75A
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WA4LLR <wa4llr@...>
Hi. I am brand new to the group. Just purchased the 75A AM kit. A friend tells me that the current manual has the orientation of Q2 incorrect. Is that right. Just starting the assembly. Thanks for any info. 73, Dave WA4LLR Sent from my Verizon, Samsung Galaxy smartphone |
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AG1P Ron
The following message was captured by the ghost in the machine:
Hi. I am brand new to the group. Just purchased the 75A AM kit. A friend tells me that the current manual has the orientation of Q2 incorrect. Is that right. Just starting the assembly. Thanks for any info. 73, Dave WA4LLR
72 - Ron - AG1P 4SQRP Volunteer Moderator
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Hello Dave That has been confirmed. The silk screen in the board is reversed. 72 Johnny AC0BQ On Thu, May 14, 2020 at 2:25 PM AG1P Ron <ag1p@...> wrote:
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Check out the 4SQRP website at 4sqrp.com |
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WA4LLR <wa4llr@...>
Thanks Johnny. That is a big help. Stay healthy and God bless.
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Dave
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AndyH
Welcome Dave!
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When looking at the board from the front, the larger flat side of Q2 points to the right. Feel free to join us on the N75a sub-group as well: https://4sqrp.groups.io/g/N75/topic/q2_orientation/72687095?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,0,72687095 73, Andy On Thu, May 14, 2020 at 02:05 PM, WA4LLR wrote:
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You too! 73 On Thu, May 14, 2020 at 3:24 PM WA4LLR <wa4llr@...> wrote:
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Check out the 4SQRP website at 4sqrp.com |
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WA4LLR <wa4llr@...>
Thanks Andy!
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Timothy East
What? What happens if the component is installed backwards?
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Is this information captured in the assembly manual?
Tim
K0EMP On May 14, 2020, at 15:26, Johnny AC0BQ <jomatlock@...> wrote:
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Timothy East
I’m concerned now my assembly was incorrect
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Tim
K0EMP On May 14, 2020, at 17:25, Timothy East <timothyeast@...> wrote:
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w9ran <w9ran@...>
On 5/14/2020 5:26 PM, Timothy East wrote:
I’m concerned now my assembly was incorrectCompare to this photo that shows the orientation of Q2 in the context of adjacent components, as long as it's installed this way, you're good to go regardless of what the silk screen says: https://rantechnology.com/files/resources/D3365CDD-9FA2-F675-4CA1649C1E6BB4E7.jpg It also won't work if it's backward. My board is an early one, I assumed the silk-screen was corrected on later ones. My other comments on the Nouveau 75: https://tinyurl.com/w5saw83 73, Bob W9RAN |
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Timothy East
Weird. Mine looks like it is installed per the silkscreen. But mine works so it must be installed correctly.
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Tim
K0EMP
 On May 14, 2020, at 18:20, w9ran <w9ran@...> wrote:
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Timothy East
Oh, it appears, upon closer inspection, that the rounded edges belong to the “rear” of the component. The rear is facing the heat sink side and the other or front is facing the speaker side.
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Tim
K0EMP On May 14, 2020, at 19:04, Timothy East <timothyeast@...> wrote:
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The is a picture of my completed 75A board. This is the correct placement for Q2.
Don WA8TWM
From: main@4SQRP.groups.io [mailto:main@4SQRP.groups.io] On Behalf Of Timothy East
Sent: Thursday, May 14, 2020 20:25 To: main@4sqrp.groups.io Subject: Re: [4SQRP] 75A
Oh, it appears, upon closer inspection, that the rounded edges belong to the “rear” of the component. The rear is facing the heat sink side and the other or front is facing the speaker side.
