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Repairing a Blue & White Studio Display CRT (repost)

Reposting this thread since the old forum ate it:

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.

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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.





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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.





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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.





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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.





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Since somebody asked on the previous thread, here's a link to the disassembly guide: https://www.applerepairmanuals.com/the_manuals_are_in_here/Studio_Display_17.pdf
 

Juror22

Well-known member
Terrific work and I love the detail in your repost. It would be fun to have a CRT that big (and nice looking)!
 

re4mat

Well-known member
Nicely done! How did you figure out that there was an equivalent flyback in the first place?
 

CircuitBored

Well-known member
Thanks for reposting this! I still have two of these CRTs that need new flybacks. I have the parts, I just haven't motivated myself to haul these massive screens up onto my workbench yet.

The disassembly guide will come in very handy, cheers for adding that. Congrats on a successful repair of a great bit of kit.
 

LaPorta

Well-known member
very nicely done. It is experiments like these that will help us all in the future when parts inevitably fail.
 

KGLlewellyn

Active member
Sorry to bump an old post, but I'm gonna be doing this over the next week or so. When you soldered the wires to the wires from the flyback to the video board, was it just a matter of soldering matching wires? If not, how did you know which wires went where?
 

KGLlewellyn

Active member
So I figured it out. Wiring for the Flyback goes as follows

New Flyback Wires --> Old Wires
Black --> Red (Focus)
White --> White (Focus)
Red --> Orange (G2)

Got my new flyback installed and the Studio Display is working again! Gosh darn do I love this monitor!

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aeberbach

Well-known member
Congratulations, I had one of these monitors and the repair manual - I though disassembly looked really hard!
 

CircuitBored

Well-known member
Got my new flyback installed and the Studio Display is working again! Gosh darn do I love this monitor!

Nice job! It's almost time for me to do this job myself. I've been using my Studio CRT a lot over the past few weeks and the clicky-zoom-out moments are getting more and more frequent.
 
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