Hi all first post so apologies if i've missed an intro thread my issue is this: i have 616 which was displaying the hdmi fault, so i removed the pcb attempted to reflow chip rechecked no change i then attempted a second time this time heating for a longer period after this a new problem came up when the amp was plugged in the 9v relay on the power supply pcb just clicked constantly and not power up. So i thought i may have caused a short on the board and the unit was going into a protect state, i checked the pcb over could not see anything obvious i then removed dts chip completely and reballed, before resoldering i connected the pcb back up to the amp same fault (9v relay clicking). Im now at a point were i have refitted the chip and the power fault is still present. I have also just had the ribbon cable from the psu connected with no other connection to the pcb and the fault was still present. Any help would be gratefully appreciated
I'm in the same boat with an older unit. On mine the HDMI iC was overheating. Before I have touched it, it was working, except the HDMi part. After I have replaced two times the HDMI IC(different IC), all I'm getting, is this relay constantly clicking. I was suggested to replace the relay, the resistor before it and a transistor. I haven't had time to do this job yet.
On the vertical power supply board connected to the power cable there is a relay that is responsible for turning power on to the system when it receives a signal from the Main CPU. Onkyo uses a 1/2 watt 150ohm resistor (R9015) in this circuit to bring the voltage down to 9V and in my experience (I have fixed 5 or 6 systems with this problem), what happens is that this resistor begins to degrade causing the failure of the relay, a diode (D9011) and a transistor on the HDMI board Q7016. If you simply change out the relay, diode and/or the transistor, the system will work for a short time but they will blow again unless you change that resistor as well.
This circuit has VERY LITTLE tolerance for resistor degradation. I have measured the resistor at 146 ohms and found that it would still blow the transistor and diode so I now use only 1% tolerance resistors to fix this issue.
Sorry my bad i meant JL901A connector the relay engages when pins 1 and 3 are shorted, i have removed power pcb and will test it separately, so if i was to input a 12vdc between pins 1 and 3 of the JL901A connector the relay should stay on, would this be enough to confirm the problem is elsewhere ?
Last Edit: Sept 9, 2019 3:49:42 GMT -5 by beagle39
That relay is a 9V so simply place a 9V battery across its leads to test it. You will still have to check that diode though.
The way this circuit works is that when the Main CPU sends the signal to turn on that relay, Pin 126 goes high. This drives a couple of things but in this circuit, it applies power to the base of a prebiased NPN transistor which turns it on allowing current to flow from the collector through the emitter to ground. On the other side is a 12V supply line connected to a 150 ohm resistor which (now that it has a source to ground) brings the voltage down to 9V. This in turn allows current to flow through the relay turning it on. BUT, Onkyo installs a small diode in the reverse direction to protect the Main CPU (and in theory that transistor though it often blows when hit with reverse current). My current theory is that when that resistor drops below 146 ohms, it increases the voltage/current just enough to blow this diode (and often the transistor) causing the symptoms you are seeing. Essentially, the MAIN CPU is trying to turn on but is sensing a reverse flow of electricity coming from the transistor and immediately shuts down to protect itself.
You can bridge anything you like but understand that if you force this circuit on and it blows that MAIN CPU, you are screwed. That CPU has internal flash and can only be replaced if you have the correct flash programmer (and of course, the code for an NR616). Oh yeah, Renessas (who makes this CPU) won't sell it to you. I have tried ordering it through Mouser and Digikey and the answer is a flat out "NO".
When you bridge pins 1 and 3 on JL901 you are essentially bi-passing the transistor and applying ground directly to the relay/diode allowing the flow of electricity through the relay. This doesn't tell you if the diode is bad but it is a strong indicator (to me) that the transistor is blown. These are pre-biased transistors so there is no easy way to test them. Fortunately they are cheap so replacing it is the easiest option. As I said before, if the resistor has degraded it usually damages the coil in the relay, the diode as well as the transistor so if you don't change them all, expect it to happen again.
Last Edit: Sept 9, 2019 7:20:13 GMT -5 by tjmotter
Measure the resistance across the coil of the relay as well. The datasheet says it should be about 324 ohms +- 10%. If it has drifted too far off of this consider it damaged and plan to replace it. If you try to measure it while on the board note that the diode (and a capacitor) sit across those two contacts so you may have to test it in both directions.
If it isn't the power circuit, it is most likely a component that has failed into a short on the HDMI board. Time to do some deeper diags on the board. I would suspect that the SII part is the most likely culprit so to check this, can you take a measurement of the resistance at TP8303 to ground as shown in the attached picture? TP8303 is the 1.2V rail. In my experience, the resistance of this line to ground is a good indicator of the health of the HDMI chip.
I took this from a working board and as you can see it shows close to 500 ohms. I would consider this to be a perfect board. I have another that reads 335 ohms. This one works but the chip is showing signs of wear. Anything under 200 ohms I would consider garbage.
Last Edit: Sept 18, 2019 15:42:06 GMT -5 by tjmotter
300ohms is high enough that it shouldn't be causing the continuous restart but it is low. A brand new part should read over 700ohms. It is possible that it is failing into a short as soon as power is applied. I would install the board in the system, place a probe on that test point and turn on the system to see if you are getting 1.2V.
Measured test point powered its fluctuating between 0 and 0.5vdc as the relay opens and closes , if the 3 way cable is not connected to JL801B i'm reading 1.3vdc @ the test point and no clicking relay, not sure this information helps but found by accident by forgetting to connect
lfcfan: Hi Todd, have been reading endlessly about the topic, and I really don't think that I'll be capable to 1. do the job myself as I don't have enough of the right equipment, and it looks like only the people who have access to TI exclusive distribution networ
Apr 9, 2020 17:17:06 GMT -5
skydronelink: Thank you I advance
Jan 29, 2020 4:01:41 GMT -5
skydronelink: Hi Repairaj, I have the same issue, but I am not able to get the cap value, I can tell it is the same board but deffirent rev cause of the side CAP is not the same value ! any idea how I can get the right burnt cap value?
Jan 29, 2020 4:01:31 GMT -5
skydronelink: Hello Jerme, thank you for the those images, is there is any chance to get the C2 (Cap) value or an image for it ? Thank you in advance.
Jan 27, 2020 23:15:06 GMT -5
skydronelink: Hello Sergio, I have the same issue, but I am not able to get the cap value, did find out what is the cap value?
Jan 26, 2020 18:01:17 GMT -5
jbmeyer13: Wolfy's Marquee isn't working? Did you spill a pint on it and short the MB?
Apr 25, 2019 8:32:28 GMT -5
wolfman: Always the same sarkasm Kurt that's why I never checked in until now. I knew you wouldn't give me a cheerful answer so let you hang for a while. Removed the last part you probably are a decent guy Eye to Eye.
Apr 19, 2019 18:55:30 GMT -5