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.

New General Lee will not convert.....

J

Jimmy Hughes

Member
Sep 4, 2015
3
1
13
46
I need some help....
I have a brand new General Lee that I am trying to convert to 11 meters. The issue I have is, after removing the resistor cluster, my external display shows 27.1850 (channel 19 on 11 meters) for only five seconds, then it reverts back to 25.XXXX MHz again. It will do this every time I power cycle the radio, I have never had this happen before. I checked the gray wire on the band selector switch (band D wire), it it has continuity through the plug, all the way to the solder side of the board. I have looked over every trace and all components with a large desk top lighted magnifying glass. All traces and components look to be perfect. I can not find any bad solder joints.
This one has me scratching my head..... Has anyone experienced this before, or can think of anything that might help? So far, I have read thru TONS of forums, watched several videos, and no one has mentioned having this problem before. I even expanded my search looking up other radio brands as well to see if this has plagued someone else.

Thank for the help!
 
  • Like
Reactions: Handy Andy

Time for a look at the PLL tuning voltage. If it falls to nearly zero when the counter reverts to 25 MHz there is PLL trouble.

If it shows channel 19 even briefly the conversion was a success. Unfortunately, the success rate of Viet-made RCI radios is hit-and-miss.

Might only be a soldering fault. Most likely not a conversion issue.

73
 
  • Like
Reactions: Crossbow
Are you using the (Wonderfully inadequate) RCI - MB8719 or the RCI 145106 - both chips are possibly ok, your issue sounds like the main freerunning 10.240 to 16MHz VCO clocks - one is not keeping up with the other.

IF you use the 145106 PLL - check Pin 8 - if it changes status - the Frequency counter "dies" to a default frequency - showing the faster clock is still running.

The RCI - MB8719 - it's pin 6...

You'd see both change status once the Frequency counter defaults to 25MHz

To me, the "faster clock" not controlled is still running is your L22 and L20 - IC10...

The MB8719/145106side using 10.240 is not - your 10.240 side - so that affects L17...

Best way to see if the VCO just needs a tweak is to go to the outer bands and observe the Frequency counter to see if it stabilizes - if you have to go higher up in frequency to get it to lock - L17 can be tweaked - if you find going lower and you lose lock - you have a problems in the 10.240 VCO side - it uses two varactor's - so if you are unable to tune the full range - suspect the varactor's in the VCO side.

TP3 helps with that - scope it to see if something appears

Another thing to check is to see if your X4 TX 10.695 is working - your transmit side...

- if you're in lock and able to key up
- keep it keyed up into a dummy load not long just a minute or so see if it drops
- time this event so you can see if TX holds this condition to lock
  • - if it doesn't go out of lock and stays working - may be regulation issues - gotta' look at TR41/TR40...then to the switch stuff off of the 4558 chip TR38/TR37/TR36...
  • If Regulation voltage steady - the problem is in the communication between the IC10 and PLL (C105 and C106 work like an RF divider / splitter pushes down signal level so it's more sensitive on PLL's Pin 2 to the effects) which then shift to IC10's output low-pass filter (L50 C76) as well as C105 / C106)
  • - TP2 and Frequency counter input jumper can be scoped to see if the mixing derived error correction signal - the loop itself - is even appearing on Pin 2 of the PLL - if it doesn't show or you have a jumbled mess of swooshing frequencies on pin 2 of the PLL- then IC10 is not communicating with anything - but it is trying to double it's output Xtal - X2 (14MHz).
 
  • Like
Reactions: Shadetree Mechanic

dxChat
Help Users
  • No one is chatting at the moment.
  • @ Wildcat27:
    Hello I have a old school 2950 receives great on all modes and transmits great on AM but no transmit on SSB. Does anyone have any idea?
  • @ BJ radionut:
  • @ ButtFuzz:
    Good evening from Sunny Salem! What’s shaking?
  • dxBot:
    63Sprint has left the room.
  • dxBot:
    kennyjames 0151 has left the room.


      Top Bottom
      Back