Siglent SDM 3055 Dark Display - Page 1
Forum section: electronics / repair

author: Joe510070
author_rank: Newbie
timestamp: November 28, 2021, 03:13:47 pm
content: I have an SDM3055 I took a chance on and lost. I have a green power button light and a completely dark display.On the main board I do have a solid green LED. According to the limited service manual I’ve found TP-1 to TP-3 voltages are good. I’m unsure where TP-86 references to, but to ground I’m seeing .6V not the 16V in the manual. I suspect I have the wrong point to measure from…On the Analog Board all voltages T-1 to T-8 are good.This unit does not have the SD slot on the main board, it’s unpopulated.I’ve reached out to Siglent for support several times and have yet to get a response.From my reading occasionally these units get corrupted firmware that needs to be reinstalled. I have no activity on a usb stick when plugged in, so I’d suspect the OS isn’t coming up… I also reseated all plugs and the ribbon cables.I’d appreciate any suggestions to get this unit running again. Anyone know how to reinstall the firmware without an SD adapter on the board? Any other ideas?Regards,Joe

author: tautech
author_rank: Super Contributor
timestamp: November 28, 2021, 09:25:12 pm
content: Hmmm, later models omitted the MicroSD card socket on the MB as FW versions for them could use USB recovery if/when necessary. That yours doesn't get to the boot logo suggests some sort of other failure which is unusual IME.Let's just see what Siglent NA comes back with once they get to your email.

author: Joe510070
author_rank: Newbie
timestamp: November 28, 2021, 09:52:30 pm
content: After doing some searching here, another user found a damaged ribbon cable when his showed the same problem. I’m a bit hesitant to pull that connector without knowing it’s specs and availability. I did go over the unit with a magnifier, everything looks perfect. Maybe the ribbon is damaged inside the socket…Everything I’ve heard about Siglent is very positive, but this unit is clearly out of warranty. Hopefully they can help. Any suggestions would be most appreciated! I’ll let everyone know when I hear from them.

author: tautech
author_rank: Super Contributor
timestamp: November 29, 2021, 12:44:32 am
content: Quote from: Joe510070 on November 28, 2021, 09:52:30 pmYes if you have no display activity at all the display cable would be a good suspect.If it's been removed and refitted there is a chance it hasn't been fully inserted and that's what I would investigate first.You might also check if it's not just a backlight issue by shining a bright torch at the display once it's powered up.

author: Joe510070
author_rank: Newbie
timestamp: November 29, 2021, 02:45:35 pm
content: Thank you for the reply! I did remove the board side ribbon cable, the only issue I see is a couple severe folds in the cable. It looks like an AWM 20624, 50 pin, 300mm. Is there a preferred replacement part or number for this? I also don't see any sign of a backlight in the display.Reading through the voltage checks in the manual I no not see where they want the ground reference, I used a pin on TP-1. The only one off was TP-86 @.6V not 16V as shown, perhaps there is a problem in the main board. Ill double check these measurements later today.I did get some history from the seller. He said that it was included in an Amazon Mystery Box. So its possible this was a non-working unit, returned and never used. Inspecting the unit there is no sign of burned components, and not even a scratch on the case. its in pristine shape.

author: bdunham7
author_rank: Super Contributor
timestamp: November 29, 2021, 03:03:35 pm
content: Quote from: Joe510070 on November 28, 2021, 09:52:30 pmWhy do you assume this? I believe that their warranty is from the date of purchase if you have a receipt, from the date of manufacture if you do not. Is that not correct?

author: tautech
author_rank: Super Contributor
timestamp: November 29, 2021, 03:15:02 pm
content: Quote from: Joe510070 on November 29, 2021, 02:45:35 pmYes the ribbon cable has a couple of 45 degree completely flat folds where it runs along the PSU divider to the front panel and display.Sure the ribbon cable is available as a spare but not sure if Ohio have it but they probably do.You could dismantle further and do continuity checks.

author: Joe510070
author_rank: Newbie
timestamp: November 29, 2021, 03:24:48 pm
content: I not the original owner of this device, so no receipt. Perhaps it’s true the warranty is from the date of manufacture, I’ll try to figure out that date. I’m still trying to get a reply from Siglent, over the weekend they may not be in the office. That’s a good thought, thank you!

author: tautech
author_rank: Super Contributor
timestamp: November 29, 2021, 03:26:33 pm
content: https://siglentna.com/service-and-support/warranty-information/

author: Joe510070
author_rank: Newbie
timestamp: November 29, 2021, 03:37:59 pm
content: I removed the tape to check the ribbon cable, and broke the calibration seal sticker.. That may void the warranty.5.4 Repaired by anyone who is not from SIGLENT Maintenance Center or an authorized maintenance branch.I’ll try them on the phone later to see what they say..

author: tautech
author_rank: Super Contributor
timestamp: November 29, 2021, 03:44:04 pm
content: Quote from: Joe510070 on November 29, 2021, 02:45:35 pmSC16 is specified as circuit GND. See TP key on P21.P25https://int.siglent.com/u_file/document/SDM3055_ServiceManual_SM06035-E01C.pdf

author: tautech
author_rank: Super Contributor
timestamp: November 29, 2021, 03:55:30 pm
content: Quote from: Joe510070 on November 29, 2021, 03:37:59 pmWith the Troubleshooting section checks properly completed you should 100% be able to identify the faulty section for to get any replacement parts.Do you have a scope to check the analogue board clock ?Do you have a flashing LED on the mainboard ?Oh and BTW we have never had a DOA unit from Siglent of any type.Work carefully through the troubleshooting section to positively identify where the fault is and then source the parts from Siglent. Normally this should be a warranty claim however it seems it was written off which explains why the previous owner received it in an Amazon mystery box.This might imply Siglent won't accept warranty on it as it's already been written off.

author: Joe510070
author_rank: Newbie
timestamp: November 29, 2021, 03:59:31 pm
content: I just got off the phone with Siglent. Turns out the manufacture date is Spring 2021. They will send an RMA and cover the unit under warranty.I really want to thank you guys, my situation went from bad to the best outcome possible. I feel a little dumb for not checking if it was warrantied, but appreciate it!Siglent as a company is truly first class. I've really impressed with the customer service!

author: tautech
author_rank: Super Contributor
timestamp: November 29, 2021, 04:05:45 pm
content: Quote from: Joe510070 on November 29, 2021, 03:59:31 pmMaybe you got lucky then, hope it all works out.

author: Joe510070
author_rank: Newbie
timestamp: December 10, 2021, 02:15:30 pm
content: Just an update. I called Siglent, spoke to one person who looked up the serial number and provided an RMA.In less than 10 days round trip I have a working meter complete with fresh calibration.I’m really happy with the high level of service from Siglent, very nice company to deal with!Thank you everyone here that helped me out!