Re: Enermax PRO 82+ 525W repair
got it sck054
Syn-fi
Member
Last Activity: 03-16-2022, 08:25 AM
Joined: 05-17-2013
Location: Manchester
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Re: Enermax PRO 82+ 525W repair
hi, what is the value of the NTC designated at THR1?
thank youLeave a comment:
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Re: Bad DC Offset TL072 Op-amp
I'm still getting contacted about this many years down the line.
Another failure is a Harris marked chip 74HC04 Hex inverter SMD (U30) which sends S/H (sample and hold) to the TDA DAC. Tell tale sign will be a lack of a 35khz chop (the DP4 samples at 35khz). The encapsulate seems to be disintegrating and eating traces...i removed one of these, because of aberrant S/H and there was black ooze underneath.
In this scenario you might have a Bad DC offset and red-lined LED on say 3/4 but not 1/2 inputs. The TDA DAC has only 2...Leave a comment:
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Re: Bad DC Offset TL072 Op-amp
hi,
i have fixed more of these DP4+s since.... around 10-15 now
Now i have a better understanding of the cause(s) of failure.
So, as the last poster pointed out failure of an op-amp is unlikely - he's right. I fixed the unit by remaking shorted traces with the heat gun now i'm much wiser and knowledgeable i also armed with an analog scope.
What seems to be happening on the DP4+ is a mixture of electrolytic discharge from capacitors, particularly those near the 5 voltage regulators being right next...Leave a comment:
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Re: Bad DC Offset TL072 Op-amp
Hi guys,
Finally fixed this. I took it to an electronics repair place but even they gave up. I then recovered the unit about 2 weeks ago and in between times i have learned a great deal more about D/A circuits and Op-Amps. Anyway it turns out that the OpAMp on input 1, a 4565 was faulty and then two further Op-Amps TL072s near the A/D end of the circuit, which feed back into the Analog part of the circuit were faulty too.
I only started looking further up and down the audio change after i checked the DC offset circuitry...Leave a comment:
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Re: Lucesco Halley (Richard Sapper) Lamp PSU
hi re cooling
PCB is glued to a heatsink which is then connected to a 5v fan which operates on a heatpipe. I would say its adequately cooled and does not get hot.
thanks for the tips re leds. let me work at this and get back to you all.Leave a comment:
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Re: Lucesco Halley (Richard Sapper) Lamp PSU
Hi,
The dc brick is 24v
There is a 5v dc fan
The the rest must go to the LEDs. There's only one led panel with two rows which must be in series. I think it's 2.4-2.9v per led from the readings I get from the working LEDsLeave a comment:
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Re: Lucesco Halley (Richard Sapper) Lamp PSU
one way to tell if the powerboard is at fault is to see if the green light on the DC powerbrick goes off when you plug it in. It should stay on at all times.
I think when the light shorts it kills off some of the Schottkys on the powerboard and at that point the DC powerbrick must have a failsafe to stop voltage going backwards and so shuts itself down. It is a product design fault in my opinion.Leave a comment:
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Re: Lucesco Halley (Richard Sapper) Lamp PSU
hi,
its 9mm x9mm with a slight notch on one side to indicate which way it should go in.
@DownUnder
Re. replacement board. Impossible. i've tried. I contacted the company that took over Lucesco's IP (philips Lightolier) and they had one replacement arm with light but they wanted $500 for it and 10 months later its gone.
I could have a look at the board for you or suggest components. Whats the precise problem?Leave a comment:
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Re: Lucesco Halley (Richard Sapper) Lamp PSU
hi the problem is finding two pin SMD leds with the this pin configuration. You will see that the legs on the pins on either side are not symmetrical, they are stair-stepped.
you are right i may as replace the lot as there is already a dull one on the working array. I don't think a surge blew-it more likely a short because of the way the joints come together. Its a design defect or compromise.
If you have any ideas of SMD LEDS that could work do let me know. there are about 2.9v forwards voltage...Leave a comment:
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Re: Lucesco Halley (Richard Sapper) Lamp PSU
if your referring to the group of 3 shottky's 1A 100v SMB's (on the underside) i've changed them over already and its made no change. I think the crack was just cosmetic
I think given there is power to one row of LEDS the problem must be one defective LED in the other row the problem I now have is sourcing those 2pin SMD Leds or a substitute.Leave a comment:
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Re: Bad DC Offset TL072 Op-amp
I'll report back when i have checked the regulators properly. They seem to have two ground points because the heatsink also has a groundingLeave a comment:
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Re: Lucesco Halley (Richard Sapper) Lamp PSU
hi thanks for responding.
I was beginning to think that it could be a faulty SMD LED but willing to check out the board some more as i the schottkys did bring it back to life 50Pc.
Which diode are you referring to? The small zeners on the underside DSC_9381.jpg or the larger black Zener on the topsideLeave a comment:
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Re: Bad DC Offset TL072 Op-amp
VR2 looks to be out
VR7 should be + 15v
In - 29.49v
out 14.82v
VR1
In - 29.49v
out 4.44v
VR2 -should be -15v
In 29.29v
Out -24.30v
VR8
In 29.28v
Out 13.63v
VR6
in - 14.36v
out 9.34vLeave a comment:
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Re: Lucesco Halley (Richard Sapper) Lamp PSU
Underside has three more schottkys : 10BQ100
a 3 terminal positive regulator and then a ATMega48V 8 bit Microcontroller
The Powerbrick is fine and puts out 24.1v and the correct current.Leave a comment:
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Re: Lucesco Halley (Richard Sapper) Lamp PSU
heres some shots of the board...Leave a comment:
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Lucesco Halley (Richard Sapper) Lamp PSU
hi
I have a LED lamp by Richard Sapper which, was the last product Lucesco made and it probably took them out in 2006/7, with the crash of course.
Anyway the patent concerning the lamp allows for 360 movement between joints and a counter-weight. So you have 3.5mm audio jack connectors between joints. Finally, at the base a weird Power controller which is connected to a external 20v 1a power brick.
Ok one of the joints shorted as it was not connected fully and that blew the power controller. I managed to fix this by replacing a Schottky Diode seemingly... -
Re: Bad DC Offset TL072 Op-amp
Hi,
Thanks for your detailed analysis. I have swapped over the hc4053 switches and it doesn't appear that they are at fault. Equally the TL072 seems fine too, when swapped over with the other channels. Re voltages I am going to struggle to test these across the board with a multimeter. But surely if the voltages were off, that would effect the other channels and introduce DC on ch3/4.
Could the ADC be sending too much current that isn't compensated for later ? Is it worthwhile flipping out the ADC and swapping it for ch3/4Leave a comment:
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Re: Bad DC Offset TL072 Op-amp
the entire schematic is here:...Leave a comment:
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Re: Bad DC Offset TL072 Op-amp
here you go.
Just be reading an article regarding oscillation and this does some to be the likely problem. But i can't see that the 0.1uf ceramic caps are at fault. Could it be the film caps?...Leave a comment:
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