Disconnect all loads from the regulators and see if they work normally now.
If not, you may have capacitors reversed, or the regulators installed wrong.
Is your wall wart AC or DC?
If not, you may have capacitors reversed, or the regulators installed wrong.
Is your wall wart AC or DC?
I notice you have an earlier board (without the direct connections for an LCD display)
I'm wondering if the reset controller is wired correctly as there are differences,
please check posts #1042, 1043, 1123,
I'm wondering if the reset controller is wired correctly as there are differences,
please check posts #1042, 1043, 1123,
Ah, thank you so much! I remember reading that when I first realised I had ordered the old boards, and then proceeded to completely forget it whilst waiting for parts to arrive. Video shows the board functioning more like it's supposed to when the push pull is removed, when I tried installing it backwards I was getting a blank screen, so I would imagine I've fried the push pull when desoldering it, will order a replacement to test! Thanks for the help and bearing with my inability to read instructions!
The SG4 gerbers in the first post are not revC. I had the same issue today. Was getting no Vcc with the current limited power supply. Removed and reversed the MCP101 and got power where I am supposed to. Hope I didn't fry the chip. Haven't installed the uP yet to try.
The SG4 gerbers in the first post are not revC? Does this mean my recently assembled PCBs with processors should be dissembled and I need to order new boards? Or order all new parts? How should I best proceed?
If you got your boards from Oshpark they are ok. If you ordered from another PCB house using the Gerbers and you are using the mcp101 from the bom, then you need to install the mcp101 backwards.
This week I breadboarded an SG4 + Chinese Class D amp module + Transformer to my Thorens TD160S and the sonic improvement was noticeable. However after a power off - power one cycle the voltage output at the transformers usually drops to around 36v or so. Using a need to turn the pot on the amplifier module to get the voltage back to around 120V. I tried toggling the SG4 to stby and back, changed power up order etc but this always happen. Wondering if anyone else has seen this? Its not a big deal but a minor nuisance as I need a DVM hooked to the output everytime I start up. I have ordered another cheap amp module to try.
This evening I’ve decided to fire up for the first time my SG4 board bought back in 2019. Unfortunately I’ve got a strange message on the display (see picture). Parts are as per parts list ordered from mouser, pcb is checked for correct parts placement and orientation. Any help will be appreciated.
Attachments
Hi appsmyth, I had a similar problem on one of the 3 boards I built. It turned out to be a short near U3 on the bottom of the board. The OshPark board had a short to a via on a trace coming from U3 and I was getting a blank segment. I scraped the short clean and it worked as it should after.
Thank you for the tip ZUM911.
The board looks ok no sorts. I’ve de-soldered DS1833 but no change either.
Problem not solved.
The board looks ok no sorts. I’ve de-soldered DS1833 but no change either.
Problem not solved.
If it turns out to be the board, I may have spares.
Does it work properly besides the display?
Does it work properly besides the display?
For a reason the microcontroller after power up needs a reset to start the program. Found out accidentally when I pushed the DS1833. Then all functions are working properly.
Any ideas?
Any ideas?
Most microcontrollers need to be held in reset until the power is stable. Make sure your DS1833 is generating a reset or release after your power has stabilized. Too early and the controller might lock up, or not at all and it is probably in an uninitialized state.