VideoGUY Posted February 11, 2002 Share Posted February 11, 2002 whats up everybody, got a quick question for you since i don't completely understand receiver and amplifier architecture, just a basic understanding....so here goes. we were having a party this weekend, and we use an older pioneer stereo reciever to power four speakers. two in A and two in B, and during operation both A and B are selected. well needless to say, after about two hours of fairly loud playing (80 some-odd people were there) the music suddenly quit. the top of the receiver was pretty warm, not so hot that you couldn't leave you hand there. i am sure it was going through plenty of stress. my hope was that it was just a fuse, but there is no external fuse located on the back of the receiver. so once everyone emptied out, we plugged it back in and you can here the power supply click on. but the LCD on the front doesn't light up and of course no sound comes out either. are their internal fuses in receivers (i hope)....we weren't in the best shape to take it apart so i haven't opened it yet. my gut feeling says its probably the capacitors for the amp, which would mean it is shot right?? what do you think it could be? how should i start trouble shooting it and do you think its just a piece of junk now? let me know whatcha think.....thanks ------------------ Home Theater System Includes: ------------------- Sony STR-V444ES Fronts: RF-3 Center: RC-3II Rear: RS3-II Sub: KSW-12 (Fuse: SB 1.2A) TV: Sony WEGA 27" DVD: Sony (Model# ?) This message has been edited by VideoGUY on 02-12-2002 at 09:39 AM Quote Link to comment Share on other sites More sharing options...
Kilowatter Posted February 11, 2002 Share Posted February 11, 2002 Several years ago my brother-in-laws Pioneer integrated amp did the same thing. He had it cranked up really loud and it just quit. I checked it out for him and what I found was Pioneer had a fuse link hidden in the transformer on the input (120 vac) side. If I remember correctly it also had a AGC type fuse. I bypassed the burned out link fuse and it worked fine for several years after. P.S.The link fuse was stuffed down in the windings. use a multimeter to find it or take it to a repair shop and tell them what to look for. ------------------ Denon AVR-3802 Denon DCD-1520 Sanyo DS31590 31" TV Panasonic A120U DVD Sony SLV-N71 Hi-Fi VCR RCA Satellite System Klipsch Tangent 5000 mains Klipsch Tangent 1000 rears Klipsch Tangent Center Theater Quote Link to comment Share on other sites More sharing options...
lynnm Posted February 12, 2002 Share Posted February 12, 2002 Hopefully Kilowatter is correct!.. However - I - Unfortunately suspect that that amp has seen its last big party unless someone is prepared to spend more money on it than it is worth! Basically - the setup you describe suggests that the amp was presented with a load that it could not handle and the output tranistors got barbequed. ------------------ It is meet to recall that the Great Green Heron rarely flies upside down in the moonlight - (Foo Ling ca.1900) Quote Link to comment Share on other sites More sharing options...
VideoGUY Posted February 12, 2002 Author Share Posted February 12, 2002 thanks guys. i am gonna try and pick it up today an poke around and see what i can find. if there is a hidden fuse then that would just be luck (and very cost effective...lol) but we will see. lynnm i think your right, it probably was a lot of load for the reciever; considering its age and four speakers. we'll see what i can find and see what the internal damage is. thanks for the help and i will let ya know if i need anything else. This message has been edited by VideoGUY on 02-12-2002 at 09:43 AM Quote Link to comment Share on other sites More sharing options...
djk Posted February 13, 2002 Share Posted February 13, 2002 "I bypassed the burned out link fuse and it worked fine for several years after. " The next time you have a party it will just burst into flames instead. I can imagine that all your fuses have either a penny behind them or tin-foil. Safety? Fusible links in the transformer primary are a one-shot on purpose, the insulation has been overheated. If concerned about safety, get a new transformer. The next time you have a party, rent an amp from a music store. Quote Link to comment Share on other sites More sharing options...
VideoGUY Posted February 13, 2002 Author Share Posted February 13, 2002 djk...i would have to agree with you. its kind of like the old school idea of putting a penny in the fuse box in your home (when they had fuses and not breakers). it was a great idea cause you didn't have to go downstairs to change the fuses. but then again, you won't have to go downstairs when you house burns down either. heres the update. i took the cover off last night, and to my luck i found and agc fuse over by the power supply. it was basically black on the inside. like i said before, you could hear the power supply click on but nothing else would happen. i am thinking (correct me if i am wrong) that since the fuse was shot, that current was never getting to the reciever, thats why the LCD wouldn't turn on and no sound would come out. sounds good to me in theory....does that make any electrical sense?? so i am going to replace the fuse tonight and see what happens. the amplifier capacitors and all the circutry all looked fine. nothing was burnt out or destroyed like i was expecting to find. just real dusty. so i am gonna clean it with some air, replace the fuse and see what happens. it could have been that it just got a power surge (there were lights and foggers plugged in everywhere) and the fuse pretty much saved itself. we'll see, and i will let ya know. i would rather spend the 1.00 on the fuse than buy a whole new receiver.... This message has been edited by VideoGUY on 02-13-2002 at 09:08 AM Quote Link to comment Share on other sites More sharing options...
