Strand MX48 " set up corrupt" problem

[Robertdazzler]

No access to my theatre during Covid has resulted in the Ni-MH memory battery being completely discharged. On power up failed to charge so replaced battery. Display now shows ERROR 1386 "set up corrupt" check sum error. Suggesting Internal battery discharged..  Indeed the voltage on this is low and falls rapidly. The manual suggests CONTINUE or Quit. Continue merely steps to the next test which is also failed ( checksum again) . What is meant by QUIT?. Manual says -cause set up to be reset to factory defaults but how?

I am out of ideas now and need help!

[pmiller056]

I'm not familiar with the internal details of these controllers. If the memory battery is soldered onto the PCB, there is a high risk that some of the internal battery fluids have leaked onto the PCB. This fluid is corrosive and will wreck a PCB, quickly eating through copper tracks and vias, Cleanup and restoration is possible, but time consuming if components have to be removed to repair damage. There is a high risk of further related problems in the future, compromising the reliability of the controller.

[Robertdazzler]

Thanks for that. I have already found lots of damage caused by fluid leakage and hopefully rectified same. I now find all checksums are corrupted. Something is loading the internal battery I have not found the reason yet. Critical question is how to go back to factory settings?

 

[Robertdazzler]

Fault seems to be in the Power/interface board PCB1014/1 REF 1952

Is anyone thinking of retiring/scrapping an MX48, if so I could be in the market for this part-+  b  

[alistermorton]

I'm not sure with the MX-48, but the GSX and LBX had a small white button on the front edge of the motherboard which you hold in during power up to do a full factory reset.

Edited October 18, 2022 by alistermorton

[Robertdazzler]

Sadly have not found anything like that. First fault shown is "Set Up Corrupt" "Clear is supposed to clear "set up" or "whole System" to factory settings. it seems that all data check sums are corrupt. I am close to throwing in the towel here.

[alistermorton]

Ah - when our GSX has been allowed to discharge it usually won't power up properly after charging, displaying all manner of checksum errors and using the (admittedly very small and hard to spot) white button is the only way to progress. It's a shame if there isn't something similar on the MX.

[alistermorton]

Don't know if this is any help, but much of the circuitry is similar to the GSX/LBX consoles MX technical manual

[Robertdazzler]

Thanks for circuits alister. The symptoms I see are just as you describe : corrupt checksums etc.

The main control unit and fader modules test out OK if I jump past all the failed diagnostic stages. I am pretty sure the problem lies in the power supply /interface board. Do you have the circuit for that bit? I will look again for the white button but that will need serious dismantling.

[Robertdazzler]

Sorry, it is there I just hadn't looked well.

[Robertdazzler]

Problem finally solved after about 100hrs of trying, thanks to Alistermorton's supply of the technical manual for MX48 I was able to identify the culprit which was flattening the 3.6V on board battery:  VT1 had a shorted b-e junction which meant that the battery discharged when power off at the same rate as it should charge when power on. Using a conventional transistor and a good charge appears to have put everything right without the need for a reset to factory settings. Somehow the Grand master fader had a track open circuit as well. No idea how these had occurred.

Thanks again Alister. I would not have been able to solve this without your help!

 

[alistermorton]

Glad you were able to restore your desk to working condition.