26th Mar 2023, 1:08 pm | #1 |
Heptode
Join Date: Jun 2018
Location: Carmarthenshire, Wales, UK.
Posts: 569
|
Alba 3312
Can any tell me on the service sheet for this model which is the coupling capacitor please
|
26th Mar 2023, 1:26 pm | #2 |
Heptode
Join Date: Jan 2006
Location: Cornwall, UK.
Posts: 506
|
Re: Alba 3312
Using Trader 1344 sheet:
C52 0.01uF is the audio coupling capacitor from V4 anode to R30 which goes to V5 grid. You may also want to change C56 (V5 anode to chassis) as failure will stress the output transformer and C60 across the mains bfore powering up. |
26th Mar 2023, 7:28 pm | #3 |
Heptode
Join Date: Jun 2018
Location: Carmarthenshire, Wales, UK.
Posts: 569
|
Re: Alba 3312
C56 is according to data sheet a 0.002uf but what voltage should it be please
|
26th Mar 2023, 8:22 pm | #4 |
Heptode
Join Date: Jan 2006
Location: Cornwall, UK.
Posts: 506
|
Re: Alba 3312
In general, capacitor working voltage should be no less than that of the originals. I would expect C56 to be 1000V working as there can be high peak voltages on the output valve anode.
C60 can just be snipped out for initial tests but a replacement should be a Class X type for use across the mains. You will probably need to change others as well. The ones going to external sockets C1, C2, C3, C47 and C48 should be Class Y types for safety reasons. |