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Post by jeremy on Dec 29, 2013 20:54:52 GMT -5
Hello everyone!
I have a Pioneer Elite VSX-09TX HT Receiver I purchased a bit ago to put together an elite system. I'm pretty familiar with repairing electronics, particularly receivers, but I have gotten stumped on this unit.
The problem initially was you could power the receiver on, the receiver displays and one relay clicks (main power relay), then immediately displays "POWER OFF" for about 6 seconds on the display. Then the unit shuts down into protection.
I opened it up and inspected the amplifier block, found the front left channel had blown and I suspected that was the cause. The N channel and P channel Fets were wide open, as were a couple of SMD resistors on the bottom of the amp board. I went ahead and replaced all the parts with genuine originals, and the receiver still has the same exact issue.
The good thing is, the new parts did not self destruct. I am honestly stuck as to where I should proceed from here. I have the service manual (Sadly easy to find vs the USER manual which was a PITA to locate) so if I can get some assistance I would greatly appreciate it.
Thanks, Jeremy W |
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Post by mastertech on Dec 29, 2013 21:37:27 GMT -5
Well look who found his way, LOL. Kinda late tonight so I will check better tomorrow. Did you check R1067 and R1072?
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Post by jeremy on Dec 29, 2013 22:15:44 GMT -5
Yep, I have Nashou to thank for that, glad to see you lurking around yet!!  As for R1067 and R1072 yes, I checked both the emitters and they were open, I replaced them with exact replacements. I should also add that I did check over the amplifier block again after powering it up, nothing opened up in the front left channel, and all the other channels FETs checked out so I didn't go much further on the others. Tomorrow sounds fine M.T. Thanks again, and glad to see ya again!!  Jeremy W |
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Post by mastertech on Dec 30, 2013 12:40:26 GMT -5
There are 2 IC type fuses on that amp board (ic1501 and ic1502). Check them next.
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Post by jeremy on Dec 30, 2013 13:44:09 GMT -5
Already checked those, they both read short on the diode scale. That was actually the first thing I checked too. I do want to ask one thing though, the FETS I bought are exact numbers and brand (international rectifier IRF9540, IRF540, N and P channel) But I noticed on digikey that the new ones have letters after them. (IRF540NPBF, and IRF9540NPBF-ND) there were a few variations of them and I bought the 100v 23A ones. Other than the letters on the end, they look identical. Also I tested the new ones on the ohm scale and in one direction they read 29meg then if you reverse the leads they read 20meg, all the other original pioneer FETS that checked out read open both directions when testing them on the ohm scale. I guess I'm just curious if that could be the reason it stays in protection? Hope that made sense!  |
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Post by mastertech on Dec 30, 2013 13:58:38 GMT -5
The added numbers are usually only newer version types of the originals. If a minor change is made in production it is given an added on number. Other times the different ending numbers are mounting types. Change 1 ending number and you will get a SM instead of a through hole.
How easy is it to get at connector CN1051 on the amp board and do some testing with it powered on?
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Post by jeremy on Dec 30, 2013 14:05:13 GMT -5
The amplifier blocks on this model are the collector of the amp itself so they have a charge on them while on, I can probably rig some tool to assist me in testing. The connection is pretty open but I have about 2 inches of space between both heat sink blocks. In other words, I am able and willing  |
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Post by mastertech on Dec 30, 2013 15:04:25 GMT -5
How about the cabling from that connector? Or the connector that cable goes to. I just need you to watch for DC on pins 1 and 2 as you plug it in and power it up and after shut down.
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nashou
Unmoderated Off Topic
Tech in Training.....
Posts: 1,239 
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Post by nashou on Dec 30, 2013 17:36:12 GMT -5
Welcome Jeremy!!!! Have fun guys! Nashou |
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Post by jeremy on Dec 30, 2013 17:36:56 GMT -5
Hey MT, sorry it took a while to get back to you. The connector is actually on a board that connects directly to the amp board so its direct, no ribbon cable. I should be able to manage it safely
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Post by jeremy on Dec 30, 2013 17:37:38 GMT -5
Welcome Jeremy!!!! Have fun guys! Nashou Thanks Nash! |
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Post by mastertech on Dec 30, 2013 18:03:31 GMT -5
Let me know what you get.
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Post by jeremy on Dec 30, 2013 18:05:15 GMT -5
okay mt, on CN1051 Pin 1 (DC) In standby when the receiver is plugged in it reads +4.65v, when powering it up it drops down to .8mv so basically nothing, Pin 2 (OL) Reads half a .5mv in standby, powered up it reads -14.5v. When powered back off Pin 1 goes back to 4.65v in standby, and Pin 2 goes back to .5mv
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Post by mastertech on Dec 30, 2013 18:26:13 GMT -5
Ok, looks like both protects are being activated so you will have to disable them and the see which channel has DC on it. To disable OL you will have to remove D1055. To disable DC you will have to see it you can bend pin 1 over in connector CN1051. If pin bend is not possible let me know and I will look further. This is easier then removing SM transistor, well for now anyways. BUT, if you think it is just the FL still causing a problem then removing R1107 will disable just that channel of the DC protect. And if it still goes protect after that we can look further.
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Post by jeremy on Dec 30, 2013 18:30:54 GMT -5
What board should I be looking on for R1107 and D1055? I don't think the amplifier board has any through hole diodes on it, only SMD ones on the bottom. It does have through hole resistors on it though.
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