E4350B Solar Array Simulator with "secondary DN" error - Page 1
Forum section: electronics / repair

author: JTAG
author_rank: Newbie
timestamp: February 12, 2016, 10:51:52 pm
content: Dear all,I share this to maybe help others. I was unable to find any pictures of the inside (could have been simply the dipswitch setting) or anyone else with this error. So I think this is a first. Of course these devices are scarce so I wont help many, but hey who knows!Background:I have a long running project being a maximum power point tracker to charge a 48Volt LiPo battery from a solar panel (for this type of race boat). The project ended up during a little longer then the summer.... now its winter thus I needed PV like solar power source. With the desire to continue with the project I needed an alternative, I needed a solar array simulator. These devices do what the name implies, they try to emulate the electrical behavior of a solar panel. I ended up finding on ebay a seller in my country that was selling the device I was looking for. The ebay listing stated: Perfect condition, however when I tested the device on the sellers location it ended up giving "secondary DN" error. Resulting: I bought it for a very low price.Error:The displays shows alternating "Addr 9" and "secondary DN". The service manual states that there is no serial communication with the DSP board -> DSP board is detective.Analysis:The design is really nice, the front panel has a serial connection with the GPIB board and the GPIB board will on his turn communicate with the DSP board. When measuring on this serial cable (from GPIB to DSP board) I saw serial communication, the DSP however gave no response. I took the DSP board en tested the clocks -> all OK. Tested FPGA -> It loads and made its CONFIG_DONE pin high -> OK. Then I looked at the databus pin D0. On powerup there was activity for a few millisecondes followed by nothing at all. On some of the databits the measured voltage was 2.5V (stationary) of the possible 0V and 5V, I think this is not a normal state on the databus (but i am no expert in this old technology with RAM ROM and CPU separated). After a few times trying I noticed that sometimes the communication on the bus was longer then a few ms, namely about 5 seconds, but it froze after that. My thought was that something on the bus hang, not knowing what I tried a few things ( soldering most of the SMD chips, around the DSP, heat and cold but no results ). I measured the SC26C92 (serial interface) and it really received the data from the GPIB board, on its output was nothing. I tested all digital power supplies -> OK.Repair:I watched numerous videos of the signal path blog and observed quite often that when the problem was on the CPU side the memory had issues (if you are reading, thanks for making these awesome videos!). Me being a little impatient ended up with the shotgun approach, ordering the DSP and RAM IC's. I first received the RAM, after replacing the RAM the SAS came back to life!I just tested the regular powersupply functionality of the device on a DC load and it all looks perfect now. The solar array functionality can only be activated trough GPIB (IV curve setting).Some pictures:If you think, what is that tacky stuff, it is flux! Loads of flux. I love flux and I am to lazy to clean it of ( I might need it later on that place).If someone happens to own this or a similar device: I am looking for software to control it, it doesn't matter how hacky it is. So please please pleaaaassseee.Kind regards,Danny BokmaPC0DBNetherlands