| Kasino U 100 ? & Hola! [message #25512] |
Mon, 05 September 2016 17:40  |
yuzerneigm
Messages: 15
Registered: September 2016
Location: p-town
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Junior Member |
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Well hello all! New to the site here. I have an old Kasino U 100 and i messed it on up. Changing out the power cord i caused the fuse to blow somehow. Replaced the fuse and now I'm getting very low volume that starts to break up when the volume is dialed up. Just wanted to ask u all what it might be in case its happened to anyone before. I'd appreciate any feedback
thanks!! Chris
Eat rich
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| Re: Kasino U 100 ? & Hola! [message #25515 is a reply to message #25512] |
Tue, 06 September 2016 06:24  |
stevem
Messages: 4773
Registered: June 2004
Location: NY
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Senior Member |
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Hello and welcome!
Please discribe for me how you went about installing a new power cord , as messing up on its installation should have if anything blown the fuse or circuit breaker on the wall outlet you had the amp plugged into and have done any harm to the amp!
So is the new cable wired up correctly now?
Was the amp working ok before the cable install?
If the amp is not blowing a fuse now atleast that's one good thing, but the only guess I can take is that you bent a component up against another when working inside the amp.
A first guess would be the two leads off of the bias diode that loads into a clip between the two output transistors are shorter to each other or the diode is pushed into the clip too far and was shorting out?
[Updated on: Tue, 06 September 2016 06:24] Report message to a moderator |
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| Re: Kasino U 100 ? & Hola! [message #25517 is a reply to message #25512] |
Tue, 06 September 2016 19:15 |
yuzerneigm
Messages: 15
Registered: September 2016
Location: p-town
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Junior Member |
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The power cord is wired up correctly and I've removed the death cap. When I reinstalled a new fuse and powered up there was very low volume. I'll check ur suggestions and get back. Thanks so much!!!
Eat rich
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| Re: Kasino U 100 ? & Hola! [message #25519 is a reply to message #25512] |
Wed, 07 September 2016 20:13 |
yuzerneigm
Messages: 15
Registered: September 2016
Location: p-town
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Junior Member |
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Well, here's what I've come up with. I turned on the amp again this pm and noticed a spark. There's a black round thing that has 4 wires attached via tab connectors. It's location is right in front of the tranny and next to the fuse. Anyway, the connector is broken that connects the red wires to the tab closest the front of chassis. This red wires connects from there to the pilot light and then to what is one of the two big filter caps. Other wires connected are 2 purple that apparently connect to tranny and 1 green to the other filter cap. This is the only odd/bad connection I can visibly see. Let me know what u think. Appreciated!!!!
Thanks,Chris
Eat rich
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| Re: Kasino U 100 ? & Hola! [message #25520 is a reply to message #25512] |
Wed, 07 September 2016 20:58 |
yuzerneigm
Messages: 15
Registered: September 2016
Location: p-town
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Junior Member |
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Oh and seeing as how input/output jacks tend to get cruddy I cleaned them and ran a patch cord in and out of the "module input" jacks. When putting the cord in the amp gave loud popping and noise as if I was tapping the plug with my finger tip at cranked volume. Odd. What are the "module input" jacks for?
Eat rich
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| Re: Kasino U 100 ? & Hola! [message #25521 is a reply to message #25512] |
Thu, 08 September 2016 07:03 |
stevem
Messages: 4773
Registered: June 2004
Location: NY
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Senior Member |
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They are made to feed other speaker cabinets that where offered back then and had power amps built in.
The point in these amps where they tap the signal off is the output side of the preamps and the input side of the power amp, hence the popping you where hearing when tapping the end of the cable !
If you ever have a amp the does not work doing this simple test will atleast confirm that the power amp section is working.
[Updated on: Thu, 08 September 2016 07:04] Report message to a moderator |
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| Re: Kasino U 100 ? & Hola! [message #25525 is a reply to message #25512] |
Thu, 08 September 2016 14:53 |
yuzerneigm
Messages: 15
Registered: September 2016
Location: p-town
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Junior Member |
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So does this sound like a preamp circuit or power amp problem?
I kinda assumed that was the bridge rectifier after some research. My thoughts go to the possibility that the disconnected red wires between the bridge rec and filter cap originally caused the fuse to blow when I powered on the amp after changing the power cord. I'm guessing that it shorted to the chassis or what ever since I hadn't noticed it had been disconnected. Could this have damaged the bridge rectifier, power cap or anything else in its path causing the lack of volume.