Kilowatter Posted February 13, 2002 Share Posted February 13, 2002 quote: Originally posted by djk: "I bypassed the burned out link fuse and it worked fine for several years after. " The next time you have a party it will just burst into flames instead. I can imagine that all your fuses have either a penny behind them or tin-foil. Safety? Fusible links in the transformer primary are a one-shot on purpose, the insulation has been overheated. If concerned about safety, get a new transformer. The next time you have a party, rent an amp from a music store. The amp had a main fuse protection in it(AGC type). That is why I did not replace the link fuse w/ a inline. the link fuse was "hidden" inside the transformer and of a lesser value than the main, since it blew and the main did not. The tranformer showed no signs of overheating i.e. discolored windings and/or burnt odor. ------------------ Denon AVR-3802 Denon DCD-1520 Sanyo DS31590 31" TV Panasonic A120U DVD Sony SLV-N71 Hi-Fi VCR RCA Satellite System Klipsch Tangent 5000 mains Klipsch Tangent 1000 rears Klipsch Tangent Center Theater Quote Link to comment Share on other sites More sharing options...
VideoGUY Posted February 13, 2002 Author Share Posted February 13, 2002 ahhh....i gotcha. i was thinking you bypassed the main fuse...that makes a little sense. and sounds safer to me than what i was thinkin'. ------------------ Home Theater System Includes: ------------------- Sony STR-V444ES Fronts: RF-3 Center: RC-3II Rear: RS3-II Sun: KSW-12 (Fuse: SB 1.2A) TV: Sony WEGA 27" DVD: Sony (Model# ?) Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 13, 2002 Share Posted February 13, 2002 Good deal, the unit has a internal fuse inside, and it was blown. Clean it up real good, and throw a new fuse in. And hope. Sometimes things are fried and can't tell visually. But hopefully that Fuse saved your unit. Good luck! Quote Link to comment Share on other sites More sharing options...
VideoGUY Posted February 14, 2002 Author Share Posted February 14, 2002 well i went to radio shack looking for a new fuse and bought the closest one i could find. i needed a 125v 3.15amp, and the closest i could find was a 125v 4amp. so i figured i would buy it just to see if i could get the thing to turn on. on a side note....it was "fast-acting". i know my ksw sub needs a "slow-blow", what about recievers?? is fast acting correct? i know they make a couple different kinds right? with the fuse in i plugged the unit in and all looked ok till i hit the power switch...hahaha. unfortunately as soon as the unit powers on the fuse blows. any idea what can be causing this? i am not sure what would be next to check for. again, everything "looks" good. nothing looks or smells burnt. and the power supply sounds like it is clicking on and off. mike stehr...the unit is filthy with dust, i figured i'd clead it once it was working (if). any suggestions would be great....thanks for the help....and let me know what i can do, or if its junk. ------------------ Home Theater System Includes: ------------------- Sony STR-V444ES Fronts: RF-3 Center: RC-3II Rear: RS3-II Sun: KSW-12 (Fuse: SB 1.2A) TV: Sony WEGA 27" DVD: Sony (Model# ?) Quote Link to comment Share on other sites More sharing options...
djk Posted February 15, 2002 Share Posted February 15, 2002 The fuse inside the transformer is not just a spare fuse in series with the main fuse.It is there to prevent fire if the transformer overheats.It's a UL/government agency thing.The fact that the main line fuse is black means that the amp is hosed (I hope this isn't too technical).The only question a qualified technician will have is "how much money are you willing to spend on this".You've replaced the fuse with a bigger one, quit while you're ahead. Quote Link to comment Share on other sites More sharing options...
VideoGUY Posted February 15, 2002 Author Share Posted February 15, 2002 how much money....probably not very much, really don't think it is worth it. i think we'd be better off pooling some cash and buying something new. but thanks for the info...i figured when the fuse kept blowing something go messed up pretty bad. for the most part i understood what you said though....thanks for the info ------------------ Home Theater System Includes: ------------------- Sony STR-V444ES Fronts: RF-3 Center: RC-3II Rear: RS3-II Sun: KSW-12 (Fuse: SB 1.2A) TV: Sony WEGA 27" DVD: Sony (Model# ?) Quote Link to comment Share on other sites More sharing options...
djk Posted February 16, 2002 Share Posted February 16, 2002 The parts cost very little, probably $15~20 for new ouputs, drivers, and misc.But the guy's time is worth something.A guy could buy a $4 exacto knife and remove his own gall bladder if he wanted to too.In theory it is easier to do than fixing the amplifier, takes less time too.I still think I would hire it done for me.Unless it is a '75~'80 vintage Pioneer I wouldn't bother. Quote Link to comment Share on other sites More sharing options...
