Overload Board

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Re: Overload Board

Postby kf1z » Tue Oct 19, 2010 9:03 am

If you use overload HI then you install R736 and R739. R737 and R738 are NOT installed.

If you use overload LOW, then R737 and R738 are installed, R736, and R739 are NOT installed.

This is not clear in the schematic notes.

I use Reset high, and ground it to transmit.

To reset after an overload, you un-key the transmiter, then key it again.
It actually saves a step, since you would un-key the TX on an overload anyway, then pusha reset button, and key the TX again...




Also, for a 30 volt carrier voltage, your preliminary setup would be 1.2 volts at TP1 with +12vdc at the input.
Reason?
The schematic notes say that 0.8v is the approximate setup for a 45v carrier.
45/12= 3.75 ( factor of target voltage 45v, by the test voltage 12 )
3/3.75=0.8 (target voltage 3v divided by the difference factgor 3.75)

so for 30 volt carrier....
30/12=2.5
3/2.5=1.2


Of course, this is just a preliminary setup. you need to readjust this to 3 volts once you have it in-line and your 30 volt carrier present.
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Re: Overload Board

Postby kf1z » Tue Oct 19, 2010 9:22 am

You said you have 2.5 volts at TP4

Is this with, or without 12v on the input? or both?


I assume you do not have the input and output connected to the PWM filter and the RF deck (respectively) at the time of testing? or do you..?
If your input is connected to the PWM filter... then you may already have around 14volts at the input.

But you should be able to adjust TP1 below 3 volts with R702
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Re: Overload Board

Postby K9ACT » Tue Oct 19, 2010 9:51 am

kf1z wrote:If you use overload HI then you install R736 and R739. R737 and R738 are NOT installed.

If you use overload LOW, then R737 and R738 are installed, R736, and R739 are NOT installed.

This is not clear in the schematic notes.



Indeed. I assume as there is onlyt overload Lo on the PWM board that this is the only way the OLboard can be configured using it. Is this correct?

>I use Reset high, and ground it to transmit.

This is not just unclear but the opposite resistor combination specified in the schematic.

It says to install 736 and 739 for reset HI.

>so for 30 volt carrier....
30/12=2.5
3/2.5=1.2

Thanks. I will set it up as you have it but still think there is a problem.

js
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Re: Overload Board

Postby K9ACT » Tue Oct 19, 2010 10:03 am

kf1z wrote:You said you have 2.5 volts at TP4

Is this with, or without 12v on the input? or both?


Either way.

>I assume you do not have the input and output connected to the PWM filter and the RF deck (respectively) at the time of testing? or do you..?
If your input is connected to the PWM filter... then you may already have around 14volts at the input.

I tried all sort of combinations and am a little foggy now but the first test was with the filter in and a 5ohm dummy on the output. The 12V supply I was using is only 1amp and could not supply 12V but the results at TP1 were about the same as with no load.

How is this setup to be set up to get the 1.2v with the 12V supply? I will use a beefier supply once I understand what I am doing.

js
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Re: Overload Board

Postby kf1z » Tue Oct 19, 2010 10:11 am

K9ACT wrote:
kf1z wrote:If you use overload HI then you install R736 and R739. R737 and R738 are NOT installed.

If you use overload LOW, then R737 and R738 are installed, R736, and R739 are NOT installed.

This is not clear in the schematic notes.



Indeed. I assume as there is onlyt overload Lo on the PWM board that this is the only way the OLboard can be configured using it. Is this correct?

>I use Reset high, and ground it to transmit.

This is not just unclear but the opposite resistor combination specified in the schematic.

It says to install 736 and 739 for reset HI.


js


Which is just what I said. nothing opposite about the resistor combinations..
Except I said Overload Hi, instead of RESET high/low like it should be. (just to add confusion, my mistake...sorry)


But you can use RESET high OR low, and use Overload high or low.
You don't HAVE to use overload high, if you use reset high, for example.

BUT for the pwm generator board, you use the overload low from the ol/eff board, yes.
But, you can use either RESET low OR high.

As I said, I use RESET high, but use overload low to the pwm gen board.


In both cases, the high, or low, correspond to the voltage state the input OR output is in in case of a 'reset condition" ( standby, or overload.)

So, for RESET HIGH. if this input is HI then the OL board is in RESET state.
To transmit, then, this input must be LOW.
That's why it's called RESET HIGH.
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Re: Overload Board

Postby kf1z » Tue Oct 19, 2010 10:14 am

K9ACT wrote:
kf1z wrote:You said you have 2.5 volts at TP4

Is this with, or without 12v on the input? or both?


Either way.

>I assume you do not have the input and output connected to the PWM filter and the RF deck (respectively) at the time of testing? or do you..?
If your input is connected to the PWM filter... then you may already have around 14volts at the input.

I tried all sort of combinations and am a little foggy now but the first test was with the filter in and a 5ohm dummy on the output. The 12V supply I was using is only 1amp and could not supply 12V but the results at TP1 were about the same as with no load.

How is this setup to be set up to get the 1.2v with the 12V supply? I will use a beefier supply once I understand what I am doing.

js


First thing Jack...
Measure the voltage that is already present at the input. as I said, you may already have a voltage there.
(caused by the charge-pump in the output board I think...)


