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Thread
2005-07-01 by gil_we
When turning it on, all leds lite up, no sound. I checked the voltages and instead of 15v there are only 3.7v measured at the PS. I found that the 15v voltage drops as you connect the main module board to the PS. If disconnected from the PS the system runs on the required 15v. Any suggestiopn where to begin checking the module board?
2005-07-02 by Travis Shire
The +15v rail drops *when* you plug in a connector? You re not doing this with pwr on are you? NEVER do that.....ever. There s a ton of CMOS ic s in there that
2005-07-02 by gil_we
Thanks, I'll look into the heating opamp, However, I noticed something that maky be confusding. The 7805 regulator back is directly connected with its middle leg, put with no seperator into the heatsink... not shure it that is OK or the middle led is in short with the ground that way... the other regulator has a plastic back. In case I don't find any heating opamp, how would you trace that ? The 5v / -5v rails seem fine so far. Also, afaik, when all leds lite up, does it mean the synth doesn't actually pass the reset phase ? Thanks. --- In kawai_sx210@yahoogroups.com, "Travis Shire" <boardjunkie@t...> wrote: > The +15v rail drops *when* you plug in a connector? You're not doing this > with pwr on are you? NEVER do that.....ever. There's a ton of CMOS ic's > in there that will be ruined from the voltage spikes created when > plugging/unplugging a connector with pwr on. You've already found > incorrect voltages....you seem to know what they should be. There may be > 3 terminal regulators for the +/- 15v (this powers the audio op- amps) > such as 7815 (+15v) and 7915 (-15v). If that's the case, one pin is v in, > one pin is v out (15v regulated) and one pin is gnd. > > Make sure the +5v digital rail is at 5v (or very close, within a 10th of > a volt) with no ripple. All logic functions will need it to be stable for > the CPU to do *anything*. > > Best track down a schematic for the power supply pcb and trouble shoot > each rail. > > There is also the possibility that something is dragging a v-rail low due > to a short. Op amps can do this....look for one that gets abnormally hot > in a few seconds after power up. > > Do some detective work and let us know what you come up with. > > > > ----- Original Message ----- > From: gil_we > To: kawai_sx210@yahoogroups.com > Subject: [kawai_sx210] OT: Juno 106 doesn't start > Date: Fri, 01 Jul 2005 07:21:00 -0000 > > When turning it on, all leds lite up, no sound. > > I checked the voltages and instead of 15v there are only 3.7v > measured > at the PS. I found that the 15v voltage drops as you connect the main > module board to the PS. If disconnected from the PS the system runs > on > the required 15v. > > Any suggestiopn where to begin checking the module board? > > > > > SPONSORED LINKS > Music sampler Music synthesizers Synthesizer music > Synthesizer Sampler > > ------------------------------------------------------------------ -- > > YAHOO! GROUPS LINKS > > * Visit your group "kawai_sx210" on the web. > > * To unsubscribe from this group, send an email to: > kawai_sx210-unsubscribe@yahoogroups.com > > * Your use of Yahoo! Groups is subject to the Yahoo! Terms of > Service. > > > ------------------------------------------------------------------ --
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2005-07-02 by gil_we
Found one 80017A that's hot as hell !! It's the first one from the right. I wonder if the short is in the chip itself or is caused by another component that interacts with it... I can see that TR18 transistor, which interacts directly with leg #2 of that IC has a solder joint on one of its legs - as there was a wire connected to it in the past. The entire machine looks like it has some mod appiled to it (a jack was added to it). The tranny itself is not shorted. --- In kawai_sx210@yahoogroups.com, "Travis Shire" <boardjunkie@t...> wrote: > The +15v rail drops *when* you plug in a connector? You're not doing this > with pwr on are you? NEVER do that.....ever. There's a ton of CMOS ic's > in there that will be ruined from the voltage spikes created when > plugging/unplugging a connector with pwr on. You've already found > incorrect voltages....you seem to know what they should be. There may be > 3 terminal regulators for the +/- 15v (this powers the audio op- amps) > such as 7815 (+15v) and 7915 (-15v). If that's the case, one pin is v in, > one pin is v out (15v regulated) and one pin is gnd. > > Make sure the +5v digital rail is at 5v (or very close, within a 10th of > a volt) with no ripple. All logic functions will need it to be stable for > the CPU to do *anything*. > > Best track down a schematic for the power supply pcb and trouble shoot > each rail. > > There is also the possibility that something is dragging a v-rail low due > to a short. Op amps can do this....look for one that gets abnormally hot > in a few seconds after power up. > > Do some detective work and let us know what you come up with. > > > > ----- Original Message ----- > From: gil_we > To: kawai_sx210@yahoogroups.com > Subject: [kawai_sx210] OT: Juno 106 doesn't start > Date: Fri, 01 Jul 2005 07:21:00 -0000 > > When turning it on, all leds lite up, no sound. > > I checked the voltages and instead of 15v there are only 3.7v > measured > at the PS. I found that the 15v voltage drops as you connect the main > module board to the PS. If disconnected from the PS the system runs > on > the required 15v. > > Any suggestiopn where to begin checking the module board? > > > > > SPONSORED LINKS > Music sampler Music synthesizers Synthesizer music > Synthesizer Sampler > > ------------------------------------------------------------------ -- > > YAHOO! GROUPS LINKS > > * Visit your group "kawai_sx210" on the web. > > * To unsubscribe from this group, send an email to: > kawai_sx210-unsubscribe@yahoogroups.com > > * Your use of Yahoo! Groups is subject to the Yahoo! Terms of > Service. > > > ------------------------------------------------------------------ --
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2005-07-02 by Travis Shire
All led s lighting means the cpu is locked up....not running any code. Take care of any pwr supply issues first, then look to the logic. Could be anything
2005-07-02 by Travis Shire
Try clipping this ic s supply voltage pin (do it so it can be resoldered if need be) and see if the v rail returns to normal. If so, you found the problem. ...
