68kMLA Classic Interface

This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.

Click here to select a new forum.
Compact Mac CRT - what are its power requirements?
Posted by: Trash80toHP_Mini on 2017-01-13 14:26:51 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?
Posted by: techknight on 2017-01-13 16:08:13 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.
Posted by: Trash80toHP_Mini on 2017-01-13 19:43:33 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:
Posted by: techknight on 2017-01-13 19:58:35 Well i doubt its in a spec sheet anywhere.
Posted by: Trash80toHP_Mini on 2017-01-13 20:09:07 WAG: about half of what's available?
Posted by: Trash80toHP_Mini on 2017-01-14 08:29:50 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! [🙂] ]'>
Posted by: techfury90 on 2017-01-14 10:54:05 You could get a kill-a-watt, actually, I might have one laying around you can use.
Posted by: Trash80toHP_Mini on 2017-01-14 11:47:36 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.
Posted by: CC_333 on 2017-01-14 13:25:00 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
Posted by: Trash80toHP_Mini on 2017-01-14 13:44:39 If I do a panel or board populated with however many of these: are necessary to cover all the voltages, can I leave it in place under use? The case will have clear sections in it for readout anyway. DC-100V-10A-Voltmeter-Ammeter
Posted by: Scott Baret on 2017-01-16 23:40:48 Clinton still makes the 9" CRT, believe it or not! They sell it as a CCTV display in self-contained form. https://clintonelectronics.com/products/monitors/7in-12in-monitors/ce-mm9/ This may give you some insight into your questions on power consumption, especially if your plans were to power it in some way not connected to the Mac. In all honesty, I sort of want to get one of those monitors. I like the style of them!
Posted by: Anonymous Freak on 2017-01-17 01:14:40 Hey, right there on the web page! Power Consumption20 Watts (1.667 Amps)
Posted by: Trash80toHP_Mini on 2017-01-17 19:27:06 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.
Posted by: Scott Baret on 2017-01-17 22:36:35 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. Both 🙂 If I had a patio room it would be a neat little TV to have out there.
Posted by: Trash80toHP_Mini on 2017-01-18 05:19:22 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?
Posted by: techknight on 2017-01-18 16:10:17 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.
Posted by: Gorgonops on 2017-01-19 11:04:31 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.)
Posted by: CC_333 on 2017-04-17 16:48:12 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
Posted by: Themk on 2017-04-18 12:38:25 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.
1 >