Re: Delta DPS-150GB PSU failure
I replaced 10 small electrolytic caps as suggested above. Then I plugged the power supply into the wall socket and checked the trickle pin with the meter. It showed 4.95V power.
I wanted to test the PSU without connecting it the motherboard. I found a post in the macrumors forum that describes how to turn this PSU on: one needs to wire the TRKL and the PowerON pins together.
The corresponding thread is [URL="https://forums.macrumors.com/threads/what-should-i-do-with-my-crappy-old-beige-g3-and-how-do-i-turn-on-the-psu.1845233/"]here.[/URL]...
powermax
Member
Last Activity: 08-02-2022, 02:33 PM
Joined: 05-27-2017
Location: Oldenburg
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Re: Delta DPS-150GB PSU failure
It looks like the only series that offer 1 uF and 2,2 uF @ 50V caps is SMG (SMQ-E).
Okay to go with them?Leave a comment:
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Re: Delta DPS-150GB PSU failure
Is the schematic for a 1A-3A available somewhere?...Leave a comment:
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Re: Delta DPS-150GB PSU failure
Well, the unit originally had three 25V and one 50V Rubycon caps.
Chemicon KY isn't available anymore. KYA 50V is a bit thicker - I need to check first if they fit into the available space.
KZE caps have a rated endurance of either 2000 or 10000 hours.
Rubycon offers 5000 hours as well......Leave a comment:
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Re: Delta DPS-150GB PSU failure
I'm looking for replacement caps. I have a couple of Chemicon KY ones and wanted to order more of the same kind but they seems to be discontinued by the manufacturer.
These look like a good replacement to me:
[URL="https://www.mouser.de/ProductDetail/Rubycon/25YXF47MEFC5X11?qs=T3oQrply3y96QKWCriJgLQ%3D%3D"]https://www.mouser.de/ProductDetail/Rubycon/25YXF47MEFC5X11?qs=T3oQrply3y96QKWCriJgLQ%3D%3D[/URL]
[URL="https://www.mouser.de/ProductDetail/Rubycon/25YXJ47M5X11?qs=T3oQrply3y%2F3J8S0Pc4Y1g%3D%3D"]https://www.mouser.de/ProductDetail/Rubycon/25YXJ47M5X11?qs=T3oQrply3y%2F3J8S0Pc4Y1g%3D%3D[/URL]...Leave a comment:
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Re: Delta DPS-150GB PSU failure
Markings: 1uF 50V
Measures: 948,1 nF, ESR = 2,4 Ohm, VLoss = 0,4 %
Markings: 1uF 50V
Measures: 938,2 nF, ESR = 2,2 Ohm, VLoss = 0,4 %
Markings: 2,2 uF 50V
Measures: 2180 nF, ESR = 2,1 Ohm, VLoss = 0,9 %...Leave a comment:
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Re: Delta DPS-150GB PSU failure
For 1 uF and 2,2 uF caps, my testing device measured the ERS > 2 Ohm.
The ERS of the other caps lays below 1 Ohm.Leave a comment:
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Re: Delta DPS-150GB PSU failure
I have a device for measuring various components. It shows the following for the desoldered 100 uF cap (C901):
112,5 uF
ESR = .41 Ohm
Voss = 1,5 %
(see the attached picture)
I could measure all caps after desoldering. Would that be meaningful?
I have no possibility to heat up the PSU to 50° without risk of damaging the unit......Leave a comment:
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Delta DPS-150GB PSU failure
Hello crews,
I got a faulty Delta DPS-150GB PSU from a Power Macintosh G3 Beige.
The computer has suddenly stopped working.
I checked the PSU and found out that there is no voltage on the trickle rail. That explains why the Mac doesn't power on.
An initial visual inspection has revealed neither blown components nor bulging/leaking caps. The main fuse is good, too.
Judging by the markings on the PCB, the PSU was built in April 1998.
I therefore assume that replacing all caps except the big ones won't do any harm.
Nevertheless,...Last edited by powermax; 07-03-2022, 11:12 AM. -
Re: Help to identify a vintage IC
Pressing S1 will short pin 1 to the ground and thus cut off Cuda's power efficiently resetting the latter. Right?...Leave a comment:
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Re: Help to identify a vintage IC
Yes, I agree that the unknown IC looks like a power supervisor thingy, similar to Max801/Max808 but not exactly. If I'm reading the schematics correctly, Cuda gets its power from our IC via pin 1, not 8. That's because Cuda's VDD is on pin 13.
