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Post by friedchips on Aug 22, 2022 12:32:00 GMT -5
A few months ago I bought an Onkyo TX-SR444 with the infamous no sound issue.
I am suspecting the DTS-chip as it seems like a common failure points with Onkyo receivers from this era but I'm not sure how to confirm it.
When checking the firmware version it reports a bunch of garbage when looking at the DSP version.
At first it started with no issues except no sound but after poking around, it booted to Amp Diag which spat out "NG : LCRSLSRBLBR" and "DET. PROTECT: V". When measuring VProtect at the connector of board BAPRC-1758 I got about 5V.
After this I started looking at the pre amp board (BCCLA-1734), measuring all components except the capacitors on the front and transistors on the back of the board. All resistors was at least 5% within spec and all transistors measured good except Q6030 which had a short.
I replaced Q6030 with an identical transistor (Toshiba TTC004B), put the receiver together and reset Amp Diag.
It starts and I measure 32mV on VProtect but still no sound.
My knowledge of repairing electronics pretty much ends here and I'm hoping that someone here has any ideas of how I should continue. Appreciate any help!
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Post by tjmotter on Aug 22, 2022 16:00:25 GMT -5
The 444 series came well after the DTS chip issues so this is not likely a DSP issue. From what you describe, you have a blown output channel. When the TTC004B blows you can bet that other components are gone as well. I don't have the time to dig out the Service Manual for this model but tibimakai might be able to help you. In my experience, when one of these goes, you will find multiple blown resistors (probably R5180, R6020 and R6070), at least one capacitor (C6040 and/or C5100) but I also wouldn't be surprised to find that Q5030 is bad. These part numbers come from the NR646 service manual but they are probably similar to the 444. |
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Post by tibimakai on Aug 23, 2022 10:01:14 GMT -5
When some transistors are blown, I go over on that channel and inspect each component before and after the repair, to make sure that everything is OK, I parallel measure with a similar channel.
Tj is right, 100% sure there are other blown components there.
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Post by dobrykamil on Aug 26, 2022 11:03:51 GMT -5
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Post by friedchips on Aug 30, 2022 12:28:22 GMT -5
Thanks for all the suggestions!
I will try checking the components again and flashing the DSP-chip.
Do I need to get a new one or is it possible to reflash the old one?
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Post by dobrykamil on Sept 1, 2022 14:48:58 GMT -5
You don't flash dsp chip mate, only its SPI memory chip, think it's Q3401.
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srt
Junior Member
Posts: 90
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Post by srt on Feb 5, 2023 9:48:22 GMT -5
Hi I have same model and the issue was in protection enabled but all channel was ok and I protect and v protect measure 0 volt at terminal, then I changed diodes near to the MCU which connected to I protect and v protect receiver came alive but no sound at all. DSP firmwares shows bunch of questions marked , then I programmed spi chip which got from this thread .still firmwares shows bunch of question marks , then I checked communication line between DSP and MCU all shows proper continuity,also one thing I noticed that MCU resetting the DSP in every seconds. Please help
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Post by pradeepkp on Jul 22, 2023 4:11:47 GMT -5
Hi I have same model and the issue was in protection enabled but all channel was ok and I protect and v protect measure 0 volt at terminal, then I changed diodes near to the MCU which connected to I protect and v protect receiver came alive but no sound at all. DSP firmwares shows bunch of questions marked , then I programmed spi chip which got from this thread .still firmwares shows bunch of question marks , then I checked communication line between DSP and MCU all shows proper continuity,also one thing I noticed that MCU resetting the DSP in every seconds. Please help Can you explain how to program dsp |
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srt
Junior Member
Posts: 90
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Post by srt on Aug 25, 2023 6:05:07 GMT -5
Using Flash chip programmer
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