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Re: TR7 next problem


 

Good ideas Jim and I will get at doing that today. It is windy and raining here quite hard. A good job inside hi hi. I will let you know how it goes. Many thanks for the suggestions?and help.

Jim VE1RB

On Wed, Jan 1, 2025 at 12:24?PM Jim Shorney via <jimNU0C=[email protected]> wrote:

At this point I am suspicious of that 1.3 MHz reading. That may be a spurious reading. It seems to me that the VCO should not be able to run there. What is the level of the signal? The frequency determining components are L502 and the varactor diodes. Resist the temptation to try to adjust L502. As a long time tech told me back in the dim past, when you have a failure "it is never the alignment".

At this point I think I would inspect the solder connections in the high VCO circuit under magnification and good lighting. You could have a failed joint or via. Check the voltages on the three JFETs. C156 or C517 could be suspect. You have a working low VCO to compare voltage and resistance readings to.

On Wed, 1 Jan 2025 07:41:18 -0400
"Jim Harris via " <radiove1rb=[email protected]> wrote:

> Yes Gary I did the ground on RFC505? when looking at the frequency on
> the counter and it does drop a lot. So I guess you are saying the High
> VCO is oscillating at 1.3 MHz . If that is the case there must be
> something wrong on that board unless the info it gets is wrong. Hope
> this helps.

--

73

-Jim
NU0C





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