SILO branded tv - model SL-4013 - no image, Nonbacklight, doesn’t always turn on

[ngth82]

Has anyone ever worked on a “Silo” branded tv?

I have one. Model SL-4013. The tv is in great physical shape.

The tv only comes on very now and then. The backlights are good - I dismantled the tv and checked out the strings.

The backlight circuit comes up to ~35V when it’s not working. It goes up to 75V to illuminate the strings when it works.

The big cap stays at 165V in a working and broken state.

The tv doesn’t always turn on either with the remote or the power button. The tv’s red standby LED doesn’t turn green.

The SMPS, main and TCON are all integrated as a single board. As far as I see, the caps and diodes are good. There’s also little to no silk screen on the board to help with pin identification.

[neilc6]

Probably an eeprom issue. Actually a flash IC. 8 pin SOIC beside main procesdor. Try freezing it with an upside down can of duster before plugging in.

[nomoresonys]

Hard to tell by the picture, is that a bad cap there by the plastic zip-tie holding those wires?

[CapLeaker]

Heat up the caps on the main board a little bit with an hair dryer and see if the tv turns on every time. If it does, give it a full recap.

[ngth82]

Thanks for the quick suggestions... Sorry for the poor lighting. I've left this TV in the garage - in quarantine if you will. I'll have some additional time to look at this tomorrow.

Originally Posted by neilc6

Probably an eeprom issue. Actually a flash IC. 8 pin SOIC beside main procesdor. Try freezing it with an upside down can of duster before plugging in.

The SOIC8 is a 25Q16BSIG - a quad SPI flash made by GigaDevice. I've run out of freeze spray and canned air. I'll have to source more cans. Good call.

If we weren't locked down, i'd just remove the SPI flash and take it to work to read out the contents and verify the device integrity on the DediProg.

Originally Posted by nomoresonys

Hard to tell by the picture, is that a bad cap there by the plastic zip-tie holding those wires?

Negative, the zip-tie area is a screw (please refer to the new pics here).

Originally Posted by CapLeaker

Heat up the caps on the main board a little bit with an hair dryer and see if the tv turns on every time. If it does, give it a full recap.

I heated the board up earlier and it didn't do anything. I've removed all of the caps and tested each one with my capacitance meter. They appear to all be good.

[neilc6]

Originally Posted by ngth82

The SOIC8 is a 25Q16BSIG - a quad SPI flash made by GigaDevice. I've run out of freeze spray and canned air. I'll have to source more cans. Good call.

I "repaired" the same device on a Proscan recently with intermittent turn on by erasing it and reprogramming it. Did order some replacements on Aliexpress in case the tv comes back but could take months to get in.

I have a cheap ch341 usb programmer and a wide socket adapter. I read the IC after freezing and looked for some ascii copyright info in the bin file which is usually near the end of the data as a sanity check on the original bin.

[CapLeaker]

next i'd do the eeprom.

[ngth82]

I was going through junk boards and found a 25Q16CSIG. The "C" device datasheet says the programming time is faster than the "B" version that i have on the board.

The other parameters and pinout appear to be the same from a quick glance.

Also, I do have a Total Phase Aardvark that will read SPI devices. I just need to make an adapter board before i attempt to connect to it and read the contents out.

-Thomas

[ngth82]

Hi all -
Update - I was able to extract the SPI flash contents by wiring up my Aardvark SPI flash programmer to it. I dumped the contents twice and compared the binary contents with a diff tool. Looks the same.

As noted in Post #8, i found a 25Q16CSIG SPI flash from one of my junk boards. The "C" version is electrically equivalent, it just has faster timing so it should be a drop-in compatible.

I programmed the 25Q16CSIG. The programming verified as good (see screenshot and pics). I used an old T-CON with the same SMT pads and hooked up the MISO, MOSI, CLK and CS# lines to a header and provided power to the device.

I placed the 25Q16CSIG on to the Main board, but it doesn't do anything differently. It still takes multiple attempts at turning it on.

Any other ideas besides the EEPROM?

My compressed air cans are being delivered next week.

[ngth82]

I guess my best option for a quick sanity check is to get a known good firmware image and a replacement SPI flash. SILO doesn't appear to provide one.