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Repairing a Blue & White Studio Display CRT


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Finally doing a quick write up of this repair I did last year. Thought it might be useful to others who are looking to fix their monitors.

 

My Studio Display I’d recently purchased on eBay had a failing flyback transformer, which was unfortunate since the plastics and the tube itself were all in great condition. The monitor would make a loud click/popping spark noise and the image would go away and come back with a zooming effect. 
 

I found that the HR46162 was a equivalent part to the original. Despite a forum post elsewhere I saw where the poster thought the HR Diemen flyback wasn’t correct because it didn’t have the same number of pins, I took a chance and ordered one from https://www.electronica-usa.com/product_HR46162.html. Before ordering I noticed that (with the old flyback still in-circuit) the missing pins were directly connected to others, so I figured it would be fine. Turned out that yes, those missing pins are internally connected.

 

MA4cA3U.jpg

 

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The new flyback came with an instruction to disconnect a particular capacitor from the monitor’s circuit board. I found a cap with the same silk screened PCB reference number as the instructions and cut it off. The new flyback didn’t quite fit in place of the old one due to closely packed components, but I shaved off an unused part of the flyback’s board to fit it.

 

ajKfTAC.jpg

 

I ended up cutting the wires from the old flyback that went to the video board, and soldered the new flyback’s wires to their ends since the new one didn’t have connectors on those wires.

 

FDyRMfK.jpg

 

To give the new flyback as long a life as possible by keeping it from overheating, I installed a spare PC case fan I had lying around in the top of the RF shield for the monitor. I found a 5V supply in the monitor and soldered some pins to it and ground so I could just attach the case fan easily.

 

6KlpTb9.jpg

 

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With the new flyback transformer, and after adjusting the G2 and focus, the monitor looks great! The Diamondtron CRT is just fantastic.

 

qXypieI.jpg

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This is a a really great resource. Thank you for putting in the time! I have both the B+W and the Graphite versions of this monitor so will likely put this to good use. 

 

20 hours ago, dontdoxmeman said:

The Diamondtron CRT is just fantastic.

Hear hear!

 

One question remains: how on Earth do you take these things apart? I may be missing something obvious but I've never figured it out.

 

If you could post a disassembly guide that would be great!

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  • 1 month later...

What monitor is this? is this the Sony trinitron 21" version? or? 

 

I have one that someone brought me a couple years back to repair, and it too needs a flyback. Goes into overcurrent shutdown for anything greater than 640x480 resolution. 

Edited by techknight
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  • 68kMLA Supporter

Based on the screen to bezel ratio, it looks like the 17" which has a Mitsubishi Diamondtron aperture grille CRT.  I quite like Diamondtron CRTs- most I've encountered seem to have different phosphors and AR coatings than Trinitrons, offering deeper blacks even in brightly lit spaces.  I'm not sure if the Diamondtron is a licensed version of Trinitron or if it's an independent design after Sony's patents expired.

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Posted (edited)

I believe that the chassis for all of the Studio CRTs were sourced from LG, whether it's a 17" Diamondtron or a 21" Trinitron tube.  LG didn't offer a 21" aperture grille monitors at this time, so their closest models around the time would be:

 

1. Studioworks 221U which had a 21" shadow mask FST tube,  4 port USB hub, and 1800x1440@80Hz or 1600x1200@90Hz "flicker free" maximum resolution

2. Flatron 915FT Plus which had a 19" aperture grille tube, 4 port USB hub, and 1800x1440@70Hz or 1600x1200@85Hz "flicker free" maximum resoluton (like the Studio Display 21)

 

Maybe one of these uses a substansially similar chassis and flyback?

Edited by rsolberg
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  • 1 month later...
Posted (edited)

Bringing this thread back to share something I discovered about this monitor that was frustrating me to no end until I figured out the problem.

 

My 17” Studio Display refused to work with any VGA switch. It would stay in standby mode, thinking the computer was turned off. I then tried a female/female gender cable and connected directly to the VGA cable and it still didn’t work as an extender from the monitor’s attached cable. None of my VGA cables did. After a lot of multimeter probing off and on for a few days, I had determined that all my VGA cables have pin 11 wired to ground. Testing the Apple display’s attached cable, pin 11 was not wired to ground. Suspecting that Apple did something nonstandard with this legacy IBM monitor ID pin, I pulled pin 11 out of one end of my VGA cable, hooked that end up to the switch, and it worked!

 

TLDR: the studio display CRT (VGA) is compatible with VGA/KVM switches if you use a VGA cable on the switch without pin 11 connected (or at least not grounded). Don’t know if pin 11 has some function when using the monitor with a Mac, but it seems to work normally, including auto standby mode when the Mac sleeps.

Edited by dontdoxmeman
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