I'm servicing one 20 year old 20w exciter so I thought I could post some pictures of the inside...
First comes modulator, very strange and complex one. It has some kind of ALC with diode at the output so it measures power across the band and set voltage on driver transistor. Output is about 135mW. Lock range is about 10MHz without expanding / squezeing coil.


Then, old PLL and my replacement one (with MC145151). Old one could lock only odd frequencies, and I could only guess dip switch combination
Old:

Replacement:


Stereo coder, with 4066 switch, properly filtered...



And power amp, MRF237 and some Philips transistor



Triple filtered, still works perfectly.

I can believe it, Made with ''real components''.
Could the Philips device maybe a BLW 60C perhaps?

SOTS 87 7 wrote:I can believe it, Made with ''real components''.
Could the Philips device maybe a BLW 60C perhaps?

My first guess (and only a guess), would be BLY89 ?

Plus that doesn't look like an MRF237, it's the old bolt down TO60 type like the 2N3375/3632, BLY35/36 etc.

teckniqs wrote:Plus that doesn't look like an MRF237, it's the old bolt down TO60 type like the 2N3375/3632, BLY35/36 etc.

It is not MRF237 for sure. I made a mistake since I had 237 in my hand when I was typing post... it was 4am... Sorry for that!