CurtPalme.com Home Theater Forum

**Curt Palme** · Posted: Mon Feb 03, 2014 3:29 pm Post subject: Reworking my retro Graphics 808s

So yesterday before the Superbowl, I decided to upgrade/repair my retro BG808s. I've owned it for... wow, 12 years now? Bought it off ebay for $500. Now, to be truthful, it's the second Retro 808s chassis I've had, the first one had a very slow glycol leak, and since the set sits at a 45 degree angle within the box, the glycol ran down into the chassis, and nuked the motherboard one day with a loud BANG! I also sourced the second BG808s chassis on eBay for $500 about 6 years ago.

This beast has 49.000 hours on it! Original tubes, go figure. I re-glycoled the blue tube due to fungus in it, but it was more of a haze than a fungus. It covered the entire face of the tube and the inside of the C element, and caused massive hazing. The green and red tube did it to a lesser degree, but I decided to change the glycol in the R and G tubes yesterday. Also, I was going to change the clear C elements to tinted ones out of a Sony G70.

So I started with the green. New glycol, cleaned the chamber, etc. Assembled it and managed to put the red C element on the green tube. OOPS! Mr. Green

Put in the green tube correctly the second time, then did the red. Reassembled everything, and noticed that I had worse hazing on the green tube than when I started. WTF? Turned out that I managed to get a drop or two of glycol on the front of the C element that I didn't see, and it smeared as I was putting the lens back on. Minor disassembly while the projector was back together, and no more haze.

I then found out that the main focus of these lenses has to be very slightly defocused to get the corners bang on. All stock lenses on this set, but when I had the center razor sharp, I couldn't get diddley for focusing at the edges. May try a different set of HD114 lenses next weekend to see if I can improve it, but it's pretty good overall.

Due to the way the neck boards are situated, setting the G2 is a 2 person job, one person in the front of the set, the other in the back, so I didn't set those (I know they are off the calibration mark), but I did marvel at the lack of tube wear on these tubes after 49000 hours! There is a tiny bit, but it's right to the edges of the tubes, and even and barely there. Emission of the Pt18 tubes is fantastic. I attribute this due to me having the contrast at well under 50 since I've had the set.

Once I converged and did astig, etc, I marveled at the picture quality of this set. Freaking amazing! The reds definitely were richer. By fluke, I got that 55" Samsung LED Smart TV going, and hung it in the bedroom this weekend. It's super sharp, but seriously, give me the 1997 vintage BArco retro behemoth over that Sammy any day.

Love my 350lb retro! Very Happy

digitalayon · Joined: 02 Mar 2009 Posts: 921

Since when does an 808 weigh 350? Did you put 9 inchers in it?

**AnalogRocks** · Posted: Mon Feb 03, 2014 4:35 pm Post subject:

fragzero · Joined: 30 Aug 2012 Posts: 344

Quite certain there is a difference between the HD18/134 C-elements and the HD114/115 etc (barco) lenses. Certain Decibel could give you some more information!

**Curt Palme** · Posted: Mon Feb 03, 2014 5:39 pm Post subject:

Guys, this is a RETRO set that weighs 350 lbs and comes in two halves, the screen and the chassis. It uses the HD 114 lens set on it, not the HD18s.

fragzero · Joined: 30 Aug 2012 Posts: 344

**Curt Palme** · Posted: Mon Feb 03, 2014 5:44 pm Post subject:

Ahhh you know what, I never thought of that!!!

thanks, that makes sense! I'm not changing it though, I'll live with the slightly worse edge focus, but will see if I can get the HD18s to fit on the set.

fragzero · Joined: 30 Aug 2012 Posts: 344

There is a thread somewhere on the forums written by Decibel, those C-elements have a different curve, pretty certain he will comment on this thread when he sees it Smile

**Curt Palme** · Posted: Mon Feb 03, 2014 5:56 pm Post subject:

I've seen that with 9" sets. The earlier analog Barcos had a different curve than the later digital ones, due to the cheap TAC4 lenses. I haven't seen that with 8" sets before...

