Build Your Own Arcade Controls Forum
Main => Audio/Jukebox/MP3 Forum => Topic started by: Z0MBIE on November 13, 2013, 11:37:47 am
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I have a CD-100H and the right channel is out. I have narrowed it down to the amp. Fuses good. Is there anything that's common that goes out in these amps I can look for? Already checked for dry solder joints and visually inspected caps.
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check your jumper on the volume terminal strip.
if you have a single volume pot (like the one that comes on the back of the juke), be sure it's set to mono not stereo.
make sure all the screws on the strip are tight.
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All connections are good. I determined that it was the amp by replacing it with another one and jukebox works fine now. However I need to fix this one to go back into the jukebox I took the good one from.
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double check the fuses inside the amplifier. there is 2 smaller pre-amp boards each with 2 fuses.
don't just visually check them, actually pull out the voltmeter and do a continuity test on them. sometimes they can break close to the end cap from vibrations where you can't see it.
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Already did before posting, not exactly a total n00b on electronics. Thanks.
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okay okay, don't get your panties in a bunch. I'm just covering all the bases. I can't count the amount of posts on here where people have said "Check the power supply" and they were all like "yeah totally checked it, it's good" when in fact all they did was look and see the red light was on (which shows 5 volts is good), but the power supply had blown out the 12 volts.
:banghead:
check out the 13 pin jumper in the middle of the amp. it's a passthrough for an optional audio switching board so it links the RCA input of the amp through to the preamps. if something is wonky there, it will cause dead channels. it should have all the wire loops on the bottom of the connector.
give all your EQ dials a twist back and forth and make sure something there isn't causing issues.
if it's still not working after those, and since you have a donor amp, switch the preamp board with the good amp and that will narrow down where the issue is. (whether the pre amp or driver sections)
i would recomend against switching the driver boards at this time. preamp is fine it's mostly passive. but if the driver boards have an issue, you'll end up having to fix 2 amps.
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LOL did not mean to come across like that. I can't swap out parts between the 2 any more because it's sold. Seems I never get an easy fix.
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if you have a set of (amplified) computer speakers you can probe the 13 pin bypass connector for a right signal.
(http://techpubs.sgi.com/library/dynaweb_docs/0650/SGI_EndUser/books/Octane_OG/sgi_html/figures/speaker.headph.port.gif)
play something on the jukebox...
you should ground the headphone plug to the input RCA sheild (or pin6) with an alligator clip or something and then press the tip of the headphone jack to pin 2 and pin 9 of the 13 pin bypass, these are your left and right channels from the preamp before they get amplified.
if you have both left and right signals there, you have an output stage issue.
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I just thought someone with experience repairing these amps might know what components usually fail causing this. I appreciate the help but it seems like a bunch of messing around.
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Z0MBIE
your output stage fuses are not blown...as u stated
so no reason to fux with the drivers
u are in a pre-drive problem
do as the nick said
that is a first basic step foward
if u here sound there ?
then u can deduce which way to go
ie foward stream or down stream..
i for 1 would never willy nilly swap driver panels
that is a fast way to kiss a few $$$ by by
ed
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there is nothing "usual" about any issue really. i went through the "usual suspects" already. the volume pot, the connectors, the fuses. if it ain't that, it's something more.
Without a backstory, I have nothing to go on. If you said it was working one second and not the next after you cranked up the volume louder than normal, I'd have something to go on. if you hooked up a new speaker, i'd have something to go on. if for the last few times it's been played the bass has sounded off, I'd have something to go on...
You have absolutely no idea what the problem is, nor do I. So basically with these tests i'm asking you to do, I'm systematically finding what ACTUALLY works and all that will be left is what isn't...and it's the what isn't that we are interested in.
:dunno I don't know, i'm not the one standing there with an amp that doesn't work. literally it would take me 5 minutes to deduce the problem with these same tests and come up with a fix. i have to wait for you to do the test and reply to find out.
test the preamp with the amplified computer speakers and see if you are getting a right sound signal at the connector. if you aren't, you have an issue in your preamp board you need to fix. If you do, you have an issue in your driver section.
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like the nick said
it is in the DETAILS
ed
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I guess I will need to test that. Can't right now as the CD player was used in another jukebox also.
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disabling the mute circuit (unplug 3 pin connector with orange/ black stripe from computer)
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mp3 player hooked up to RCA connectors on amp
=
music.
:cheers:
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Fixed it. Guy that works on these told me toalways check the transistors on the heatsink first found a bad one but replaced both for that side so works now.
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the 2N6287 & 2N6284 transistors have a habit of "testing" okay, even with a B&K 510 transistor checker - the de facto standard instrument for testing transistors.
the problem is they test fine with low voltage, but break down at high voltage.
enough with the lesson,
check your speaker wiring, it's been known for the crossover and even the subs to be wired incorrectly.
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Working this connector in and out fixed my dead left channel problem.
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Like I said after replacing those transistors all is working fine now.