Electronics > Repair

Fluke 5500a repair attempt

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dcmxx:
Yes I got there pressing the reset button. But it's intermittent sometimes it shows, sometimes don't

But what I’m seeing is that those messages are independent, and are stored in the display board

I modified the pinout of the motherboard connector, that's why I removed the rs232 transceivers

In fact the cpu board was stalled, one of the reset lines was low. I corrected that and the processor tries to read the fw from the memories, I see activity in the address lines, and data lines, but i don’t see any activity in the tig, fig, tds or fds lines, also I don't see any activity in the CS1 line that should select the u26 and u27 memories. So I’m stuck. i don't really know what’s happening

This board is requiring much modding, and right now I don't want to cut any traces.

Any chance to sell me one of your A9 PCBs? I could populate it with many of the components of this board

ddrl46:
I've made a few mistakes on my A9 board related to the RS232 interface which I would like to correct first.
Most importantly however I have verified that my board is able to boot correctly and talk to the in-guard circuitry.

I'll let you know when I have these new boards available.

dcmxx:
I'm looking forward for the new boards

I will keep trying to make this board work and post if I make some progress

dcmxx:
I made a mistake when I splitted and merged the bin files for the memory chips. The processor was crashing and asserting the HALT line.

So, now I really made some progress.  I corrected the bin files. And reprogrammed.

I also found that the 68C681 should be populated or else the firmware also doesn't run correctly. The IRQ line has to be disconnected from the processor as the 5500's A9 uses IRQ4 and the 5520's uses IRQ6.

Now when I turn it on I get consistent behavior, the Starting up screen shows each time, CS0 and CS1 seems to be working as expected. If I press the reset key when turning it on, I get the RESET key hold down screen correctly.

I start to hear some relay switching after some seconds of power on, but the calibrator doesn't seem to fully start up.

Srikanth:
Hi,

         I have same problem Fluke 5500a calibrator, Please guide me how to flash the firmware in to main CPU board, I tried to communicate with RS485 Host port through Hyper terminal no response from the CPU card. All supply voltages are showing correct. Due to power fluctuation may be firmware got corrupted. Thanks for your support.     

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