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DJduck replied to Zalman ZM600-HP crackling noise

in Troubleshooting Power Supplies and Power Supply Design

01-12-2019, 01:48 PM
Re: Zalman ZM600-HP crackling noise

Yes! Heureka!
It was the primary cap. A 420V 390uF CapXon 85C rated turd. Put in a 220uf 450v Nichicon temporarily to test it and it runs nice and quiet now. Should I go for a 450V replacement? 450v 390uf. Or should I go for a higher capacity as well? The unit is rated 600W 80+. I don't know about Zalman PSUs, been away from computers for a few years but this one looks well made, made by FSP, IIRC they were decent, no? It's got a cool heatpipe cooler
Probably wouldn't hurt to pull the rest of the CapXon and Teapo...

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DJduck replied to Zalman ZM600-HP crackling noise

in Troubleshooting Power Supplies and Power Supply Design

01-10-2019, 02:28 PM
Re: Zalman ZM600-HP crackling noise

That is actually a really good idea.
But unfortunately (or maybe fortunately?) there is no visible arcing on neither side of the board. The noise seems to be coming from the transformer or primary side.

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DJduck started a topic Zalman ZM600-HP crackling noise

in Troubleshooting Power Supplies and Power Supply Design

01-09-2019, 04:55 PM
Zalman ZM600-HP crackling noise

Hello!

Been a while since I've posted on this forum.
I bought a dead Zalman ZM600-HP for 5€, hoping to fix it for my new-to-me AMD FX build. Powering it on at first it showed no signs of life. Opened it up and found the fuse was blown. Going down along the circuit revealed three shorted MOSFETs on the PFC heatsink and the two primary switching MOSFETs were giving funny readings as well. Replaced all five and tested everything else, everything seemed to be reading OK. Replaced the fuse and assembled the unit. +5VSB read good. Powered it on, fan comes on, lights come on,...

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DJduck replied to Replacing LCD with slim LCD? Need an answer ASAP

in Troubleshooting Laptops, Tablets, and Mobile Devices

02-17-2015, 02:28 PM
Re: Replacing LCD with slim LCD? Need an answer ASAP

No luck selling one here for such price. Last E5420 I saw went for 165 with an i5.
I actually got lucky and bought a Lenovo T420 with i7/8gb/500gb/Nvidia 4200M for 150 ...

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Last edited by DJduck; 02-17-2015, 02:30 PM.
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DJduck replied to Replacing LCD with slim LCD? Need an answer ASAP

in Troubleshooting Laptops, Tablets, and Mobile Devices

02-17-2015, 02:13 PM
Re: Replacing LCD with slim LCD? Need an answer ASAP

Dang, that connector position, thanks for pointing that out.
I just discovered that Dell has the connector on the top, while Acer's is on the bottom. Unfortunate.
Should I still buy the machine an try to flip it for profit? Business class laptops is hot stuff here, not many people buy pleb-class machines here

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DJduck started a topic Replacing LCD with slim LCD? Need an answer ASAP

in Troubleshooting Laptops, Tablets, and Mobile Devices

02-17-2015, 12:46 PM
Replacing LCD with slim LCD? Need an answer ASAP

Here's the deal:
I can get a Dell Latitude E5420 with an i5 for only 60$, but the catch is that it has a cracked screen. Everything else works, looks great, charger included, etc...
I have an older, piece of junk Acer Timeline something, might have been a T4810, that also has and LED screen with the same measurements. But the Dell has a regular LED while the Acer has a Slim LED. Would they be swappable?
Need an answer ASAP, as I told the seller I'd make up my mind by tomorrow morning

Thanks!

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DJduck replied to Resprom EMS1511 dead :(

in Troubleshooting Audio Equipment

10-19-2014, 05:02 AM
Re: Resprom EMS1511 dead

Got it working!
It was a grounding issue!

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DJduck replied to Alpine CDA-7840 low volume

in Troubleshooting Audio Equipment

10-19-2014, 03:58 AM
Re: Alpine CDA-7840 low volume

Check how the signal is on the output IC's input legs. If it's normal, your problem is likely the chip, if it's too low, your problem is the pre-amplifier.
That's the first thing I check on car stereos

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DJduck replied to Resprom EMS1511 dead :(

in Troubleshooting Audio Equipment

10-18-2014, 03:02 PM
Re: Resprom EMS1511 dead

It worked fine without a cap before
Most good designs don't require output caps, some need inductors, but only cheap designs use output caps.

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DJduck started a topic Resprom EMS1511 dead :(

in Troubleshooting Audio Equipment

10-18-2014, 10:11 AM
Resprom EMS1511 dead :(

Haven't posted on this forum for a while, but here I am again, with another problem.
So basically, I bought a Bulgarian made Resprom commercial amplifier (with the 100V line transformers removed) a while back to use it in my PA setup. But this thing ended up sounding so bloody brilliant, that I just couldn't resist using it in my main audio setup.
Then I started fiddling around with it. Recapped it and changed output wires. Now I started making it into a fully featured home stereo amplifier, which included removing all the useless wiring and connectors. The stuff that I removed is...

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Last edited by DJduck; 10-18-2014, 10:19 AM. Reason: picture
DJduck replied to JVC RX-552VBK, no output from speakers or headphones.

in Troubleshooting Audio Equipment

08-24-2014, 03:21 AM
Re: JVC RX-552VBK, no output from speakers or headphones.