WMcD Posted February 16, 2002 Share Posted February 16, 2002 I'll make a blind guess. It could be that something in the amp shorted out and created an overcurrent condition, maybe failure of a output transistor. That took out the fuse. Now with a new fuse, an over current relay is cycling and clicking but eventually the new fuse blows. The cycling shows the transformer, or part of it, might be good. Of course this doesn't quite explain why the over current relay didn't just shut down the unit and save the components. I had a Triniton which died last year. I found an internal fuse and replaced it. When I turned on the unit, there was white smoke from someplace on a circuit board. Since it had given 14 years of service, I thought it best to take it to the dumpster. Maybe it's time to buy a new rig. There's lots of good stuff out there. Gil This message has been edited by William F. Gil McDermott on 02-16-2002 at 09:58 PM Quote Link to comment Share on other sites More sharing options...
kfalls Posted March 23, 2002 Share Posted March 23, 2002 An obvious clue here is the display stopped functioning. So it sounds like the problem is with a portion of the power supply, not necessarily the tramsformer. A shorted voltage regulator is my guess. I haven't really looked at receiver schematics recently, with most I have looked at being tube amps, but usually there are several voltage supplies running off the same transformer supplying power for control logic, processing, Op Amps, etc. Also, when purchasing a replacement fuse, if you can't find the exact value it is better to get one of lesser amperage. Fuses blow when they draw more current than they are rated for, if the engineer placed a 3.15a fuse in the circuit, you definitely don't want to draw 4a before the fuse will blow again, it may take several components with it, which I'll bet happened when you powered it back up with the 4 amper. Also Pioneer used IC outputs, which are not able to dissipate heat as well as discrete transistors, it's very possible the load of 4 speakers over a long duration was too much for it and the outputs are shorted. Long story short, give up the old Pioneer and buy a new receiver. Quote Link to comment Share on other sites More sharing options...
Audio Flynn Posted March 23, 2002 Share Posted March 23, 2002 Some times you just gotta chuck the old stuff. Unless it is really classic. The older Technics, Pioneer and Marantz receivers were the backbone of entry level 2 channel music listening for many years. I had a cousin give me an 80 pounds Technics 170 watt receiver from the 70s. I played around with it on and off for 6 months but was afraid with as quirky as it was it may smoke my speakers. Gave it to a local high school rock band to use as a power amp for their stage monitors. Quote Link to comment Share on other sites More sharing options...
LyleS Posted March 25, 2002 Share Posted March 25, 2002 Hi Kfalls... while reading your knowledgeable reply, I wondered if you have some insight into the problem I'm currently trying to get fixed... I have a Denon POA-2800 power amp that I picked up used. It would work fine for a period of time, then suddenly I would hear a crackling noise through the speakers. My repair technician seems to think the problem is a static discharge, but after spending several days resoldering connections in the amp, he is unable to pin down and resolve the problem. What makes it more difficult for him to resolve is that the problem occurs intermittently only, not consistent. Any ideas? ------------------ Gear: Klipsch La Scala ;THX home cinema: KT-LCR, KT-SW15 Onkyo Integra DTR-7 THX Denon POA-2800 Amplifier Panasonic RP91 DVD NAD 7140 Stereo receiver (Pre Only with Denon Amp) Quote Link to comment Share on other sites More sharing options...
kfalls Posted April 18, 2002 Share Posted April 18, 2002 LyleS, The crackling sound disdurbs me. My first guess would be a faulty capacitor, most likely in the power supply. Years of use and build-up of heat tend to dry out the electrolyte in electrolitic capacitors. This would answer why it would discharge after the receiver has a chance warm up befroe it happens. It could also be a crack in the circuit board which opens and closes as the receiver heats and cools. I've never heard of a problem with static electricity. I assume he believes there's a voltage difference between your source and receiver caused by a build-up of static on one or the other. A simple grounding wire between the two should resolve it. Since most audio gear don't supply grounded AC plugs, ensure the polarity of each is the same (wide blade in the wide slot, narrow in the narrow slot) before grounding them together. Intermittent problems suck. If the problem was more frequent, or continuous you could use a cooling spray on the board to see if temperature was a factor. This is an older model Denon, I assume, so the quality isn't a factor and well worth repairing unless you just want an excuse to buy a new receiver. Try grounding, and check the electrolytic caps for possible bulging at the rubber ends. Hope this helps. Sorry I didn't get back to you sooner, but I look at several different BB and Forums. Quote Link to comment Share on other sites More sharing options...
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