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Electronics => Repair => Topic started by: TheDefpom on July 07, 2016, 10:29:04 pm

Title: Marconi 2305 Repair
Post by: TheDefpom on July 07, 2016, 10:29:04 pm

Hi Guys and Gals,
I thought I would just post a recent repair I did for a Marconi Modulation Meter, which I picked up from eBay as a faulty unit, I found a few issues with it, but I got it all fixed.

I put a video up on YouTube showing the issues I found, one of which was due to good old Tantalum capacitors failing.

https://www.youtube.com/watch?v=zbMts4fv8dw (https://www.youtube.com/watch?v=zbMts4fv8dw)

Title: Re: Marconi 2305 Repair
Post by: jkf1000 on July 07, 2016, 11:33:47 pm

Thanks for posting the video. I know when I purchased my 2305 quite a few months back there was very little information out there. Mine was advertised as sold as seen and untested but fortunately it is working perfectly so far, all I have had to do is new LEDs throughout, and remove and re-seat the lefthand LCD to clear a bit of oxidation on the contacts. Very useful bit of kit, just a bit on the large size. Karl

Title: Re: Marconi 2305 Repair
Post by: TheDefpom on July 08, 2016, 05:41:53 am

I found a service manual online before I purchased it, so I had that to refer to also, although in reality it wasn't what allowed me to fix it, just looking around and testing/reseating things allowed me to narrow it down.

The manual was only helpful to test the power supply outputs.

I would if uploaded it here too, but the forum doesn't allow a 3MB file upload.

Title: Re: Marconi 2305 Repair
Post by: tautech on July 08, 2016, 06:24:29 am

Quote from: TheDefpom on July 08, 2016, 05:41:53 am

I found a service manual online before I purchased it, so I had that to refer to also, although in reality it wasn't what allowed me to fix it, just looking around and testing/reseating things allowed me to narrow it down.

The manual was only helpful to test the power supply outputs.

I would if uploaded it here too, but the forum doesn't allow a 3MB file upload.

You can post up a link to it Scott, those that find this thread in the future will be thankful.

Title: Re: Marconi 2305 Repair
Post by: TheDefpom on July 08, 2016, 07:02:46 am

I find two manuals online:
The first seems complete, the second appears to be missing all the detailed drawings etc.

http://www.fracassi.net/iw2ntf/manuali/Marconi%20Instruments%202305.pdf (http://www.fracassi.net/iw2ntf/manuali/Marconi%20Instruments%202305.pdf)
http://exodus.poly.edu/~kurt/manuals/manuals/Other/MARCONI%202035.pdf (http://exodus.poly.edu/~kurt/manuals/manuals/Other/MARCONI%202035.pdf)