Pioneer VSX-1122K won't turn on - Page 1
Forum section: electronics / repair

author: tibimakai
author_rank: Contributor
timestamp: September 17, 2014, 08:11:08 pm
content: Hi everybody.I have picked up this receiver from Ebay, with the idea to repair it. I have managed to repair a couple receivers this way, but this one is way over my head.I'm not an expert, I'm doing this as a hobby and a slight money source.It seems dead if I push the power button.I have managed to find a service manual from elektrotanya under Pioneer VSX-60.http://elektrotanya.com/pioneer_vsx-60.pdf/download.html(under the picture, will apear a Get manual after a while)By resetting it, it will turn on and it will display Power on and it will stay this way indefinitely.I have tried forcing a firmware update, did not react to that, I have measured some voltages, they seemed right, like SMPS output 5.6V is there, +/-12V, +/-5V, +/-56V, -23V FV are there.If I reset it, then there is a 4.2V at RAC at C9501 connector on the HDMI board(D-main) coming from the SMPS board. I assume, that is the power on voltage.Final transistors are not shorted. Each amp has a test connector, at pin #3 which is the point between the two final transistors, I'm measuring 0.020-0.30V. I don't know how much should it be there.After reset, there is only one relay click(SMPS standby), the speaker relays do not click at all.Any ideas on what should I check next?

author: tom66
author_rank: Super Contributor
timestamp: September 17, 2014, 09:32:03 pm
content: Check the PROTECT signal (or similar) which could be labeled PRO or PROT. Usually a HIGH will indicate protection triggering: shorted output (overcurrent etc.) or bad transistors. (0.3V is quite high - though usually not enough to trigger it, the limit is usually around 2V.)

author: tibimakai
author_rank: Contributor
timestamp: September 18, 2014, 04:21:45 am
content: Hi Tom, we meet here too? At badcaps, nobody is helping me, so I have tried here.It's 0.020-0.030V and not 0.2V.I will look into that protect, thank you for the idea.It's very hard to measure thing in this receiver, to be able to remove the D-main and other boards, I would need some extender ribbon cabels, which of course I don't have.I have tried by removing the back cover and placed some grounding wires at each board, but it would through an error code(FL light LED would blink.I see another receiver with the same problem on Ebay. I have aked that person, on how did this happened, but he never answered.I'm just hoping that is not the D main board is the problem, because that board is like $545.

author: tibimakai
author_rank: Contributor
timestamp: September 19, 2014, 03:00:18 am
content: On page #35, there is a Temp protection circuit, where are two pins at IC3004, one is #72 and the other is # 81.On pin #72(TR_Detect/Normal 5V and TR Thermal 0V) I'm measuring 4.22V and on pin #81(TEMPSD5/Normal 5V and RADI THERMAL 0V) I'm measuring 5.027V. This look good.Not sure about that 4.22V it's not 5V though.Another protection circuit is the Overload and DC protection circuit. It's on page #33.There are two pins, that I should measure, pin #71(XOLERR) and pin #80(XDCERR).At pin #71, I'm measuring 4.405V and at pin #80, I'm measuring 4.865V.I don't know, how much these should be, but since the V+5V_ST is 5V and these voltages are after two resistors, they seem right no?

author: tibimakai
author_rank: Contributor
timestamp: September 19, 2014, 03:05:49 pm
content: I have forgot to mention, that all this was measured with the receiver plugged in and was not turned on(reset).

author: tibimakai
author_rank: Contributor
timestamp: September 20, 2014, 09:06:05 pm
content: Nobody can help?

author: tautech
author_rank: Super Contributor
timestamp: September 20, 2014, 09:21:04 pm
content: Many higher power amps have output protection that will be displayed as PROTECT or similar in a fault condition.Ensure your speakers meet the amps requirements and are connected at power on.I have one that will go to Protect in high humidity....I should give the PCB a clean.

author: tibimakai
author_rank: Contributor
timestamp: September 20, 2014, 09:33:31 pm
content: Thank you, for your reply.The receiver, should work without any speaker connected to it, no?Without resetting it, it seems completely dead.What do you think, about the overload and DC voltages, that I'm measuring, they are tripping the protect mode or they are fine?I'm not an experienced repairman, but I think that they look good and I may have some software issue. How could I check that? If I could load a new firmware, somehow.I have repaired a while back a 1022k, which had rusted standby relay(sealed). That one it was dead too. Since than, Pioneer switched to a different relay(with cover). It was a Denon part number, so Denons can have these bad relays in them too.

author: tautech
author_rank: Super Contributor
timestamp: September 20, 2014, 09:44:27 pm
content: Quote from: tibimakai on September 20, 2014, 09:33:31 pmGet a User manual too, it should give advice on speakers.I normally suspect hardware not software.Study the Protect circuitry and understand how it works/triggers.I'll try to study the schematic too when I have some time.