But a voltage at TP4 with no load makes me wonder.
I hope Steve chimes in on this one, because as I understand it, if there is 0 current flowing through the hall-effect densor, there should be 0 volts at TP4
.
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Re: Overload Board

Postby K9ACT » Tue Oct 19, 2010 11:17 am

kf1z wrote:


First thing Jack...
Measure the voltage that is already present at the input. as I said, you may already have a voltage there.
(caused by the charge-pump in the output board I think...)

.[/quote]

Before I get to that, it was my turn to screw up terms. I said reset lo when I meant hi so we are good on that... ground to transmit.

Now, under what conditions should I measure that voltage?

I have the board wired to the PDM board, 18v, ground, OL lo to OL lo, nothing connected to input or modulator output, now what?

Please bear with me as I need pretty basic steps.

js
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Re: Overload Board

Postby kf1z » Tue Oct 19, 2010 11:36 am

If the PWM filter is not connected to the input of the OL board, and the output of the board is not connected to the RF deck....

Then there should be 0 volts at the input of the ol board.

Now, you should be able to connect 12 volts + to the input... and the gnd of that 12volt supply to a ground on the board of course..

You should be able to adjust TP1 below 3 volts with R702 though...


So I think double checking the components would be a good thing if you cannot do that.

I know you probably have... but something is amiss definately...
Last edited by kf1z on Tue Oct 19, 2010 11:55 am, edited 1 time in total.
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Re: Overload Board

Postby kf1z » Tue Oct 19, 2010 11:52 am

I just double checked my ol board.

With 0 volts at the input, TP4 also reads 0 volts. Just as it should.

So.....

There's got to be a bad, or incorrect component... maybe a solder bridge? somewhere there.
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Re: Overload Board

Postby K9ACT » Tue Oct 19, 2010 2:09 pm

I think I found the problem.

The -18v connections completely escaped my attention.

I assume I still need the ground.

So, back at it after beer time.

Thanks,

js
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Re: Overload Board

Postby kf1z » Tue Oct 19, 2010 2:30 pm

Ah yes....

+18, gnd, and +18 from the pwm gen board are needed! :D

Hope that solves all.......
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Re: Overload Board

Postby K9ACT » Tue Oct 19, 2010 6:50 pm

kf1z wrote:Ah yes....

+18, gnd, and +18 from the pwm gen board are needed! :D

Hope that solves all.......


Seems to but the setup procedure is a bit confusing. I did the best I could understand with 12V in and am in the process of hooking it up to the rig but I am not sure just what I need to do to actually use it.

My understanding is that I need to add a relay closure to ground the Reset hi upon keying.

I assume that an overload will kill the pulse stream and then I manually unkey.

Sounds like you said that all I have to do is key again and I will be back up but that sounds to simple.

How do I reset?

What am I supposed to do with the unused Lo reset? I note says to unassert but I don't know what that means.

js
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Re: Overload Board

Postby kf1z » Tue Oct 19, 2010 7:55 pm

Add a relay closure to bring reset hi to ground on TX.

Loop your HV DC supply relay through the relay contacts on the OL board.


In the event of an overload, the OL board will kill the pulse train, and remove the HV DC.

Then you unkey, and key again. that's it.. you "reset" by unkeying (let reset high, go high)
if the overload condition persists... then go find out why.

If you installed the resistors for reset low, remove them. that takes care of reset low.


-----

Now, do you have the PWM output connected to the board, and the output connected to the RF deck?

If so, measure the voltage present at the input.
There may be approx 14vdc there. is so, we use that voltage for the preliminary setup.
Use the calculations I gave earlier... for 14 vdc at the input, set TP1 to 1.4vdc with R702

If you do NOT have the PWM connected to the board, THEN you can apply 12 volts to the input, and set TP1 to 1.2 vdc.


Now, attach a wire to the ground on the board, long enough to reach TP4.
adjust R706 and R708 so there is -10.5vdc at TP1 with the gnd wire connected to TP4, and 0 volts when you disconnect the gnd wire from TP4.
It takes some fiddling with , but is a crucial step to get right.


Set the other steps as given in the schematic.

Then, connect the ol board input to the PWM filter, the output of the board to the RF dec, if you haven't already.
Now, put the transmitter into TX, full operating output, and repeat the setting of TP1 to 3 vdc. (R702)
Then check and reset if needed TP2 to 3 volts while in TX and 0 volts in RX. (R706, R708)

That should do it!
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Re: Overload Board

Postby K9ACT » Tue Oct 19, 2010 11:43 pm

I have it working now but I can't get it calibrated correctly.

I had it up to 200W carrier but just about any level of modulation faulted it.

Things only got worse readjusting things. As I left it, it faults at about 4 amps. with no modulation.

I am not sure about this 3v at TP1 and 2 relative to my lower voltage. Should this be fudged for 30V also? Where does the 3V come from?

At 200W (7A) TP1 would only go to about 2.9V with pot fully clockwise and TP2 was about the same.

What exactly determines the trigger level?

js
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Re: Overload Board

Postby K9ACT » Wed Oct 20, 2010 10:27 am

Here are a few more data points...

With 12v in and dummy load on mod output, max at TP1 is just under 1v so I can not set it to 1.2.

At higher levels of input, the voltage at TP1 increases proportionately but never to 3v.

the threshold voltage is set at 3.

Seems like something is still amiss.

js
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