe you did not hear the hiss then and maybe that PS was able to handle the sensor problem. That sensor is now not affecting shutdown with having that ic removed. However that is not the only thing bypassed to it could be something else. I am just trying to rule things out and I would like to rule out that sensor for the noise anyways. Maybe try just disconnecting that CN201 wire harness and jump the pins on the PS and start the projector up and see if it still makes the noise.
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Post by jeremy on Dec 15, 2016 23:11:29 GMT -5
Will do and get back to you MT
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Post by jeremy on Dec 15, 2016 23:39:32 GMT -5
Okay shorted that out and it still makes the noise
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Post by mastertech on Dec 16, 2016 16:00:41 GMT -5
Well it looks like we are at a cross roads. I have gone over the schematics of this circuit and this is what I see. IC202 is a switch that will turn on PC102 if a problem is detected in the power output lines. And if PC102 is turned on it shorts pin 2 of ic102 to ground telling the projector to shut down.
Now when everything is installed you have ic202 turning pc102 on but it should not be since all your line voltages appear to be correct. In investigating ic202 it is what is called a shunt regulator. What that is is a switch that is activated by a specific voltage or less (called the trip voltage). The problem is we do not know what the actual trip voltage is suppose to be. You tested 2.8vdc when running.And this is based off a 6vdc line. So is the 2.8vdc correct or is it to low and that is what is tripping ic202?
Without this info we cannot be sure where the problem is. Now we could continue doing some more testing but it would be much quicker if we knew just what the voltage should be at R214 where you tested. So. 1 option would be to do the test on the good power supply board. You are fortunate to have a good one because if not then we would have to continue blind. Of course if you do not want to do the voltage test on the good board then we have to continue blind anyways. You would not have to remove any parts for the test. Just check the voltage on that resistor. What what do you say?
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Post by jeremy on Dec 16, 2016 16:33:54 GMT -5
Checking the voltage on the good PS is no problem, thats why it's still here  . I'll take the good PS apart and test and get back to you with the results. Curious though, if say the trip voltage was say 2.5v and the voltage reading slowly continues to drop from 2.8 when powered on (like 10-20mv every 2 seconds), that would cause the shut down right? So what is causing the voltage to decrease if thats the case and not stay constant? Just thought I'd ask while I was replying  |
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Post by jeremy on Dec 16, 2016 18:45:39 GMT -5
Ok, sorry it took so long but these aren't the easiest PSU's to get into and test, lol. Anyway, testing on + side of R214, the good PS reads a solid 2.426vdc in standby, and powered on with the lamp running.
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. I'll take the good PS apart and test and get back to you with the results. Curious though, if say the trip voltage was say 2.5v and the voltage reading slowly continues to drop from 2.8 when powered on (like 10-20mv every 2 seconds), that would cause the shut down right? So what is causing the voltage to decrease if thats the case and not stay constant? Just thought I'd ask while I was replying 