Tim K0EMP On May 14, 2020, at 19:04, Timothy East <timothyeast@...> wrote:
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w9ran <w9ran@...>
On 5/14/2020 7:04 PM, Timothy East wrote:
Mine looks like it is installed per the silkscreen. But mine works so it must be installed correctly.Not really, you have it installed correctly however, just like in my photo. This transistor is thinner than the TO-92 case which is what the silk-screen represents, but the flat side of the transistor must be oriented to face the three blue resonators as you have done. If you had installed Q2 with the flat side of the package aligned with the flat side of the silk-screened diagram, it wouldn't work. 73, Bob W9RAN |
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Timothy East
Thanks.
I am very relieved. This is about the nicest kit outcome I have built yet. I was not relishing the idea of trying to reinstall that component.
Tim
K0EMP
From: main@4SQRP.groups.io <main@4SQRP.groups.io> on behalf of w9ran <w9ran@...>
Sent: Thursday, May 14, 2020 8:17 PM To: main@4SQRP.groups.io <main@4SQRP.groups.io> Subject: Re: [4SQRP] 75A On 5/14/2020 7:04 PM, Timothy East wrote:
> Mine looks like it is installed per the silkscreen. But mine works so > it must be installed correctly. Not really, you have it installed correctly however, just like in my photo. This transistor is thinner than the TO-92 case which is what the silk-screen represents, but the flat side of the transistor must be oriented to face the three blue resonators as you have done. If you had installed Q2 with the flat side of the package aligned with the flat side of the silk-screened diagram, it wouldn't work. 73, Bob W9RAN |
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nm0s_qrp
The Q2 silkscreen on the 75 and 75A is backward. The rig will work with Q2 backward, but power output will be reduced.
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Here is the data sheet on Q2.
From: main@4SQRP.groups.io [mailto:main@4SQRP.groups.io] On Behalf Of nm0s_qrp
The Q2 silkscreen on the 75 and 75A is backward. The rig will work with Q2 backward, but power output will be reduced. |
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Timothy East
Sorry for this seemingly elementary question. But, as this component isn’t shaped exactly as others, I want to make sure I’ve installed it correctly.
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There is writing on one side of the component and no writing on the other. With the heat sinks on one side and the speaker on the other, which side is the writing side to be facing? Towards the speaker or towards the heat sinks????
Please,
Tim
K0EMP On May 15, 2020, at 10:24, Donald A. Kocsis <dkocsis@...> wrote:
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Timothy East
So, the Q2 component has writing on one side but is flat on both sides. It’s not shaped like a Capital D.
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I installed it with the side with the writing on the flat side of the D. Like in the silk screening.
Now that I know that is backwards, I removed the component with some difficulty. I managed to remove the pad on the bottom side of the board. I replaced the component turned around with the writing on the opposite direction with the writing facing the
speaker side or the rounded side of the silkscreening “D” . The center leg is soldered from the top and the two legs are soldered from the bottom. But I see no change in power when tuning it.
In fact I’m afraid I might have had it right to begin with. But won’t now be able to change it back.
Can some one help me with this?
Tim
K0EMP
On May 15, 2020, at 12:01, Timothy East <timothyeast@...> wrote:
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Jim, N5IB
This is a good excuse to do a little engineer/detective work involving the schematic and the data sheet.
The schematic shows that the Source of Q2 is to be connected to the ungrounded side of R8. The data sheet (see message # 22052) has a pictorial that identifies the Drain, Gate, and Source leads unambiguously. Close examination of the PC board shows a trace, on the top side of the board, hiding under that black solder mask, from R8 to one of the pads of Q2. That pad must be therefore be intended for the Source lead, and all the rest will fall into place. Of the two flatted sides of Q2, the wider one must face towards the blue resonators - as shown in a couple of posted pictures. Tongue-in-cheek aside to Dave, NM0S ... When you get to the Pearly Gates, Dave, and I have no doubt you've earned your way in, St Peter is going to look in his QRP logbook and exclaim, "Welcome NM0S, but... why, oh why, oh why the fascination with black solder masks? We usually send those to the repair techs in that 'other place' as their pennance" LOL Truth, Justice, and white screens on green masks forever!! Jim, N5IB |
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