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Compact Mac CRT - what are its power requirements?

Trash80toHP_Mini

NIGHT STALKER
I'm fixing to remove the stock CRT from my SE/30 and wondering how many watts doing so will free up for running expansion and mass storage options from the stock PSU?

 

techknight

Well-known member
welp. Cut the sweep supply wire and put an ammeter in the middle, measure the current draw on a full white CRT, and its voltage. 

Using the measured voltage and measured current, you can figure out wattage consumption. 

 

Trash80toHP_Mini

NIGHT STALKER
LOL! Thanks loads, tk. I was hoping for an answer that was non-destructive and didn't involve hurting my brain with Ohm's law.

Anybody else? :lol:

 

Trash80toHP_Mini

NIGHT STALKER
I was wondering if I might be going about this backwards? First pass would be measureing the pins on the end of the AB->MLB connector. That doesn't look right  in my skull though. I've got a pretty strong feeling that an attempt at testing while not under load would be an error in the ID10T class.

I've got a notion that I may need to build an extension cable with amperage(?) test points built in to monitor/determine power draw of the logic board's various voltages in a non-destructive manner. Figuring out the CRT circuitry's requirements would be great to know up front, but monitoring the climbing requirements of my insane contraption at various stages of development seems like it might be a great way to keep the power budget in check?

Dunno, my brain hurts when processing Ohm's law, but setting up an electron plumbing rig for the new autoranging digital multimeter toy to give me various individual readouts to simplifying the methodology to the point of just plugging them into a spreadsheet looks like it might be a fun first project.

Me builds spreadsheets for breaking functions like Ohm's black magicals into automagicals just fine! [:)] ]'>

 
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Trash80toHP_Mini

NIGHT STALKER
HRMMM. Just tried powering up the CRT sans MoBo, doesn't appear to do anything. We can hook one up to see if there's a power draw in that config. If not, the total figure for CRT/MLB doesn't do the trick. They have to be decoupled or measure the CRT under load as tk suggested.

 

CC_333

Well-known member
Well, the CRT won't do anything without the logic board telling it what to do, but it should draw more than zero.

If you can determine the wattages of the logic board and any spinning media and subtract those from the machine's total draw, whatever the difference is should be for representative of the CRT's wattage.

???

c

 

Trash80toHP_Mini

NIGHT STALKER
Thanks guys, I can live with that figure for now!

Scott, do you want it for a cute little B&W TV or as a Display? It's just a TV from everything I read.

 

Trash80toHP_Mini

NIGHT STALKER
Well, if you've got Apple II, you'll have yourself a nice little monitor there, no VGA though. Is 800 lines a higher than usual "resolution" for a TV?

 
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techknight

Well-known member
I am having a hard time believing that clinton still manufactures CRTs. If they do, they are the absolute LAST. 

But they probably have a bunch of backstock and thats it, as it seems they are promoting their LCD monitors alot more than the CRTs. 

 

Gorgonops

Moderator
Staff member
A search of Alibaba.com suggests that if you *really* want to sell a CRT TV there are still outfits in China willing to churn them out for you. (There are *many* listings for 14" color tubes in particular, so many it suggests that somewhere in the world people are actually still buying small color CRT TVs en-mass.)

 

CC_333

Well-known member
Old-ish thread, but...

To answer Gorgonops, they're probably people in Japan, as they seem to really like old-fashioned technology (they were the last to get rid of LaserDiscs and I believe also VHS, among other things).

c

 

Themk

Well-known member
They could also be used for really low budget people too, as these Chinese companies can likely churn out these 14-inchers really cheaply. Perhaps a complete TV set, complete with a DVD player in the bottom would cost only $70-90. edit: I double checked the prices, looks like they are to offer them for under $50 a piece! Add shipping, DVD player, and I think you could realistically target a $90 TV set, thats quite cheap, and many of the manufactures are advertising 720P capability.

Edit: It looks like a few of them specifically talk about Africa and the Middle East. But there are probably people in Japan buying these too.

I'm really curious, I hope other people share their thoughts on this.

Also, Gorgonops, I wonder if those Chinese CRT outfits could churn out some computer monitor tubes, or maybe some 9-inch tubes for compact mac tube replacement.

 
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