Korg Electribe ER-1 mkII repair - Page 1
Forum section: electronics / repair

author: feedback.loop
author_rank: Frequent Contributor
timestamp: September 09, 2019, 12:38:17 am
content: This Korg ER-1 had a burned 5V DC-DC converter, which, most probably, killed some other important parts such as the micro-controller, DSP and memory. The DC-DC converter was repaired, but there were no signs of life, and the DSP seems to run too hot. At the moment this looks beyond economical repair.

author: Ordinaryman1971
author_rank: Frequent Contributor
timestamp: September 09, 2019, 04:55:04 pm
content: Did you price the DSP replacement? Any availability?

author: feedback.loop
author_rank: Frequent Contributor
timestamp: September 09, 2019, 08:41:48 pm
content: I see some on AliExpress for $25-30.I am afraid that having no copy of firmware, it does not make much sense to order expensive parts.

author: LateLesley
author_rank: Frequent Contributor
timestamp: September 09, 2019, 11:47:11 pm
content: What about if youcouldget firmware? It's not free though, and might make it too pricey still.http://electribe.cc/wp/about/

author: feedback.loop
author_rank: Frequent Contributor
timestamp: September 10, 2019, 02:06:21 am
content: Quote from: LateLesley on September 09, 2019, 11:47:11 pmFirst of all, this is an update to load through MIDI assuming a working machine with some sort of a boot loader in it at least. I need an image of the flash memory, which is not the same.

author: feedback.loop
author_rank: Frequent Contributor
timestamp: September 24, 2019, 04:54:52 am
content: Got myself a TSOP48 adapter for TL866 programmer.It was a part of a $22 set.To be continued...

author: feedback.loop
author_rank: Frequent Contributor
timestamp: September 29, 2019, 05:49:35 am
content: Desoldered the flash. It is alive! Now I think it makes sense to proceed. I will order replacement MCU and DSP.

author: LateLesley
author_rank: Frequent Contributor
timestamp: September 29, 2019, 02:34:16 pm
content: Awesome! Good luck with the repair. Look forward to updates.

author: james_s
author_rank: Super Contributor
timestamp: September 29, 2019, 05:16:34 pm
content: I've fixed a couple of these that thankfully were less severely damaged. In both cases I'm fairly certain someone plugged in a power adapter of the wrong polarity. For reasons I've never been sure of, music gear seems to almost all use the weird center-negative power adapters while 99% of everything else is center positive. People assume that if the plug fits that it's ok to use which in this case obviously it is not.

author: feedback.loop
author_rank: Frequent Contributor
timestamp: September 29, 2019, 08:53:09 pm
content: No, wrong polarity cannot kill this thing. There is a very simple and effective protection - a diode right after the power connector. It drops a few hundred millivolts, but who cares.However, a higher voltage can kill it. Say, above 16V can be fatal for this DC-DC converter chip.

author: james_s
author_rank: Super Contributor
timestamp: September 29, 2019, 11:40:51 pm
content: I wonder if they revised it and added a diode? Or maybe they were a different model, but I know they were Korg Electribe devices. Pretty sure the ones I fixed didn't have a protection diode but perhaps they did and it was overvoltage that zapped them.

author: feedback.loop
author_rank: Frequent Contributor
timestamp: November 02, 2019, 08:01:19 pm
content: It works!The firmware is attached.

author: james_s
author_rank: Super Contributor
timestamp: November 02, 2019, 09:13:27 pm
content: Awesome! Nice job!So it turned out to be the MCU and DSP?

author: feedback.loop
author_rank: Frequent Contributor
timestamp: November 02, 2019, 09:16:58 pm
content: DSP and at least one of the memory chips, maybe both, and maybe MCU as well, but it is not clear.

author: feedback.loop
author_rank: Frequent Contributor
timestamp: November 03, 2019, 07:52:04 pm
content: A couple of red LEDs on the front panel have lenses broken off. These seem to be Panasonic LN282RPX, which are obsolete.https://www.digikey.com/product-detail/en/panasonic-electronic-components/LN282RPX/P547-ND/410764Any ideas where to get them?Thanks.

author: fzabkar
author_rank: Super Contributor
timestamp: November 03, 2019, 10:12:44 pm
content: Quote from: feedback.loop on November 02, 2019, 08:01:19 pmDid you get hold of the firmware update package? FWIW, I wrote a tool to convert Roland's 7-bit MIDI formatted firmware binaries to 8-bit flash BINs. Perhaps Korg's format is similar?

author: Whales
author_rank: Super Contributor
timestamp: November 03, 2019, 10:46:29 pm
content: Aww, those LEDs are cute.Do you need anything more than the cylindrical end? Would a thin 3mm LED held a bit taller do?Unfortunately this will give you a different brightness and possibly a different colour tint. It might be worth considering the option re-LEDding the whole board, as distasteful as that might sound.

author: LateLesley
author_rank: Frequent Contributor
timestamp: November 03, 2019, 11:25:26 pm
content: Any chance you could use ones of a similar 2mm form factor? These don't seem quite as long I don't think, but might do the job?https://www.ebay.co.uk/sch/i.html?_osacat=0&_odkw=2mm+led+round&_from=R40&_trksid=m570.l1313&_nkw=2mm+led+round+red&_sacat=0EDIT : I found these, which are 8.0mm high, instead of 7.9mm??https://www.digikey.com/products/en/optoelectronics/led-indication-discrete/105?k=&pkeyword=&sv=0&pv966=282200&sf=1&FV=37%7C395219%2C-8%7C105%2C525%7C395219%2C2029%7C122870&quantity=&ColumnSort=0&page=1&pageSize=25But I see their mcd rating is a lot larger....How about these? A little shorter at 6mm and dimmer, but closer to the original specs?https://www.digikey.com/product-detail/en/lite-on-inc/LTL-1214A/LTL-1214A-ND/3198382

author: feedback.loop
author_rank: Frequent Contributor
timestamp: November 06, 2019, 04:49:57 am
content: Thanks for suggestions. I have seen the ones with flat top. I would think they should fit, but they will look different and probably will have different color and brightness. Should be fine if all are replaced - 17 red and 5 green ones.I still hope to find Panasonic ones.

