CurtPalme.com Home Theater Forum

[Ohmess]

Thanks man. Parts are inbound.

LVPS is next.

[Nashou66]

I hope those will work out and nothing else went in the line of those, check all the resistors and diodes again that are near them or in the circuit from the schematic i sent you.

good luck

Athanasios

[Ohmess]

Will do. One thing that was odd when I was checking the circuits last night was the readings on two of the resistors.

I removed the CVA again after I put the projector back together to pull the ribbon cable to see if I still had an LVPS error, and both the 560 ohm resistors that had given me strange readings earlier (R415 and R515) measured 560 ohms. I ordered replacements anyway, and likely will replace them.

I guess this gives me time to work on my C element change.

[Nashou66]

I wouldnt change those. They measure diferent when in the PJ i just tested got .5 ohms while pluged in and also if i remove the ribon cable. Out of the PJ they meauser dead on !

Athanasios

[Ohmess]

ITS ALIVE!!

Replaced transistor Q 301, diode D300, resistors R317, R318, R301 and R310 and its working!! Thanks Nashou for your diagnostic help.

Now, should I do more upgrades or watch the thing for a while?

[Nashou66]

Enjoy it before you have another snafu!!! After I messed up my FCM, even though i had two more spares, I punished my self by not allowing me to watch it till i fixed it !!!
I know I am a sick individual But watch it get used to how it looks and then after some time do some more work. then see if it made any improvement or just helped stabilize the PJ.

But I feel just a good as you do maybe more , I kinda felt responsible since i started the thread i was afraid of people making mistakes and then pointing the finger at me !
So being able to help in the diagnosis makes me happy i was able to help you and also gave me satisfaction in my new found ability to track down board level problems. Thats what happens when you read the service manual and begin to understand the theory of how the marquee and CRT in general works, also having messed things up a few times also helps .

Keep up the good work !!

and thanks Again for the kind words

Athanasios

[Ohmess]

Yes! You are forever guilty and will have to help me fix my projector from now on!

[Ohmess]

Ok, I know I was told to enjoy the projector for a while, but...

I have a neck board question.

Whilst awaiting the parts to fix my CVA, I modified the neck boards that came with the 9" tubes I purchased. I figured these would ultimately become the neck boards I would use, and it was easy to work on them because I didn't have to take my projector apart to do so.

On to my question. I have done all the mods in the Marquee Mods and Maintenance thread to all three neck boards. I tried each one in turn on my blue tube this evening for the first time. With the first two, the tubes appeared to be overdriven, casting a bluish hue on anything I put on the screen. In addition, there are five thin blue lines that run across the picture from left to right, cutting the picture into sixths. I also noticed when I removed these, the two large resistors on either side of the neck boards are very warm to the touch.

The third one works well!

How does one troubleshoot neck boards?

[Nashou66]

You might have some solder shorting something on one of the Chips, did you change them all or just the Main SOIC RGB op amp. All I can say is go over everything closely with a magnifying glass. I always check those small pins closely as even a smaller than hair size solder line can cause that. Also when youwere doing the neck board did you check as you went a long? Add the resistors, then check,and the caps then check, do one chip then check? if not its a lot harder to figure out what you have done wrong, Alway check little by little so if something is wrong you know it was the last thing you changed.

Go back over and recheck the op amps, maybe remove one and put the old one back on. you'll just have to keep checking things.

And those resistors do get hot, were they more hot than the one VNB that worked fine?

Athanasios

[Ohmess]

I only replaced U4 and U2. I used an Intersil EL5166IS at U2 and a TI OPA2134UAE4 at U4.

I didn't step through each of the changes because my CVA was out of commission. Bad form, I know.

Thanks again. That's very helpful, and I notice an improvement with each set of modifications.

[Ohmess]

My solder jobs around the chips were good. On one of the neckboards, I found a problem with a solder joint around the tantalums at C29, and on the other, it looks like there may be solder flowing underneath between C29 and C30. I won't get to rework these until Sunday.

You would think soldering those surface mounted things would be easy, but I had a lot of trouble with them.

I watched a recording of the Chinese Gran Prix last night and when they switched to the good cameras, I can see a huge improvement in my picture. Progress for sure.


Hey Athanasios, another question for ya:

Since I am again attacking the neck boards, I have a question about something you did to yours. In the Mods thread, you state:

This is from McPherve's suggestion on the AVS archives, you can also replace C2(100nf) with a better film cap I haven't done it yet but will then add a 100pf across C2 as well

C2 looks to be a surface mounted ceramic cap. If I were to follow this suggestion, can you point me to a specific replacement part? Thanks.