Really appreciate all of your thoughts on this!!
Thanks so much!!, Chris
Eat rich
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| Re: Kasino U 100 ? & Hola! [message #25527 is a reply to message #25525] |
Fri, 09 September 2016 00:40 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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If as you say the red wire was disconnected, the positive side of the power supply was missing from the amp when you turned it on. This would cause the power amp to shift the speaker output to the negative side of the power supply, which probably caused the fuse to blow. What damage was caused by this is unknown and really unpredictable. The best way to find out is to test the parts.
If you have replaced the fuse and turned the amp back on, if the bridge rectifier was damaged, the new fuse would blow. Same for the power amp transistors, well most of them at least.
If you can power up the amp, leave the speaker disconnected for now until you check for voltage on the speaker jack. Measure the dc voltages at the two main filter caps. The red wire is the positive side and the green is the negative side. You should read somewhere around 40 dc volts pos and neg. Read the dc voltage across the speaker jack. You should get a reading of less than 1/2 dc volt at the speaker jack. A few millivolts is more normal there.
All of this assumes that you have the equipment and skill set to work on a live amp.Remember that a live amp can do you physical harm, so if you don't feel comfortable in making these tests, then don't.
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| Re: Kasino U 100 ? & Hola! [message #25528 is a reply to message #25512] |
Fri, 09 September 2016 02:38 |
yuzerneigm
Messages: 15
Registered: September 2016
Location: p-town
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Junior Member |
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Thanks chicagobill. I'm skilled and safe enough to do this just not knowledgeable enough to know the info u guys have. But with ur help I'll probably figure it out. Thanks so much!
Eat rich
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| Re: Kasino U 100 ? & Hola! [message #25533 is a reply to message #25512] |
Tue, 13 September 2016 00:35 |
yuzerneigm
Messages: 15
Registered: September 2016
Location: p-town
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Junior Member |
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well shoot fire!! I just don't know. Still getting low, low signal with a hard breakup distortion that fades to clean as the notes ring. Thanks folks!!!
Eat rich
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| Re: Kasino U 100 ? & Hola! [message #25535 is a reply to message #25512] |
Tue, 13 September 2016 22:33 |
yuzerneigm
Messages: 15
Registered: September 2016
Location: p-town
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Junior Member |
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When I run signal from those preamp outs I'm getting the same business. Very low signal that sounds garbled and distorted. Must be in the preamp circuit?
Thanks again!
Chris
Eat rich
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| Re: Kasino U 100 ? & Hola! [message #25536 is a reply to message #25512] |
Wed, 14 September 2016 00:09 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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I will assume that all 4 channels are distorted the same way?
I believe that this model is similar to the K100-5. The preamp boards are supplied with a plus and minus 8 volt dc. The 8 volt supplies are generated on the main power amp board. Check to see if the two supplies are working and getting to the preamp and mixer boards.
Just to be sure, please look at the different boards in the amp and list the board numbers here.
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| Re: Kasino U 100 ? & Hola! [message #25546 is a reply to message #25512] |
Wed, 14 September 2016 16:13 |
yuzerneigm
Messages: 15
Registered: September 2016
Location: p-town
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Junior Member |
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Ur right pleat. I believe this to be a bass amp. Its a 1x15 combo and has 3 jacks (high, low & footswitch) on the front panel. The knobs are volume brite treble bass & some tone switch pots. The pc boards are pc 5013 on the back side 5023 on the front.
Eat rich
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| Re: Kasino U 100 ? & Hola! [message #25547 is a reply to message #25512] |
Wed, 14 September 2016 17:44 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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Well, a single channel bass amp with Selectone and Selective Boost.
The basic starting point is the same, there are two low voltage power supplies that come from the power amp board to the preamp board. Check the voltages, do you have both plus and minus 8 volts supplies?
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| Re: Kasino U 100 ? & Hola! [message #25554 is a reply to message #25552] |
Thu, 15 September 2016 00:38 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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Yes, that is a problem.
The two voltage regulators are on the power amp board. The negative side tracks the positive side, so check the positive side circuit first. Once it is fixed, the negative side will probably come up as well.
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| Re: Kasino U 100 ? & Hola! [message #25572 is a reply to message #25512] |
Sun, 18 September 2016 13:01 |
yuzerneigm
Messages: 15
Registered: September 2016
Location: p-town
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Junior Member |
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Might there be a way to tap staight nto the power amp? Essentially to bypass the preamp and use just thepower amp? Thanks so much guys! You've really been cool!!
Eat rich
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