author: feedback.loop
author_rank: Frequent Contributor
timestamp: November 06, 2019, 04:51:26 am
content: Quote from: fzabkar on November 03, 2019, 10:12:44 pmI am not sure what are you talking about. What problem are you trying to solve?

author: LateLesley
author_rank: Frequent Contributor
timestamp: November 06, 2019, 07:03:58 am
content: Quote from: feedback.loop on November 06, 2019, 04:49:57 amOk, I did a bit of googling. I found this place which says they have stock.https://ph.infinite-electronic.hk/product/Panasonic_LN282RPX.aspxhttps://www.components-store.com/product/Panasonic/LN282RPX.htmlI found several similar links, it seems all roads lead to HK for stock.

author: feedback.loop
author_rank: Frequent Contributor
timestamp: November 09, 2019, 03:19:53 am
content: I do not know these sites. They might be fraudulent.http://www.erai.com/ERAI_Blog/3153/__Fraud_Alert__High_Risk_Websites_That_Take_Your_Money_and_Run_They are not in this list, but have very similar names.

author: LateLesley
author_rank: Frequent Contributor
timestamp: November 09, 2019, 06:32:35 am
content: Well, yeah, that is always the danger of going outside the known good suppliers.And looking at the fraud page, it does look like the logo and name have similarities. Good catch. And A good warning to all us hobbyists.Apologies for linking to them.And thank you for the warning.

author: feedback.loop
author_rank: Frequent Contributor
timestamp: December 07, 2019, 12:32:33 am
content: I finally received a 10-pack I bought on AliExpress for $1.20 (1.92 with shipping) to give them a try.https://www.aliexpress.com/item/32819577430.htmlAs I expected, they have slightly different color (brighter red), they are slightly longer, not rounded, and noticeably brighter.I believe this should work fine if all LEDs are replaced, including green ones.If someone really wants to do fine adjustments, in the unit they sit on spacers, so in principle they can be lowered, and they can, perhaps, be rounded, but that is a lot of work. I am not going to bother. They stick out a little, but it does not seem to be a problem to me.So I am thinking about ordering one more 10-pack of red ones, and a 10-pack of green ones, and replacing all of them.

author: Nedreud
author_rank: Newbie
timestamp: September 19, 2024, 07:26:19 pm
content: I took a chance on a deadES-1 mkII"RHYTHM PRODUCTION SAMPLER" from eBay and no surprise it didn't work when connected with the correct power supply.Carefully comparing the schematic for the ES-1 mkI (I note it's "Provisional Version, Revision: 1.00" and therefore likely a leaked pre-production copy) and checking voltages on the board I was only getting +0.79V where I was expecting to find +5V for the DIGITAL section. I didn't spot it at first, but eventually noticed that theS8520step-down switching regulator-controller is toast (IC39on the board):Not as dramatic as the melted mess onfeeedback.loop's ER-1 mkII, but a very similar failure. They're protected from reverse polarity, but I don't think these devices can stand an over-voltage for too long. Spec sheet says 18V is the absolute maximum theS-8520can handle. It's not clear ifF3, the CPH6302 P-Channel MOS Silicon FET, is dead too, but neither of these things are more than a $/£/€ or so.I note that the code onIC39isBOJU, which makes in aS-8520F50MC-BOJT2Uwhich is the S-8520 Series F, 5.0V output, 300kHz Osciallation Frequency with No Overload Protection and "Lead-free (Sn 100%), halogen-free"!For future reference for anyone else that finds themselves in a similar situation, here is a photo of the power supply area. Note that this is theES-1mkII KLM-2507board. I believe it's functionally the same as the mkI, but the board itself has been revised because the component numbers don't make the mkI schematic:And here is the PSU section of the schematic. Again note this is themkIschematic for boardKLM-2197, which I have overlaid withmkIIcomponent numbers inred(use at your own risk, this is my best guess tracing and inspecting the board):Thanks again tofeedback.loopfor his invaluable YouTube videos.

author: hooverphonique
author_rank: Contributor
timestamp: November 11, 2024, 10:39:27 pm
content: Quote from: feedback.loop on September 24, 2019, 04:54:52 amHi,sorry for thread necro.. Judging from your following posts, you got this working for flashing a 29F800?Is your programmer a TL866A/CS? I have the TSOP48/SOP44 adapter set for that, with TSOP and SOP ZIF socket hats, but I've never managed to get them to work with 29F800's (both TSOP and SOP) (haven't tried other chip models).. The minipro sw says the adapter is 'V3', but I cant get it to recognize the chip id, or do a successful program/verify cycle.. Do you by any chance remember if you had to do something special to make it work?Otherwise I'm suspecting my TSOP/SOP adapter has been faulty from the beginning.

author: feedback.loop
author_rank: Frequent Contributor
timestamp: November 12, 2024, 03:57:18 am
content: Quote from: hooverphonique on November 11, 2024, 10:39:27 pmTL866CS + TSOP32/40/48 adapter V3Just tried reading 29LV800BA TSOP48. Works fine.