Beagle
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amp repair
My keyboard amp's line output has stopped working completely. there was no "warning" - no staticy sounds, no intermittent operation - one day it worked, the next day it did not.
I don't think I'm going to be able to find a schematic on it, it's an obsolete Roland KC-100 (they stopped making this model) and I've heard you can't get Roland schematics anyway.
what's the chances it will be something easy to diagnose and repair if I open it up and try it myself? any thoughts on where to look first?
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spacey
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Re:amp repair
2012/08/28 09:13:40
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Beagle
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Re:amp repair
2012/08/28 09:39:36
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hmm - well. $5 to join for 7 days would get me the service manual. might be worth it, IDK.
I've never been fond of those sites that make you pay for old manuals. I'll have to think about it.
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spacey
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Re:amp repair
2012/08/28 09:46:30
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Man you're tight! Here - maybe it's worth $3.00? Do ya squeak when ya walk?
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Guitarhacker
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Re:amp repair
2012/08/28 09:46:32
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Certainly in the D/FW area, you should be able to find a technician who could repair it. I'm sure there is someone there of that level of experience who knows that stuff like the back of his hand and could probably repair it w/o the schematics.
My website & music: www.herbhartley.com MC4/5/6/X1e.c, on a Custom DAW Focusrite Firewire Saffire Interface BMI/NSAI "Just as the blade chooses the warrior, so too, the song chooses the writer "
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Karyn
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Re:amp repair
2012/08/28 09:50:24
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Have you tried turning it off then on again? 
Mekashi Futo. Get 10% off all Waves plugins.Current DAW. i7-950, Gigabyte EX58-UD5, 12Gb RAM, 1Tb SSD, 2x2Tb HDD, nVidia GTX 260, Antec 1000W psu, Win7 64bit, Studio 192, Digimax FS, KRK RP8G2, Sonar Platinum
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Guitarhacker
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Re:amp repair
2012/08/28 09:51:25
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My website & music: www.herbhartley.com MC4/5/6/X1e.c, on a Custom DAW Focusrite Firewire Saffire Interface BMI/NSAI "Just as the blade chooses the warrior, so too, the song chooses the writer "
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spacey
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Re:amp repair
2012/08/28 09:55:13
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Reece Here...for only $2.00...just mail the two to me and download anytime. Two is low as I go. (thanks Herb) You did check the fuse and the wall outlet didn't you?
post edited by spacey - 2012/08/28 10:00:20
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jbow
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Re:amp repair
2012/08/28 10:09:24
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I'd open it and look at the line out jack and look to see if there is a burnt looking resistor near it but don't touch anything other than the jack with your hand. It is a good idea to keep one hand in your pocket when poking around in an amp. Anyway, maybe a wire came loose on the jack, especially if it is working otherwise.
Good luck and be careful.
J
Sonar Platinum Studiocat Pro 16G RAM (some bells and whistles) HP Pavilion dm4 1165-dx (i5)-8G RAM Octa-Capture KRK Rokit-8s MIDI keyboards... Control Pad mics. I HATE THIS CMPUTER KEYBARD!
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Psalmist35
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Re:amp repair
2012/08/28 10:11:44
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☄ Helpful
I'd ditch BitBridge if I were you!
George Foreman Grill; Ginsu knifes; Clapper; Home Grown Intel i7 -6700K 16G Ram; Sonar Platinum; MOTU 896HD; Tascam US2400;
My Music
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Karyn
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Re:amp repair
2012/08/28 10:16:56
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Reece, looking at the schematic you need to check the jumper cable to the line out socket.
Mekashi Futo. Get 10% off all Waves plugins.Current DAW. i7-950, Gigabyte EX58-UD5, 12Gb RAM, 1Tb SSD, 2x2Tb HDD, nVidia GTX 260, Antec 1000W psu, Win7 64bit, Studio 192, Digimax FS, KRK RP8G2, Sonar Platinum
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Beagle
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Re:amp repair
2012/08/28 10:18:52
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spacey
Man you're tight!
Here - maybe it's worth $3.00? Do ya squeak when ya walk?
actually it's not the money that bothers me - I don't trust those sites. maybe without merit, but they just seem "shady" to me.
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Beagle
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Re:amp repair
2012/08/28 10:24:41
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spacey
Reece Here...for only $2.00...just mail the two to me and download anytime. Two is low
as I go.
(thanks Herb)
You did check the fuse and the wall outlet didn't you?
Guitarhacker
google search turned up several sites that have it for free.
http://elektrotanya.com/roland_kc-100.pdf/download.html this is only one of them.
did either of you try to actually download it? see this is exactly why I despise these 3rd party manual websites - not the actualy mfg. try to download it. it doesn't actually work. it takes you to another screen which says you can download the "free toolbar" to search for the document you want. no thank you. if you click on the page itself it brings up only that first page. I cannot find any way to actually download the real manual from that website. Michael - it's not going to be the fuse or the wall outlet - because as I said it's ONLY the LINE OUTPUT of the amp that doesn't work. the amp works fine otherwise.
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Beagle
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Re:amp repair
2012/08/28 10:25:43
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Karyn
Reece, looking at the schematic you need to check the jumper cable to the line out socket.
Karyn - thank you! where are you looking at the schematic??? I need to see where that jumper is.
