Help with Yamaha Pro-Amp

Netlist · 10th April 2003, 04:23 PM

Hi,

Anyone here has experience with or a schematic of a Yamaha PC1002 PA amp?
At switching on, the amp goes immediately in protection.
Output transistors ok. Bridge rectifier ok, voltage remains long enough at PSU-caps. No resistors burned.

/Hugo

OliverD · 10th April 2003, 05:37 PM

Have you checked the amp's output before the speaker relay? If there is not too big an offset, probably something is wrong with the protection circuit itself.

Sorry, no schematic, but I don't think you really need one to fix an amp.

Netlist · 10th April 2003, 07:58 PM

Thanks for the reply.
The amp shuts off immediately, so it's not possible to measure anything. Basically, a schematic would be handy to debug the protection circuit or to find out if and where it could be disabled. (Saves a lot of time).

/Hugo – will debug it anyway.

Netlist · 11th April 2003, 08:30 AM

The mains switch was broken.
Thanks for the help

/Hugo

10th April 2003, 04:23 PM	#1
Netlist diyAudio Moderator Emeritus Join Date: Jan 2003	Help with Yamaha Pro-Amp Hi, Anyone here has experience with or a schematic of a Yamaha PC1002 PA amp? At switching on, the amp goes immediately in protection. Output transistors ok. Bridge rectifier ok, voltage remains long enough at PSU-caps. No resistors burned. /Hugo

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Yamaha AX-930	jleaman	Analogue Source	6	21st November 2010 11:43 AM
Yamaha cdx 900	stex	Digital Source	4	23rd January 2010 11:44 AM
Yamaha RX-777	quasi	Solid State	4	15th November 2007 12:58 PM
Yamaha A-550	angel	Solid State	4	18th January 2006 01:22 AM
Yamaha CDX-490	newbie123	Digital Source	1	3rd December 2005 03:31 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

10th April 2003, 05:37 PM	#2
OliverD diyAudio Member Join Date: Nov 2002 Location: Germany	Have you checked the amp's output before the speaker relay? If there is not too big an offset, probably something is wrong with the protection circuit itself. Sorry, no schematic, but I don't think you really need one to fix an amp.

10th April 2003, 07:58 PM	#3
Netlist diyAudio Moderator Emeritus Join Date: Jan 2003	Thanks for the reply. The amp shuts off immediately, so it's not possible to measure anything. Basically, a schematic would be handy to debug the protection circuit or to find out if and where it could be disabled. (Saves a lot of time). /Hugo – will debug it anyway.

11th April 2003, 08:30 AM	#4
Netlist diyAudio Moderator Emeritus Join Date: Jan 2003	The mains switch was broken. Thanks for the help /Hugo