Blew the irf510's up, substituted irfp260's in there place...
#ubitx-help
Well, pushing the limits on the irf510 mosfets, they caved on me. So, digging through my junk I found four irfp260's and soldered them in as an effort to get back on the air. So far, it seems to work,
By
Ghericoan
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#44691
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Re: Soldering gun or iron
Likewise somewhere I have my original Weller Soldering Gun from around
1958! Yes, it still works but I don't really have a use for it. I do
have a huge Weller soldering iron for replacing Can
By
Dave Bottom <ars.kd6az@...>
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#44690
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Re: Micro BitX No Audio TDA2822?
Some of these clones seem to blow for no particular reason.
I think we primarily must limit the supply voltage, not so much the current under load.
Though they are really good at dealing with
By
Jerry Gaffke
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#44689
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Re: Micro BitX No Audio TDA2822?
The DPAK package is perfect.
http://uk.farnell.com/stmicroelectronics/l78m05abdt-tr/ic-v-reg-5-0v-smd-dpak-3-7805/dp/1366575
By
Joe Puma <kd2nfc@...>
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#44688
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Re: Micro BitX No Audio TDA2822?
Quiescent current into the TDA2822 is around 6ma, peaks can be 1 Amp.
Though?100ma might be sufficient for moderate speaker volumes.
You would need two resistors for a voltage divider, and maybe
By
Jerry Gaffke
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#44687
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Re: Micro BitX No Audio TDA2822?
One could use a voltage drop resistor. The higher the current draw, lower
would be the voltage to the TDA2822
[email protected]> wrote:
By
Ashhar Farhan
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#44686
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Re: Micro BitX No Audio TDA2822?
Regarding Joe's suggestion of using the Raduino's LM7805 to power the TDA2822:
One objection I would have is the extra wire, needs to be dealt with every time?
I unplug the Raduino.? Though not a
By
Jerry Gaffke
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#44685
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Re: 13.8 v power supplies safe for bitx?
Jerry,
I'm not sure everyone understands what foldback current limiting
is. Your message 40729 explains it well. In action it is like a fuse.
The power supply opens the power lead until the operator
By
Tim Gorman
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#44684
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Re: RD transistors, unobtanium?
IRF510 and IRF512 both have a Vds max of 100v.
According to these guys, at least, not many IRF512 datasheets out there:
? ??http://www.njsemi.com/datasheets/IRF510%20-%20IRF513.pdf
The IRF510 has a
By
Jerry Gaffke
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#44683
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Re: Soldering gun or iron
It might be worth looking for some auctions as well. I've never understood how I did anything with solder before my metcal sp-200 iron I've had for 20 yrs now. It's way more iron than I need and
By
N1AFF - formerly KB1JPW
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#44682
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Re: 13.8 v power supplies safe for bitx?
True.? The standard current limiting supply I described is not something to lean on
to avoid driving the final too hard, that's not what I was suggesting.
If there's a current limit on the finals,
By
Jerry Gaffke
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#44681
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Re: Micro BitX No Audio TDA2822?
Could work, first time this was suggested.
An extra wire, the Raduino regulator would get hotter.
?
By
Jerry Gaffke
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#44680
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Re: RD transistors, unobtanium?
Title. Fake news.
Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ
Owner - Operator
Big Signal Ranch – K9ZC
Staunton, Illinois
Owner – Operator
Villa Grand Piton -
By
K9HZ
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#44679
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Re: RD transistors, unobtanium?
Where did this info come from?
RF Parts shows these in stock.
I just purchased both the RD16HHF1 and RD15HVF1 in quantity from RF parts
and received them in 2 days.
Mitsubishi still shows these on
By
Dave Bottom <ars.kd6az@...>
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#44678
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Re: RD transistors, unobtanium?
Actually, the closest available MOSET to the IRF510
is the IRF512, which is the same device, only it is rated
for a drain voltage of 100v. It goes by other numbers as well.
There are many devices
By
John Backo
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#44677
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Re: 13.8 v power supplies safe for bitx?
When you current limit the PA you are doing the same thing that happens
when you overdrive a linear amp and cause flat-topping, i.e. the PA is
driven out of its linear range.
That causes spurious
By
Tim Gorman
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#44676
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Re: Micro BitX No Audio TDA2822?
Jerry has the group discussed pulling 5v from somewhere else like use the 5v that powers the Raduino? Maybe temporarily until they can get a regulator and or new WX chip?
Joe
KD2NFC
By
Joe Puma <kd2nfc@...>
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#44675
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Re: Raduino oscilators. 33mhz and 57mhz. Documentation says one thinng, but this is what I measured.
Jerry,
A lucid and easy to follow explanation! Thank you!
tim ab0wr
"Jerry Gaffke via Groups.Io" <jgaffke@...> wrote:
By
Tim Gorman
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#44674
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Re: Soldering gun or iron
I used to watch my grandfather repair tube TV’s with this one.
By
Joe Puma <kd2nfc@...>
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#44673
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Re: USB interface cable installation uBITX
I used the one foot long cable and it fit perfectly in the Hammond Case as
you can see.
I ordered it on Amazon just because they can deliver in one hour, or next
day depending on how quickly you want
By
Dave Bottom <ars.kd6az@...>
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#44672
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