Sidebar Sidebar
  • You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

siltronix mod 90 vfo questions HELP?

johnny9

johnny9

Active Member
Dec 3, 2013
376
41
38
bikini state
HOPE I POSTED IN RIGHT AREA.

i have a midland 898b base thats had a vfo hook up for yrs before i got it.it
has the pigtail coming out the front corner for the siltronix mod 90 vfo to plug into.po said it worked.
cant get it to work so took covers off the vfo.
its missing 2 of the 3 crystals,but it has a switch for,and in this order.

cb,hf,xtal1,xtal2 and xtal 3.
do these 3 crystals have to be in place to work in cb mode?
it looks like they just control the 3 xtal modes but im not sure on that.

i found online that all 3 crystals are the same."7.860" and the 1 crystal in it says "7860.0" i assume thats the same just decimal in diff spot.

maybe the po robbed 2 of the crystals for another project lol.

also noticed when i changed the blown bulb inside it blew the new one in about 3 min..thanks for any iput on this..

i have a old cobra2000gtl i can rob crystals from but not sure if it has the
7.860 crystals in it but i can buy them if this is the reason it wont work.thanks for the help.
 
  • Like
Reactions: antiqueman1

heres some pics of the vfo.the crystal thats in there seems to have smaller pins but can be bent to work i guess..or maybe the decimal point in the diff spot of what i read is the diff in the bigger crystal pins?
 

Attachments

  • vfo tram amp 030.JPG
    vfo tram amp 030.JPG
    177.1 KB · Views: 26
found out in a youtube video that it dosent need the 3 crystals to operate,however with 1 crystal "7860.0" in the xtal 3 position on the vfo you can switch back to your normal radio channels..

also found out the model 90 and all siltronix vfo,s have a number on the back of the plate..mine has a number 6,which makes it a model 90-6 and that means it was meant for my midland 13-898b radio.
all info on what the model 90 vfo is compatible with can be found here.

SILTRONIX VFO CHART
 
IIRC the radio has to be on channel 23 to work with the VFO. A crystal for that channel is removed and the VFO wired to where the crystal was. I can't remember for sure but I am reasonably sure I wired the PA jack to the crystal socket so it was just plug and play and I am sure about the channel 23 thing.
 
well i could be wrong also,but dad said he remembered it being chanel 22a ?
i told him the midland 898b went from channel 22 to to a "red colored" ex then channel 23.
he laughed and said thats what used to be 22a then,now marked ex on my radio and was for the vfo accoding to the previous onwner..
on the video i found the guy operated his radio,not a midland,on channel 14 or 13 with the vfo..
couldnt sleep 2nd time this week up all night so in a lil while im hooking it back up and checking the vfo on all channels,and if cant get it working i will take to botttom cover off the radio and make sure nothing is un hooked..

this cb radio stuff is way harder than buiding engines and suspentions lol;)
hey capitain k,check my last post in abc amp thread to make sure i worded it correctly,for the not so sharp people like m lol..thanks.
 
well i was so excited to find the wires in bottom of radio to be broken at the solder joints for the vfo cable..
so i did my first soldering inside a radio,and used the 60/40 rosin core solder and plugged it all up and no go:sad:
theres no cb action at all so keeping my finger crossed it will work in the am when skip is rolling in.
i did re wire a old "cpi,communications power inc,ranger plus" lil receive box made in usa,i have 2 btw,but his one receives like crazy good for some reason,and it has the red that lights up and says"on the air" so some good did come out of everything i did today;)
 

Attachments

  • 898b 013.JPG
    898b 013.JPG
    155.7 KB · Views: 11
  • 898b 019.JPG
    898b 019.JPG
    132.5 KB · Views: 11
The red EX position on the channel zelector is for feeding external audio into tbe back and using tbe radio as a small PA amp. EX has nothing to do with channels. If you wiggled tbe knob just right between EX and 23 you could get channel 24 I believe which some called 22A back before the band had 40 channels.
 
wow, you got me thinking to not give up on the vfo now..(y)
on back of radio theres 3 inputs in a row that take the same type cord/jack as the vfo.

they are labled; ex speaker,pa,and the 3rd one "rec"
so is the rec hole for the audio input you speak of id think.nothing i think id need but good to no..

then how the heck do i find the channel the vfo operates on lol :confused:

also,heres a pic of the soldered joint i re did for the vfo.
i was wondering after i did it,was it ok to use a 1/4 inch of the solder as a short post..
 

Attachments

  • 898b 040.JPG
    898b 040.JPG
    187.1 KB · Views: 12
The three RCA jacks on the back should be from left to right when looking at the back: PA output jack on the left, external auxiliary input jack in the middle,record output jack on the right.

The PA out is exactly that. Connect an external PA speaker there. Tee record output jack takes receive audio and routes it to that jack for recording directly off air. The middle jack labeled external auxiliary input is for connecting an external audio source and when you switch the channel selector knob to the EX position that audio will be amplified and routed to the PA speaker. The volume control adjusts the level.



9yWAPUYBAAAAAElFTkSuQmCC
 
thanks captaink.. so anyone out there no how,or what channel i use to use the vfo?i tryed them all and everything i could try has been done
the guy i got it from said to plug it in and set to channel ex and vfo was ready to talk..but it was not his radio originally so he prob was guessing..

this is crazy..nowhere on line can i find directions for using it..im giving up and putting the darn thing on the shelf..

next time i shoot some 12ga slugs,its the target..maybe i will put some tannerite inside and KABOOOM<can not stand it>
 
no worries here,i only listen for now(y) and even if i had a broadcast network the guy down the road has 4 in one and he would/better be got before me lol..
prob tryin to get a bigger xmas bonus:D
 
Download and READ the manual for the VFO. It clearly states what has to be done to operate it and what channel the radio has to be on. each VFO model outputs different frequencies and as such different channels may be used to connect to the VFO. Open the radio up and make sure the VFO is wired to a crystal socket inside the radio.
 

dxChat
Help Users
  • No one is chatting at the moment.


      Top Bottom
      Back