author: David_AVD
author_rank: Super Contributor
timestamp: September 20, 2014, 10:41:24 pm
content: Occasionally you'll see a hi-fi amplifier in protect mode where the fault is the CPU itself.

author: tibimakai
author_rank: Contributor
timestamp: September 20, 2014, 10:44:03 pm
content: If the CPU would be damaged, it would still be able to be turned on, by resetting the receiver?

author: 4thDoctorWhoFan
author_rank: Regular Contributor
timestamp: September 21, 2014, 02:34:20 pm
content: Do you get any DC voltage at the speaker terminals?Disconnect the speakers, attach a DC voltmeter to either the right or left output speaker terminal. Put the volume a minimum and turn on the stereo. Try both the right and left speaker terminals. Do you get any DC voltage? If you get anything more than 100 millivolts you have a problem with either the output transistors or the driver transistors and associated circuitry.

author: tibimakai
author_rank: Contributor
timestamp: September 21, 2014, 07:24:43 pm
content: The receiver does not turn on at all. Only if I reset it.

author: David_AVD
author_rank: Super Contributor
timestamp: September 21, 2014, 09:05:04 pm
content: Quote from: tibimakai on September 20, 2014, 10:44:03 pmYes, I've seen CPUs with weird issues. Not saying that's it's the case here, but it's possible. You should eliminate other causes first.

author: tibimakai
author_rank: Contributor
timestamp: September 24, 2014, 04:44:39 pm
content: In the service manual, there is a chart for troubleshooting, no power issue and I went through that.All seemed fine, but the last step. I have an oscilloscope, but I don't know how to use it properly.There are two waves in the manual and I don't know how to get them.No matter what I'm trying with the scope, I'm not getting those waves.Any help would be appreciated.https://www.dropbox.com/s/dr3x2h5jfvytab4/Document.rtf?dl=0

author: tibimakai
author_rank: Contributor
timestamp: September 24, 2014, 09:27:38 pm
content: This is the micro controller LC87F5NC8A, which is located on the front assembly.Can anyone help me to check this IC, if it's any good? Specially the scope measurements(there are two waves in the SM at troubleshooting no power chart).I can't get those results, no matter what I try with the scope.http://www.onsemi.com/pub_link/Collateral/LC87F5NC8A-D.PDF

author: jlmoon
author_rank: Unknown
timestamp: September 24, 2014, 09:48:45 pm
content: 80 - 90% of failures in these receivers are due to output overload protection relay circuits keeping DC (from shorted outputs , drivers or differential amp shift) from being applied to the speakers in turn burning up the voice coils. I would do a complete check of the Power Amp area and then secondary check the other regulators that provide power to control, RF, IF amps and such. Included in the 80 - 90 % failure are these regulators being that Pioneer is famous for driving them with way too much voltage and not providing enough heat dissipation. Look these areas over good for open current limit resistors .. etc.

author: tibimakai
author_rank: Contributor
timestamp: September 24, 2014, 10:28:51 pm
content: Final and pre final transistors and resistors are all good. I have checked the power sources and they all deliver what they suppose too.But I will look again, maybe I missed something.I have repaired a couple of receivers already and you are right, most of the time are the finals or adjacent components are the problem, then power supply ICs in Harman Kardons.Another Pioneer(1022k), had a corroded standby relay(sealed one, from 2012!!, it's a Denon part number!!).This is the first one, that it seems like has a more complex issue(not that easy to find).

author: tibimakai
author_rank: Contributor
timestamp: September 25, 2014, 05:06:54 am
content: I have found two transistors, that they don't show almost anything.These transistors have resistors in them. How would I test this kind of transistors?They are KRA103S and RT1N241C, or NTE2416 (NPN) & NTE2417 (PNP)Silicon Complementary Transistors Digital w/2 Built–In Bias 22k Resistorshttp://www.weisd.com/store2/NTE2416.pdfThese transistors, are on the IR board.I think, that I have misunderstood the troubleshooting chart.I have standby voltage, so that is yes. Next step is, if there are any error codes, they don't show, so next step is no.After this, shows other trouble.Other trouble, could mean 12V Trig which I don't have, it measures 0V. After this, shows to replace the IR board.I have started checking components and here I have found these two transistors, that don't show anything on the diode setting.

author: tibimakai
author_rank: Contributor
timestamp: September 27, 2014, 01:26:44 am
content: I have put together a good transistor and two resistors and they did not show anything either. So I assume, that those transistors are good.What could be the 12V trigger or DC 12V trigger? They should have 12V when it starts up?

author: David_AVD
author_rank: Super Contributor
timestamp: September 27, 2014, 01:41:02 am
content: The trigger output on AVRs is to turn a projector on or activate the projector screen. You associate it with one of the inputs and it activates when that input is selected.

author: tibimakai
author_rank: Contributor
timestamp: September 27, 2014, 01:43:34 am
content: Thank you.Any ideas, on what else could I check, at least to find the bad board?