This is getting me down!!!

[zepp]

I will try to explain this as easy as possible.....
I have a classic KISS, #52 with 2nd generation displays.
I also have a homebuild using the same displays, so 6 in total.
I have been having problems with the calibration of the displays since i did my mod 1. Any of the three readings started to 'float', one sec they seem to read correctly, then the next one might start to climb or fall. i can calibrate them in the evening in 100%, check in air then next morning i could have readings ITRO 0.170......0.490......0.330 in air!!!!
i have now replaced all six wires as they did have some blackening of the cores and thought this may solve it. Oh no, I have just spent 6 hours swapping LCD displays with the boards and cell and batteries and still get similar results. Now bare in mind i have 6 sets of these to play with, the odds that ALL of them are f@#ked is on the high side. The cells are 3 months old and have even tried them with a cell thats more than 12 months old and get the same.
I have also touched the soldering iron on the joints incase it was down to dry joints but still no satifactory result.
Now i have planned to go to Scapa next friday and really need to get this sorted so please, if you have any ideas then let me know.

To see a display that I just calibrated in o2 and air then watch it go from 0.210 up to 0.850, still in air is really pissing me off

[gibbon]

Sounds very frustrating. My take on this...

Cells are not to be trusted, regardless of age, they will lie to you.

Without electronics, the highest reading is the correct one... however what you are seeing with a cell going very high, I would blame on the temp compensation circuit that is built into the cell.

I would go back to first principles, I presume that you need a 10k resistor between the +ve and -ve and then measure the voltage over that.. and check against the specs for the cell.

I suggest that you have some cells that are fried in the same way and these are distributed amongst your other cells that are good so you need to identify the crap cells.

Perhaps try some of your cells (all of them) in the same test rig, and see where you get to.

Don't stress, I am sure you will suss it out in time for your trip.

[Mark Chase]

OK reeeeellllyyy stupid question

When the cell readings went from 0.21 to 0.8 in air was the head assembled or was the pod just off and in ambient air?

If in ambient air it rules out any possabuility of 02 leaking into the rig.


When it comes to an electrical issue I get stuck but surley there must be some current interfeering with the calibration? I strugle to beleive all the cells are toast unless there is something on the unit which is frying the cells. What milivolt reading do you get on the cells in air? Is it constant when checked with an Avo meter. Can you conect the avo meter to the cell and then put it in a bag of 02 and see the result.

If its within normal range then there has to be some interferance from the power supply to the hand sets. Some sort of voltage leek

At this point I would have to give up and get someone qualified to look at it

ATB

Mark Chase

[zepp]

Ok, all cells give a reading of between 10.9 and 11.8mV in air, that is out of the unit. I checked these again this morning and gave similar results. I believe i can say the cells are good from this???
Last thing last night, well early hours this morning!!! I i set all three displays to .205 in air..the reading this morning were as follows.... .250; .315; .180

[Mark Chase]

Originally Posted by zepp

Ok, all cells give a reading of between 10.9 and 11.8mV in air, that is out of the unit. I checked these again this morning and gave similar results. I believe i can say the cells are good from this???
Last thing last night, well early hours this morning!!! I i set all three displays to .205 in air..the reading this morning were as follows.... .250; .315; .180

Iknow your getting better feed back on RBW but this surley has to be some sort of current leek into the hand sets?

ATB

MArk Chase

[zepp]

Beter feedback maybe but on YD I have had an offer to borrow a complete unit Its times like this when you realise how helpful others can be, even though you dont even know them face to face.