- So I started repair on a mac laptop with a cracked/damaged LCD assembly. It is a A1286 (EMC 2325) from mid 2009, last 3 seria...
- I mean if you are not willing to throw down $13 for the schemo then time must not be a big concern, so just start digging in. I've found it pretty easy to find the place to tap into for a line in. That place usually is the fm output buffer stage. Find the main fm chip, look up the datasheet, find its L/R stereo out and tap in after the output buffer, but before the main selector switch or preamp. Then place your own dpdt switch there, that way you then select between Fm or line in. Its pretty much the only way I've found without building extra circuits. Good luck.
- I've fixed these for years as an official roland repair center. All amps in the KC series have 2 extremely common issues. #1 dirty pots, #2 loose/cold/bad solder connections on the pots, jacks, and interconnects Some KC series amps also get loose solder on some transistors and caps, but I don't remember the 300 series facing that issue. In general its really worthwhile to re-solder everything related to those parts and to never worry about it again. Also use a good deoxit to clean the pot which is best accessed thru the backside of the pot. Hope that helps!
- I've never replaced a display on this item, but I would think that its just an led that is lighting the whole thing as I've seen it commonly in low voltage/modern displays. So look for a surface mount led that is probably on the left or right side of the display and thats probably what is out. If you take pictures of the inside I could maybe direct you more throughly. Thanks
- I have a official repair shop for pioneer and yamaha and have heard this complaint MANY times before and usually had a hard time making it fail once I got my hands on it. Yamaha did a study of hdmi cords and found that some manufactures used too thin of wiring to properly handle data transfer between certain items. This MAYBE your issue. What they also found that price made no difference. $100 cords were sometimes worse than $10 ones. I suggest buying another brand at the store and seeing if it solves the issue. Good luck.
- Hey guys, So just to be clear is it the hr824 or hr824II? If its just the hr824, there is a service bulletin for the auto on function failure. This only effects models pre april 2001. So that could be an issue. I could send you the info on the fix if need be.
- SInce its a solid state amp there are most likely a few issues you maybe facing. First I'd check for loose solder connections. Its very common for the from panel controls to come loose after years of use, but its also very common for the interconnects from board to board to have cold solder joints too. Occasionally too the headphone jack or the effect send is tied in series with the signal and either that jack is dirty or loose. The only way I've found to isolate a problem like this is to open it up and tap around the board gently to moderately with the plastic back end of a screw driver when the unit is on(BE CAREFUL not touch mains voltage). If the unit exhibits the problem then. Its definitely a loose connection or similar somewhere in the unit. If not, then you maybe facing a transistor problem and those issues are best fought with a scope, multimetter, and patience. Let me know if this helps. Thanks
- Its MOST likely a loose solder connection somewhere in the unit, maybe on the front panel jack, maybe on the volume pot. It could also be the output IC TDA2050, but usually when those blow they don't sit there humming away afterward, I would suggest looking thru the unit for problems like the ones listed here. http://tetsuoelectronics.wordpress.com/2...-pro-jr-no-output/ To trace the problem better, take out the amp chassis as shown in the step by step, then with the back PLASTIC end of the screw driver, tap around and see if you get the sound to cut in and out on a specific part of the board, if so its probably your culprit. When I used to fix these a a lot I would just resolder the whole front and back panel as this just guarantees no more issues in the future. Let me know if this works, if not I can walk you thru a few other ideas. Thanks
- Really sounds like a power supply issue, probably the electrolytic capacitors. Once the electrolytic caps in the power supply start to go bad they have all sorts of power issues, from taking along time to turning on, or never turning on or turning off randomly. If you are not familiar with capacitor failure in tv's you can do a lot of research on the internet. It's really not a hard fix if you are patient and handy with a screw driver and soldering iron. Heres a good example of what you would expect to see in the power supply if you took the back off.: https://www.google.com/search?q=bad+capa... I would replace every single electrolytic capacitor in the power supply. Also if you use higher quality capacitors it will last longer than it did before too. If you are not comfortable with removing them, you could look into buying a complete power board replacement on ebay or bring it into a repair shop. Hope this helps good luck.
- Its a mild long shot, but probably what happened is some of the connections have come loose from the board inside. I bet it broke from the left side, leaving the right side connected as that where the power is. First you'll have to crack it open and see how bad it looks inside. Maybe take a picture if you'd like and send it over and I can judge from there. If it looks possible you'll probably need to make little jumpers from the connector to the board using bits of leftover wire. It won't be fun and you'll need a small tipped solder iron to do some(steady hands help too) but hey you keep it outta the landfill. Good luck.
- In my experience with subwoofers they tend to get really hot in use due to them being sealed. This tends to lead to failure of capacitors(most
ly the electrolytic ones). Which exhibit problems when they warm up. IE. they don't filter the power correctly(or block DC) so the switching supply leaks its noise into the circuitry. If you had it repaired a while ago you might have brought it to a shop that uses cheap caps that will only last 1000 hours or less, therefore they might be bad again. Or they might have only replaced the bad ones, not all of them. My suggestion is to replace ALL the electrolytic caps. I recommend the UPW or UPM Nichicon electrolytics as they have a 5000+ hour lifespan at a decent price point. You will need no schematic to do so, just patience and a decent soldering iron. Hope that helps. I can expound more if you need me too. Thanks
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