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CS-80 loss of +8.5 and -6.5 voltage on PSU

CS-80 loss of +8.5 and -6.5 voltage on PSU

2008-12-31 by Heath Finnie

In my continuing adventures with this thing I realized that my latest problem is a loss of
these two voltages from the PSU. I replaced IC722, and both 1000uf caps. I'm trying to follow
the instructions and run the PSU separate from the rest of the synth by connecting the +15
to +15S and -15 to -15S and I'm not getting any proper voltages running it this way.

Heath

Re: CS-80 loss of +8.5 and -6.5 voltage on PSU

2008-12-31 by David Rogoff

--- In yamahacs80@yahoogroups.com, "Heath Finnie" <heathfinnie@...> wrote:
>
> In my continuing adventures with this thing I realized that my
latest problem is a loss of these two voltages from the PSU. I
replaced IC722, and both 1000uf caps. I'm trying to follow the
instructions and run the PSU separate from the rest of the synth by
connecting the +15 to +15S and -15 to -15S and I'm not getting any
proper voltages running it this way.

What are you getting? What are the voltages on the +8.5v and -6.5v
outputs? What are the outputs of the rectifiers (@ C730 and C731)
feeding the regulator circuits? For the obvious, have you checked the
fuses (F721/F722)?

Shouldn't be that hard to trace the problem.

Good luck!

Re: CS-80 loss of +8.5 and -6.5 voltage on PSU

2009-01-03 by galaxiesmerge

I would strongly recommend that you use a programmable or variable
multi-output bench power supply unit to ensure that your synth is
still in fact working.

However, first use a voltmeter and ohm-meter to test the synth for
shorts on the rails and the voltmeter to test your power supply outputs.

When working with PSU's, having a bench power supply is invaluable in
ensuring that your gear is actually working (i.e. that you have
decoupled your work on the PSU from work on the synth).

Cheers!

--- In yamahacs80@yahoogroups.com, "Heath Finnie" <heathfinnie@...> wrote:
>
> In my continuing adventures with this thing I realized that my
latest problem is a loss of
> these two voltages from the PSU. I replaced IC722, and both 1000uf
caps. I'm trying to follow
> the instructions and run the PSU separate from the rest of the synth
by connecting the +15
> to +15S and -15 to -15S and I'm not getting any proper voltages
running it this way.
>
> Heath
>

Re: [yamahacs80] CS-80 loss of +8.5 and -6.5 voltage on PSU

2009-01-07 by Christof Lorenz

Have you solved the problem ?
If not: check the 0.47 Ohm resistors right behind TR709 and TR714 !
These are Metal Oxyde Film Resistors, they are used as a kind of fuses and melt away if there is too much current...

Christof

----- Original Message -----
From: Heath Finnie
To: yamahacs80@yahoogroups.com
Sent: Wednesday, December 31, 2008 6:42 PM
Subject: [yamahacs80] CS-80 loss of +8.5 and -6.5 voltage on PSU


In my continuing adventures with this thing I realized that my latest problem is a loss of
these two voltages from the PSU. I replaced IC722, and both 1000uf caps. I'm trying to follow
the instructions and run the PSU separate from the rest of the synth by connecting the +15
to +15S and -15 to -15S and I'm not getting any proper voltages running it this way.

Heath





[Non-text portions of this message have been removed]

Re: [yamahacs80] CS-80 loss of +8.5 and -6.5 voltage on PSU

2014-01-15 by <nightmusic1974@...>

Hi everybody, i'm new to this group, and it happens that i have the exact same issue with +8,5 and -6,5 for a few days now.I would follow Heath Finnie procedure by replacing IC722, and both 1000uf caps.I would also check TR09 and TR14 as you suggested Christof, but where do you find those ones? i dont see them on the SVU circuit board and wiring? (http://therogoffs.com/cs80/manuals/CS80_Service_Manual/60%20-%20SVU%20Circuit%20Board%20&%20Wiring.jpg)

Thank you!

Re: [yamahacs80] CS-80 loss of +8.5 and -6.5 voltage on PSU

2014-01-16 by David Rogoff


On Jan 15, 2014, at 12:47 PM, <nightmusic1974@...> <nightmusic1974@...> wrote:

Hi everybody, i'm new to this group, and it happens that i have the exact same issue with +8,5 and -6,5 for a few days now.I would follow Heath Finnie procedure by replacing IC722, and both 1000uf caps.I would also check TR09 and TR14 as you suggested Christof, but where do you find those ones? i dont see them on the SVU circuit board and wiring? (http://therogoffs.com/cs80/manuals/CS80_Service_Manual/60%20-%20SVU%20Circuit%20Board%20&%20Wiring.jpg)

Welcome to the group!   As to the +8.5/-6.5 supplies, I’ve always found the problem to be a semi or hard short, usually one of the caps on the TSB boards.  It’s possible it’s the op-amp or transistors in the PS, but I haven’t run across that.  As to where TR9 and 14 are hiding - they’re on the heatsinks, not on the PCB.  I can’t remember right now whether they’re the big TO3 transistors or (I think more likely) the TO220 transistors.  If the latter, they’re a massive pain to get to!!!

Good luck and let us know what you find.

 David


[yamahacs80] CS-60 FS VGC!

