I don't have the unit you have so I can't open one up and look. Here
is a link to their site where I see they list a new CPS 150 at
$652.00. Anyway, maybe somewhere on that page is a tech manual that
might help. Good luck.

"Croline" wrote in message ...
hello

i have something to ask, it's kind of boring : my PSU for my soundcraft (a
CPS 150) needs some new component especially a resistance. but the problem
is that it's burnt so i can't figure out the colored marks on it to buy a
new one which would be exactly the same.

if you have some time and a skrewdriver, you would really save me : just
tell me the colors (from left to right) you see on resistance R32, or even
better : take a picture. im asking this because i can't find any schematic
of the CPS 150 and it's the only way for me to know : to ask somebody to
open his CPS150 and tell me. i know this may sounds goofy ...

thanks
matthieu

Sorry, I left the link off my first reply.

http://www.soundcraft.com/pdf/usa_resale_price.pdf

I don't have the unit you have so I can't open one up and look. Here
is a link to their site where I see they list a new CPS 150 at
$652.00. Anyway, maybe somewhere on that page is a tech manual that
might help. Good luck.

thanks everybody !

someone sent me the schematic by mail : R32 is 2.7Kohms, exactly.

i bought the resistance and soldered it, as well as some other components,
and now my PSU works damn fine ! and the board too, i think i got 2X less
parasites : cool !

but the radiator is still damn hot. is it normal ? never checked before...
(it's an old PSU : 1992)

thanks again
matthieu

I could use a copy of that schematic if you have the time.

m.

--


mike rekka at hotmail dot com hates spam


"Croline" wrote in message
...
thanks everybody !

someone sent me the schematic by mail : R32 is 2.7Kohms, exactly.

i bought the resistance and soldered it, as well as some other components,
and now my PSU works damn fine ! and the board too, i think i got 2X less
parasites : cool !

but the radiator is still damn hot. is it normal ? never checked before...
(it's an old PSU : 1992)

thanks again
matthieu

but the radiator is still damn hot. is it normal ? never checked before...
(it's an old PSU : 1992)

thanks again
matthieu



They do get hot. These supplies come with a variety of soundcraft desks -
the Spirit Studio is quite a large one and therefore takes a fair bit of
current, thus more heat. Best thing you can do is to make sure there is
plenty of air round the heatsink to keep it as cool as possible, which means
it will last much longer. Don't put the supply inside a cabinet.

Incidentally, most of the soundcraft supplies I've repaired have had blown
bridge rectifiers. They seem to use the minimum spec possible. I always
replace them with the highest current highest voltage devices available in
the same package, usually just a few pence or cents more expensive! It
might be an idea to get some as spares.

Gareth.

They do get hot. These supplies come with a variety of soundcraft desks -
the Spirit Studio is quite a large one and therefore takes a fair bit of
current, thus more heat. Best thing you can do is to make sure there is
plenty of air round the heatsink to keep it as cool as possible, which
means
it will last much longer. Don't put the supply inside a cabinet.

it is inside some kind of big box, opened on the rear, but maybe it's not
enough, there are SCSI hard drives there maybe it's not that good. i'll find
a better place.

Incidentally, most of the soundcraft supplies I've repaired have had blown
bridge rectifiers. They seem to use the minimum spec possible. I always
replace them with the highest current highest voltage devices available in
the same package, usually just a few pence or cents more expensive!

i did replace them with the what the dealer gave me : the same but it's 6A
not 4A (or something like that... i'm not a technician). it works real fine
now, i'm amazed how much it removed a lot of parasites. i use to have a
buzzzzzzzzz when setting gain to top. now i have some beautiful white noise
=)

thanks for your answer
matthieu

hello

I could use a copy of that schematic if you have the time.

what do you mean ? you want the schematic ? for what purpose ? (curious)

matthieu

Well, I have one of these power supplies for my Spirit Auto and it's slowly
cooking itself to death. I've ordered a replacement (should be here in a
week) and would like to rebuild my current supply for use as a backup. The
schematic would be handy for upgrading some of the components.

m.

--


mike rekka at hotmail dot com hates spam


"Croline" wrote in message
...
hello

I could use a copy of that schematic if you have the time.

what do you mean ? you want the schematic ? for what purpose ? (curious)

matthieu

hello

(first of all sorry for my english...)

i sent you the schematic, and i crosspost here for those who may be
interested. if you want to repair your CPS 150 i can give you this advice :
just unmount the main circuit. look at the soldered side : you'll see some
brown parts, the circuit is burning are some places. all the components at
these brown places needs to be renew. it won't be expensive it just take a
little time. (some repair shop would have take me 120$ to do the work and 10
long days, i did it all myself and it did cost me 3$ for the components -2
bridge rectifiers, one resistance, one black thingy -im not an
electronician-)

you must especially renew these 2 bridge rectifiers, it seems you can
replace them with stronger models (ask your electronic dealer if it's ok).

