Blew up antenna port A on my new RSP2. :(

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Jimbo
Posts: 2
Joined: Wed Sep 27, 2017 1:12 am

Blew up antenna port A on my new RSP2. :(

Postby Jimbo » Wed Sep 27, 2017 1:49 am

Not quite sure what happened yet but my brain was apparently switched off while testing some equipment (at work, ugh) with my brand new RSP2. I'm not sure if it was some DC or excessive RF power level, but that likely doesn't matter at this point - lesson learned, again, doh.

Antenna port B is still fine, so I'm hoping to perhaps fix this myself. It might be as simple as replacing a blown transistor (or two), labelled A7N, or perhaps the 8-pin IC labelled 251. Any thoughts as to which components were the likely fuse in this case, and suitable replacement components I might be able to obtain from Digikey?

I must say that I'm glad to be out of the electronics business, now that components are smaller than fly poop.
Last edited by Jimbo on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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DF1KZ
Posts: 19
Joined: Fri Nov 27, 2015 1:37 pm

Re: Blew up antenna port A on my new RSP2. :(

Postby DF1KZ » Sat Sep 30, 2017 3:20 pm

Hello Jimbo,

imho the devices you mention are diodes like BAV99 (A7). They work as limiters.
If port B and HiZ is still working I would try to remove this diodes and make a test whether reception is possible.
The IC labelled 251 is a antenna switch. Hopefully you didn't blow that.

Wolfgang

Reason: No reason
SDRplay (RSP1, RSP2 pro) with:
RFsystems DX-10 (14kHz to 50MHz), ICOM Discone AH8000 (10MHz to 2GHz)
12m above ground

Jimbo
Posts: 2
Joined: Wed Sep 27, 2017 1:12 am

Re: Blew up antenna port A on my new RSP2. :(

Postby Jimbo » Sun Oct 01, 2017 5:28 pm

I haven't tried the hi-z input yet. The port selection switch still responds to control, and it passes port B through just fine, so I'll cross fingers and hope that I merely cooked the little diodes.

I'll pick up some of those diodes and give it a try. My recollection of SOT-23 was of a larger package, but maybe my old eyes are misleading me.

Danke, Jimbo
Last edited by Jimbo on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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F1BJB
Posts: 108
Joined: Wed Jul 15, 2015 4:24 pm
Location: Beauvais France

Re: Blew up antenna port A on my new RSP2. :(

Postby F1BJB » Mon Oct 02, 2017 2:33 pm

On many DVBT dongles the diodes are directly connected to the RF input
So any DC on the coaxial kills them.
Bad design a small capacitor is needed.

Reason: No reason

DF1KZ
Posts: 19
Joined: Fri Nov 27, 2015 1:37 pm

Re: Blew up antenna port A on my new RSP2. :(

Postby DF1KZ » Mon Oct 02, 2017 4:49 pm

imho there are decoupling capacitors used for the inputs of RSP1/2. They are situated in front of the limiting diodes BAV99W of Port A and Port B so the diodes will not be destroyed by DC (but maybe by to much HF).
The HiZ-Input does not seem to have capacitors in front of the diodes, they are connected directly to the connector.
I'm not sure, whether the BIAS-T on Port B can be destroyed by external DC, but I would not try to connect 12V to Port B.

Wolfgang

Reason: No reason
SDRplay (RSP1, RSP2 pro) with:
RFsystems DX-10 (14kHz to 50MHz), ICOM Discone AH8000 (10MHz to 2GHz)
12m above ground


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