roland kc-500 amp repair

[54bassman54]

new to the forum{ my first post } so sorry if this post is in the wrong area.

need a schematic for roland keyboard amp kc-500. users amp was fried by 120vac on the direct out. some traces burned, several resistors fried and no way to tell values.

any advice will be appreciated.

54bassman54

[Enzo]

Hi and welcome.

I don't have that one, maybe someone else does. This board tends to be mostly tube guitar amps, with a few of us willing to get into solid state stuff.

Two other resources come to mind. Try ther forum at Keyboard mag, maybe someone there would have it.

Otherwise, bite the bullet and pay for the service manual from ROland.

[54bassman54]

Hi and welcome.

I don't have that one, maybe someone else does. This board tends to be mostly tube guitar amps, with a few of us willing to get into solid state stuff.

Two other resources come to mind. Try their forum at Keyboard mag, maybe someone there would have it.

Otherwise, bite the bullet and pay for the service manual from ROland.

thanks for the reply, and quite a bullet it is. i contacted roland several months ago about the manual for this amp, and i was told 10$. the owner finally got it to me after several months, and i contacted roland again, expecting to pay the $10, which is what i told the owner it would cost. roland now wants $35, claiming that "ink to print these manuals is very expensive". kind of a hard pill to swallow, especially with that attitude.

thanks again and i will try the places you suggested.

[SPARESROLAND]

Hi Bassman

Do you have an email address where I can send a pdf copy of the KC500 amp?

Very best regards
Steve

[54bassman54]

thank for the assist. my email. is 54bassman54@gmail.com

best regards,

michael

[Enzo]

Hi Steve, thanks. You are welcome to post documents right in the threads, unless that violates some company policy at your end. pdf files up to about 2MB can be put right in the posts.

[fluxmov]

Hi Steve,

could you perhaps send the PDF to my address (mackie@4m4e.de) as well?
Our school band's KC 500 died last year and I'd like to revive it very much :-)

Best regards,
Daniel

[Bruce / Mission Amps]

Surprisingly, out of nowhere yesterday, I also have a KC-500 in for a repair... it would be nice to have a copy myself, although I suspect this is going to be a blown speaker. Regardless, I always appreciate having proper documentation for mass produced equipment.

[fluxmov]

Hi Steve,

thank you very much for the service manual.

Very best regards
Daniel

[cmolica]

Roland KC 500 service manual

Hi Bassman

Do you have an email address where I can send a pdf copy of the KC500 amp?

Very best regards
Steve

Hey Steve may I jump on this bandwagon too?

I've got 40v coming out of the power supply into the board and I dont think thats good.

cmolica@comcast.net

THANKS!!!!

[km6xz]

If you do not have it yet, I posted it to my new unfinished web site for my new unopened pro audio repair shop:
http://www.sound-pros.com/tech/roland_kc-500_[ET].pdf
It is 8megs so too big to post here.

Isn't the internet great! In my old shop I had a room just full of file cabinets for service manuals and information that was hard to find back then, Now with file sharing and sites offering the manuals or schematics, I feel better about starting a new shop after 8 years of absence without the treasure trove of manuals. There are few legacy pieces of gear here so the old information would be less important anyway and new gear often not having any service information for a while it looks like I'll be doing a lot of design analysis and reversing engineering even with simple repairs.

[cmolica]

Roland KC 500 Transformer

Hi I got the schematic of the main board but cant determine:

A) what is the output voltage of the transformer

B) Where to buy a replacement if it is bad.

I get 117v coming in and 40.3 coming out AC.

HELP!

[km6xz]

That sounds about right. Why do you suspect the transformer? Are you getting 45-54volts DC on one side of R201 and 20-30volts to ground on the other lead of R201, and the same on the two leads of R202?
What are the symptoms according to the customer? Don't replace any parts until proven defective, especially the expensive transformer.

[km6xz]

How did 120VAC get inserted into the direct out? What are you referring to when you say "direct out": Line Out, Speaker out, Phones Out?

[cmolica]

Wow thanks for the help.

All good points.

It turns on but no sound.


Its getting 57 Volts on the left side of R201 and 40.1 on the right.

Its getting 57.2v on the left side of R202 and 51.7 on the right.

do advise.