Electronics > Repair
Fluke 5440B repair
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Rax:
These will come in handy (see below) - extender boards I designed and fabricate for the 5440A/B. They were instrumental in fixing my 5440A, and they helped some others that used them in their repairs.
They're keyed for the compounded combination of slots for all modules in the main compartments.
Rax:
Some progress today with this.

First thing I had to acknowledge today was that my board needs an accessory little pad to serve A4. I enclose pics on how I built it. Having the custom EDAC card edge connector handy helped. I also had to trim a "two contact" segment, and the same for the PCB part. It works perfectly as built.

I'm still digesting through the data I collected, but here's what I'm seeing this far:

* setting a non-faulty condition output (say, 40V) sets K1 off and K2 on (about 4.5V over it)
* going into a fault-triggering condition (say, 100V), outputs a non-compliant output (about 60V for a setting of 100V), which, upon the unit actualizing the fault, turns K2 off (0V over it from the 4.5V just prior to that) and resets the unit and puts the output in STBY
* the other thing the manual says pay attention to is the reading over C9. I am seeing about 26.6V over the output over it unless the fault occurs and then the drop over it goes to zero.
Rax:
Pics
TheDefpom:
Something to consider is that those old relays often give trouble due to oxidisation on the contacts, I have come across this issue in different pieces of equiment.

it is probably worth opening each up and running a piece of paper soaked with deoxit through each one to clean them up.
Rax:
I've collected more info per SM troubleshooting steps, none of which makes a ton of sense yet to me in terms of origin of the fault(s).

For instance, 4-23 at p.4-29. I'm measuring the below with a DC voltmeter, though maybe I should look at these with a scope.

* TP2-TP1 20V out: 0V (expected, this doesn't engage yet the 23-275V HV path). 25V out: 14.5V (ramping up slowly, which doesn't look right; but the output is solid and correct). 35V out: 13.4V (sloping down now). 60V: 7.3V. 100V: 2.25V, which goes to 0V upon fault condition actuating the monitoring system. 300V: 2.5V (same as 100V)
* TP2-TP3 20V out: 0V. 25V out: -16V (slowly ramping up in absolute value, as above). 35V out: -14.35V (same fluctuation as above). 60V: -7.9V. 100V: -2.4V (zeroes at fault). 300V: -2.65V (zeroes at fault)Noone of the above is anywhere near the +-40V indicated by Table 4-7. Additionally, they vary widely with the set voltage, which I'd have expected to rather stay close to those +40V or -40V turning the state of the triacs on or off (if I understand how they're supposed to work).

Generally speaking, setting 100V out outputs about 57V (though sometimes seems to go to 100V, then dropping at this 57V), which triggers the fault condition, fires the error code and puts the unit in STBY. If I request 300V out, the same happens, though I don't this I've ever seen it outputting more than the 65V it settles at, right before the unit gets switched to STBY.

Further on the same procedure (step 5), when I try to measure state at pin 8 of P21 (TS1+) relative to the PCOM (23/13), for:

* 20V out: 4.46VDC
* 30V out: 3.8V
* 70V out: 3.8V which goes to 4.46V at fault triggering
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