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Post by Deleted on May 31, 2021 11:27:07 GMT -5
Latest addition to my AVR collection is a Pioneer SC-LX56, acquired for next to nothing with no audio output but no error message displayed. DSP part of the firmware version was showing * * * so that pointed to the usual TI chip problem.
I replaced both IC9002 and IC9702 (2 x DSP model) with the 'D' variant chip but still no audio out - at least they're normal leaded devices and not BGAs, so soldering them in wasn't too bad apart from the big ground pad underneath, which needed some solder paste and careful use of a heat gun.
I couldn't find a firmware dump for IC9004 or IC9703 online but decided to remove them and read the contents to see if they looked corrupted or were just blank like my VSX-2021 was. IC9004 was blank from 0-10000h, which it shouldn't be but IC9702 looked ok. I compared 0-10000h from IC9702 to the same address range from a working VSX-922 file I have (same DSP chip and year model) and found this was almost identical apart from 2 bytes. Armed with this discovery I copied 0-10000h from IC9702 and pasted it into the blank area in IC9004.
After refitting the two flash chips, there was still no audio out and the * * * remained in the firmware version but I now had UE22 flashing on the front display. I tried a full firmware update via USB and it installed 100% and the unit burst into life.
£1300 9 channel receiver bought and fixed for £65 all in... that'll do nicely thanks to Pioneer and TI.
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Post by tibimakai on Jun 1, 2021 11:00:41 GMT -5
Great job!!
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Post by Deleted on Jun 22, 2021 8:01:52 GMT -5
Having got the SC-LX56 working I realised the firmware in the two DSP flash chips will be the same as the high end models LX76/86.
I've now got my sights set on a (UE22 failure) SC-LX86 as the next 'project' upgrade.
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Post by Deleted on Jul 9, 2021 12:18:28 GMT -5
I didn't have to wait long for a UE22 faulty SC-LX86 to pop up on eBay, or pay much to acquire it... two new DSP chips and a reload of the DSP firmware and it's taken the the place of it's sibling SC-LX56. £2200 receiver for £42.99 - very nice it is too! Surely I can't be the only one bothering to fix these superb, if slightly dated bits of kit??    |
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Post by mastertech on Jul 12, 2021 9:27:35 GMT -5
Very nice work.
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Post by tibimakai on Jul 12, 2021 10:34:38 GMT -5
Tjmotter used to be the expert with these issues, but on Onkyos, but I believe he quit working on Onkyos(this hobby).
I have never learned how to deal with the software side. I only deal with amps/preamps and some HDMI issues(replacing the HDMI ICs).
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Post by dobrykamil on Jul 14, 2021 13:53:37 GMT -5
Hi
Have you tried reloading fw first? Do you have to replace DSPs every time?
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Post by Deleted on Jul 14, 2021 14:29:43 GMT -5
I always remove the 8 pin flash memory to check if it's been corrupted before condemning the DSPs. It's much easier to fix that than remove and replace 176 pin QFPs.
I've fixed three SC-LX models now and all of them needed new DSP chips as well as the firmware reloading in the 8 pin flash memory. The VSX-LX models with BGA DSPs often work after being reflowed but can also need the flash memory correcting.
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Post by dobrykamil on Jul 14, 2021 14:52:15 GMT -5
I always remove the 8 pin flash memory to check if it's been corrupted before condemning the DSPs. It's much easier to fix that than remove and replace 176 pin QFPs. I've fixed three SC-LX models now and all of them needed new DSP chips as well as the firmware reloading in the 8 pin flash memory. The VSX-LX models with BGA DSPs often work after being reflowed but can also need the flash memory correcting. Thanks for your prompt reply. Can you still buy genuine Ti DSPs? If so, are you getting them from Aliexpress? |
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Post by Deleted on Jul 14, 2021 16:14:03 GMT -5
I bought my DSP chips from a China based supplier on eBay. They look genuine and all work fine so far. The SC-LX86 is in daily use now because my tv is a Panasonic Pro plasma display and doesn't have any built in speakers.
