Demuntification of flashed over sockets in a Jansen bass 50

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PaulWD
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Demuntification of flashed over sockets in a Jansen bass 50

Post by PaulWD »

For giggles, a repair this week for a mate'

before, with a flashover between screen and grid. Burnt about a 2mm hole though the board:
IMG_20230330_181913_1.jpg
IMG_20230330_181913_1.jpg (3.9 MiB) Viewed 3109 times
And here's after judicious use of hacksaw and new ceramic sockets mounted to chass:
IMG_20230407_163550.jpg
IMG_20230407_163550.jpg (5.49 MiB) Viewed 3109 times
Not shown is replacement of caps or installation of trimpot for bias.

In-between the two photos, 50 years worth of gunge was washed off the chassis using persil and hot water:
IMG_20230402_113124.jpg
IMG_20230402_113124.jpg (4.27 MiB) Viewed 3109 times

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Re: Demuntification of flashed over sockets in a Jansen bass 50

Post by Bg »

PaulWD wrote: Mon Apr 10, 2023 3:20 pm For giggles, a repair this week for a mate'

before, with a flashover between screen and grid. Burnt about a 2mm hole though the board:

IMG_20230330_181913_1.jpg

And here's after judicious use of hacksaw and new ceramic sockets mounted to chass:

IMG_20230407_163550.jpg

Not shown is replacement of caps or installation of trimpot for bias.

In-between the two photos, 50 years worth of gunge was washed off the chassis using persil and hot water:

IMG_20230402_113124.jpg
Awesome :)
So, is that low alcohol or no alcohol at all? mmmm, no alcohol, do you want to try it? Noooooooooo.

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MikeC
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Re: Demuntification of flashed over sockets in a Jansen bass 50

Post by MikeC »

Bg wrote: Mon Apr 10, 2023 4:05 pm
PaulWD wrote: Mon Apr 10, 2023 3:20 pm For giggles, a repair this week for a mate'

before, with a flashover between screen and grid. Burnt about a 2mm hole though the board:

IMG_20230330_181913_1.jpg

And here's after judicious use of hacksaw and new ceramic sockets mounted to chass:

IMG_20230407_163550.jpg

Not shown is replacement of caps or installation of trimpot for bias.

In-between the two photos, 50 years worth of gunge was washed off the chassis using persil and hot water:

IMG_20230402_113124.jpg
Awesome :)
Nice! 45-odd years ago I had a Jansen Bassman 75 go up in smoke like this!
Whakanuia o mea kei a koe

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RectifiedAmps
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Re: Demuntification of flashed over sockets in a Jansen bass 50

Post by RectifiedAmps »

Great work!

I've seen an arced bassman that burnt through ceramic sockets! The voltages in Jansens (and Holdens) are just unreal.

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Re: Demuntification of flashed over sockets in a Jansen bass 50

Post by PaulWD »

Cheers. Was all going smoothly until I checked the heater voltage. I forgot that jansen used 12.6v taps. At least I checked before plugging in the tubes. Heaters were rewired making use of the filament CT to get 6.3v

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