Marcoin TF1101 sig gen

[Refugee]

I have acquired one of these for a very reasonable price plus more liquid tax than the asking price to collect it from Rugby.

It was part of an estate dispersal that was offered on UKVRR.

The carry handle is a bit of a token as it is a bit heavy to be portable.
There is a bag containing some old capacitors so perhaps the works will need little more than inspection before it is ready to go

Has anyone got one of these they have restored?
The full manual was easy to find on the web so no need for a data request for this one.
It is in pretty good nick with just a couple of minor scratches on the sides.
It has the classic Marconi styling of the day with the picture frame style front panel and the pendulum dial that was such a feature of these instruments.

[Radio Fixer]

Is that just Audio being RC?  I expect beautifully crafted but too big for my bench.  I have a somewhat smaller, and importantly now lighter, Advance SG62B that I restored.  Another nice instrument.

   

I once acquired a huge, a real hernia job, Marconi RF generator (DC to blue light) but to restore it just getting all the controls and front panel off was going to give me nightmares.  I sold it on.  It really fitted the description of a boat anchor.

Good luck with yours

Gary

[AlanBeckett]

Advance J1, J2, 81 and 81A are the af Generators. The 81 is a bit of a 'Brick Outhouse'.

   

Alan

[Refugee]

I bet the Advance looks like it is just as well built as my Marconi. The scale looks like it is trying to copy a Murphy B40.

[AlanBeckett]

Yes, the Scale very B40, B48, Airmec. It's build quality is a bit odd. It's mostly on a PCB but it looks as though bits were added on, as though from a simpler Unit. However, I haven't found an Advance af Generator with a similar PCB yet.
It works splendidly provided I'm strong enough to get it on the Bench

Alan

[Refugee]

The Marconi has a dial that rotates while the pointer remains fixed. I also have a little Heathkit with a springy plastic pointer that rotates over a scale printed on the front panel.
This Marconi is definitely in a higher league with an output signal level that can be relied on with a meter and attenuator that will be pretty well calibrated.
It is going to take me a while to check it all out and fire it up as it is the seedling planting season and to make things even worse I have a roof to fix too.
When I do check it out I will post lots of photos for you all to look at.

[AlanBeckett]

Come, come, my Seedlings are going like a bomb and yesterday I painted one of the Shed Rooves with Bitumastic  
It's fair to say that I failed to give it a second coat today despite the splendid weather, although my excuse is as I was climbing the Ladder one of the Rungs failed. It's now on the Bonfire pile.
It's equally fair to say that I haven't made it into the Garage/Workshop either

Tomorrow's another day, I hope.

Alan

[Refugee]

I have lifted the covers off today to reveal a nice clean chassis.
First I spotted that there is a cordless drive on the fine frequency control. When I turned it around I found that the next section of the drive does indeed have a cord.
   
   

It has a very nice chassis layout with easy access to all the components and I have even spotted military arrow logos on some of the large capacitors.

It has a lovely 4 gang variable capacitor.
All the valves look like they have got good getters and it looks like it has been powered up at some time perhaps when the two capacitors were changed.
These old capacitors look like they have come from the oscillator section as there are two mustard capacitors in there and also there is an electrolytic capacitor C15 that does not look original. It is in the level stabilizer circuit.

   
   
   
   

So what if any work needs to be done before I show it some power?

Time for a close visual inspection in conjunction with the service information.
The first issue I spotted was a "zit" on C24 output transformer snubber and the the series resistor on C23 is high on the other half of the output transformer primary. They are Dubillier paper types and are very likely to fail leaky.
There is another large blue paper capacitor like the ones that have already been changed in position C20 output stage phase splitter. If leaky it will drive the single triode phase splitter on so that the output will become distorted at high level due to the valve turning hard on on the peaks of one side of the signal.
The previous owner should have looked at this one as well as the two in the oscillator. Now I will have to have a look for another mustard to match the other two already replaced ones.
There was a spot of wax on the cabinet floor and this was traced to the cathode resistor in the output stage. It does not look like it has been very hot and the transformer measures all right on both halves of the primary.
There are two very large grid coupling capacitors that are the most likely culprit for this and they will drill out for restuffing without issue. These are C21 and C22.

I have also spotted tin whiskers growing on the chassis and they really do show up on camera too. Zoom it up and have a look.

[Radio Fixer]

As you say and as expected beautifully built. Thanks for the good photo's. Always interesting to look inside these old instruments.

Gary

[Refugee]

Next session will be the Megger on the coupling capacitors especially on the output pentode grids and resistance checks.
Then it will be first light and yes there is a nice big red one on the front.