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Post by Deleted on Jul 15, 2021 6:34:04 GMT -5
Tjmotter used to be the expert with these issues, but on Onkyos, but I believe he quit working on Onkyos(this hobby). I have never learned how to deal with the software side. I only deal with amps/preamps and some HDMI issues(replacing the HDMI ICs). I think Tjmotter was far better qualified than me to sort out software issues on these receivers. I didn't have a lot of luck with Onkyo ones I worked on due to the DSP chips being harder to get. The firmware issues on the Pioneers I've fixed have mainly been a case of copying a firmware dump from a working unit after replacing the DSPs. I got lucky with the SC-LX models as they have 2 identical DSP chips and 2 separate flash memory chips. It was only part of the primary one that got corrupted, so I was able to copy that from the secondary. A fair bit of trial and error was involved but if it doesn't work, you don't have much to lose. Once I get them working and updated to the latest firmware, I remove the flash chips to read back the known working firmware for any future repairs. |
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Post by tibimakai on Jul 15, 2021 10:31:12 GMT -5
You are reading and writing only the flash chips, right? You are not dealing with the microcontroller, right?
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Post by Deleted on Jul 15, 2021 11:05:01 GMT -5
You are reading and writing only the flash chips, right? You are not dealing with the microcontroller, right? That's correct... For most of the Pioneer AVRs I've repaired, they either started working after re flowing the BGA DSP or replacing the QFP DSP but most have needed the associated flash memory chip removing, erasing and reloading with a file dump from a working unit. I couldn't find any info on doing it by talking directly to the micro and using the main firmware update file from Pioneer to correct the problem, so I had no choice but to de solder the chips and put them in my programmer. Fortunately they are just 16Mb or 8Mb 8 pin devices that are easy to remove and re fit.
More recently I replaced the TSOP48 1Gb NAND flash used by the SC-LX56 media controller as I was having trouble with it becoming slow to respond to front panel and remote commands after a week or so of use. It would eventually freeze altogether, requiring a factory reset. I figured this might be due to bad blocks in the NAND but it tested OK on removal. I read the contents and copied it to a brand new device, so only time will tell if this has cured the problem. There is also a 64Mb NOR flash used by the main micro, which may also be responsible for this issue but from what I've read the NAND is more likely to fail over time.
The sluggish/freezing up problem was quite an issue for Pioneer on these models from what I've read online and it often happened to fairly new units. I've not found anyone who came up with a fix for it other a warranty replacement unit from Pioneer. The only other anomaly I noticed on my unit was neither the NOR or NAND device was the same make or part number listed in the service manual. The NAND in mine was SKHynix and the manual shows a Toshiba part, while the NOR in mine is a Spansion and the manual shows a Macronix one. The Spansion part isn't supported by my programmer, so I have left it alone for now. The firmware in that isn't common to the SC-LX86 like the media controller, so I would like to be able to read it at some point if only to make a backup in case of failure.
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Post by Deleted on Jul 15, 2021 13:33:49 GMT -5
The QFP DSP chips are easier to replace than BGAs in my opinion but they still have their issues. There is a ground tab under the chip which requires quite a lot of heat to get off the board.
I use a scalpel to cut the legs around the chip body first and remove them from the board with tweezers and a fine tip iron. Then heat the centre of the chip with a hot air gun for about a minute to free it.
Once the board is cleaned I put solder paste on the tab of the new chip and the centre pad on the board and position it to solder down. Once all 176 pins are done, I heat the centre of the chip to flow the solder paste underneath.
I found this takes about 90 seconds to achieve a good joint. Any less than this and the chip doesn't power up and the receiver continues to show UE22.
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Post by holtphoto on Nov 7, 2021 7:34:59 GMT -5
Hi am new to the forum!
My aim in joining is that I have purchased a Pioneer SC-LX56 with the error code you have spoke about. For £80 free postage how could I not..
My question is I have nil knowledge on anything to do with fixing this amp😂
Is it an easy fix? Is it worthwhile trying to fix this by myself.
Kind regards John
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