45943Re: [softrock40] RXTX Ensemble
- Jul 20, 2010Hi,
Your voltage measurements below are not consistent will the right components mounted in the right locations.
For example: your measurements have a base to emitter voltage of -1.17 volts which should be about -0.7 volts when Q3 is conducting. Please make sure a 2N3906 transistor in mounted in the Q3 position.
Tony Parks kb9yig@... http://www.kb9yig.com
On Tue, 2010-07-20 at 16:59 -0700, Norm wrote:
Thanks for your reply,
The ABPF is off, pin 4 of U4 has 9.22V on it, 0V when grounded. Q3's emitter has 12.1V , the base
has 10.93V and the collector 2.3V.QSD EN has 2.95V measured c69.
QSE clk 0,1 QSD clk 0,1 were all 7.04 mHz. QSE at pin 5 of U5 was 2.49V and QSD at pin 6 of U5 was 2.95V.
Pins 1 and 15 of U10 still have 5.04V on them.
I hope from this you can help me figure where my problem is.
Sent: Tuesday, July 20, 2010 2:04 AM
Subject: Re: [softrock40] RXTX Ensemble
----- Original Message -----
Subject: [softrock40] RXTX Ensemble
>the RXTX Ensemble draws 27.63mA normally
> and 27.65mA when I short pin 4 of U4 to ground.
For a start the PTT is not working. What is the voltage at U4 pin 4? And
the voltages around Q3? Both with U4 grounded and not.
>The only thing that wasn't correct in the checks was the continuity check
>between c27 to c39 has continuity all the time,
(Only after sorting out Q3 PTT) This is correct for RX. If it does not
switch on TX this will be due to a faulty Q10 or voltage at QSD EN.
Is /PTT high? This makes QSD EN high.
If it is then Q9 should pull U10, 1 & 15 low.
> U10, pins one and
> 15 both have 5Volts on them,
But this is wrong for RX. Q9 should pull this low, what is QSD EN volts?
73 Alan G4ZFQ
The receive doesn't
> work although it did during the stage when we tested it. I'm old
> and couldn't remember how I wound the transformers so I rewound
> T2,3,4 and 5. I've built most of the SoftRock kits with no trouble,
> but this one's kicking my butt. I had a bunch of BS170s so I
> replaced Q9, 10, and 11 to no avail. What could be holding the PTT
> high. I've checked parts placement twice, Ohmed all the resistors
> before I installed them.
now that all the parts are in place
> but I'm sure it worked correctly during construction.
> Sorry for such a long post, but it looks like I won't be able
> to finish this one without help.
> Thanks, 73, Norm, k6uo
> Yahoo! Groups Links
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