Francisco · Joined: 05 Apr 2007 Posts: 305 Location: The Netherlands

Hi Curt, I once bought à retro 808s with only 3000hr's for 300€, dumped the chassis parts and converted it to a front BG808s LC with a bg808 chassis. Also used the G70 colored c-elements and HD18 lenses. They have different curve, and because the HD 114 are short throw for retro you can not fit the HD18 in it, which also have to be adjusted. Now if you can find c-elements from a zenith 1200 which also had colored c-elements and used the HD215 lenses you could be lucky. But they are very rare.
Mine also had PT18 tubes and they are razor sharp indeed, and with 120mhz amp's 1080p is easy cake for this machine.
I really enjoyed it for several years.

Francisco · Joined: 05 Apr 2007 Posts: 305 Location: The Netherlands

One more thing, you can adjust G2 by turning the whole chassis within the lower unit, turn the G2 trimpot turn unit and watch the amp's led to turn off.

**Curt Palme** · Posted: Mon Feb 03, 2014 9:16 pm Post subject:

OK, good information. I have had 4 Zenith 1200s here over the years, but will not destroy one to maintain my retro! Smile

the image for me is good enough, and the slightly soft focus in the corners is not worse than the improvement that the colored C elements give. Since the set is being used in 16:9 mode anyway, the corner defocusing is not noticed as much.

Decibel · Joined: 31 May 2007 Posts: 904 Location: Roma - Italia

**Curt Palme** · Posted: Tue Feb 04, 2014 1:50 am Post subject:

Thanks! goes to show that I don't read every thread here.. Smile

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

Pics Curt... I used to just look at the pictures in magazines, i reckon itd be worth a shot on forums too Laughing

**AnalogRocks** · Posted: Tue Feb 04, 2014 3:08 am Post subject:

km987654 · Posted: Tue Feb 04, 2014 8:25 am Post subject:

Did anyone make a 9" retro set?

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

Yeah there was an RCA set sold here that was 61" or 64" with 9" tubes, i think the JVC sets also had 9" tubes ( the same one they used to give away on funiest home videos over here back in the 90s )

Not sure about the 64" Toshibas they sold here, some of those were composite and s-video only for the local market, where are Europe got RGB inputs as well.

The Panasonics and most of the later Sonys had P16s in them, alot of the LGs and Samdungs had P14s.

**Curt Palme** · Posted: Tue Feb 04, 2014 2:49 pm Post subject:

Watched the beast again last night. Not happy! Very Happy

Convergence drift, and last night the lack of focusing bugged me. May need to switch back to the stock clear lenses, but I realized with the lack of concave rear lens elements, I might just be able to put in gel sheets of color tinting. I definitely like the better reds in the image..

Fortunately, someone just gave me a low hour retro chassis, so I'll swap out the convergence tray, convergence power supply and H and v boards one at a time to see where the drift is coming from. Convergence drift is a bit rare in Barco 808 chassis, so this merits investigation, because this chassis has done it for a long time. When I swapped the tubes out, I made sure that all tube hardware was nice and tight, so that's not it.

noos@xp37+ · Joined: 17 Jun 2008 Posts: 464 Location: Berlin/Munich

Many Retros came with a 117-12 on green an a 114s for blue an red. I did resolution tests with them and the 117 are far better (overall and edge focus). 117s were als better then HD18 and close/the same to HD134(many versions out there!). So combining 117s with lee filters foil should give a stunning picture. Hd117 are great great lenses.

One other thing: When adding water to the glycol of an LC system or using pure water, the edge focus moves out to the user in fp. So in rp it will move inside the screen. Curt, when you focus the center with the hd114 on the hd18 c-element, is the ideal edge focus inside the retro or outside with the viewer? If outside (at the user side) you could add a little water to the glycol until center and edge zones merge perfectly. By the way, the more water you add - the more resolution you get.