CurtPalme.com Home Theater Forum

rawlk · Joined: 25 Nov 2015 Posts: 11

Hey All!
Super new to the CRT world. Got introduced by a friend that had been raving about them for the last several weeks but never actually owned one. To call his bluff, I purchased one from craigslist that seemed to be in pretty good condition and is one of the 'higher quality' ones from the 90's.

Long story short, I know very little about the projector and old-school electronics (sorry, I'm 22 and work at a big tech company Smile

). The furthest I've been into equipment like this is resurrecting blown power boards out of some larger subwoofers.

The projector worked fantastically for about an hour. Rough calibration was going relatively smoothly ( https://goo.gl/photos/RBx55MrgcRrDYfiB6 ) and out of the blue, the red tube decided it had a mind of it's own. Now, any time the projector gets powered up, it simply cycles the red tube (green starts to turn on as well) and resets. Remote is practically unresponsive other than the power button. Nothing smells like its burning. There was a bit of an odor ~10min in, but I expect that was from sitting in storage for ~1yr + transportation. I'm hoping its something relatively simple, but I'm game for digging in and replacing things.

Video of power cycle -> https://goo.gl/photos/mp4TNYAsP54TinVR8

Any troubleshooting tips?

I'm super excited to be browsing around on here, you all have some pretty wicked setups. I wont be super bummed for bad news, but It'd be fantastic if we could get it up and running Smile

edit - fixed video link -.-

**Curt Palme** · Posted: Wed Nov 25, 2015 11:38 pm Post subject:

You're linking to the picture again with the video link. Welcome, and possibly a good score. THe 9000 is now considered old, btu overall the Marquee chassis very reliable. I've thrown out most of my parts for it though, but don't despair just yet.

First thing to check is if the back heatsink that runs across the back of the set is one solid piece, or is split into two halves. hopefully the rear heat sink is one solid piece, and flips down. That means you have a later 9000, and most of the 8500/9500 parts will fit into the 9000 chassis. If it's two halves that plug into the motherboard, then it will be up to possibly finding a second set, or finding someone here with one, as I've chucked all those parts. Select parts are backwards compatible though.

But.... you may not need specific parts just yet.

So what you're saying is that the red tube turns on before the others, goes bright, then the set shuts down (the high voltage) to protect the tubes, then fires back up?

MY guess is that the red CRT socket/video amp is toast.

http://www.curtpalme.com/ElectrohomeMarquee_Layout7.shtm

Unless you have old Thomson tubes (post a pix of your CRT socket if it looks different than the above), the 8500/9500 CRT sockets will also fit the old style 9000.

To check, pull the red CRT socket off the tube, and make sure it doesn't touch anything in the set. Fire back up, and see if the blue and green tubes fire up normally now. If so, your red CRT socket is most likely shorted, and I've got those. If it still cycles, then put the red CRT socket back on, making absolutely sure that the white wire is connected to the right pin as shown above.

If it still cycles, then your HV power supply is most likely bad, and those are also backwards compatible, and I've got those as well.

Cheers!

rawlk · Joined: 25 Nov 2015 Posts: 11

Thanks for the incredibly quick reply Curt!

Video link is fixed, hopefully it'll help describe my problem a bit better. When the red tube is powering up, you can see the faintest of light starting up in the green and blue but then they all cut out at nearly the same time. So, yes, sounds like what you were describing.

The SN of the beast is 601100007 . Manufactured in '95 but it has a service tag from '96*? saying it has been serviced. Not sure if that is identifying enough to tell the model, but I'll verify via the heatsink tonight and take a peak at the tube socket tonight.

**Curt Palme** · Posted: Thu Nov 26, 2015 2:21 am Post subject:

Ok, it's what I thought. The red tube is coming on full, is overloading the power supply, and the HV shuts down to protect the tube. Rinse, and repeat. Smile

You should have a late model set. Pre 1995 and they had all sorts of issues, btu those got sorted out by 1995, so you should be good save for that red tube issue. Best case, that white wire has lifted or broken off. Reconnect it, and you may be good to go. Worst case the red tube is shorted (doubtful), but good thing it's the red, as I have lots of good used ones for dirt cheap!

rawlk · Joined: 25 Nov 2015 Posts: 11

Looks like you were spot on. Removing the board on the back of the tube yields a totally working B/G projector Razz

Also, as you mentioned, it does have the split heat-sink, so appears to be the earlier model... :/
https://goo.gl/photos/Fnp6UY4x6PQWK2Gh9

So the video amp doesn't look to have any crazy burns, heat spots or the sort. When they fail, do they fail spectacularly? Looks like I might be in need of some parts from someone...

Thanks for the help thus far!

Misc pics of the projector:
https://goo.gl/photos/dqr3yHTQ4NeVUGPX7

redfox001 · Joined: 16 Mar 2009 Posts: 2257 Location: The Netherlands

He those boards are very available for little. You could take a shot at the blue caps put a multimeter on them set to diode and see if one is shorted. Also clean those red HV leads to the tubes with some alcohol they can start sparking when there is enough dust on them.