Pin 8 of U12 seems to be connected to +5V of the logic board.
Bingo!
...
Leave a comment:
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Re: Help to identify a vintage IC
Thank you for the interesting suggestions!
I know for sure it's used at least in Macintosh Quadra 840av and PowerMac 6100.
Assuming it's a serial SRAM, what's your guess on the possible pin functions? From what I see in the schematic:
1 seems to be +5 V power source + that strange S1 switch
2 is connected to the trickle power (standby power) coming from the PSU
3 is connected to PC1 of the MCU (data line)
4 GND
5 not connected ?
6 is...Leave a comment:
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Help to identify a vintage IC
Hi crews,
I'm trying to repair a vintage computer circuitry that contains an unknown IC in the DIP-8 package. It was used in several Macintosh computers around 1993/1994.
The IC in question is marked with the Apple logo and contains the following digits: '90 0120'. I attached a zoomed picture of the IC as well a schematic showing the related components.
The IC in question (U12) could be an ASIC. But it could be also a custom version of some other IC like the Cuda MCU (U17) which is just a custom version of the 68HC05.
The unknown IC (U12)... -
Re: Astec AA16990 PSU failure
I've built a "load device" that consist of two 2 Ohms, 25W Ohmite tubular resistors connected in parallel and two 12 Ohms, 25W Vishay wirewound resistors in parallel mounted on an improvised heatsink. This device loads the 5V rail with 5A and the 12V rail - with 2A. The -12V rail remains unloaded.
Now I get the following voltages:
+5V rail ----> +4.98V
+12V rail ---> +11.86V
-12V rail ----> -12.08V
Everything seems to be okay now. The voltages are stable too, although the test lasted...Last edited by powermax; 07-28-2017, 04:47 PM.Leave a comment:
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Re: Astec AA16990 PSU failure
Oh yes, you're right! That shows that I can't fully trust those (bogus) values on the PSU's case.
Thank you very much, Sir! I'll do the tests and report the results....Leave a comment:
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Re: Astec AA16990 PSU failure
Yes, I learned to pick at least the doubled wattage because I'm not going to "fry an egg" with the load resistor
Good advice, thanks a lot! The question is that the 5V rail of my Astec PSU has the max. power of 11.6A. Should I test this PSU with a load close to its maximum, say 10A? If yes, what combination can I use to meet the required resistance of 0.45 ohm, 55W?...Leave a comment:
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Re: Astec AA16990 PSU failure
Ok, thanks! BTW, [URL="https://www.badcaps.net/forum/showpost.php?p=72692&postcount=23"]This post[/URL] does explain in details how the mentioned bulb test works.
Okay, is it correct that I'd need to attach a 1 Ohms/25W resistor to load the 5V with 5A and a 6 Ohms/24W resistor to load the 12V rails with 2A?Re: Astec AA16990 PSU failure
Ok, thanks! BTW, [URL="https://www.badcaps.net/forum/showpost.php?p=72692&postcount=23"]This post[/URL] does explain...Leave a comment:
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Re: Astec AA16990 PSU failure
Yes, such a "testing" circuitry built using incandescent bulbs has been already mentioned several times in this forum. Unfortunately, I couldn't find anything concrete.
Do you have any tips or helpful tricks on how to build such a testing circuit for my PSU?...Leave a comment:
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Re: Astec AA16990 PSU failure
When I disconnect the fan, the -12V rail shows "-11,4V". With the fan connected, it has only -4,4V...Leave a comment:
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Re: Astec AA16990 PSU failure
I replaced four small caps (C46, C11, C207, C30) and "AS431B" with "TL431AI".
Good news: the fan spins, nothing has exploded so far.
Bad news: the rails are still low (+5Vrail = 4.34V, +12Vrail = +7.20V, -12V= -4.4V). The voltages fluctuate quite much.
I'm testing the PSU without load. I've read somewhere that these ol' PSUs don't operate correctly without a proper load. Is it true?Last edited by powermax; 07-24-2017, 01:36 PM.Leave a comment:
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