I'm waiting for my replacement PCM1804, too.
Hoping that it will solve the issue with my QMX.
I would agree to Andy. There seems to be an issue with this chip, but if you just take a look at the order backlog for the assembled devices and Hans comments about packing 1000+ kits, the defects are still in the permille range.
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On Thursday, 11 July 2024 05:18:32 -04 John Rabson via groups.io wrote:
> Is the 1804 a successor to the COSMAC 1802 which we flew in Oscar
> seven and Oscar nine? It was the only space qualified processor which
> we were allowed access to.
Greetings John,
it is an A/D converter. Please see attached datasheet.
>
> John G3PAI F5VLF
>
> > On 11 Jul 2024, at 10:56, Philip Thompson via groups.io
> > <pcteee@...> wrote:
> >
> > Hmmmmmm!? this PCM1804 issue is giving me the jitters!
> > Ordered a QMX+ a few days ago and if this is a problem. I don't have
> > the tools or skills to replace the chip. If I do get a faulty one,
> > is there a returns procedure or is the board scrap? Being
> > pessimistic I know but there seems a fair amount of chat on this
> > issue... Fingers crossed
> > Phil? G4JVF
Hi Phil,
it happens very rarely.
If you sift through the archives you will find several knowlegable OMs who have the skills and the equipment to help in such rare cases.
Wether you ordered a kit or an assembled unit? make yourself thoroughly familiar with the assembly and operating manual before you start building/using the QMX(+).
Also have a closer look at this video:
?
73 de Eike
--
Eike Lantzsch KY4PZ / ZP5CGE
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On 11/07/2024 09:56, Philip Thompson via groups.io wrote: I don't have the tools or skills to replace the chip. But you have ham friends who probably have? Or there will be someone on here local-ish to your QTH who can help. And remember, you only hear about the problems not the many hundreds of boards that work fine first time.
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On 11/07/2024 10:18, John Rabson via groups.io wrote: Is the 1804 a successor to the COSMAC 1802 which we flew in Oscar seven and Oscar nine? It was the only space qualified processor which we were allowed access to.
John G3PAI F5VLF
No.
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Is the 1804 a successor to the COSMAC 1802 which we flew in Oscar seven and Oscar nine? It was the only space qualified processor which we were allowed access to.
toggle quoted message
Show quoted text
On 11 Jul 2024, at 10:56, Philip Thompson via groups.io <pcteee@...> wrote:
Hmmmmmm!? this PCM1804 issue is giving me the jitters!
Ordered a QMX+ a few days ago and if this is a problem. I don't have the tools or skills to replace the chip.
If I do get a faulty one, is there a returns procedure or is the board scrap?
Being pessimistic I know but there seems a fair amount of chat on this issue...
Fingers crossed
Phil? G4JVF
|
Hmmmmmm!? this PCM1804 issue is giving me the jitters!
Ordered a QMX+ a few days ago and if this is a problem. I don't have the tools or skills to replace the chip.
If I do get a faulty one, is there a returns procedure or is the board scrap?
Being pessimistic I know but there seems a fair amount of chat on this issue...
Fingers crossed
Phil? G4JVF
|
The devil is in figuring out in which step of the procurement to testing process most A/D failures happen. Hans likely has some failure data from the kits they've assembled. I wonder how those compare to field failures (admittedly a harder number to compile)?
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Re: Terminal emulation for QCX ?
Thanks Hans :-)
Listening to it again, I think what you were talking about was that the QMX has built-in test and alignment tools, similar to QCX.
Very interesting presentation b.t.w. really enjoy getting more of an insight into the clever design behind these kits.
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Re: Terminal emulation for QCX ?
Hello Eben
May be a verbal typo :-/? ? QDX and QMX-series support terminal log in with a terminal. QCX-series do not. QCX-series have a 38400bps?CAT port, but not a terminal login with PuTTY.?
In the recent QMX+ talk Hans gave to the RSGB
At around 47:00 he mentions terminal emulation via putty for the QCX...
Did he maybe mean the QDX ?
I've had a look at the operations manuals for QCX, QCX+ and QCX-mini, and find no references to terminal emulation ...
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Terminal emulation for QCX ?
In the recent QMX+ talk Hans gave to the RSGB
At around 47:00 he mentions terminal emulation via putty for the QCX...
Did he maybe mean the QDX ?
I've had a look at the operations manuals for QCX, QCX+ and QCX-mini, and find no references to terminal emulation ...
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Re: Issues with summer travel and hot cars?
I think?you will?carry a camera also. I want all nato allies know russian cameras works at minus 25 celsius, degrees , I tested in deep freezer. :) I wrote that if the temperature drops suddenly in Utah :)
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Re: QMX+ audio amp/speakers
Steve, I’m working on the speaker idea also.
Have you found any issue with the speaker’s magnetic fields interfering with the toroids directly below?
I’m doing a half height implementation so if you have issues mine would be worse with the speakers sitting directly on the dev board just 5mm above the toroids.
I’ll probably run through all the tests for each band with and without the speakers just to see what it looks like.
