Folks - hoping for some help. Have a Sony STR-K502P, used it for years as a 5.1 surround sound. Upgraded and its sat in the garage for 3-4yrs, now i'd like to use it to power some speakers just for background music, and it won't turn on.
I tried the 'reset' instructions, but no joy there. I got myself a multimeter, took the lid off, but have no idea what to do. I'm not experienced at all with circuit boards - but i'm hoping there's a couple of basics someone could talk me through, just to see if there's a simple/easy fix?
For now, I checked the fuse - the only fuse I could find, which seemed fine. I stuck the multimeter into where the power cord meets the board, and got 115v, so I guess that tells me the cord is good. I removed the fuse, plugged the power cord in, and tried the multimeter on either side of the fuse contacts, and got a big fat 0.
Any simple stuff in layman's language I can look for/try??
Really appreciate any advice,
Matt
I tried the 'reset' instructions, but no joy there. I got myself a multimeter, took the lid off, but have no idea what to do. I'm not experienced at all with circuit boards - but i'm hoping there's a couple of basics someone could talk me through, just to see if there's a simple/easy fix?
For now, I checked the fuse - the only fuse I could find, which seemed fine. I stuck the multimeter into where the power cord meets the board, and got 115v, so I guess that tells me the cord is good. I removed the fuse, plugged the power cord in, and tried the multimeter on either side of the fuse contacts, and got a big fat 0.
Any simple stuff in layman's language I can look for/try??
Really appreciate any advice,
Matt
All modern remote controlled electronics need to have a standby power supply in order to supply a voltage in order for the remote to operate. Checking for the stby voltage is easy. Look for a connector marked CNP912, try to measure +5.6VDC on pins 1 and 2, 1 is ground. The connector should be on a small board close to the power cord.
Craig
Craig
hi - thanks for your reply. So I located the connector on the small board - it's actually right next to the fuse I measured - the fuse is on the small board also. I could not get any sort of reading from the connector at all - just 0.
Anything else I can try?
Anything else I can try?
You did measure with the unit plugged in correct?
Find D914 and D915 and measure the AC voltage on the anode of each, the end with the arrow head. Put your meter is ACV mode and put a lead on each diode, I'm guessing you should read 4-5VAC or so, it won't be much. This will tell us if the little stby transformer is working.
Craig
Find D914 and D915 and measure the AC voltage on the anode of each, the end with the arrow head. Put your meter is ACV mode and put a lead on each diode, I'm guessing you should read 4-5VAC or so, it won't be much. This will tell us if the little stby transformer is working.
Craig
thanks - Any idea where I can find those? I've had a really long inside, and I can't fin anything starting with a 'D'? Also, to measure the voltage through a diode, how do I do that - just each prong of my multimeter on either side of the diode?
yes - it was plugged in. Any idea where I can find D914 and D915? I looked everywhere but don't see them. Also, how do I measure a diode correctly - just pop one prong on each end of the diode?
D914/5 are directly across from where the power cord plugs into the board. There's a small strip of circuit behind the small transformer we're trying to check. They right next to a large capacitor, C950. With your meter in ACV mode put one test lead on D914 diode, the end with the arrow, and the other lead on D915, the end with the arrow, should read 3-5VAC between those two points.
Craig
Download the manual from HiFi Engine if you don't have it, it's free just have register.
Craig
Download the manual from HiFi Engine if you don't have it, it's free just have register.
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Did you measure CNP902 or CNP912? CNP902 is right next to the fuse. CNP912 has four wires in it, pin 1 is on the end by itself with a space to pin 2.
ok, my confidence is low that i'm doing this right - I found 914 and D915 - they're tiny!! So I tried to get something from them - i'm not sure which end is the arrow, it has a yellow stripe on one side - so in order to get any kind of reading:
One prong on stipe side of D914
One prong on non-stripe side of D915
I get 9.5ACV
One prong on stipe side of D914
One prong on non-stripe side of D915
I get 9.5ACV
One lead on each non-stripe end, the arrow should be on the board itself, you are measuring ACV.
Measure CNP912, pins 1 and 2, for 5-6VDC
On a diode the the striped end is the cathode and plain end is the anode, I want you measure the plain end. On the circuit board and/or schematic the line end is the cathode and the arrow head is the anode.
Measure CNP912, pins 1 and 2, for 5-6VDC
On a diode the the striped end is the cathode and plain end is the anode, I want you measure the plain end. On the circuit board and/or schematic the line end is the cathode and the arrow head is the anode.
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let me add - if I put the probes on the non-stripe end of d194 & d195 I get 10ACV. If I put them both on the striped ends, I get 0ACV
>>> One lead on each non-stripe end, the arrow should be on the board itself, you are measuring ACV. <<<
ok, yes, measuring the two non-stripe ends I get 10ACV
ok, yes, measuring the two non-stripe ends I get 10ACV
ok, for CNP912 - I assume where the red on the ribbon represents where pin 1 is - there's a gap on the connector before pin 2. I measured pin 1 to pin 2: 13.25DCV
The stby power supply seems to be working. I don't have the Service Manual on my home 'puter so we'll continue in the morning.
Craig
Craig
With unit plugged in push the power button do you hear a small click sound coming from that small circuit board?
The relay, RY901, not getting energized is the reason the unit won't turn on. You verified the power supply for relay seems to be working so now we need to figure out why the relay is not energizing. Back on CNP912, pin 4 is the signal that is supposed to energize the relay. Put your meter in DCV mode, the black lead on ground, CNP912 pin 1 is OK and the red lead on CNP912 pin 4 and press the power button, anything?
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