CurtPalme.com Home Theater Forum

[cosaw]

The electronics repair shop has done what I said and suggested a ceramic resistor. As far as I understand traditional wirewound ceramics (the big boxy white ones) are just not suitable. However ceramics do also come in a cylindrical variety and we MAY be talking about those in the Barco. Ceramics are usually wirewound and high wattage. The wire winding allows for great accuracy and a tight tolerance rating allowing small accurate resistances more easily. However the winding introduces impedance - I'm not sure how much in reality and whether that will be a problem or not in this case. The next problem is that Ceramic Wirewound resistors are usually bulky and much higher wattage. I think these resistors are probably 1/4 watt or so to allow them to blow easily. As to what other components could be at fault, could be caps I suppose but I'd think a transistor somewhere. Bare in mind I'm no electronics expert.

Anyway, all that being said I can't for the life of me work out what the banding is and what I've found calls in to question what I said in the first paragraph a bit with regard to wattage. I've pulled the convergence tray on my 808 to look for similar resistors and I've come up with the same ones. Well for starters, the size of these things is far more likely to be a 2 watt resistor, unless fusible resistors are sized differently. So the banding on the face of it looks like Black, Grey, Grey, Black, Brown. Or if there is a Red band hiding in front it would be Red, Black, Grey, Grey, Black, Brown. Really need the schematic here. The other way round that would be Brown, Black, Grey, Grey, Black, (Red).

So to go further I pulled the convergence tray on my Data 500 and found the same resistor banding on some other 'SR' resistors - possibly smaller though/lower wattage. One of them had been replaced with a resistor with actual writing on the side instead of banding. This indicated R10 10% - which means 0.1ohm 10% tolerance. Not sure how the banding fits with that at all. If I can find the schematics for my Data 500 then I'll look it up to confirm.

EDIT: I'm more confident that this is correct. Brown (1), Black (0), Silver (x 0.01), Silver (10%), Black (?). Yes it's questionable, because of the last black band, but it makes sense for the value agreeing with the one I found in my Data 500. 10 x 0.01 = 0.1 Ohm. 10% tolerance (seems pretty high by modern standards but I don't think its a big problem). So not sure what the last black band is - I don't think there is a black band for Temperature Coefficient, which is usually what an extra band is for.

SECOND EDIT/FINAL CORRECTION: Just had a look and there is a black band for Temperature Coefficient and it equates to 250ppm/K.

So you have 0.1 Ohm 10% 250ppm/K. The temp coefficient is the least important I would think after all we're talking only a 10% tolerance anyway.

Need to know the wattage as that will be the important factor for fusibility I would have thought. It looks about 2 watt in size but I don't really think that's a good enough guide in this instance.

The problem is - as already indicated - the resistors are probably the least of your concerns.

Can anyone else verify my resistor colour code banding?

[km987654]

That board is plugged into the frame and attached to the convergence driver board by cables. We know the driver board works fine as you had it in the other projector. The I2C errors are not electronic or electrical issues they arise because that driver board does not match the control board in the other projector. It would be my guess the driver board is OK. So the problem is either a simple not seated properly when power applied problem or something in the frame is causing the issue. My bet is a seating problem but you would need to replace the resistors and have some spare ones just in case and then we could run through a process to identify the issue. You can find these boards on eBay.com for reasonable prices if you are not in any hurry.

By the way be careful of the terminology. The board pictured is the convergence output board. The board in front of it is the convergence driver board.

[barclay66]

Hi,

Please do not replace the safety resistors (SR1 and SR2) with regular ones!
Safety resistors are equivalent to fuses and replacing fuses with other components can lead to additional damage like burnt traces etc.
According to the BD808 schematics (the only one I have at hand) SR1 and SR1 are resistors with 0.1 Ohms and 0.4 Watts. These are not easy to be found as they are special non-inflammable types. As a replacement, You could use resettable PTC fuses (see: http://www.bourns.com/data/global/pdfs/mfrx72.pdf).
As far as I'm able to calculate the power requirements of the convergence amps, I'd recommend using the MF-RX135/72 (1.35A hold current / 2.7A trip current) or the MF-RX160/72 (1.6A hold current / 3.2A trip current).
If there's a short, those fuses will trip and will reconnect after the short has been removed.

In any case, there must be a reason why SR1 and SR2 were destroyed. I'd suggest checking for shorts against ground after the resistors. There are some voltage regulators (IC604/605/611/612) which could have caused this...

Regards,
barclay66

Edit: Just verified with the BG1209s schematics. Same values for SR1 and SR2 there...

[cosaw]

[barclay66]

BTW:

If I'm not mistaken (or have given it away already), I do have a complete convergence drawer from a working BG808 in storage. At that time I had a BG801s and some ideas on upgrading it. Later I got my Marquee and never touched it again. If You'd like to have it, just shoot me a PM...

Regards,
barclay66

[CasetheCorvetteman]

And it wont be the capacitors that caused the failure, but it seems a few in my Barco have gone a bit iffy and its worth checking them while youre there. Do use cheap rubish ones though.

[barclay66]

CORRECTION

As I verified with the picture on page 2 of this thread, I saw that we are talking of SR1 and SR2 on the Convergence Output Board. I was mistaken as on the Convergence Driver Board there are SR1 ... SR4 too.

