Thanks for your input - it's nice to see a thread that went to sleep back in August 2011 re-awakened!
I've just embarked upon the total restoration of a 1936 Ekco AC77 which is in quite a state. The power supply has a separate chassis so I've started on that first. At some point in its life it has already had a replacement twin 8µF capacitor unit fitted (Hunts of course!), billed as the 'Little Giant' and housed in a paper box which was just swinging free on its wires. The wires from the old caps had been snipped off, the wires on the replacement twisted together, and the joint taped over with insulation tape. Solder? Nah - there was a war on!
Out of curiosity I checked the old caps with the ESR/Cap meter I referred to earlier, and as might have been expected, it didn't even recognise them as caps - they behaved not as caps but as 19Meg resistors. I've got a few NOS 8uF caps so I reformed a couple of them over a period of several hours on my home-brew Radio Bygones cap reformer which has more than earned its keep since I built it. Leakage dropped to less than 500µA and their capacitance and their ESR were healthy. I've posted a few pics. The old caps in their cardboard housing; the display on the cap meter showing them as 19 Meg resistors; an NOS cap being reformed; a close-up of the meters on the reformer showing less than 500µA leakage at the rated voltage of 450V, and finally, a readout of a reformed NOS cap showing that it has an ESR of 2.8R, and a capacitance of 7.864µF.
(Ignore the rusty chassis - it will be stripped, de-rusted and re-sprayed before re-assembly).
Hope that's of interest.
I've just embarked upon the total restoration of a 1936 Ekco AC77 which is in quite a state. The power supply has a separate chassis so I've started on that first. At some point in its life it has already had a replacement twin 8µF capacitor unit fitted (Hunts of course!), billed as the 'Little Giant' and housed in a paper box which was just swinging free on its wires. The wires from the old caps had been snipped off, the wires on the replacement twisted together, and the joint taped over with insulation tape. Solder? Nah - there was a war on!
Out of curiosity I checked the old caps with the ESR/Cap meter I referred to earlier, and as might have been expected, it didn't even recognise them as caps - they behaved not as caps but as 19Meg resistors. I've got a few NOS 8uF caps so I reformed a couple of them over a period of several hours on my home-brew Radio Bygones cap reformer which has more than earned its keep since I built it. Leakage dropped to less than 500µA and their capacitance and their ESR were healthy. I've posted a few pics. The old caps in their cardboard housing; the display on the cap meter showing them as 19 Meg resistors; an NOS cap being reformed; a close-up of the meters on the reformer showing less than 500µA leakage at the rated voltage of 450V, and finally, a readout of a reformed NOS cap showing that it has an ESR of 2.8R, and a capacitance of 7.864µF.
(Ignore the rusty chassis - it will be stripped, de-rusted and re-sprayed before re-assembly).
Hope that's of interest.
Regards, David.
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
BVWS Member.
G-QRP Club Member 1339.
'I'm in my own little world, but I'm happy, and they know me here'
