Re: When will high power supplies become single ICs?

Posted on 44 minutes ago

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Ha, thinking of on board power generation, I've mentioned before that the Abit KA7 generates its own 3.3V supply from the ATX 12V, and doesn't use the PSU 3.3V at all (as far as I can tell). And that was over 20 years ago. I used to think the size limit for switching supplies would be the output …

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Re: When will high power supplies become single ICs?

Posted on Yesterday, 22:39

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Some USB fast chargers are pretty impressive, if not quite a single chip. Honestly, 100W from a tiny plug in brick? I wonder if the biggest problem for switching supplies is getting the output inductor size down? I know many years ago I had to design a buck dc-dc supply to fit on a daughter board, …

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Re: Test and troubleshoot PC@LIVE motherboards

Posted on Yesterday, 22:02

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by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I check with the card on the voltages, and something has mostly changed for the better, checking the 1085, finally the voltages are exactly (enough) as they were thought to be, practically like this: PIN1 0.27V | PIN2 1.50V | PIN3 4.92V Yay! i also measure Q3 = CEB6030AL and Q5 = CEB703AL here: Q3 …

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Re: Chicony CH-498B voltage regulator mod help.

Posted on Yesterday, 18:13

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It seems to me a very inefficient energy conversion since it wastes almost 50% in heat. If I find myself in such a case again, I will try to use more modern technology, it may even be easier. Oh, they're horribly inefficient. But they're also cheap, small, quiet (electrically I mean, no switching …

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Re: K6-2P Mobile CPUs

Posted on Yesterday, 17:33

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by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

BitWrangler wrote on Yesterday, 15:43: MVP3 are usually good for quite a bit. I wanna get to the bottom of the table here... But what about the two unmarked options: all 1-2 and then JP8 set to 2-3?

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Re: Anybody has info on this monitor: Reuters CMV123NE?

Posted on Yesterday, 14:47

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by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Miphee wrote on Yesterday, 14:44: Poor man's multisync. I'd guess that if Reuters were selling these to share traders and the like that the whole system was anything but poor man's anything. But that's just a guess.

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Re: Anybody has info on this monitor: Reuters CMV123NE?

Posted on Yesterday, 12:36

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The listing describes it as EGA, although it seems a bit odd that it's described as working, but the photos don't actually show an image on the screen. It does have a better picture of the front panel controls, which have a colour mode select switch: rauters-cmv123ne-ega-monito.jpg Modified NEC …

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Re: Anybody has info on this monitor: Reuters CMV123NE?

Posted on Yesterday, 00:23

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Dunno. 6 BNCs could be component RGB pass through. I could imagine a news type place wanting to have the same picture on a bunch of monitors around the place, so In/Out would be handy. TTL/PGA switch could be to do with Professional Graphics Adapter: https://en.wikipedia.org/wiki/Professional_ …

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Re: Test and troubleshoot PC@LIVE motherboards

Posted on Yesterday, 00:09

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The label behind the chipset has been removed, I had put a photo before, the trace is visible for the thickness and for the proximity to the slot1, nearby there is another one that is the same thick but I don't know what it connects. Oops, I missed that. Thanks. So I think we've got most of the 1. …

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Re: Test and troubleshoot PC@LIVE motherboards

Posted on 2021-12-01, 22:06

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The trace of slot1 that connects A1 and A3 is just below the slot, I can see it by eye, however I take a photo of the detail, it continues under the slot and comes out before EC20 (you can see because it is much thicker than the others), then it passes in the back and continues towards the chipset, …

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Re: Test and troubleshoot PC@LIVE motherboards

Posted on 2021-12-01, 19:52

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

These are the measurements made, let's start from 1085 and its 3PIN, I measured a resistance of 21.6ohm between PIN1 and PIN2 (22.2-0.6 crossing the leads), keeping in mind that the resistances are R94 = 10A = 124ohm and R95 = 39X = 24.9ohm, for these two it is not possible to measure them …

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Re: Early P5 + P54C (Socket 4 + Socket 5) mainboard

Posted on 2021-12-01, 19:05

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Something just occurred to me about those PI5Cs. Those diodes next to each of them might control power to the Vcc pin. That way they don't have to route to both !BEA and !BEB, and just turn the power on or off. Drive pin 2 of the diode high to connect the bus, or let it float/drive it low and Vcc …

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Re: New processors for old sockets.

Posted on 2021-12-01, 13:07

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Programmable Array Logic, type of programmable logic device: https://en.wikipedia.org/wiki/Programmable_logic_device Similar to, but not the same as, Programmable Logic Arrays.

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Re: Test and troubleshoot PC@LIVE motherboards

Posted on 2021-12-01, 12:30

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Ok thank you very much, thank you very much for your patience, but now thanks to your very detailed explanations, I understand what I was wrong. For the 1085 everything is ok so, now I have to redo the measurements, this time with the tester on 200OHm, I was using the diode test and I was wrong. …

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Re: Early P5 + P54C (Socket 4 + Socket 5) mainboard

Posted on 2021-12-01, 12:01

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Regarding whether how all the PI5C3884 are wired and enabled, then I can confirm that both BE(A) and BE(B) are shorted to ground (regardless of the JP33 settings) - which are active-low (I.e., always enabled). This goes for all the PI5C3884 on either side of the Socket 5. That sounds weird. Why …

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Re: Chicony CH-498B voltage regulator mod help.

Posted on 2021-12-01, 11:37

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Congratulations, glad it paid off. Nice that you've been able to undervolt and overclock at the same time. And I think you've ended up pretty close to the expected voltages; based on your measurements of the resistors then the measured voltages are all <0.7% from the calculated value. Even going by …

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Re: Test and troubleshoot PC@LIVE motherboards

Posted on 2021-11-30, 21:41

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The best thing for understanding the 1085 is the datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/108345fh.pdf Page 2 shows what the 3 pins are: pin 1 is Adjust, pin 2 is Vout, pin 3 is Vin. The output voltage is adjustable, and for the link you gave the output has been …

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Re: Chicony CH-498B voltage regulator mod help.

Posted on 2021-11-30, 18:49

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

On the spare regulator, is there a resistance between pins 3&4 (Ground-Vout)? Infinite resistance between pins 3-4, tested on the soldered one and on the others I have (I still have the first ones) The capacitor is C32, it's positive lead is connected to the far end of R20 and of course the …

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Re: Chicony CH-498B voltage regulator mod help.

Posted on 2021-11-30, 17:55

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I've had the 5v-3v jumper in 3v position, and I used the pin1 hole of the LT instead of the pin 5 hole of the MIC to prevent touching the legs. My hands aren't very steady and I have to take the measurements more than once to be sure. Always a good idea to find the easiest place to take a …

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Re: Chicony CH-498B voltage regulator mod help.

Posted on 2021-11-30, 17:49

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I go on a bit long here, but eventually realise that some of the measurements are caused by a capacitor charging up. I'll leave what I originally wrote as it at least shows what I was thinking. The short version is that I still can't see anything wrong, and the regulator should be putting out around …

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