Marconi TF2950/5 Radio Test Set
 

Hi All.
I have acquired one of these units in good order but have power supply problems. The PSU circuitry is different to the only circuit information I have been able to find - a problem identical, I think, to a previous poster on this forum. The /5 seems to indicate a different model in a number of areas.

I have seen references to a Marconi Instruments Yahoo group but haven't been able to find the group using the Yahoo search tool. Does anybody know if the group still operates? and if so where it can be found.
Many thanks

Re: Marconi TF2950/5 Radio Test Set
 

The group is here I hope:-

https://groups.yahoo.com/neo/groups/...struments/info

marconi_test_instruments

Re: Marconi TF2950/5 Radio Test Set
 

Hi,
many thanks. Don't understand why this didn't come up when I searched on "Marconi" but then who understands Yahoo.

Re: Marconi TF2950/5 Radio Test Set
 

It may have been my post to which you refered. The main PSU on mine works, but the battery charging circuit does not and is totally different to the manual I found online, I cannot honestly remember if the main PSU is the same as shown in the on-line manual; I suspect it may not be. The battery charging was a "nice to have" and I have gone no further with it due to a plethoria of other things that have demanded my time. Mine also has an annoying fault with the deviation metering circuit - I cannot seem to get enough gain out of it - that I have never got to the bottom of.

If there is anything I can do, in terms of measuring anything on mine, that will help you please ask, but I will not be able to get at mine until about the 25th.

Also, this kit appears not to have actually been manufactured by Marconi, rather being a piece of badge engineering instead.

73

Ian G8KSZ

Re: Marconi TF2950/5 Radio Test Set
 

Hi Ian,
Yes it was your post i referred to. Pretty much the same symptoms on my unit - nothing on the battery side but the main HT OK. One "feature" which puzzled me for a while is that the main HT does not come on when the unit is switched On - you have to switch to Charge (and a Battery voltage is then displayed) and then back to On at which point normal HT appears. The batteries are completely dead of course. I did wonder if the dead batteries are the source of the problem - maybe the battery charging circuit is smart enough to recognise when no battery is present (or dead) and inhibit itself. But I don't feel like shelling out for 3 new batteries without being a bit more certain about what is going on.
As you say, made in Germany - no idea who by. The standard of construction is high but surprisingly old-fashioned I thought - cotton covered wiring and hand soldered PCB's. I particularly like the 1/8" steel plate case that the unit comes in - none of your flimsy aluminium rubbish here, thank you!
I do want to be able to use the unit on battery so will continue my investigations - let you know if anything useful results.
cheers

Re: Marconi TF2950/5 Radio Test Set
 

I may be home briefly on Friday, Saturday and at least part of Sunday if you want anything measuring.

Regards

Ian