To measure the AC voltages, there should be two AC wires, just measure between them. If there is only one "active" AC wire, measure between the wire and ground. At least that is how it should be, me thinks.

As for the 4.8V rail, It should either use a regulator or a transistor or something to regulate it, or perhaps a zener. Find the component that controls the rail and check it. If it's a regulator, measure input and output. If there is input but no output, that regulator is toasted. If no input, you...

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DJduck started a topic Philips HTS-5000W won't power on

in Troubleshooting Audio Equipment

07-05-2014, 08:49 AM
Philips HTS-5000W won't power on

Hello, comrades!
A friend gave me this home theater thing and it won't power on. When plugged in, standby light comes on and you can hear a whining sound from the PSU. When power button is pressed, whine goes away but no display. Checked PSU voltages and all seems to be in order.
Need help with this one!

SM:

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DJduck replied to Yamaha RX-V563 - any hope?

in Troubleshooting Audio Equipment

06-11-2014, 11:36 PM
Re: Yamaha RX-V563 - any hope?

Well the problem is that this is a pretty uncommon receiver. Guy who had it before me had been hunting one down for about a year with no luck. He looked on ebay, forums, local repair shops, etc... with no luck.
I already tore it to pieces because I don't have room to keep broken stuff, I have barely enough room for my working stuff. I usually sell what I fix but I keep a few items every now and then, and I have stacks of stuff.

As for the Yamaha's STK chips and other parts, I will be building a new amplifier soon and I might...

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DJduck replied to Yamaha RX-V563 - any hope?

in Troubleshooting Audio Equipment

06-11-2014, 11:00 AM
Re: Yamaha RX-V563 - any hope?

Yep,this thing's DSP is absolutely toasted. It can't even run in protection cancel and diagnostics mode. Teardown time!

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DJduck replied to Yamaha RX-V563 - any hope?

in Troubleshooting Audio Equipment

06-10-2014, 10:48 AM
Re: Yamaha RX-V563 - any hope?

I see a few slightly bulged Nichicon VR(M) capacitors near STK chips, but i doubt changing these would make any difference? They are 10v 100uf.

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DJduck replied to Yamaha RX-V563 - any hope?

in Troubleshooting Audio Equipment

06-10-2014, 06:51 AM
Re: Yamaha RX-V563 - any hope?

Well, all the power supply voltages seem to measure okay, so it simply looks like the DSP board has genuinely kicked the bucket. And I have FAR too little knowledge about digital audio and digital stuff in general to mess with that board.
I paid 10€ for it, and I think I got a good deal, this thing contains a goldmine of good parts. STK chips from this receiver will be used to build a new amplifier and power supply electrolytics are going straight into my Samsung L4A.
If anyone has any more ideas on what to measure or replace, let me...

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DJduck replied to Yamaha RX-V563 - any hope?

in Troubleshooting Audio Equipment

06-10-2014, 06:09 AM
Re: Yamaha RX-V563 - any hope?

I looked around a little more and there are no voltage regulators on DSP board. It gets its power from power supply board marked Operation (2) in service manual.
How likely am i to get this thing to work? As far as I know the DSP is simply not powering on, therefore no other thing powers on. Or is something else wrong? Hmmm....
I have fixed analog (mostly vintage) amplifiers before but none of yhis damn digital BS.

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DJduck replied to Yamaha RX-V563 - any hope?

in Troubleshooting Audio Equipment

06-10-2014, 04:16 AM
Re: Yamaha RX-V563 - any hope?

Here are some readings from connectors to DSP board.
DC volts, black probe on ground
CB82:
PRV2 1.88V
THM 0.86V
XMP WR 0V
PRY 3.26V
/PDET 3.15V
/RESET 3.27V

CB81:
IG -0,52V
+5I 4.47V
+5XM 5.01V
+5D 5.02V
DG 0V
DG 0V
DG 0V
+3.3D 3.31V
HG 0V
+3.3H 3.27V
+6.3VH 6.28V
+5VSB 5.02V

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DJduck replied to Yamaha RX-V563 - any hope?

in Troubleshooting Audio Equipment

06-09-2014, 11:31 PM
Re: Yamaha RX-V563 - any hope?

I don't think there was corrosion, and there certainly were no burns. I can post a pic of DSP board later.
As for voltages, I don't remember if DSP got it's voltages from regulators on it's a own board or from the PSU board, will check later.
For anyone who is interested in helping, first above thank you, and second, please downlad the service manual from my first post. It has PCB and schem. For all board incl. DSP.

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DJduck started a topic Yamaha RX-V563 - any hope?

in Troubleshooting Audio Equipment

06-09-2014, 02:03 PM
Yamaha RX-V563 - any hope?

Hello. I have a Yamaha RX-V563 with a dead DSP board in it. Previous owner had a plant sitting on it, and when they went to water said plant, water was accidentally spilled inside the receiver, right on top of the DSP board. So it is likely that the main processor is now fried, and possibly some other logic. Rest of it (amp, PSU, transformer, etc...) seems fine tho.
Right now it clicks the relay on standby board and that is it. No display, no lights.
Just out of curiosity, I replaced C402 (0.01uf film cap) with no results.
Any hope for this machine? Is there a way to get...

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