Film-Tech Forum ARCHIVE: Barco 20C

This is topic Barco 20C - LPS not detected in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Michal Matys (Member # 8614) on 07-24-2018, 08:49 AM:

Hi guys,

I have a strange issue on Barco 20C projector.

The projector ran last show in december 2017. Meanwhile it was transported from one site to another and was in storage until now.

After I have connected the projector to test it, I got following error messages:

- LPS at least one LPS not detected and error
- LPS - zero LPS detected

Until this day I have done following:

replaced LPS
replaced Cinemacontroller board
replaced Signal backplane
tested the cabble which goes from backplane to lps with multimeter - all pins ok
replaced smps
replaced fan control board

The diodes on LPS are as supposed to be on projector which shows no error (checked with manual as well). When I unplug the communication cable, the diodes are off, when I connect it back again, they are ON.

The projector does not show the LPS fw version or anything, it is behaving like there is no LPS but obviously the LPS does communicate with the projector via the cable since the diodes are lit when connected.

I believe I am out of ideas and so is Barco support, but maybe some of you will think of something worth trying?

Thanks!

Michal

Posted by Juan Jose Vazquez (Member # 10496) on 07-24-2018, 09:46 AM:

Hi everybody.

Can yo replace ir check the address cable, this cable might be the issue too.

Could someone tell me if I'm breaking some forum rule? since I have not presented myself.

Greetings!

Juan Jose

Posted by Leo Enticknap (Member # 534) on 07-24-2018, 11:01 AM:

I think Juan is on the right track - either the address cable, or a something is F-ing with the signal in the LPS unit nearest the backplane (the one on the left, if I remember correctly).

Suggestion: swap the two LPS units around. If the problem then changes from sometimes it recognizes only one LPS and sometimes none, to a situation whereby the only error you get is one LPS only recognized (i.e. you no longer have it not recognize either), then that would suggest that the problem is in the LPS unit that was closest to the backplane, and is now furthest after you swap them. If it makes no difference, replace the address cable extension section between the two LPS units.

Posted by Ioannis Syrogiannis (Member # 3235) on 07-24-2018, 11:48 AM:

Good evening Michal, it’s been a while…

Not that I have the idea that will light the way, but, when you write that you “replaced LPS”, you mean that you replaced both LPS modules?
Or do you mean that the 20C you are referring has an older, single LPS, that later Barco has replaced with two individual LPS modules, with the appropriate fixation frame?
Did you try to replace the LPS cables, that don’t come with the new LPS?
Regarding the various replacements you made, you don’t specify if they took place separately or all in one time.

I was wondering if in any of this replacements, did you inquire the part that in DP2000 was named “LPS communication interface” and its cabling. In 20C’s service manual, I can find its place at page 357, but not the part itself. You can see yourself that between the Signal Backplane and the CTLB IN socket on the left LPS, the cables are the same colour in the first and multiple colours in the second. (It can be that in your case it was all blue, I wouldn’t know.) When you checked the cable, didn’t you notice any difference? Did you check thoroughly? I should underline also that if you check the cable from one end to another, that doesn’t secure the actual connections between the planes/modules and the cable itself.
I believe I have came across that “LPS communication interface” cousin in an old 20C or 15C recently, when changing from a single to a two-module LPS set. Yet, the scheme I am referring to could be debris from the DP2000 service manual carried to the 20C one. I’ll give that to anyone in doubt.

If I had time and spare equipment, I would interchange the cables that go from the Signal backplane to the LPS with another projector’s.
Other than that, I would try to connect only the one module, removing any connection I could from the other, and see what is the info I get from the system, or even if I can strike the lamp on.

Posted by Michal Matys (Member # 8614) on 07-24-2018, 12:49 PM:

Hi Ioannis, long time indeed! Hope you are well.

I replaced the old type module (twolps) for 2x single lps which I am sure are working fine. Do you mean the LPS interface board (R765248K)? I see it in dp2000 spare parts, but nothing in 20c, I have no idea if this part is located somewhere in 20c, did not see it.

I can try the cable with another projector probably, from what I checked I will have to take it appart to get to the cable since its ziptied everywhere, wish me luck [Smile]

.

The colour are same on each side of the cable, thats why i thought there is nothing in between backplane and lps, just direct connection via this cable. I tried connecting just one module but the issue stays the same.

Tommorow I will search for the lps interface board if there is any..

Posted by Ioannis Syrogiannis (Member # 3235) on 07-24-2018, 01:08 PM:

Well, if your multimeter does the trick, I wouldn't want you to try on my account...
If barco didn't suggested it, I might as well be wrong.
Yet, I would firstly try to find out what one of the two LPSs would do on its one.
The simple tricks that might show where is the problem.
Maybe start by removing communication cables from the LPS back to the signal backplane, and see what makes the difference and what not.

Posted by Michal Matys (Member # 8614) on 07-24-2018, 01:26 PM:

I played with the cables, when I unplug the backplane -> lps cable the lps diodes go off (the communication ones) but error is the same in barco. When I put it in it goes ON, but still with the error, seems like there is something else blocking the coms between zhe lps and cinemacontroller...

Posted by Adrian Avram (Member # 7931) on 07-25-2018, 12:55 AM:

Hi Michal,

I am not familiar with the Barco projectors, but since the projector has been moved, and also kept in storage, you could check the connectors (both male and female) of the CTLB IN/OUT, CTRL IN/OUT and Address cables for any signs of corrosion on the pins.