CurtPalme.com Home Theater Forum

km987654 · Posted: Sat Feb 28, 2009 10:37 pm Post subject: RGB Output Amp R7621735

These amps seem to fail regularly in my PJ they just lose all gain.

Do these amps just fail or is there something else that can cause them to fail?

They run the VPH06 chip.

Tom.W · Joined: 09 Mar 2006 Posts: 6635

Are you replacing the VPH06 or swapping boards ?

Could be poor heat transfer.

https://www.curtpalme.com/forum_archived/viewtopic.php@t=15126.html

What resolution and refresh rate are you using ?

km987654 · Posted: Sun Mar 01, 2009 7:00 am Post subject:

I have replaced the board to recover from this problem. I do have some VPJ06 chips to replace the VPH06 chips on these boards but I started thinking that the number of failures is high and always the same thing, the amp loses gain. I know there are streaking problems with this amp but should it fail so frequently I have lost 4 amps in about the same number of months. I have used both the 7621735 and 762173 both with the VPH06 chip and both fail the same way. So either this type of amp is prone to failure or perhaps something else in the PJ is causing them to fail.

These amps have the large metal heat sink that wraps around the entire board and they are cooled by two overhead fans so heat should not be a problem. Although I can't tell if the compound has gone hard so I will pull some apart and check this.

Tom.W · Joined: 09 Mar 2006 Posts: 6635

Are they all failing on the same tube ? I haven't lost one in all of ten years using my BD 808.

The Sanyo spec sheet...

km987654 · Posted: Sun Mar 01, 2009 7:45 am Post subject:

You know I can't recall. When they first started to fail I moved amps around and I have lost track. The current failure is on red.

Tom.W · Joined: 09 Mar 2006 Posts: 6635

Just something I remember reading...

http://archive2.avsforum.com/avs-vb/archive/index.php/t-649506.html

km987654 · Posted: Sun Mar 01, 2009 8:26 am Post subject:

Thanks for the link some very interesting information indicating a lot people were interested in changing chips to improve bandwidth.
A project I am considering is putting the 120mhz neck boards from an bg808s in my PJ. This involves a lot of physical changes to the PJ and I didn't want to do this to simply destroy the amps because something is causing them to fail.

Tom.W · Joined: 09 Mar 2006 Posts: 6635

http://archive2.avsforum.com/avs-vb/archive/index.php/t-503870.html

Time to go to sleep!