2005-07-07 by gil_we
Thanks, the guy who own the synth has finally decided to get it back, so I didn't have the chnace to do that finally. --- In kawai_sx210@yahoogroups.com, "Travis Shire" <boardjunkie@t...> wrote: > Try clipping this ic's supply voltage pin (do it so it can be resoldered > if need be) and see if the v rail returns to normal. If so, you found the > problem. > > > > ----- Original Message ----- > From: gil_we > To: kawai_sx210@yahoogroups.com > Subject: [kawai_sx210] Re: OT: Juno 106 doesn't start > Date: Sat, 02 Jul 2005 09:56:48 -0000 > > Found one 80017A that's hot as hell !! > > It's the first one from the right. I wonder if the short is in the > chip itself or is caused by another component that interacts with > it... > > > > > > > > --- In kawai_sx210@yahoogroups.com, "Travis Shire" <boardjunkie@t...> > wrote: > > The +15v rail drops *when* you plug in a connector? You're not > doing this > > with pwr on are you? NEVER do that.....ever. There's a ton of CMOS > ic's > > in there that will be ruined from the voltage spikes created when > > plugging/unplugging a connector with pwr on. You've already found > > incorrect voltages....you seem to know what they should be. There > may be > > 3 terminal regulators for the +/- 15v (this powers the audio op- > amps) > > such as 7815 (+15v) and 7915 (-15v). If that's the case, one pin is > v in, > > one pin is v out (15v regulated) and one pin is gnd. > > > > Make sure the +5v digital rail is at 5v (or very close, within a > 10th of > > a volt) with no ripple. All logic functions will need it to be > stable for > > the CPU to do *anything*. > > > > Best track down a schematic for the power supply pcb and trouble > shoot > > each rail. > > > > There is also the possibility that something is dragging a v- rail > low due > > to a short. Op amps can do this....look for one that gets > abnormally hot > > in a few seconds after power up. > > > > Do some detective work and let us know what you come up with. > > > > > > > > ----- Original Message ----- > > From: gil_we > > To: kawai_sx210@yahoogroups.com > > Subject: [kawai_sx210] OT: Juno 106 doesn't start > > Date: Fri, 01 Jul 2005 07:21:00 -0000 > > > > When turning it on, all leds lite up, no sound. > > > > I checked the voltages and instead of 15v there are only 3.7v > > measured > > at the PS. I found that the 15v voltage drops as you connect the > main > > module board to the PS. If disconnected from the PS the system > runs > > on > > the required 15v. > > > > Any suggestiopn where to begin checking the module board? > > > > > > > > > > SPONSORED LINKS > > Music sampler Music synthesizers Synthesizer music > > Synthesizer Sampler > > > > > ------------------------------------------------------------------ > -- > > > > YAHOO! GROUPS LINKS > > > > * Visit your group "kawai_sx210" on the web. > > > > * To unsubscribe from this group, send an email to: > > kawai_sx210-unsubscribe@yahoogroups.com > > > > * Your use of Yahoo! Groups is subject to the Yahoo! Terms of > > Service. > > > > > > > ------------------------------------------------------------------ > -- > > > > -- > > ___________________________________________________________ > > Sign-up for Ads Free at Mail.com > > http://promo.mail.com/adsfreejump.htm > > > > ------------------------------------------------------------------ -- > > YAHOO! GROUPS LINKS > > * Visit your group "kawai_sx210" on the web. > > * To unsubscribe from this group, send an email to: > kawai_sx210-unsubscribe@yahoogroups.com > > * Your use of Yahoo! Groups is subject to the Yahoo! Terms of > Service. > > > ------------------------------------------------------------------ --
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