UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Marconi TF1041C

Skywave · 3rd Dec 2013, 7:49 pm

This thread is a follow-on to my post entitled "Manual for Marconi TF1041C VTVM".
Since I intend to repair & renovate this item, it seems appropriate to start a new thread - appropriately named. My last post in that related thread, in which I started to discuss such a renovation, has been copied here as below, since it is in this thread where that aforementioned post clearly belongs.

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I'm running into big problems with this item. It's time for a general appraisal of my options to get this item working properly.

It has been necessary to carry out a number of further repairs, including replacing the 12AT7 and various passives, all of which being routine repair work, was not a problem. But the problems really began when I tried to perform the calibration: the various settings would not give reliable and consistent results. Apart from the fact that the various pre-set calibration resistors are of the cheap and unreliable open-frame skeleton type, all of which need replacing, (there are other faulty components somewhere, too), a more serious concern is when a comparison is made between the model B and the model C, it is evident that Marconi realised that the model B had some serious design errors related to the calibration, which they have attempted to correct in the model C - which, in itself, is fair enough: such is the nature of the design & evolution of many products.

Now in order to attain a reasonable degree of accuracy and reliability with my unit, it seems logical to rework the entire front panel section so that it becomes a C model - thus making this entire item a true TF1041C, rather than the 'half-and-half' unit that it is now. However, "logical" as that may be, the amount of work and expense involved in doing that rework & re-design is far from trivial, mainly on account of the method and style of the construction of this unit and with a very real possibility that wiring errors could easily arise, leading to more work and trouble.

All of which leaves me in a bit of a quandary. One option I have is to go shopping for a 'real' TF1041C, either to use as a spares source (if not functional), or it that item is fully functional, retain my existing 'TF1041B/C' as a spare parts source. So on that basis, a 'Wanted' request at this Forum seems now to be worthwhile.

► 'Wanted' thread now produced.

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Al.

3rd Dec 2013, 7:49 pm	#1
Skywave Rest in Peace Join Date: Jun 2006 Location: Chard, South Somerset, UK. Posts: 7,457	Marconi TF1041C - an overhaul. This thread is a follow-on to my post entitled "Manual for Marconi TF1041C VTVM". Since I intend to repair & renovate this item, it seems appropriate to start a new thread - appropriately named. My last post in that related thread, in which I started to discuss such a renovation, has been copied here as below, since it is in this thread where that aforementioned post clearly belongs. ------------------ I'm running into big problems with this item. It's time for a general appraisal of my options to get this item working properly. It has been necessary to carry out a number of further repairs, including replacing the 12AT7 and various passives, all of which being routine repair work, was not a problem. But the problems really began when I tried to perform the calibration: the various settings would not give reliable and consistent results. Apart from the fact that the various pre-set calibration resistors are of the cheap and unreliable open-frame skeleton type, all of which need replacing, (there are other faulty components somewhere, too), a more serious concern is when a comparison is made between the model B and the model C, it is evident that Marconi realised that the model B had some serious design errors related to the calibration, which they have attempted to correct in the model C - which, in itself, is fair enough: such is the nature of the design & evolution of many products. Now in order to attain a reasonable degree of accuracy and reliability with my unit, it seems logical to rework the entire front panel section so that it becomes a C model - thus making this entire item a true TF1041C, rather than the 'half-and-half' unit that it is now. However, "logical" as that may be, the amount of work and expense involved in doing that rework & re-design is far from trivial, mainly on account of the method and style of the construction of this unit and with a very real possibility that wiring errors could easily arise, leading to more work and trouble. All of which leaves me in a bit of a quandary. One option I have is to go shopping for a 'real' TF1041C, either to use as a spares source (if not functional), or it that item is fully functional, retain my existing 'TF1041B/C' as a spare parts source. So on that basis, a 'Wanted' request at this Forum seems now to be worthwhile. ► 'Wanted' thread now produced. ----------------- Al.