The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

Thanks - there are definitely some semiconductors labelled Q3 on the board.

I'd managed to get the datasheet of Rick's preferred Sanyo equivalent (below), but that doesn't give the case markings. I've just scoured the component drawers in the lab at work and found 3 types of varicaps, BB405B ...

What is the voltage each side of R102?

8.02V and 7.91V (on the Q100 collector side)

Goop now removed, the board is as in the new photo.

You can test the VCO, by checking the voltage at the junction of R107 and R108 the voltage should go up has you go from channel 1 to 40

TP1 has constant 2.67V regardless of channel selected

if it not check the voltage at the Base of Q100 the ...

Am I right is suspecting that the PLL components are beneath the wax in the photo?

Thanks Gents, I'd have a look at the levels in the PLL, but it appears to be buried in the waxy goop used to prevent fiddling with the pot-cores. Any tips on how to remove it?

Additionally, what lettering is on the varicaps? I can't see any semiconductors with 251 on them...

Rick - in another ...

Hi

I'm hoping that someone here has seen and fixed this before...

My previously fine vehicle mounted Maycom EM-27 has stopped working. The displayed symptoms are that the channel number digits now start flashing a few seconds after channel selection, and there is no reception or transmission ...