Apple 24" iMac A1225 EMC2134 with a Delta ADP-240 AF B SMPS, won't start

mkinn · 02-21-2016, 06:46 PM

Slight click when power button is pressed, HD spins up for 1/2 a second, then shuts down. Obviously, it is trying to power on, because the HD spins up for a 1/2 second. I don't suspect any shorted diodes or semi's. I do not have a schematic, or I could do the troubleshooting myself. Please feel free to be very technical. I have an ESR meter, and a Hakko 880 de-soldering machine.

This is a 240W power supply, and has been replaced with a newer power supply, the APPLE 661-4478, an almost identical 250W version which includes a "pressure wall" which probably has to do with airflow.

**CapLeaker** · 02-21-2016, 07:43 PM

Since you have an ESR meter, check them capacitors. I see a few that look like they ran hot. Are there more caps under these heat sinks? Maybe check the secondaries if they are putting out. Looks like they are two 12V rails and a 24V rail.

mkinn · 02-21-2016, 09:28 PM

I took the power supply out.
I had to cut the heatshrink off the 2 33uf 35V caps with a sharp exacto knife.
I found the following ESR values:
33UF 35V (130°) X2 - 1.0 ohms
100uf 35V - 0.5 ohms
220UF 35V X2 - .25 ohms
820UF 25V - .25 ohms
470UF 16V - .25 ohms
1000UF 16V X6 - .1 ohms
150UF 50V - .25 ohms
120uf 450V X2 - .25 ohms
All caps are RubyCon 105° caps, except the 33uf 35V ones.

Seems like they are all within spec for these caps.
Meter: Electronic Design Specialists 88A In-Circuit DCR ESR Cap Analyzer

**stj** · 02-21-2016, 10:08 PM

they dont sound in-spec to me.
what series are those rubycons?

mkinn · 02-21-2016, 11:31 PM

33UF 35V (130°) X2 - 1.0 ohms - RX30
100uf 35V - 0.5 ohms - (PW)P
220UF 35V X2 - .25 ohms - (HD)P
820UF 25V - .25 ohms - ZLH
470UF 16V - .25 ohms - (PW)P
1000UF 16V X6 - .1 ohms - ZLH
150UF 50V - .25 ohms - ZLH
120uf 450V X2 - .25 ohms - BXA

**stj** · 02-22-2016, 12:07 AM

there is no way a ZLH should have esr that high.
1000/16 for example, should be 0.029 NOT 0.1

**Stefan Payne** · 02-22-2016, 01:41 PM

But is the ESR meter able to show anything below 0.1??

**stj** · 02-22-2016, 02:02 PM

these need to be re-tested off-board too.
i suspect they are a bit cooked.

mkinn · 02-22-2016, 02:46 PM

Complete recap, same problem.

**stj** · 02-22-2016, 03:47 PM

make a list of the chips on the underside.
it could be an op-amp or voltage comparater on the way out tripping a false error.

guruji · 08-25-2020, 07:13 AM

i am stuck with the same smps what i want to know the pfc boosting cap what is the voltage i get 334Volts generally should be 390V.on dap017 on pin 2 i get 3volts pin no 16 just 6.2 volts.Does anyone know the valuve for zd36 near d2 & Q2

**nassimhamdi** · 06-08-2021, 04:51 AM

what a bout ic's voltages???

02-21-2016, 06:46 PM	#1
mkinn New Member Join Date: Aug 2014 City & State: Birmingham AL My Country: USA I'm a: Knowledge Seeker Posts: 7	Apple 24" iMac A1225 EMC2134 with a Delta ADP-240 AF B SMPS, won't start Slight click when power button is pressed, HD spins up for 1/2 a second, then shuts down. Obviously, it is trying to power on, because the HD spins up for a 1/2 second. I don't suspect any shorted diodes or semi's. I do not have a schematic, or I could do the troubleshooting myself. Please feel free to be very technical. I have an ESR meter, and a Hakko 880 de-soldering machine. This is a 240W power supply, and has been replaced with a newer power supply, the APPLE 661-4478, an almost identical 250W version which includes a "pressure wall" which probably has to do with airflow. __________________ Michael Kinnaird 43+ years I.E.E.E A/V tech

02-21-2016, 07:43 PM	#2
CapLeaker Leaking Member Join Date: Dec 2014 City & State: Atlantic Canada My Country: Canada Line Voltage: Ground, 0Hz I'm a: Hobbyist Tech Posts: 4,798	Re: Apple 24" iMac A1225 EMC2134 with a Delta ADP-240 AF B SMPS, won't start Since you have an ESR meter, check them capacitors. I see a few that look like they ran hot. Are there more caps under these heat sinks? Maybe check the secondaries if they are putting out. Looks like they are two 12V rails and a 24V rail. Last edited by CapLeaker; 02-21-2016 at 07:51 PM..

