Columbia model C302 aka Marconi T32A.

[Barnsley Bill]

Hello there, first time poster.

I've got an old Columbia Model C302 that I've had in the garage for a number of years and I'm looking to repair. I'm struggling to understand how to thread the cord that goes around the wheel and what cord to buy to refresh the old cord with new.

Would anyone have any idea how I might fix this or a wiring diagram explaining how to repair? Its the cord that controls the tuning on the radio.

Please see images attached. Any help greatly appreciated.

Thanks Bill

[vinrads]

Hi Bill you need to remove the chassis first ,then we may have an idea how to re string it , Mick.

[Techman]

I've worked on the radiogram version of this chassis a few years ago, so can give you some first hand advice.

An interesting observation for those who haven't yet noticed is that the chassis is actually stamped out for much larger and earlier, probably octal based valves, but it's actually fitted with adapters for more modern valves - take care when and if you pull any of those valves that you don't bust the glass pips on the bottom side of the valves.

The one that I worked on had a totally burnt out mains transformer (the large thing on the right of your picture) caused by being plugged in and run with the original grid coupling (that) capacitor still fitted. So what I'm saying is that the chassis will need more serious work than just replacing that drive cord if it's to run reliably without clouds of smoke and a horrible smell and a very expensive transformer rewind.

I told the chap at the time that if he could find a good replacement transformer, then I'd fit it for him. He sourced one off ebay that was nearly the same, but had a higher voltage HT winding and a lower voltage rectifier heater winding. It was also physically slightly different, so the frame had to be swapped over from the old transformer. It was a bit of a performance and if it wasn't for the fact that he was a mate then I wouldn't have taken the job on. He's still got it and it's still running 12 years on as far as I know - we also had to replace the old Plessey record deck and then modify the replacement to make it fit and work.

There may be service information for a similar chassis to the one you've got that may show the drive cord fitting if you have a look through the index of the link highlighted in red at the top right of this web page.

[Cobaltblue]

Electronically this seems to be very similar to the Marconi T32DA.

However I suspect the stringing is similar if not the same as the Marconi T29 whose stringing drawing is attached.

Cheers

Mike T

[Stuart R]

I've sure I've used the T32DA sheet as guidance for the same Gram version that Techman was working on.

Here's one photo that shows what you're up against, pulleys hidden at the front of the chassis that 'bend' the tuning cord round by 90 degrees.

If you purchase the service sheet download, that may give you some useful guidance, but if it's not exactly the same model, have a good look around the radio before you begin dismantling it. There maybe subtle differences; do the control knobs simply pull off, or do they have grub screws? Worth double checking before you break them!!

My photo includes a shot of a hastily replaced capacitor (or two), one of them being the Grid Coupling one that everyone here will suggest is replaced before you consider powering up the set for any great period of time. Leave an electrically leaky old one in place and it can cause expensive damage.

Good luck.

SR

[FERNSEH]

Marconi T32A all right. Was the chassis made by Plessey or EMI?

DFWB.

[Techman]

I mentioned that the original deck in the Columbia radiogram version that I worked on was a Plessey. However, I tend to refer to all these oddball decks as Plessey types, when I've just remembered that it was the HMV 45000 78rpm autochanger, so going on that I think that the chassis is likely to be made by EMI too.

[Barnsley Bill]

Thank you for all your replies everyone, much appreciated. Could I ask what fishing line I would use? Is it Nylon fishing line, or corded line what fly fishermen use? The numbers are a little confusing, is there a strength of line I should use e.g 4lb etc?

[Station X]

I use what's known as backing line.

[Barnsley Bill]

Thanks, I'll give it a shot. Thanks everyone for your support