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Beagle
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Re:amp repair
2012/08/28 10:28:05
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jbow
I'd open it and look at the line out jack and look to see if there is a burnt looking resistor near it but don't touch anything other than the jack with your hand. It is a good idea to keep one hand in your pocket when poking around in an amp. Anyway, maybe a wire came loose on the jack, especially if it is working otherwise.
Good luck and be careful.
J
thanks for the advice Julien. yes, I'm quite aware of safety. by day I'm a Test Engineer (EE), so I deal with things like that all the time at work. that's why I should be able to do this myself if I have a schematic.
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Bub 
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Re:amp repair
2012/08/28 10:29:19
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I agree about those sites Beagle. Ive found a couple manuals on those sites I passed on.
As for your amp ... I dont know how old it is, but it could be something as simple as a cold solder joint, or blown fuse. Especially those surface mount ones thqt they make to look like resistors and diodes. The other thing, try a different cable and keyboard.
"I pulled the head off Elvis, filled Fred up to his pelvis, yaba daba do, the King is gone, and so are you."
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Bub
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Re:amp repair
2012/08/28 10:31:59
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Usually if you have speaker output but no line output, its something simple.
"I pulled the head off Elvis, filled Fred up to his pelvis, yaba daba do, the King is gone, and so are you."
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Beagle
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Re:amp repair
2012/08/28 10:32:10
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thanks bub, yes, I plan to try to look for blown resistors, fuses, bad solder joints (harder to find) and diodes.
but it's not going to be a problem with the keyboard or input cable since I can use the amp normally except for the line output.
but I did try a different cable from the line output to the board. that didn't work - that's why I am sure it's a problem inside the amp with the line out only.
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Beagle
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Re:amp repair
2012/08/28 10:34:19
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WAIT! sorry herb & Michael - I found the place to actually download the manual on that page! it's the little link inside the paragraph.
downloading it now. thanks again and sorry for bustin' yer chops about those sites.
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craigb
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Re:amp repair
2012/08/28 10:50:40
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Personally, I'd start off by eating some becan. It may not cure the problem, but I'd feel better about it right away...
(And, I'm lucky, there's a very good repair shop in Portland for exactly this type of stuff!)
Time for all of you to head over to Beyond My DAW!
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Karyn
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Re:amp repair
2012/08/28 10:51:32
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Reece, now you have the manual (with schematic) you should see a jumper cable from right next to the line out socket to near IC4 (the line out amp).
Mekashi Futo. Get 10% off all Waves plugins.Current DAW. i7-950, Gigabyte EX58-UD5, 12Gb RAM, 1Tb SSD, 2x2Tb HDD, nVidia GTX 260, Antec 1000W psu, Win7 64bit, Studio 192, Digimax FS, KRK RP8G2, Sonar Platinum
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Beagle
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Re:amp repair
2012/08/28 10:54:25
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Karyn
Reece, now you have the manual (with schematic) you should see a jumper cable from right next to the line out socket to near IC4 (the line out amp).
yes, thanks! that jumper and the R86 resistor would be my first suspects.
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Psalmist35
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Re:amp repair
2012/08/28 10:57:51
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Karyn
Reece, now you have the manual (with schematic) you should see a jumper cable from right next to the line out socket to near IC4 (the line out amp).
Pffft! I thougt you were refering to the jumper between the amp and the keyboard.
George Foreman Grill; Ginsu knifes; Clapper; Home Grown Intel i7 -6700K 16G Ram; Sonar Platinum; MOTU 896HD; Tascam US2400;
My Music
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Beagle
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Re:amp repair
2012/08/28 11:01:55
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bapu
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Re:amp repair
2012/08/28 12:52:50
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Did you check the cable?
{runs out of the room}
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Beagle
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Re:amp repair
2012/08/28 13:20:11
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Guitarhacker
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Re:amp repair
2012/08/28 13:44:26
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yeah... I agree with you on the links on the pages..... you just gotta look and search to find the correct one....
glad you got it.
My website & music: www.herbhartley.com MC4/5/6/X1e.c, on a Custom DAW Focusrite Firewire Saffire Interface BMI/NSAI "Just as the blade chooses the warrior, so too, the song chooses the writer "
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Danny Danzi
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Re:amp repair
2012/08/28 15:43:16
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Reece, try giving these people a call for your amp. They are a service center for many known brands of gear. I've not yet used them myself, but this contact information came to me with some high praise and credibility. I was told "if these guys can't fix something, it can't be fixed...period."
Audio Electronics
10870 Plano Rd. Suite C
Dallas, TX 75238
214-349-5000
I did call them for info on fixing an old piece that I have that no one else will touch. I happened to have had the piece at a new repair place here in NJ that I thought wouldn't be able to fix the piece, so I was ready to ship it out to these guys in Texas. The guy in NJ fixed it though luckily. But it never hurts to have a credible contact for repairs. :) Good luck.
-Danny
My Site Fractal Audio Endorsed Artist & Beta Tester
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Beagle
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Re:amp repair
2012/08/28 15:50:08
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thanks Danny. I'm going to attempt it myself first.
that, and actually that's an hour's drive one way in GOOD traffic for me. I live on the southwest side of Ft. Worth and that store is on the northeast side of Dallas. DFW is a very large place!
but I'll check them out if I can't fix it myself. thanks.
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