Now the corrected text:

Hi,

Please do not replace the safety resistors (SR1 and SR2) with regular ones!
Safety resistors are equivalent to fuses and replacing fuses with other components can lead to additional damage like burnt traces etc.
According to the BD808 schematics (the only one I have at hand) SR1 and SR1 are resistors with 0.1 Ohms and 0.7 Watts. These are not easy to be found as they are special non-inflammable types. As a replacement, You could use resettable PTC fuses (see: http://www.bourns.com/data/global/pdfs/mfrx72.pdf).
As far as I'm able to calculate the power requirements of the convergence amps, I'd recommend using the MF-RX160/72 (1.6A hold current / 3.2A trip current) or the MF-RX185/72 (1.85A hold current / 3.7A trip current).
If there's a short, those fuses will trip and will reconnect after the short has been removed.

In any case, there must be a reason why SR1 and SR2 were destroyed. I'd suggest checking for shorts against ground after the resistors. The STK392-040 are amongst the few possible candidates having caused this...

Regards,
barclay66

[dentree]

Well this is a lot of useful information, don't know what I would do without you guy's, I think I have enough information to present to a Techo to sort out the convergence tray problem...................

I had this CINE 8 running (with nice picture) for the first time last night, everything ran quite nicely....but tonight when I turned it on it ran quite normally for about 20 minutes or so, then it shut down, I gave it another go, same result with an accompanying strong 'metallic' smell, turned off and on again no pictures, red led's on EHT lit and the metallic smell,
I took out the EHT no smell detected there, but strong smell from QUAD, have taken it out, nothing visible, but very 'metallic' smell, especially from the Resin packed side, I assume that it tells me it's a goner, that being the case has anyone got a Quad spare to sell, the number is R762717 and the EHT which is probably Ok has a numberR762716

Regards
Trevor

[cosaw]

Downer. You're getting no luck with this machine it seems. So now it would appear you are two Quads short. You have my sympathies.

[dentree]

CORRECTION


I do not know whether this is the correct procedure for contacting Curt, if it is, then the last couple of posts pretty much explains the QUAD issue, so the question is do you have the correct one for the Cine 8, if yes I would welcome the information regarding cost and postage to Australia.

Over the last 6 weeks or so have been quite intense dealing with this projectors issues, but the support and advice has been outstanding, now being pipped at the post with essentially what was the original issue (Quad burnout)
I think the 'Dark side' is slightly ahead of 'The force'


The Quads and EHT's in original machines:

Cine 8 ....QUAD R762717 (index number05) Burned out

EHT R762716 Still OK but threw a red LED when Quad started to burn.

Barco BG 808 QUAD R7622091 (index number 01) this was transferred to the CINE 8 and has subsequently burned out

EHT 7617427 OK




Thanks
Trevor

[CasetheCorvetteman]

I wish i could help you more Trev although ive spent the day in hospital here, im quite unwell again. Ill be fine though.

[dentree]

Given the situation as described in my last post, I would like some thoughts on this scenario:

I have a Barcographics 801s (fully functional)

The numbers on the QUAD and EHT are as follows:

QUAD 761743 ( there is no R designation preceding the number)

EHT R7617427

I read in a post from 'cosaw' I think suggesting that the Quad from a data 500 and up over is OK for the BG 808s that he has.

Well given I have removed the Quad from the Cine8 (now dead) R762717 (this one has physical burn damage)
and replaced with R7622091 from my BG 808, (now also not functioning) metallic burn smell and has been removed, one noticeable point was that both the Quads ran very hot to the touch.

Both Quads installed in the Cine 8 ran with EHT R762716

I am running the BG 801 at the moment and the Quad is running quite COOL.

Of course the burning question is (excuse the pun) Can the QUAD from the BG801s be run in the CINE 8???

If so then which EHT is required ( i have read the Barco Bulletin regarding this) but would like someone to actually tell me.

All the other QUAD and EHT information is in the previous post

Many thanks

Trevor

[CasetheCorvetteman]

They are hot because there is a short to chassis ground, this causes excess current flow.

[CasetheCorvetteman]

Sorry, ill continue. Got interupted.

Excess current flow causes excess heat. This is why things are hot.

Im about to have another morphine when these docs come back, so i may not be back for a couple days.

[dentree]

How do I investigate a short to ground from the Quad, and what and where am am I looking??

[CasetheCorvetteman]

Replace the quad, its the only way, its internal.

[dentree]

Will the Quad from The Barcographics 801s work? and do I continue using the Cine 8 EHT

[CasetheCorvetteman]

No idea, someone will know soon though

[cosaw]

[dentree]

Hi Simon,
Thanks for your input, I have read your earlier posts regarding the Quads, that why I thought I would follow it through, I was hoping Curt might have something to add to this situation, Plus I need to know if in fact he has the correct Quad for the CINE 8.
Just as an aside, One of the springs has dropped off one of my scan inverter switches, I have just taped it to the chassis (seems to stay put) I tried to put the spring back on but to no avail (must be something to do with the way you hold your mouth) ??

Shame about Casey, didn't know until today that he was not well , I sent him a message on his phone,
Anyway I am sure we all wish him a speedy recovery.

Trevor