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Demuntification of flashed over sockets in a Jansen bass 50
Posted: Mon Apr 10, 2023 3:20 pm
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 (3.9 MiB) Viewed 3426 times
And here's after judicious use of hacksaw and new ceramic sockets mounted to chass:
- IMG_20230407_163550.jpg (5.49 MiB) Viewed 3426 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 (4.27 MiB) Viewed 3426 times
Re: Demuntification of flashed over sockets in a Jansen bass 50
Posted: Mon Apr 10, 2023 4:05 pm
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
Re: Demuntification of flashed over sockets in a Jansen bass 50
Posted: Mon Apr 10, 2023 5:50 pm
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!
Re: Demuntification of flashed over sockets in a Jansen bass 50
Posted: Mon Apr 10, 2023 10:42 pm
by RectifiedAmps
Great work!
I've seen an arced bassman that burnt through ceramic sockets! The voltages in Jansens (and Holdens) are just unreal.
Re: Demuntification of flashed over sockets in a Jansen bass 50
Posted: Tue Apr 11, 2023 12:00 pm
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