--
Randy, N4OPI
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I wonder if there's a way to test these (quickly) before they go out so that the DOA ones get swapped before they are kitted/used in a build...
The common PCM1808 module seems to have a high DOA rate also.? I am one of the T41 builders and have had 3 out of 5 DOA. Maybe the manufacturer isn’t doing a great job testing, or the baddies are slipping out of the factory floor sweeps.?
Larry KB3CUF? On Wed, Jul 10, 2024 at 9:20?PM Kaufman, Matt - N3AR via <matt.d.kaufman= gmail.com@groups.io> wrote: I know that Hans is a (super) busy dude, but this really seems like something that he should want to dig into; the abnormally high number of "it must be this IC" has gotten?to the point where now, people are just assuming the chip went bad when things don't work and being right in their assumption.? Anecdotally, this seems like a platform issue of some sort since this one component seems to be such a common failure point.
OK so the problem was a defective (maybe counterfeit?) PCM1804 IC.
Once this part was replaced (after purchasing from Mouser.Com) my receiver sprung to life:)
I am lucky I have the skills to replace this part myself.
The initial symptoms were once the QMX+ was turned on - I heard some noise that quickly faded out within a few seconds.
I figured from the beginning that I had a defective IC after hearing others with the same problems.
73's Michael N2ZDB
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Re: FS: QMX Low Band, With Enclosure
The QMX has been sold.
--
Jim / K7TXA
Eagle, ID
SKCC 10447T
BUG 301
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QMX+ Resistance measurements
Is there a chart of pre-power up resistance measurements?
Power socket is 15 Mohm
Antenna socket is 0.7 ohm
--
Dan Reynolds -- KB9JLO
<><
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The common PCM1808 module seems to have a high DOA rate also.? I am one of the T41 builders and have had 3 out of 5 DOA. Maybe the manufacturer isn’t doing a great job testing, or the baddies are slipping out of the factory floor sweeps.?
Larry KB3CUF? On Wed, Jul 10, 2024 at 9:20?PM Kaufman, Matt - N3AR via <matt.d.kaufman= gmail.com@groups.io> wrote:
I know that Hans is a (super) busy dude, but this really seems like something that he should want to dig into; the abnormally high number of "it must be this IC" has gotten?to the point where now, people are just assuming the chip went bad when things don't work and being right in their assumption.? Anecdotally, this seems like a platform issue of some sort since this one component seems to be such a common failure point.
OK so the problem was a defective (maybe counterfeit?) PCM1804 IC.
Once this part was replaced (after purchasing from Mouser.Com) my receiver sprung to life:)
I am lucky I have the skills to replace this part myself.
The initial symptoms were once the QMX+ was turned on - I heard some noise that quickly faded out within a few seconds.
I figured from the beginning that I had a defective IC after hearing others with the same problems.
73's Michael N2ZDB
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Re: Issues with summer travel and hot cars?
On Wed, Jul 10, 2024 at 12:35 AM, Nolan K0HAA wrote:
Should I be concerned with leaving it in a hot car in a southern Utah summer
Consider that much of the electronics in your car are powered on and exposed to temperature extremes 24/7/365, and can be expected to survive for decades. Heat is not great for batteries, though it won't kill them. A couple of hours in a parked car should be a walk in the park for your radios.? I would not leave LCD displays in direct sunlight, though.?? 73, Don N2VGU
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Re: FS: QMX Low Band, With Enclosure
Jim Bennett
I would really use the low band QMX
Fair price
How do we proceed? Paul Wamble 214-405-5876, iPhone?
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Show quoted text
On Jul 10, 2024, at 5:42?PM, Jim Bennett / K7TXA via groups.io <w6jhb@...> wrote:
?Dang it - forgot to mention - it is wired for 12 volt operation.
--
Jim / K7TXA
Eagle, ID
SKCC 10447T
BUG 301
|
I know that Hans is a (super) busy dude, but this really seems like something that he should want to dig into; the abnormally high number of "it must be this IC" has gotten?to the point where now, people are just assuming the chip went bad when things don't work and being right in their assumption.? Anecdotally, this seems like a platform issue of some sort since this one component seems to be such a common failure point.
OK so the problem was a defective (maybe counterfeit?) PCM1804 IC.
Once this part was replaced (after purchasing from Mouser.Com) my receiver sprung to life:)
I am lucky I have the skills to replace this part myself.
The initial symptoms were once the QMX+ was turned on - I heard some noise that quickly faded out within a few seconds.
I figured from the beginning that I had a defective IC after hearing others with the same problems.
73's Michael N2ZDB
|
OK so the problem was a defective (maybe counterfeit?) PCM1804 IC.
Once this part was replaced (after purchasing from Mouser.Com) my receiver sprung to life:)
I am lucky I have the skills to replace this part myself.
The initial symptoms were once the QMX+ was turned on - I heard some noise that quickly faded out within a few seconds.
I figured from the beginning that I had a defective IC after hearing others with the same problems.
73's Michael N2ZDB
|
Dirk
Chuck AI7SY
Kaufman, Matt - N3AR
Dan Reynolds
Donald S Brant Jr
Paul K5EBP
Michael N2ZDB