pll02a cybernet chassis info needed

[dj56]

On these pll02a chassis doing the channel mod to go up/down they dont broadband power wise that good the chassis that have the 10.0525 mixer xtal.

Power drops off pretty fast. Channel lock from 27.855 down to 26.515 but again little power at both ends.

Has anyone have any tricks on tuning for better power?
I know the unidens have some tricks and the upd 858pll chassis have a mod on 1 of the dual transformers so u can get good power both ends.

working on fix with the 10.0525 mixer thats all set just the power.

Same thing would happen even if done with the pll little power
thanks

[Mitch]

Do you have the Cybernet Export Manual? If you look at the circuit diagrams you will see 4 switched trimmer caps across the 4 mixer tuning cans, 2 rx/tx and 2 tx, they are switched from the band selector for the low bands. Tune the cans for mid and high channels and the trimmer caps for low channels. I have done this many times to older Cybernet radios and it does work, a bit fiddly to tune right though. The output stage is not so easy, even replacing all the components for a later design doesn't work very well (tried it) so that will limit channel spread unfortunately.

Edit: Another trick is to solder pins 2 & 3 together of the TA7310 mixer chips, that usually helps.

[Stronty]

If you need the Cybernet Export Manual it can be found - HERE

[Ripshod]

Do you have the Cybernet Export Manual? If you look at the circuit diagrams you will see 4 switched trimmer caps across the 4 mixer tuning cans, 2 rx/tx and 2 tx, they are switched from the band selector for the low bands. Tune the cans for mid and high channels and the trimmer caps for low channels. I have done this many times to older Cybernet radios and it does work, a bit fiddly to tune right though. The output stage is not so easy, even replacing all the components for a later design doesn't work very well (tried it) so that will limit channel spread unfortunately.

Edit: Another trick is to solder pins 2 & 3 together of the TA7310 mixer chips, that usually helps.

That's exactly what I did on my old colt 320dx. Following the actual designs ensures things work the way they should. I also referred to the diagrams to do the proper FM conversion (parts salvaged from a dead York 360). The export manual even shows you (indirectly) how to convert a cw tone board to a roger beep. Lad's bible back in the day.

[dj56]

The radio in question is the Lafayette telstat ssb 140 and the midland 78-999 or the GE superbase radios and other non export 02a chassis.
They are USA 40 channel chassis.

[Mitch]

The radio in question is the Lafayette telstat ssb 140 and the midland 78-999 or the GE superbase radios and other non export 02a chassis.
They are USA 40 channel chassis.

Yes of course, but all of the early 'export' radios we got in the UK (from Europe) were modified US FCC spec radios with extra boards, like crystal boards for extra bands and FM mode for the EU, and all later radios were just variations on that theme. I have had FCC radios like GE & Colt (PLL02A) and fitted FM and crystal boards to them, even eproms to convert for the UK channels. I like the older radios myself and adding extras was a hobby of mine. The radio I'm using at the moment is a Lafayette AFS-1005 (PLL02A) and I use a K40 mic on it, it's an old export model, Cybernet built but evolved from earlier US radios. The mods mentioned can be fitted to older radios with some care and later tricks can be applied usually without problems. It's worth a try