Replace Ceramic disc capac - Page 1
Forum section: electronics / beginners

author: onedumbquestion
author_rank: Contributor
timestamp: August 21, 2019, 08:07:57 pm
content: I'm trying to repair a Yamaha RX-460 receiver This is my first attempt at electronics repair I guessed that this capacitor was the reason it wouldn't turn on but I don't where to buy it Yamaha says they don't have it Specs:Ceramic disc EMI Suppression capacitor 560-2 103 H 35 for Yamaha RX-460 Receiver Yamaha part no. F1514100 On the board it's C156https://imgur.com/a/VpsHB8R

author: malagas_on_fire
author_rank: Frequent Contributor
timestamp: August 21, 2019, 08:29:12 pm
content: I think tha's a panasonic capacitor from a search on digikey related to the NS brand ( example ):https://www.digikey.com/product-detail/en/panasonic-electronic-components/ECK-ANA221MB/P9523-ND/705463103 is 10nF value so that would give you a clue on the catalog from panasonic components on the digikey website. It is the NS-A series (sorry---Again):https://www.digikey.com/products/en/capacitors/ceramic-capacitors/60?k=NS+capacitor&k=&pkeyword=NS+capacitor&sv=0&v=10&s=5689&sf=0&FV=ffe0003c&quantity=&ColumnSort=0&page=1&pageSize=25

author: Old Printer
author_rank: Frequent Contributor
timestamp: August 21, 2019, 08:44:49 pm
content: Depending on the symptoms an electrolytic (can type - polarized) capacitor in the power supply might be the problem, but i doubt a ceramic disc type would keep it from turning on. How about some details?

author: Ian.M
author_rank: Super Contributor
timestamp: August 21, 2019, 08:50:36 pm
content: Why do you think its bad? Its extremely rare for low voltage, low capacitance disk ceramics to fail unless they have been mechanically damaged.Even if it is actually bad, it would have to be either in the control circuit of the PSU, or shorting a power rail to ground, tripping the PSU's over-current protection or pulling down a control input of the Syscon (MCU), preventing the power button from being recognised for it to be able to stop the reciver turning on. Do you have the schematic, or can you otherwise trace C156's connections back to an output of the power supply or to the Syscon chip?If it is failed shorted, and dragging down a rail or MCU input, as its designated for "EMI Suppression" the odds are, if there's no other fault, the receiver will power up with it removed. If its in the PSU, *DON'T* try to power on withoiut it.*IF* it does need replacement its almost certain any brand or generic 10nF, 35V or higher working voltage disk ceramic capacitor would be suitable.

author: onedumbquestion
author_rank: Contributor
timestamp: August 21, 2019, 09:12:00 pm
content: It's a trash pick I saw a youtube video and mistakenly took the capacitor out because I thought it was the capacitor mentioned in the video I guess I'll have to test it while it's and put it back it then I bought a capacitance meter from China yesterday I'll have to wait I can return to this thread when I put it back on my bench Right now I have it packed away

author: james_s
author_rank: Super Contributor
timestamp: August 21, 2019, 09:17:52 pm
content: I don't think I've ever seen a ceramic disc capacitor cause something to not power up. You really have to gain enough understanding of how the circuit works to hypothesize what might cause the problem. Don't just blindly replace parts, that's how you turn a simple repair into scrap.

author: floobydust
author_rank: Super Contributor
timestamp: August 21, 2019, 09:34:07 pm
content: Whatever gave you the idea the cap is to blame, it's just hogwash.That capacitor C156 hasnothing to do with the amp not powering up.It just lessens arcing on the RY1 relay contacts.To troubleshoot things, use a multimeter and measure the DC voltages. See if 12V standby power is there or not at C136, if the amp is in Protect mode etc.

author: Jwillis
author_rank: Super Contributor
timestamp: August 22, 2019, 01:55:36 am
content: You didn't mention whether or not you had a service manual.https://www.manualslib.com/manual/1002353/Yamaha-Rx-460.html#manualMight help.

author: malagas_on_fire
author_rank: Frequent Contributor
timestamp: August 22, 2019, 05:25:10 pm
content: Quote from: malagas_on_fire on August 21, 2019, 08:29:12 pmAssumed that the OP has properly troubleshooted cause of faillure and try tro provide some alternatives, however it really doesn't poses any visible signs of damaged part from the picture. You can measure the capacitor with a multimeter with that function or use one of those LCR cheapo meters to check its value and the ESR. Then check manual provided by Jwillis and start troubleshoot from PSU input to different power sources.

author: onedumbquestion
author_rank: Contributor
timestamp: August 27, 2019, 05:51:38 pm
content: I haven't had a chance to work on this yet but I received info that it's a resettable fuse I'm wondering if I can reset it

author: james_s
author_rank: Super Contributor
timestamp: August 27, 2019, 10:28:39 pm
content: Resettable fuses reset themselves, if it is not resetting then either the fault condition remains or the fuse has failed.

