SIO2SD troubleshooting

[+slx]

I have a pretty old SIO2SD (bought built into an XC12 case by a guy from the UK) that ceased to work. When I connect it the upper line of the display shows about 10 "all solid" (cursor-like) characters and the lower line remains blank. The power light is on. That's all. 

 

Any hints on where/how to troubleshoot?

[TGB1718]

I don't know if yours has sockets for the chips, but if it does, I would lift them  out and re-seat them.

 

also the display if it can be removed.

 

remove and reinsert the SD card, check the SD card in your PC

 

 

Edit: Just a thought, the display might need adjusting, there should be a potentiometer to adjust, maybe on

the display itself or on the board.

 

 

 

 

Edited January 8, 2023 by TGB1718

[_The Doctor__]

all of what TGB said and finally the atmega might need a reprogramming

[HiassofT]

This sounds a lot like the old brownout fuse issue - if it's not programmed correctly the firmware in the eeprom could be trashed on power up/down and you only get the single "black bar" line when that happened.

 

Solution: reprogram the ATMEL with latest firmware and set the fuse bits correctly (there should be plenty of old topics about that issue with info about what to do here on the forum).

 

so long,

 

Hias

[+slx]

I finally got around to opening the XC12 „shell“ that houses this SIO2SD. It’s a rat‘s nest of all-grey cables connecting the microswitches operated by the original XC12 buttons and the display in the cassette window to the SIO2SD board which does not seem to have any loose chips, just SMD. There‘s a lot of hot glue around that’s starting to come loose. The cables are not braided but single core wires (like phone wires but flat) and feel a bit brittle. Due to the hot glue it’s pretty much impossible to measure continuity. 
 

I found a loose wire and soldered it to what seemed the obvious point but that didn’t change a thing (leftmost contact with the shiny blob of solder at the bottom of the second picture, all those wires go to the display).

 

Switching on I briefly get two lines of solid blocks which change to a top row of solid blocks. On subsequent power-ons the bottom line doesn‘t come on.  
 

So how can I flash this? Are the holes on the right part of the second picture some kind of programming connector?
 

I dread taking it apart as the PCB is quite different from the „normal“ SIO2SD PCB, so I‘d have to rely on notes to put it back together.