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kestrelmusic · 28th Nov 2022, 10:45 am

I've nearly finished restoring a Cossor Melody Maker 501. It is pulling in signals nicely, but the alignment is way off and I can't get it anywhere near right.

The setting of the pointer is correct for the position of the gang but the oscillator frequency is out by about 50kc/s.

Diagram of the tuned circuits attached. I don't think the coil can have gone seriously out of value as it's wax encapsulated. It can't be C16 or C18 as they are shorted out in the MW position. C9 and C13 are presumably just coupling caps and so if they have gone out of value it shouldn't affect the tuning. C15 is out of circuit in the MW position. C12 is screwed down as hard as I dare without risking damage.

Any thoughts on this?

28th Nov 2022, 10:45 am	#1
kestrelmusic Hexode Join Date: Feb 2008 Location: Wrexham, North Wales, UK. Posts: 465	Cossor 501 alignment I've nearly finished restoring a Cossor Melody Maker 501. It is pulling in signals nicely, but the alignment is way off and I can't get it anywhere near right. The setting of the pointer is correct for the position of the gang but the oscillator frequency is out by about 50kc/s. Diagram of the tuned circuits attached. I don't think the coil can have gone seriously out of value as it's wax encapsulated. It can't be C16 or C18 as they are shorted out in the MW position. C9 and C13 are presumably just coupling caps and so if they have gone out of value it shouldn't affect the tuning. C15 is out of circuit in the MW position. C12 is screwed down as hard as I dare without risking damage. Any thoughts on this? Attached Thumbnails