ferranti: Ferranti U1040-where I can get a chassis layout?

To any potential RMorg helpers,

                                             I have just started some restoration work on a Ferranti U1040 which after some valve/tube replacement, is operating fairly well.

In order to try to rectify some distoration & intermittent sound loss, I have removed the chassis, and attached  a couple of pictures of what I have found - despite working fairly well, there are the remains of what I think is a 0.01uf capacitor, which has the original wire connector at one end still soldered as can be seen.

I have tried for about an hour to see where the other end was attached, without success; perhaps the other end of the capacitor has been blown out of the radio somehow, I certainly can`t find it.

As far as I can see from the schematic, there are 3 such cpacitors fitted, and I have found the other two.

In order to replace these 3  `wax, caps`, I need to find out which capacitor it is that has blown, and where it should be connected within the chassis; apart from the one connection I still have (which is connected to the chassis itself). I cannot find a chassis layout in amongst all my sources.

Can anyone help me with this cap replacement please - this is a fairly good looking radio, and even without the blown cap operates adequately enough, but has the potential to work even better.

 

Thanks in advance for any assistance anyone can provide.

 

graham guy

Attachments:

• U1040a (45 KB)
• U1040b (57 KB)

To thank the Author because you find the post helpful or well done.

 

Hello Graham,

The only documentation readily available for the U1040 from all the sources that I know of is that on the model page from R & TVS which doesn't include a chassis layout. What voltage rating is that 0.01uF capacitor ?  That will give me a clue as to whether it's a decoupling capacitor or one connected to the power supply.

Regards ........... Howard

 

To thank the Author because you find the post helpful or well done.

Good Evening Howard - Just crap on TV eh?, anyway, thanks for the quick reply, 

   The Cap is  350Vac/700Vdc wkg( I think, it`s not too clear); I don`t have the list of components either, but may have found what it is by a bit of schematic reading, and going back to basics by following through the circuit without de-soldering too much.

There is burn damage on the on/off s/w&vol. control, and I think this may well be C61; I`ve got a couple of 0.05uf of 300V DC wkg & will try tomorrow with them in parallel to see if this does the trick temporarily.

I note that you are or were in the BVWS - do you find this of use, and have you managed to copy their CDs; it`s so frustratiting having to install them all the time?

 

Regards & thanks again.

 

graham 

To thank the Author because you find the post helpful or well done.

Howard,

           Must have made a bit of a cock-up on this one: in my impatience to try to see how the radio would work with a replacement cap, I temporarily fitted a `TCC` Supermold 350Vdc 70degC 0.1 uF cap - radio worked for 2/3 minutes then blew its power supply plug 3amp fuse! A duff cap do you think, or just the wrong one? I`m assuming of course that I am changing/installing the correct cap in the first place - C61 between the s/w live out & the chassis?

Guess I`d better wait for the correct cap.

 

graham

To thank the Author because you find the post helpful or well done.

 

Hello Graham,

That 350V DC capacitor wasn't up to the job (and old stock), you need one rated at at least 275V AC which is roughly equivalent to 630V DC. Best type of capacitor to use across the mains is a 275V AC class X2 safety capacitor, see part number 1166459 on Farnells UK website. It was correctly fitted.

Regards ........ Howard

 

To thank the Author because you find the post helpful or well done.

Hello Howard,

                   As you can see from the attached photo`, I have replaced the offending capacitor, and the radio is now back and working as before; no worse but not discernably better. My only slight misgiving is that the cap is one of several new ones I have which, although marked as X2 & with the EU symbol, also state "Tat Yao" - now it is probably just my old-fashioned prejudices, but I wonder just how safe & reliable these are likely to be. I probably shouldn`t be bothered really, and anyway if I opened up my latest flat screen TV, would find that Mr Tat or Mr Yao had made most of the components.

What I did manage to do in the process was damage the on/off s/w, probably with an iron being too hot, but it is the non-live side that is open-circuit, so I`ve temporarily just shorted those contacts out. The volume control is also a bit of a `hit & miss` anyway, so I`ll be looking to rob one from amongst the tons of radio junk I have lying around

I would like to change out the other two waxies - I think they are C1 & C27 in the schematic. The only problem with doing this is that I would need to use another of the Tat-Yao caps, and the two that need to be replaced are marked " 4vA AC / 1000VDC. I`ve not seen the aV symbol before but assume it`s  reluctance or impedance?

Given the relative positions of the two caps, would it just be better to leave them do you think?

 

Thanks again,

Graham

Attachments:

• DSC00094 (147 KB)

To thank the Author because you find the post helpful or well done.