Meadowphysics legacy - modular clock and grid not working

hi! I’m a legacy Meadowphysics user and I have a non-varibright grid. I recently soldered the i2c pin headers on my Meadowphysics and am able to communicate with it from the teletype. It responds to my commands and is fully functional… except… now the clock knob does not function and I am unable to get any response on my grid. The grid does work with the teletype and I am using an offworld 2 power supply. The modular still powers up and shoots off triggers. The default clock cycle the unit is running on is very fast. The unit will slave to an external clock too. Again the main issue is that there is no grid lights and the clock knob is unresponsive. Could everything else be working on a Meadowphysics and not any of those features?

I am by no means an expert but a good quality photo of the soldering job might be a place to start the debugging process (I can compare to the module I have here)

  • If the i2c cable is disconnected does the module return to normal function?
  • Are there any solder blobs that might have fallen on a different part of the board causing a short?
  • Are the individual PCBs still firmly connected?
  • Assuming this is the original trilogy meadowphysics module does the current case have +5v line with sufficient output?

Good questions. I’ll try to answer the best I can.

  1. Disconnecting the i2c cable has no impact.
  2. I can’t see any blobs of solder on the board but have a look at the pic
  3. The boards are connected as firm as I can get them whenever I plug in.
  4. The case I’m using is Tiptop Mantis so I’m confident it has the right power source available. There isn’t a designated 5v connection.

I tried retouching the USB and clock pins but now the unit powers up only one solid LED next to output.

I just wanted to add the i2c headers but now I feel I might have botched the whole unit :frowning:

Thanks for the help!

This is probably a question for @tehn or @dan_derks but part C21 is populated on the main cpu/runes board of my module (rev 140711) and it looks like it is missing on yours. My recollection was that the original trilogy series modules required +5V from the power supply in order to power attached USB devices.

UPDATE: I can’t find any specs on the Mantis power supply other than that it contains a “zeus” power supply. The specs for the μZEUS say: 2000mA at +12V, 500mA at -12V, 170mA at +5V.

The docs for meadowphysics specifically mention that while idle +5V consumption is 42mA with nothing attached but significantly higher (up to 600mA) with a grid attached (which is well beyond the capacity of the μZEUS power supply).


Wow! Thanks for your consideration :slight_smile:

If there is a missing part then that’s not going to be something I can fix (I have no experience with SMD). I sent a message to tehn so I’ll wait to see what the service options might be.

I have the offworld so the boost in power consumption wasn’t an issue with a grid attached to the MP.

Thanks again!

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that huge cap was a test attempt to quiet the grid’s LED noise. it works for some grids, not all. generally if noise is a problem use a splitter.

the ADC failing, however, sounds like static damage. e-mail and we can set up a repair.

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Thanks for the confirmation. I must have not handled it properly. My unit is on its way :slight_smile: