tegwin
|
 posted on 7/2/08 at 10:25 PM |
|
|
Why use a lightbulb when a multimeter will do
Im feeling like such a retard...
I have just stripped down a projector to try and diagnose a fault with it...
Plugged my multimeter into the projectors power supply to measure output voltages and switched the projector on...
The multimeter lit up like a lightbulb!!!
Apparently the projector bulb runs on 600V Dc which is slightly more than the multimeter can handle....
So I now have one melted probe, and have obliterated almost every component inside the multimeter...I think its FUBAR!
It stinks in here now!!
 
|
|
|
|
|
blakep82
|
| posted on 7/2/08 at 10:26 PM |
|
|
yeah, projector bulbs are pretty hardcore..
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
|
|
|
paulf
|
| posted on 7/2/08 at 10:28 PM |
|
|
Next time get a good quality autoranging meter such as a Fluke or similiar.There still not indestructible but a lot tougher than the diy types.
Paul.
|
|
|
SeaBass
|
| posted on 7/2/08 at 10:28 PM |
|
|
Erm... Why the feck have you bypassed the 200ma fuse with a piece of copper wire??
That probably hasn't helped?
Or did you do that after you blew the crap out of the fuse!
Cheers
[Edited on 7/2/08 by SeaBass]
|
|
|
tegwin
|
| posted on 7/2/08 at 10:28 PM |
|
|
The depressing thing is that im no closer to figuring out whats wrong with the darn thing...
Bypassed the quick blow fuse afterwards so I could test the remaining components on the multimeter....sadly most of the critical ones are wasted!
The fluke autoranging multimeters look good, but at £50 upwards they are a bit dear....might just get another £9 one...doesnt matter so much if I melt
it again
[Edited on 7/2/08 by tegwin]
|
|
|
SeaBass
|
| posted on 7/2/08 at 10:32 PM |
|
|
Most projectors fail from when the ignitor circuitry for the vapour arc lamp fails...
[Edited on 7/2/08 by SeaBass]
|
|
|
onzarob
|
| posted on 7/2/08 at 10:34 PM |
|
|
600v DC can kill you as well 
what is the issue with the projector? I would say the Multimeter is toast
|
|
|
tegwin
|
| posted on 7/2/08 at 10:36 PM |
|
|
Thats about as far as I got, the power supply works, the mainboard/processor works, the LCD module works....didnt get as far as testing the bulb
control unit/ignitor module...
Im guessing getting spare modules would be so stupidly expensive....looks like new projectors all round then
|
|
|
paulf
|
| posted on 7/2/08 at 10:37 PM |
|
|
Yes but well worth the money as it will last much longer and if working on industrial circuits with high current carrying capacity realy essential in
case of similiar mishaps, so a worthwhile investment if you intend on doing much electrical work.
There are also other cheaper auto ranging meters available.
Paul.
quote:
Originally posted by tegwin
The fluke autoranging multimeters look good, but at £50 upwards they are a bit dear....might just get another £9 one...doesnt matter so much if I melt
it again
[Edited on 7/2/08 by tegwin]
|
|
|
tegwin
|
| posted on 7/2/08 at 10:40 PM |
|
|
Hmm...Fair point...
This one doesnt look too bad...
http://www.rapidonline.com/productinfo.aspx?kw=85-0725&tier1=Tools%2c+Fasteners+%26+Production+Equipment&tier2=Test+Equipment&tier3=M
ultimeters&tier4=MS8221C+series+Autorange++digital+multimeter&moduleno=70935
Has quite a few usefull functions....
The automotive multimeter that rapid sell also looks really usefull for setting up engines, not sure I can justify that though
|
|
|
TGR-ECOSSE
|
| posted on 7/2/08 at 11:04 PM |
|
|
quote:
Originally posted by tegwin
It stinks in here now!!
When electronic components like that go bang its usually cyanide they give off Its probably nothing to worry about though
|
|
|
caber
|
| posted on 7/2/08 at 11:06 PM |
|
|
Err projector lamps may run about 600V, starting pulses can be measured in Kilovolts! Best keep fingers out of them
I presume this is a video projector. They are supposed to have case interlocks to prevent the ignition circuit working when the case is open they are
also supposed to stop the lamp if it is running as , unprotected, they can give you a nasty case of arc eye as they are very high inUV.
Best diagnosis is to listen for the striking pulses sounds like an arc fizzing. If you can here this on switch on look down the lens and see if you
can see the arc in the lamp. you may not be able to see it as some keep the LCD dark until struck. If the sound is there then it is likely you have a
dead lamp, open the projector and look for any tracking on the board or around the lamp, if the ignitor has started doing this the projector is
scrap. If you can't hear the ignitor either this has gone or the electronics that run it are gone. If you can get parts then try swapping out
boards, there is not much you can do with a meter in there apart from checking the LV power supply that drives the signal electronics.
Good luck and nbuy a decent meter! I have a Fluke 75 that is over 20 years old and still does the biz and I have not managed to fry it! Before that I
had an AVO 8, actually I still have it and it still works it is just too heavy to cart about!
Caber
|
|
|
02GF74
|
| posted on 8/2/08 at 09:48 AM |
|
|
maplins sell 2 for a fiver or something stupid like
that.
I guess if you want to poke about some more, you will need to put in 2 drop resitors to reduce the voltage.
It goes up to 600 V DC.
|
|
|
onzarob
|
| posted on 8/2/08 at 09:59 AM |
|
|
quote:
Originally posted by 02GF74
maplins sell 2 for a fiver or something stupid like
that.
I guess if you want to poke about some more, you will need to put in 2 drop resistors to reduce the voltage.
It goes up to 600 V DC.
Sorry can you explain to me how that will work. a) without burning out the igniter circuit and b) generating allot of heat.
I suggest not doing anything without a circuit diagram, If you have Kv starting voltages and 600V DC running voltages you can seriously damage
yourself...let alone the equipment.
|
|
|
RazMan
|
| posted on 8/2/08 at 10:12 AM |
|
|
I reckon it will buff out with a bit of T-Cut
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
|
|
|
tegwin
|
| posted on 8/2/08 at 10:34 AM |
|
|
LOL...
New multimeter is in the post....projector has been binned!
|
|
|
.jpg)
