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

Hi Guys.

still didnt get my superstar 7000dx - got lost in the post - at least i got a refund!!

Anyway: i now have a belcom ls102, which is fine EXCEPT the flippin' thing will onl;y tune UP in frequency - even when i turn the tuning knob anticlockwise, it still tunes up.
whats gone wrong there? any ideas? It has been modded to cover 26-29Mhz.

any help would be greatly appreciated!

seeya

Jimbo 26CAT23

Have not seen one of there radios for over 20 years. I still have one some ware.

Common fault IC312 (MC14011B) Quad 2-input NAND Gate or it's one or two of the IC 306,307,308 and 309(MC14510B) BCD up/down counters. you can check to output of the MC14011B but you will need a Scope to see the pulses one side of the gate is + going and the other is - going, or dry joint on the VFO PCB. Hope this helps. Let know now you get on.

Rick.

hi rick

thanks for the info.

having a look now; it seems intermittent 9sometimes it actually does tune down, then about 2 seconds later its only tuning up. im going for a dry joint here. I'll redo the joints and see what occurs.

also now noticed there is a dead carrier on usb. Feedback probably!

latest. could be a dodgy 1khz/100khz step switch!!

latest. note to self - check antenna is connected.

radio now seems to be in order!!

still desperate for some alignment tips if anyone knows which ones to peak for rx!!!

I will see if I can find the service manual. I know there some Coils you do not want to adjust or you will have a lot of trouble on your hands with out the right test gear.

Rick (Euro Radio Co).

thanks rick. i have some test gear here; sig gen, dev meter, am mod, distortion analyser, scope, a few other bits; i used to work for the bbc doing their outside broadcast transmitters; but it's been a while since i poked a trimmer into a coil in anger!!!

thanks for your help.

know the radio very well
there are two presets like ears very close to the phot interupter wheel
slightly adjust one of the presets that should cure the up/down error
if you wish the service man + my notes from the last 20yrs ill put them on yousentdit.com just ask

new email as from 2018

gm7bnf@yahoo.co.uk

...tnx - mike

mike

Mike,

I could use that info you have on the Belcom - my problem is similar to Soundmanjim's but mine corrects itself once the radio has warmed up.

Any info would be greatly appreciated.

Try adjusting two presets like ears very close to the phot interupter wheel, before you adjust them mark them so you can put them back ware was.

Rick.

Rick/Mike

Thanks for the suggestions - I'll have a crack at it at the weekend & let you know how I get on.