Marconi T19A

[Joe]

I've recently been working on a Marconi T19a.

All seems to now be well with it except for it not working on Long Wave. I won't say that it is dead as there's a crackle when an external aerial is connected or disconnected.

I've cleaned the wave switch several times to no effect. I can't see any bad or broken contacts and it doesn't sound at all crackly.

The circuit diagram seems to make even less sense than normal to me (it made even less when I was mistakenly using the one for the T21A!) so can anybody spot any components which are only used on LW and would be worthy of investigation?

All the best

Joe

[Mark R]

Joe
Are L6, L7 and L4 ok or open also C1 and C4.
Sounds like a coil to me though.

cheers Mark

[Joe]

Thanks, Mark. I'll check it out tomorrow.

-Joe

[tiv48]

hi jo can i add L2 c9 and c10
what happens on switch pos 1( LW preset)
i agree the trader sheet is not that easy to follow
rob t

[Joe]

The LW preset doesn't work either but the MW ones aren't great as P3 won't tune to 1033 kc/s but will only pick up weak stations further up the band.

There's no sign that the main alignment has been messed with as the cores aren't damaged and the stations are on the right places on the dial.

I've got a Bush VHF90 to put back together and then I'll have room to look at this further.

Thanks

Joe

[Joe]

The coils seem OK, though there was some confusion when the decimal point on my DMM flipped off!

The caps aren't leaking and 200 kc/s get through them OK.

As I had to set the sig gen and CRO up on my bed I've darn near broken my back bending over so will have a rest before having yet another go at the wave switch.

- Joe