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Watkins Westminster combo from 1964

As this one

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one of the rare 2x10 inch speaker ones.

4 plus 2 valves does not agree with the schematics I've found so far out there, any pointers? Not safely in a position to remove the valves yet but only a military CV number seen so far on one of them, and I suspect most faded to nothing . If no schematic found will have to try and find the little etched numbers as no valve chart inside the cab The owner wants to go out using this again , he bought new in the 60s, 2 repairs in the 70s but I cannot see the cones lasting out, they feel like tissue paper, despite kept indoors of a house for decades . Mains cable needs replacing , as does the corroded small electros, I assume the big one with the (6?)426 datecode will need restuffing/replacing. Ser no. in the 400s . All the carbon resistors are readable and othewise for its age looks healthy, even the strange cab screwcaps are present.
Reply to
N_Cook
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All the steelwork is corroded a bright sulphur-coloured lemon-yellow. I don't remember seeing that before, actual sulphur? I'll try scraping off and burning some I've recorded all the R values sequenced through the amp A previous repairer had marked V1? and V2 ? positions as ECC83, the op bottles are CV2975 so EL84, RR is marked EZ80 leaving just the valve posistioned as ,and wired cusory-looking as , a splitter driver V3? it looks like a double triode and I will test as ECC82, has 4OD etched on the envelope , when I dig out those crib sheets for that.

Reply to
N_Cook

With a bit of fossiking about , looks as though this is a close enough schematic

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Reply to
N_Cook

Not a zinc dichromate or cadmium plating?

oks

Looks like guitar amp repair keeps you folks in business. Do you do your own reconing, or do you have favorite people to do that? Can they match the cone and fundamental resonance fairly close, or does reconing inevitably change the sound?

Reply to
spamtrap1888

Not a zinc dichromate or cadmium plating?

looks

Looks like guitar amp repair keeps you folks in business. Do you do your own reconing, or do you have favorite people to do that? Can they match the cone and fundamental resonance fairly close, or does reconing inevitably change the sound?

+++

Unlikely a plating as all different makers/sources of steel, valve base skirts, retainer springs, pot casings and large capacitor clip all bright powdery yerllow. Against that - the mains Tx someone has replaced and the steel frame of that is normal colour , so perhaps some tropicalizing or spraying by the maker that has deteriorated . The op Tx is stove-enamelled so grey colour. Another thought , as stored under the stairs, if the household gas supply/meter is there and whether long-term so undetectable by human nose, North Sea gas leakage, gives off sulphur component that reacts with steel ?

The only reconing I've done is where I can remove a couple of turns of VC or a repairable braeak at a bend of the VC tails , but I do have an 18 inch speaker and cone that I will sometime? try rewinding the broken VC as the former is not burnt beyond a 2mm x 1mm spot

The prices of new cones I've seen means the usaul response "well I may as well buy a complete new speaker for that cost"

Reply to
N_Cook

I scraped off some of the yerllow and it did not go orange then red then Hadean smell on heating so perhaps some sort of steel passivation or tropicalizing treatment

Reply to
N_Cook

Just wasted an hour testing the double rectifier. No response on "goodness" test for either rectifier. Had an untested EZ81 knocking around and no reading on that either , semed unlikely . The owner tried out this amp and some amplification, but unuseable, for other noises and soon switched off. As EZ80 / 81 uses the same socket as ECC81/82 unlikely a wiring problem there and expected to have to dive into the big bakelite multiway thumbwheel switch bank. Just about to try 2x 1N4007 in the socket and thought I'd check the Avo, 9 digit code from first principles. My 1968 Avo valve data book for EZ80 and

81 has setting code 7*1 23* 6** (for amplifier anodes , not diode anodes) but it should be 8*1 23* 9** in this particular case 801 230 900
Reply to
N_Cook

so googling around that came to

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and have left a note to myself, the next time I'm inside this Avo valve tester, to modify the meter protection

Reply to
N_Cook

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