2014-01-16 by Fernando Zarone

Hello all.
I’m back after long time, due to the birth of my lady Fernanda (1,5 y ago) that set me in stand by for my keyboards… :-)
To whom it may concern:
I write because there is a friend who will sell his Yamaha CS 60. It is in EXCELLENT esthetic conditions, everything works like it should (but I am going to check it carefully if anyone is interested).
It has no legs but looks like new. Most of the “vital” caps and critical ICs have been professionally replaced already.
If interested, please let me know before he put it on auction on e*ay…
Located in Italy (Napoli).
He wants to sell it for 3000 euros plus shipping/handling
NOT MINE (I am happy with my CS80, totally refurbished, thanks again friends for the support you gave me in pursuing that goal)

Fernando

Re: [yamahacs80] CS-60 FS VGC!

2014-01-16 by Fernando Zarone

PS
I forgot to mention, It comes with the original case lid…


Il giorno 16/gen/2014, alle ore 10:37, Fernando Zarone <fernandozarone@...> ha scritto:

> Hello all.
> I’m back after long time, due to the birth of my lady Fernanda (1,5 y ago) that set me in stand by for my keyboards… :-)
> To whom it may concern:
> I write because there is a friend who will sell his Yamaha CS 60. It is in EXCELLENT esthetic conditions, everything works like it should (but I am going to check it carefully if anyone is interested).
> It has no legs but looks like new. Most of the “vital” caps and critical ICs have been professionally replaced already.
> If interested, please let me know before he put it on auction on e*ay…
> Located in Italy (Napoli).
> He wants to sell it for 3000 euros plus shipping/handling
> NOT MINE (I am happy with my CS80, totally refurbished, thanks again friends for the support you gave me in pursuing that goal)
>
> Fernando
>
>
>
> ------------------------------------
>
> Yahoo Groups Links
>
>
>

Re: [yamahacs80] CS-80 loss of +8.5 and -6.5 voltage on PSU

2014-01-17 by <nightmusic1974@...>

Thank you David for your welcome! 

Actually what's really funny is that i started the project of completely restoring my CS80 after finding that site, from which i shared that link from... and readin your post and your last name, i just realized that it was you behind that same site! World is small among passionate people, isnt it? :-)


Thank you for those details concerning TR9 and TR14, hidden on the heatsink.I'm not sure i correctly identified them yet, but i will take the PSU off the unit this weekend (as soon as i find those jumpers for connecting 15/15S pins).

Actually, i realized that my middle-position 500mA fuse was blown, even though it looked perfectly clean; today i simply ran a continuity test with my DVM, and it failed.

My +8.5/-6.5v issue came right after my probe slipped and touched another pin around (giving me a constant sound from the headphones/speakers of the CS80 as a result), which led me to think i created a limited-time short somewhere, which then certainly blew the fuse.

But in case there's a short anywhere else (indeed, it recently happened that my BA board got damaged, after i tried to take it out but forgetting to powering off the unit, stupid me), maybe i should check some caps on other boards as you suggested.But how to do it without risking to damage the PSU in any way again, or maybe any other boards' components? Is this benchmark PSU you got the only way to go in such cases, or is there any other workaround? For example, is there a way to check some caps without running the power up? By using a signal generator maybe?


By the way…Would anybody could suggest me an appropriate oscilloscope to buy, for following yamaha tuning procedure? I only made DVM checking for now, and would love to go on further with an oscillo, is there a 'minimum model' to get? (20MHZ is enough? should i go for 100MHZ instead?).I was planning buyind a tektronix TDS 210/220 for ex.


And by the way David, thank you again for your site, such a great internet source for CS80 owners!!!


Greg

Re: [yamahacs80] CS-60 FS VGC!

2014-02-01 by Fernando Zarone

I have checked the CS-60. It is in fantastic conditions. Esthetically, nothing is missing, no burn marks, scratches or major signs of time on the panels/keys. Functionally, EVERYTHING is perfectly working as it should. Inside, the PSU has been recapped and calibrated. All of the ICs in the SH board have been replaced (photos of the inside available). If you need one, don’t think you’ll find one in such an excellent condition.
The CS has its lid, no legs. 220/230 V AC..
It is NOT MINE, this friend is a super loyal and reliable person. He asks for 3000 euros, what he paid for it one year ago.
Please contact me offlist if interested.

Fernando



Il giorno 16/gen/2014, alle ore 12:17, Fernando Zarone <fernandozarone@...> ha scritto:

> PS
> I forgot to mention, It comes with the original case lid…
>
>
> Il giorno 16/gen/2014, alle ore 10:37, Fernando Zarone <fernandozarone@...> ha scritto:
>
>> Hello all.
>> I’m back after long time, due to the birth of my lady Fernanda (1,5 y ago) that set me in stand by for my keyboards… :-)
>> To whom it may concern:
>> I write because there is a friend who will sell his Yamaha CS 60. It is in EXCELLENT esthetic conditions, everything works like it should (but I am going to check it carefully if anyone is interested).
>> It has no legs but looks like new. Most of the “vital” caps and critical ICs have been professionally replaced already.
>> If interested, please let me know before he put it on auction on e*ay…
>> Located in Italy (Napoli).
>> He wants to sell it for 3000 euros plus shipping/handling
>> NOT MINE (I am happy with my CS80, totally refurbished, thanks again friends for the support you gave me in pursuing that goal)
>>
>> Fernando
>>
>>
>>
>> ------------------------------------
>>
>> Yahoo Groups Links
>>
>>
>>
>