02-21-2016, 09:28 PM	#3
mkinn New Member Join Date: Aug 2014 City & State: Birmingham AL My Country: USA I'm a: Knowledge Seeker Posts: 7	Re: Apple 24" iMac A1225 EMC2134 with a Delta ADP-240 AF B SMPS, won't start I took the power supply out. I had to cut the heatshrink off the 2 33uf 35V caps with a sharp exacto knife. I found the following ESR values: 33UF 35V (130°) X2 - 1.0 ohms 100uf 35V - 0.5 ohms 220UF 35V X2 - .25 ohms 820UF 25V - .25 ohms 470UF 16V - .25 ohms 1000UF 16V X6 - .1 ohms 150UF 50V - .25 ohms 120uf 450V X2 - .25 ohms All caps are RubyCon 105° caps, except the 33uf 35V ones. Seems like they are all within spec for these caps. Meter: Electronic Design Specialists 88A In-Circuit DCR ESR Cap Analyzer Last edited by mkinn; 02-21-2016 at 09:32 PM..

02-21-2016, 10:08 PM	#4
stj Great Sage 齊天大聖 Join Date: Dec 2009 City & State: Europe My Country: some shithole run by Israeli agents I'm a: Professional Tech Posts: 25,274	Re: Apple 24" iMac A1225 EMC2134 with a Delta ADP-240 AF B SMPS, won't start they dont sound in-spec to me. what series are those rubycons?

02-21-2016, 11:31 PM	#5
mkinn New Member Join Date: Aug 2014 City & State: Birmingham AL My Country: USA I'm a: Knowledge Seeker Posts: 7	Re: Apple 24" iMac A1225 EMC2134 with a Delta ADP-240 AF B SMPS, won't start 33UF 35V (130°) X2 - 1.0 ohms - RX30 100uf 35V - 0.5 ohms - (PW)P 220UF 35V X2 - .25 ohms - (HD)P 820UF 25V - .25 ohms - ZLH 470UF 16V - .25 ohms - (PW)P 1000UF 16V X6 - .1 ohms - ZLH 150UF 50V - .25 ohms - ZLH 120uf 450V X2 - .25 ohms - BXA

02-22-2016, 01:41 PM	#7
Stefan Payne Badcaps Veteran Join Date: Dec 2009 City & State: Northern Germany My Country: Germany Line Voltage: 230VAC/50Hz or 400VAC/3P/50Hz I'm a: Knowledge Seeker Posts: 1,259	Re: Apple 24" iMac A1225 EMC2134 with a Delta ADP-240 AF B SMPS, won't start But is the ESR meter able to show anything below 0.1??

02-22-2016, 02:02 PM	#8
stj Great Sage 齊天大聖 Join Date: Dec 2009 City & State: Europe My Country: some shithole run by Israeli agents I'm a: Professional Tech Posts: 25,274	Re: Apple 24" iMac A1225 EMC2134 with a Delta ADP-240 AF B SMPS, won't start these need to be re-tested off-board too. i suspect they are a bit cooked.

02-22-2016, 02:46 PM	#9
mkinn New Member Join Date: Aug 2014 City & State: Birmingham AL My Country: USA I'm a: Knowledge Seeker Posts: 7	Re: Apple 24" iMac A1225 EMC2134 with a Delta ADP-240 AF B SMPS, won't start Complete recap, same problem.

02-22-2016, 03:47 PM	#10
stj Great Sage 齊天大聖 Join Date: Dec 2009 City & State: Europe My Country: some shithole run by Israeli agents I'm a: Professional Tech Posts: 25,274	Re: Apple 24" iMac A1225 EMC2134 with a Delta ADP-240 AF B SMPS, won't start make a list of the chips on the underside. it could be an op-amp or voltage comparater on the way out tripping a false error.

08-25-2020, 07:13 AM	#11
guruji Member Join Date: Oct 2012 City & State: mumbai My Country: India I'm a: Professional Tech Posts: 61	Re: Apple 24" iMac A1225 EMC2134 with a Delta ADP-240 AF B SMPS, won't start i am stuck with the same smps what i want to know the pfc boosting cap what is the voltage i get 334Volts generally should be 390V.on dap017 on pin 2 i get 3volts pin no 16 just 6.2 volts.Does anyone know the valuve for zd36 near d2 & Q2

06-08-2021, 04:51 AM	#12
nassimhamdi Senior Member Join Date: Feb 2016 City & State: ourgla My Country: algeria I'm a: Knowledge Seeker Posts: 101	Re: Apple 24" iMac A1225 EMC2134 with a Delta ADP-240 AF B SMPS, won't start what a bout ic's voltages???

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