another thing you can do (that Soundcraft did advise me) : the cable which
goes from the soundcraft board to the PSU (a grey cable) is just clipsed to
the circuit of the PSU : you can cut the cables and directly solder them to
the 4 iron "sticks".
Same thing for the connections between the radiator and the circuit.

as the radiator is very hot don't put the PSU in a cabinet (thanks Gareth)
=)

that's it. i had 2 days of hard time repairing it... don't forget to test
every connection on the circuit with a multimeter (when PSU is turned OFF
and unplugged of course) : the circuit is old and dirty ...

don't hesitate to mail me if help is needed. i'll try even if i'm really not
an electronician -but i spent 2 days on the beast so...
ttam
reverse everything to mail me

matthieu =)

In article , Croline
wrote:

hello

(first of all sorry for my english...)

i sent you the schematic, and i crosspost here for those who may be
interested. if you want to repair your CPS 150 i can give you this advice :
just unmount the main circuit. look at the soldered side : you'll see some
brown parts, the circuit is burning are some places. all the components at
these brown places needs to be renew. it won't be expensive it just take a
little time. (some repair shop would have take me 120$ to do the work and 10
long days, i did it all myself and it did cost me 3$ for the components -2
bridge rectifiers, one resistance, one black thingy -im not an
electronician-)

you must especially renew these 2 bridge rectifiers, it seems you can
replace them with stronger models (ask your electronic dealer if it's ok).

another thing you can do (that Soundcraft did advise me) : the cable which
goes from the soundcraft board to the PSU (a grey cable) is just clipsed to
the circuit of the PSU : you can cut the cables and directly solder them to
the 4 iron "sticks".
Same thing for the connections between the radiator and the circuit.

as the radiator is very hot don't put the PSU in a cabinet (thanks Gareth)
=)

that's it. i had 2 days of hard time repairing it... don't forget to test
every connection on the circuit with a multimeter (when PSU is turned OFF
and unplugged of course) : the circuit is old and dirty ...

don't hesitate to mail me if help is needed. i'll try even if i'm really not
an electronician -but i spent 2 days on the beast so...
ttam
reverse everything to mail me

matthieu =)
I have one of these as well. do they all bun out? now i'm scared. I do
have it in a completely open rack (sides back and bottom) maybe that's
why mine hasn't burnt yet? can you post a link to the schematic on the
group please?

I have one of these as well. do they all bun out? now i'm scared.

it seems a lot have the same problem because
1 - it's old (mine is 11 years old)
2 - some components aren't enough "powerful" and the soundcraft board
requires much power

if you have some time open it, unmount the main circuit and check the
soldered part : if some parts are quite brown then you'd better consider to
renew the concerned components.

the schematic :
http://perso.wanadoo.fr/canichesnoirs/schematictop.jpg
http://perso.wanadoo.fr/canichesnoir...aticbottom.jpg

(will be up in a few minutes)

matthieu

As a repair tech, I would agree with Mattieu here. Sometimes the bridge
rectifiers get hot and discolour the pcb. Eventually this may lead to dry
joints which will make the psu fail, or the bridge rectifier itself may blow
If your psu has got to this stage and you feel confident enough, I recommend
you replace the bridge with the highest voltage and current spec device in
this package you can get, and you will probably need to reinforce the tracks
as they will be coming off the pcb by now. Scrape off the etch resist
coating, polish the exposed copper tracks with a wire or glass fibre brush,
then you'll be able to solder wire over them to make them strong enough to
support the new bridge rectifier. Mount this fairly high off the pcb so as
litlle heat as possible goes back to the pcb.

If you are not so good at soldering I would let someone more experienced do
this or you may end up with a less reliable unit than when you started!! Be
sensible.

Gareth.



"Croline" wrote in message
...
I have one of these as well. do they all bun out? now i'm scared.


if you have some time open it, unmount the main circuit and check the
soldered part : if some parts are quite brown then you'd better consider
to
renew the concerned components.

[geecoast]

Mr Klein
I spotted your conversations about the Soundcraft Spirit studio. I am a design engineer who happens to be repairing a CPS150 power supply. You mentioned replacing R32 with a 2K7 resistor. That is fine...but note that it is dropping 3/4 watt of power...so you need to either fit , say, a 3 watt type or alternatively wait for it to burn out again (cos it will!!!) . This is in fact a minor design fault. They use a TL783 high voltage IC regulator which needs to drop 16 mA at its output in order to be stable....so soundcraft fitted 82 ohms as top resistor and 2K7 (with a trimpot in series) for the bottom resistor. This bottom resistor has approx 45 volts across it so draws the required 16mA but 45 X 16 =720 mW.
Also in this thread someone said the bridges will die....so true but if you upgrade them...fit them to the case metalwork using extension wires cos they too will just die again eventually otherwise (they exceed the package dissipation figures) best ones are International Rectifier "glass passivated" bridges. Shame the power supply lets down a fine mixer. I am in UK at www.coastelect.com if anyone wants to contact me re. CPS150 issues.