Inge, I already joined and asked the question for you. Here's the reply I got: In article <[log in to unmask]>, steve <[log in to unmask]> wrote: > I'm hoping that there may be somebody with a 5 channel amplifier Yamaha > DSP A-990. I like my old machine, 6 years old, a fantastic sound and > video processor. Happened to short the outputs and blew most of the 14 > power darlington transistors. I have repaired with newer equivalents > and all e-c-b voltages are OK, but 5 seconds after start, there is a > safety relay that switches power off. I can't figure out why and what > the sensors react on. Usually looking for a DC offset to protect the speakers. Maybe also oscillation. A scope should tell all. -- *Money isn't everything, but it sure keeps the kids in touch * Dave Plowman [log in to unmask] London SW Maybe Dave can help you out a little more? -Steve- -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Hfjord Sent: Monday, November 06, 2006 2:00 PM To: [log in to unmask] Subject: Re: [TN] NTC:is there a audiofil out there? Thanks Bruce, I will try that one, seems to be a cosy and useful 'club' . I knew I'd get help through TN! The width of knowledge and wisdom is immense within this group. Maybe thanks to Mr Yoda? Inge ----- Original Message ----- From: <[log in to unmask]> To: <[log in to unmask]>; <[log in to unmask]> Sent: Monday, November 06, 2006 2:57 PM Subject: RE: [TN] NTC:is there a audiofil out there? Ingemar - Throw up a posting on http://groups.google.com/group/sci.electronics.repair. You'll have to register w/the group in order to post, but there's a good chance someone there will be able to help you out. Bruce Tostevin -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge Sent: Thursday, November 02, 2006 5:26 PM To: [log in to unmask] Subject: [TN] NTC:is there a audiofil out there? Hi all, just taking a chance, 1,000 TNetters, among all there may be somebody with a 5 channel amplifier Yamaha DSP A-990. I like my old machine, 6 years old, a fantastic sound and video processor. Happened to short the outputs and blew most of the 14 power darlington transistors. I have repaired with newer equivalents and all e-c-b voltages are OK, but 5 seconds after start, there is a safety relay that switches power off. I can't figure out why and what the sensors react on. Complicated electronics. Now I just wonder if someone happen to have such a machine and if there is also someone who have schematics. Yamaha don't not respond positively on my request, say they have no service on such a obsolete amplifier. Regards Ingemar Hernefjord SMW --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------