Re: [time-nuts] Identify RFTGM-II-XO Part
Patrick,
It's possible that's one of the integrated RF amps, and not just an RF
transistor.
You should be able to tell by tracing out the circuit. The inputs and
outputs will typically be capacitor coupled, with DC fed to the output
through a chip inductor or similar choke and resistor. There are some
other variations, but that's a pretty common style part.
Here's and example. Although I doubt this is exactly what you have.
https://www.minicircuits.com/pdfs/ERA-1+.pdf
If it's one of these style amp's, you may be able to find a compatible
part if you know the rough gain required and frequency of operation.
It appears there is a mini circuits part close by, possibly tied into
this amp. Can you tell what part of the circuit this board covers? GPS
signal, etc?
Dan
On 1/10/2018 1:26 AM, time-nuts-request@febo.com wrote:
Message: 3
Date: Tue, 9 Jan 2018 23:33:33 -0600
From: Patrick Murphyfgdhrtey@gmail.com
To:time-nuts@febo.com
Subject: [time-nuts] Identify RFTGM-II-XO Part
Message-ID:
CAG1UqTg3dkjunSiOc=hrkxv7untygMKPT6XqSrfm9qMdwSD2DQ@mail.gmail.com
Content-Type: text/plain; charset="utf-8"
My recently purchased RFTGm-II-XO threw a fault today. When I opened it,
the unmistakable smell of something way too hot was released. I guess this
is one bad aspect of the totally sealed enclosures these come in. Anyway,
when I plugged it in while open, I found U105, the microwave transistor
about centered in the attached photo was getting way too hot. It appears to
be an unmarked microwave transistor, probably part of the 15MHz output
circuit. VR101 - a 7815 on the far right is also getting pretty hot. I
expect the two are connected.
Anyone have an idea of what the nomenclature for U105 is? Replacing it may
be a pipe dream, but knowing its name will be a good first step.
Thanks for any assist.
-Pat
Hi Dan,
That would be a MMIC amplifier. Transistors have Q reference
designators. U's are ICs. Take a look on the other side for markings.
It appears to have been mounted upside-down.
David N1HAC
On 1/10/18 12:22 PM, Dan Kemppainen wrote:
Patrick,
It's possible that's one of the integrated RF amps, and not just an RF
transistor.
You should be able to tell by tracing out the circuit. The inputs and
outputs will typically be capacitor coupled, with DC fed to the output
through a chip inductor or similar choke and resistor. There are some
other variations, but that's a pretty common style part.
Here's and example. Although I doubt this is exactly what you have.
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.minicircuits.com%2Fpdfs%2FERA-1%2B.pdf&data=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C00427658632047168ebd08d5584e8f93%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C636512016803493571&sdata=MUR%2FKgKEJQeJRDNUK6ADoG4fGhQFxkNF31LVg6hzPlk%3D&reserved=0
If it's one of these style amp's, you may be able to find a compatible
part if you know the rough gain required and frequency of operation.
It appears there is a mini circuits part close by, possibly tied into
this amp. Can you tell what part of the circuit this board covers? GPS
signal, etc?
Dan
On 1/10/2018 1:26 AM, time-nuts-request@febo.com wrote:
Message: 3
Date: Tue, 9 Jan 2018 23:33:33 -0600
From: Patrick Murphyfgdhrtey@gmail.com
To:time-nuts@febo.com
Subject: [time-nuts] Identify RFTGM-II-XO Part
Message-ID:
CAG1UqTg3dkjunSiOc=hrkxv7untygMKPT6XqSrfm9qMdwSD2DQ@mail.gmail.com
Content-Type: text/plain; charset="utf-8"My recently purchased RFTGm-II-XO threw a fault today. When I opened it,
the unmistakable smell of something way too hot was released. I guess
this
is one bad aspect of the totally sealed enclosures these come in.
Anyway,
when I plugged it in while open, I found U105, the microwave transistor
about centered in the attached photo was getting way too hot. It
appears to
be an unmarked microwave transistor, probably part of the 15MHz output
circuit. VR101 - a 7815 on the far right is also getting pretty hot. I
expect the two are connected.Anyone have an idea of what the nomenclature for U105 is? Replacing
it may
be a pipe dream, but knowing its name will be a good first step.Thanks for any assist.
-Pat