Hmm also not normal that R25 is missing. That one is in the blacklevel circuit so could explain this.

**Curt Palme** · Posted: Thu Nov 26, 2015 2:12 pm Post subject:

But the set was working while he was aligning it, then failed. It's just an age related problem. Rawlk, email me at curtpalme at shaw.ca and I'll talk to you about selling you one. it will be cheaper than trying to repair yours.

redfox001 · Joined: 16 Mar 2009 Posts: 2257 Location: The Netherlands

He don't listen to me Very Happy

I fixed many of those by now so it is a habit. If you want to throw this one away send it to me. I pay something for fun and to save a board from wasting.

**Curt Palme** · Posted: Thu Nov 26, 2015 4:30 pm Post subject:

Email me, I've got about 20 here if you want them for almost nothing but shipping. They range from old 50-2000 boards to later 9500s. Some are missing parts, etc.

redfox001 · Joined: 16 Mar 2009 Posts: 2257 Location: The Netherlands

rawlk · Joined: 25 Nov 2015 Posts: 11

Interesting.

So from what I gather, I should be able to confirm that it really is the neck board by simply swapping one from the blue or green over, right? Might try that tonight since the apartment is nice and empty Razz

@redfox001 - If I do end up getting a replacement, are you interested in this one? I dont SEE anything wrong with it, so it didn't catastrophically fail or anything. it should be repairable.. just not by me any time soon Smile

On the note of dust, there is quite a bit, but not in this area. I do plan on doing some heavy cleaning though and checking grounds. (alcohol & qtips are fine right?) When it is powering up, there are a few pop's/crackles that I'm a bit concerned with Razz

With the top off there is a spark on the green tube, just behind the lens, that is pretty consistent...

@Curt - email sent Smile

edit - happy turkey day!

rawlk · Joined: 25 Nov 2015 Posts: 11

After going back through some pics.. looks like the red was always a bit off. I just assumed that was the projector's default or something, used for alignment.

Even during the menus and running the ACON, the red was always just 'on' while the other tubes were turning off/on as needed:

https://goo.gl/photos/pRNyAfNs21tFk57L8

Suppose that's verification enough that something was on the verge of failing!

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

interesting machine for sure, a first generation 9000 model re-built by electrohome in 1996. They replaced all the old "metal can" neck-boards with the newer model. Hopefully they put the new VIM in it too with blue Gamma tracking.

Rawlk, did you verify the White G2 wire was firmly on the correct pin before you took the board off? It probably was since not being on the right pin will result in spot-burn on the tube at shut-down.
Be really careful on this when you swap cards.

redfox001 · Joined: 16 Mar 2009 Posts: 2257 Location: The Netherlands

That looks like bad red blacklevel and can be explained by the resistor.

Think after a while some opamps burned.

rawlk · Joined: 25 Nov 2015 Posts: 11

@draganm - Yep, everything was well seated and for grinz and giggles I cleaned it up a bit and tried it out again without any luck.

Top pin... always the top pin... any harm in just wacking off that second 'playing-with-fire' pin? Razz

@redfox001 - Still think its r25? Should I confirm with another board?

redfox001 · Joined: 16 Mar 2009 Posts: 2257 Location: The Netherlands

I am pretty damn sure yes.

Here is you confirmation that it is not normal that r25 or any other part is missing. And I took the trouble to look in the schematic and saw that it is part of the chain that samples the blacklevel and readjust automatic. Now your picture show that there is a problem in blacklevel. So .....?

However replacing will not fix this as you probable burned the opamp u4 right on top in that chain after some time or other components.

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

why would R25 just be missing though? That's not a high current circuit, it's a simple 12Kohm SMD resistor with 1/8th watt power rating

and if by some chance it burn off you would see evidence of that on the board. That just looks like it was never populated? weird Confused

redfox001 · Joined: 16 Mar 2009 Posts: 2257 Location: The Netherlands

They pop off because of soldering going bad. I just had two very low current resistors not conducting when the board was cold. It was a Moome board. Took me some time to find them. Resoldered and now the Moome works fine. It happens all the time but most times you don't see it and they are loose but still attached to one side. This one did get loose on both sides or was hit.

redfox001 · Joined: 16 Mar 2009 Posts: 2257 Location: The Netherlands

You can see R25 in this part of the schematics. It is on the entrance of U4 maintaining a reference blacklevel close to ground.

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

yeah R25 looks like reference resistor for the 5V rail supply voltage that drives the op-amp, and that op-amp calls for 5 volt minimum. With that resistor gone there's likely some ripple on the rail, tripping up the amp, and triggering EHT inhibit from the VIM's protection circuitry.

Good chance that just replacing R25 will smooth things out, unless the amp is damaged but it seems unlikely is at has a 22volt tolerance on the supply voltage, tough little bugger Wink