Re: Benchtop Power Supply Question
Well, the CMOS TLC555 can go down to 2v or so, if needed?
Well, the CMOS TLC555 can go down to 2v or so, if needed?
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Re: Benchtop Power Supply Question
You need a reference voltage for the comparators, not sure what he's using for that. Hitachi 555's are pretty ooolllddddComment
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Re: Benchtop Power Supply Question
I have almost finished a diagram's prototype for the laptops PSU project . So far , my choice went for a parallel series of LM338 , backed up by parallel diodes as illustrated in an image previously , while leaving a chance for additional ones , as necessary . Right now , I estimate LM338 power at 5A maximum , to stay on safe side , and for each another 5A , I'll add another one ..
When the project is finished , although the delays and distractions were more than to count , It will be available only for some particular friends , and through PM's .
In the meantime and for the people who liked my backups parts , my Sony Cam is back on line after some repairs , so I may re-post the previous images which were very bad , and yet , you know there are some size limits for uploads , so I'll resize them in PS as necessary .
Here's a sample of my vintage capacitors .Attached FilesComment
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Re: Benchtop Power Supply Question
that picture looks like my dustbin after a repair
parallel high current diodes doesnt work btw,
the one with the lowest voltdrop takes more of the current - then fails leaving the remaining ones overloaded.
then they fail.
happens all the time in some cheap tv psu's that try to do it.
also kills a lot of early Ryobo battery chargersComment
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Re: Benchtop Power Supply Question
Come on stj; I'm in the middle of hundreds of projects , including a 30 km FM transmitter , and the picture's background initially should look vintage
I really doubt that when they're each rated 6A. and fyi , they'll be equipped with special heatsinks similar to old CRT monitors ...
So you deserve another ...lol
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Re: Benchtop Power Supply Question
@stj;
That's how my dust bins look like ,
Attached FilesComment
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Re: Benchtop Power Supply Question
In practice what @stj claims is TRUE! You'll watch this behavior when the overall current exceeds the maximum rate per diode (plus a unknown value).Comment
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Re: Benchtop Power Supply Question
It's like pushing me to reveal more secrets I would prefer to keep it hidden!! Well fine megaraider ... How the overall current would know which one is the first when the special heatsink is making them symetric with high precision ? .
In practice what @stj claims is TRUE! You'll watch this behavior when the overall current exceeds the maximum rate per diode (plus a unknown value).
Yet , I do agree that if something is arranged chaotically , of course it will rise many different problems ..Comment
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Re: Benchtop Power Supply Question
The trick is to either go ahead and match them else current limit them, just like bjts.Comment
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Re: Benchtop Power Supply Question
No secret
... IMO a great mistake.
The heatsink, no matter how 'special' it is, only works to keep the diodes under temperature limits, and if common to keep them all at about the same temperature.
Nothing else, sorry!
Yes!Comment
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Re: Benchtop Power Supply Question
why not just use a 25A rectifier from an old pc psu?Comment
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Re: Benchtop Power Supply Question
Leave the how matter it is special , for me , and try to answer my question ... Though I won't tell you when you're right or wrong .Comment
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Re: Benchtop Power Supply Question
It's because I'm leaving the always possibility to add more Diodes/LMs in case I want to put more laptops on the table . When I'll draw the circuit , I'll leave that possibility for lot of other parts too . So nothing against rectifiers basically other than that ..
I left the core calculations for the last touch for such reasons .Comment
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No question to answer 
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I have wanting to do this project for quite sometime now and I finally found a switching power supply that will work on this desoldering gun station ZD-915 that the original switching power supply took a shit and just was not worth trying to fix it because this switching power is not quite big enough to handle the heater element and the vacuum pump
One note when I tested the switching power supply and the voltage control board I noticed that this desoldering gun heat up much faster than the original switching power supply which I was really surprised by to the point that I might buy... -
I have been working on this concept for quite some time now with limited success but recently I found a switching power supply that is setup for the voltage that this soldering station needs to operate at however it also needs part of the secondary circuit from the original switching power because you need several voltage rails
I once tried to get a ZD-915 desoldering station to work on a 18 volt battery power supply but unfortunately things did not go well but I did find a work around but I might try this idea again but going at a little differently more about this another time... -
The sub developed a constant popping every couple seconds from woofer and power LED flickering with nothing but wall AC connected. Connecting an audio cable didn't change anything. It doesn't play but a second or two of audio in between the pops.
Opened it up and discovered the power supply is making a faint clicking or ticking sound.
I measured the amp's output to the woofer and it pulses up to 50mv DC to be driver. The pulses coincide with the power supply ticking/clicking.
I measured the power supply output going to the amp board and it too has this pulsing. Voltage cycles... -
Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.
Upon bringing it home and plugging it up, it showed a standby light.
I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.
The screen seems to blackout and stay black, but with a flashlight I can see the display.
With my Playstation 4 connected via HDMI, and running a game I can hear sound.
Assuming... -
Hi all, I managed to narrow down which PCB was causing my Haier AC to throw out an E7 error code (E7 indicates that the indoor unit and outdoor unit cannot communicate). I found that the outdoor unit power board which gives 5v and 15v to the outdoor unit module board fails to fully power up.. The power Led starts to fade in incredibly slowly and the 5v and 15v power buses jump around like crazy and never reach their required voltage. I unplugged the module board from the power board and the power board powered up fine! It had a steady 5v and 15v out and the power LED came on instantly and Bright....
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