08-09-2019, 07:18 PM
Chassis out, time to try to remove the dust and debris.
Looks a bit better cleaned off, its dusty even underneath. Lots of the usual black pitch capacitors, all suspect of course. The reservoir capacitor has leaked from top and bottom, that must be duff.
A mix of valves. a Mazda mixer, Philco rectifier the rest are Mullards so its had some valves in its life yet the speaker wires seem never to have been unsoldered.
Continuity on the mains through the QMB mains switch, but my error, the thermal fuse on the transformer is sprung open. The transformer is OK, 95 ohm on the primary. So is the bit of metal I found part of the fuse link?
The fuse hook attached to the winding had a diabolo shaped piece stuck in it, must be part of the fuse assembly but I can't see how it goes together.
What am I missing? There must be some part missing, not found any part that would melt on overheat and I can't see how these two bits fit together.
Can anyone help me with how this fuse/switch goes together please? Do I have all the bits?
Output transformer checks out OK, Hung a speaker on, I fitted a brass washer on the two hooks where the thermal fuse should be and applied some power. Rectifier and output valves light up, HT is almost nonexistent due no doubt to duff reservoir and smoothing capacitors.
Removing the cans I find the reservoir can is insulated from the chassis, not according to the Trader sheet but it is on the Philips sheet so I think I will work off that from now on, Trader has been known to make mistakes when creating their sheets from an actual set. Its unusual to have the reservoir can not connected to chassis, must be part of the biasing for the valves.
Hung a couple of 47uf 250v caps on instead of the cans, the HT is now up, 287v so we have progress. No sound but its early days yet. Eyes tired now ( workshop still has the acrid smokey stink ) so call it a day, I will do a proper restuff of the cans tomorrow. Should be able to get at least the output working soon.
Looks a bit better cleaned off, its dusty even underneath. Lots of the usual black pitch capacitors, all suspect of course. The reservoir capacitor has leaked from top and bottom, that must be duff.
A mix of valves. a Mazda mixer, Philco rectifier the rest are Mullards so its had some valves in its life yet the speaker wires seem never to have been unsoldered.
Continuity on the mains through the QMB mains switch, but my error, the thermal fuse on the transformer is sprung open. The transformer is OK, 95 ohm on the primary. So is the bit of metal I found part of the fuse link?
The fuse hook attached to the winding had a diabolo shaped piece stuck in it, must be part of the fuse assembly but I can't see how it goes together.
What am I missing? There must be some part missing, not found any part that would melt on overheat and I can't see how these two bits fit together.
Can anyone help me with how this fuse/switch goes together please? Do I have all the bits?
Output transformer checks out OK, Hung a speaker on, I fitted a brass washer on the two hooks where the thermal fuse should be and applied some power. Rectifier and output valves light up, HT is almost nonexistent due no doubt to duff reservoir and smoothing capacitors.
Removing the cans I find the reservoir can is insulated from the chassis, not according to the Trader sheet but it is on the Philips sheet so I think I will work off that from now on, Trader has been known to make mistakes when creating their sheets from an actual set. Its unusual to have the reservoir can not connected to chassis, must be part of the biasing for the valves.
Hung a couple of 47uf 250v caps on instead of the cans, the HT is now up, 287v so we have progress. No sound but its early days yet. Eyes tired now ( workshop still has the acrid smokey stink ) so call it a day, I will do a proper restuff of the cans tomorrow. Should be able to get at least the output working soon.
Boater Sam.
