works like a charm! No more excessive noise from
the rca jacks/ speaker output and the sound quality is superb. I have 3 now these things and they are absolute monsters… web based gui with eq. if you see a kda500 or kda1000 on ebay that’s not working, do your self a favor and snag one as they can be had for $100 or less in most cases.
I have not seen a bad amplifier section yet as they have all had issues with the power supply but most repairs only require the replacement of one 16v 1000u filter cap. This was the most difficult one i had to fix to date
r2digital
Member
Last Activity: 07-27-2024, 07:36 PM
Joined: 09-28-2011
Location:
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Finally figured it out after taking the entire heat sink assembly out. R35 resistor was reading in mega ohms while it should’ve been a 10k ohm but at the same time while the heatsink wall out i replaced capacitor C15 since the only time you can get to it is with the wall out. All capacitors on the power supply and the main input output board have been replaced...
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https://[URL]https://datasheet.octop...ected together[URL]https://datasheet.octopart.com/FDC655BN.-Fairchild-Semiconductor-datasheet-8322017.pdf[/URL]...
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purple line shows where the trace starts at the yellow wire and ends at the negative trace of capacitor 35v 47U capacitor and should be -13-14VDC
Removed cap for better view...Leave a comment:
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I have a working KDA1000 which i opened up to compare voltages to so maybe some one can point me in the right direction.
kda500 power supply not working
right to left
4 pin
brown 8.06
black 7.93
white -0.11
gray -0.10
5 pin
green 30.16
blue 3.29
green 2.58
red/white 3.01
red 1.11
3 pin
yellow -.759 <—— this should be -13-15VDC
light blue -0.024
yellow 13.78
3 pin
black 165
brown...Leave a comment:
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I wish i was posting with a complete fix of the power supply but i am making progress. After the replacement of the switcher it now turns on and stays on between 1 and 8 attempts. Unfortunately when it does comes on all the 4 channels in the front light up detecting there's audio even when nothing is attached . However, i found that Q2 is the culprit of the random starting of the power supply. Does this seem like a suitable replacement [URL]https://www.mouser.com/ProductDetail/Nexperia/PXT4403115?qs=LOCUfHb8d9uiGvtnA%2FBgJw%3D%3D[/URL] ?https://I wish i was posting with a ...e power supply...
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Yup! you were right all along so thank you again for your help. I’ll post back in a few days with an update once i get a replacement in but i swear i never even touched that thingLeave a comment:
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ok, i have a pretty good update. I used some freeze spray on the 5 leg TOP265EG and the power supply started and stayed in stand by a few times but also a few times it turned it self completely on and was detecting signal present with in all 4 channels.Im almost positive it is bad...
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I checked several times, there is no rectifier there. It goes from that positive cap trace that was repaired directly into the transformer. I was able to check for continuity from the transformer pin on top to the repaired trace on the top of the boardLeave a comment:
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I tried resoldering the positive lead of the cap to pin 1 on the transformer which is where the trace goes but still no luck
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right to left
4 pin
brown -8.4v
black 7.6
white -.006
gray -.006
5 pin
green 32
blue 3.3
green 2.6
red/white 3.0
red 1.1
3 pin
yellow .770
light blue -.016
yellow 13.5
3 pin
black 165
brown -166
red -165
...Leave a comment:
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there is a rocker switch for main power that turns the amp on directly into standby(solid red light) when in standby the amp is able to be managed through a web gui. The amp is currently configured to turn on by audio sensing 5mv but could be changed to always on if i was able to get the power supply going again. I didn’t hear any loud noises or bangs so i was pretty surprised when it wasn’t working after the cap replacement. I will double the voltages when i get home later today but does the trace repair look suitable or should i try to solder the cap to the top side or the board ?Leave a comment:
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It looks like it’s isolated because i used some solder mask after the trace was repaired so i could definitely see how it looks wrong lol and i wish i had a more clear pic to show for that. The backside of the board had nothing left to solder too but luckily the trace in the center on top next to where the radial positive lead goes was also on the bottom side of the board so i bent the radial cap lead over to that and soldered it. But now im questioning if that will even work? I was over by that 5 legged device with flux and i even bent that little board out of the way a tiny bit so i could...
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I measured the impedance of the no series/brand caps after removal so i could find something close.
47u /35v - .400 mOhm was replaced with .200 mOhm
47u /16v - 2 ohm and replaced it with 1.7 ohm
330u /25v - 0.270 mOhm and was replaced with 0.08
100u /35v - 0.500 mOhm and was relpaced with 0.16
Does anyone think the impedance is too far off from original caps and thats why its not working ?Leave a comment:
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klipsch kda-500 amplifier suitable power supply capacitor replacement ?
I have a klipsch kda-500 that would turn on and allow me to get into the web management but it was picking up a lot of noise from audio sources so i decided to replace the smd caps on the power supply along with radial one. Some one was in here before me and they basically burned the bottom side of the traces off for the radial cap but i was able to repair it without any real problem. I thought i did a good job sourcing out replacement caps but apparently not and now i can't get the power supply to turn on it just constantly try's to keep turning on. Attached is a picture of the power supply before... -
Boston Acoustic MSUB no sound output(pics)
The off/on/auto switch was busted so i forced it into auto mode and now the blue light comes on but i don’t get any audio output. Does anyone one have any experience repairing this amplifier? I looked it over, checked some the of output transistors, some of the power resistors and cleaned that nasty conductive epoxy glue stuff off but not having much luck in the trouble shooting department.
I did however find a part of the PCB that was discolored from heat -
Harmon Kardon AVR340 no sound on 4 channels
Hello, i had this amp sitting in the closet knowing that none of the channels were working. After taking it all apart i found 4 bulging main filter caps so i went ahead and replaced those with low ESR kmet caps. However after doing this it only restored sound to Surround L, Surround R, and Center channel. The main speaker fuse on the transformer F905/F906 keeps blowing so i decided to remove all of the transistor's on those 4 channels and measure them. All transistors appear to be in good working order(turned receiver on with none of them installed and fuse still blows). Checked dual emitter resistors... -
Re: TDGAUDIO NFC-83A ceiling speaker crossover repair(no output)
Does anyone what i should check if i have no output from the tweeter/midbass? Verified the tweeter and midbass work fine individuallyLeave a comment:
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Re: TDGAUDIO NFC-83A ceiling speaker crossover repair(no output)
looks like some one already got to the PCB before me. Lots of deep scratches on the pcb. I think maybe one of them is deep enough to cut a trace to the negative post?
[url=https://ibb.co/HtQfxy4][/url]
[url=https://imgbb.com/]free animated gif flag[/url]Re: TDGAUDIO NFC-83A ceiling speaker crossover repair(no output)
looks like some one already got to the PCB before me. Lots of deep scratches on the pcb. I think maybe one of them is deep enough to cut a trace to the negative post?Last edited by r2digital; 07-31-2021, 01:00 PM.Leave a comment:
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Re: TDGAUDIO NFC-83A ceiling speaker crossover repair(no output)
I will touch up and reflow all the joints on the back of the PCB. Do the resistance values seem correct? When i check the resistance values of the same model of a working speaker the results are much closer to their rating.
For example the
25W2ohmJ=2.2ohms
10W2.2ohmJ=2.3
Should i be concerned the the different values on the non working speakers?Leave a comment:
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