The Barker 88

[Sideband]

There are quite a few variants of the '88'. Mine has a 6J5 phase splitter and push-pull 6V6's. The other valves are ECH35, EF39 and 6Q7. An AZ31 rectifier and a 6U5 (I think) tuning indicator complete the line-up.

[Silicon]

Most domestic valve radios rarely require capacitors with a 1000V rating.

They did use 1000V capacitors across the mains, across the HT windings and across the primary windings of the output transformer for very understandable reasons. High voltage transients occur at these parts of the circuit.

It would be interesting to know if these 60 year old 1000V paper capacitors have less leakage today than the 400V paper capacitors in your radio.

[Boater Sam]

It is a good suggestion to check the output transformer primary. You don't need to disconnect anything, simply check the the resistances, it is a center tapped winding so you should see a high reading, maybe 550 ohms across the whole primary and 2 readings of half this across the 2 halves.
When you have a safe mains lead you could also run the mains transformer up with the rectifier valve removed. This will also prove the on/off switch works. You should get the other valve heaters on and nothing else.
Leave it on for a while to ensure it is not getting hot.
If you wish you could carefully check that you have approx 325 AC volts on the 2 anode pins of the rectifier socket with respect to the center tap, or 650 AC volts between the 2.

[Silicon]

Always power up the radio via a 'Series Lamp Limiter' during the early stages of a repair.

The vintage-radio.com web site shows you how to do that in the projects section.

[Edward Huggins]

It would be interesting to know if there were really different makers of this model. I certainly remember the post war sets used loudspeakers made by various different manufacturers.

[Captain Dunsall]

Just wanted to say thanks to all the people who gave advice on possible faults on this old unit, ended up re-stuffing the old Hunts 16+16+8 uf elec cap and replaced the wax caps, although when tested they were still within value. Tested the metal cased Sprague caps and seemed OK, so took the advice of many "if it ain't broke don't fix it". Fitted a new lead with an earth to the chassis warmed her up and she runs really well now. Had to extend the aerial, but the sound is clear with no distortion. I have a few bits left to do just got some paint for the EF39 as the original has flaked off, the dial cord has given up so will replace, and you were all correct the Y63 magic eye has long since blinked out.
The case is OK but will polish up, and there is a white painted line around the speaker aperture which needs attention. It's taken a while to do as i have spent many evenings reading about how things work etc. before attacking with cutters and soldering iron. So what next well got a Sobell 513W or a Ferguson 238A thats still in the loft so might be a different model, but it looks the same. I will get the right model numbers and pics when i start as you guys will be helping, you just don't know it yet. The Fidelity caravan set 2546 is on hold, as with its live chassis and resistive power cable this is still a step to far at the moment, but the Tufnol case has cleaned up and looks like new and is safely tucked away.
so thanks to all
G

[AC/HL]

Originally Posted by Captain Dunsall

It's taken a while to do as i have spent many evenings reading about how things work etc. before attacking with cutters and soldering iron.

Well done, nice to hear about someone going about things the right way. There's no substitute for the studied approach.

[Keith]

Originally Posted by Captain Dunsall

J Tested the metal cased Sprague caps and seemed OK

This is in line with my experience. I have a British 19 Set full of these and they're still good after 73 years!