author: onedumbquestion
author_rank: Contributor
timestamp: September 01, 2019, 01:40:14 am
content: I got info that it's a resettable fusehttps://www.mouser.com/Circuit-Protection/Resettable-Fuses-PPTC/_/N-bm931?P=1z0z7l5Z1z0z63xI don't know I can't find it by looking at that data sheet Can C156 be a resettable fuse in the power protection circuit

author: Ian.M
author_rank: Super Contributor
timestamp: September 01, 2019, 02:49:13 am
content: Nope. Seehttps://www.manualslib.com/manual/1002353/Yamaha-Rx-460.html?page=34#manualwhere its quite clearly listed as a ceramic cap. Also if it *was* a fuse googling the code on it"103H35" fusecould be expected to find a reference to a datasheet or a seller, but it only finds this thread + a lot of irrelevant garbage.

author: onedumbquestion
author_rank: Contributor
timestamp: September 01, 2019, 10:17:26 am
content: So I'm assuming I removed the wrong component and I'll put it back in I may as well test it first How do I discharge it?

author: Ian.M
author_rank: Super Contributor
timestamp: September 01, 2019, 11:38:34 am
content: Why don't *YOU* work out the max. possible stored energy in that cap if charged to its full rated working voltage, assess the likelihood of that ever happening in the circuit it was in, then decide on a safe discharge procedure for yourself?Anecdotally: after the third time I had to repair the workshop ESR meter after some dammed fool connected it to a large HV electrolytic without discharging it first, I added a rectangle of heavy copper sheet, stuck on with foam tape right next to the test terminals and instituted the procedure that the cap leads must be tapped on the copper to short it before testing. If they'd forgotten to discharge the cap properly, the large bang when they tapped it scared them into remembering to follow procedure in future quite effectively, and I no longer had to repeatedly repair the ESR meter. When we got a digital capmeter, it got a similar copper rectangle before release into the wilds of the workshop.N.B. Shorting is *NOT* a recommended discharge procedure for high energy caps, but up to a few hundred joules, is reasonably acceptable as final confirmation the cap has been discharged.P.S. you've just used up your entire dumb question quota for the month!

author: onedumbquestion
author_rank: Contributor
timestamp: September 02, 2019, 03:33:36 pm
content: Thanks What if the proper range is set to measure voltage on a dmm then what harm could be done? Would that be a way to discharge a 35V capacitor?

author: james_s
author_rank: Super Contributor
timestamp: September 02, 2019, 04:03:14 pm
content: Why would you want to discharge it? A ceramic cap rated at only 35V is going to hold a negligible charge. Discharging only matters when the voltage is high enough to hurt you. Just reinstall the capacitor and then find someone knowledgeable to help you with this repair because you are in over your head. Without help you'll just end up destroying the unit.

author: onedumbquestion
author_rank: Contributor
timestamp: September 02, 2019, 07:26:15 pm
content: I should discharge a capacitor by connecting one lead to the other without any resistance? That can damage the capacitor can't it? I thought if I used a multimeter to test voltage that would cause the capacitor to discharge

author: james_s
author_rank: Super Contributor
timestamp: September 02, 2019, 08:06:10 pm
content: It could possibly damage a large capacitor but we're talking a dinky little ceramic cap, you don't even need to discharge it, there won't be any charge on it and the amount of energy it is capable of storing is absolutely tiny. Just reinstall it and think nothing more of it.

author: onedumbquestion
author_rank: Contributor
timestamp: September 02, 2019, 10:43:25 pm
content: OK I put it back in Turns out it works, the only thing wrong with it is the backlight bulb is out I don't know the replacement procedure but I see people saying they had to splice on a new bulb It's seemingly from another discussion 14v 80ma 4.12mm width so I'm searching for it

author: james_s
author_rank: Super Contributor
timestamp: September 02, 2019, 11:01:33 pm
content: It's always a good idea to test something out thoroughly before you start tearing it apart to try to fix it. Those little bulbs are often called "grain of wheat" lamps, I replaced the bulb in a receiver recently and just used an LED with an appropriately calculated series resistor. If the supply to the lamp is AC you can use a small bridge rectifier ahead of it.

author: onedumbquestion
author_rank: Contributor
timestamp: September 02, 2019, 11:07:49 pm
content: You mean the resistor is connected in series?

author: onedumbquestion
author_rank: Contributor
timestamp: September 02, 2019, 11:29:32 pm
content: My old bulb is 4mm replacements come in 3mm or 4.7mm

author: james_s
author_rank: Super Contributor
timestamp: September 03, 2019, 01:53:30 pm
content: So? Is the physical size critical? A smaller bulb will fit in most cases.If you don't know how to wire up an LED with a resistor I'm hesitant to advise on poking around inside mains powered equipment.

author: onedumbquestion
author_rank: Contributor
timestamp: September 04, 2019, 09:34:25 pm
content: Sorry I confused series with parallel What's the value to use ?

author: onedumbquestion
author_rank: Contributor
timestamp: September 05, 2019, 12:05:51 am
content: I downloaded the manual from the link you gave me but I can't read the schematic it's too small even at 400% in pdf reader on my 14" screen I'm trying to get the ratings for the display backlight bulb I never read a schematic before