99V scans threw channels?

[longhaireddwb]

I have a friend that has a DX99v old school, he says it wont stay on one channel. He says it acts like it is scanning for signals. Not staying on any one frequency.

He bought it used at a pawn shop for his Kenworth.

Anyone have any ideas of where I might start looking for this problem? Or maybe someone has seen this before? I haven't got my hands on it yet but most likely this weekend.

Anyone?

 

[TonyV225]

may need a new channel selector or the PLL is messing up

 

[longhaireddwb]

Thanks for the reply Tony. I'm hoping that its just a bad solder joint on the PLL. Time will tell. Like I said, Ill get it this weekend to check out. If anyone has ran across this before please post up what you found and the repairs.

Thanks to this forum for all the help and learning I've gotten from you all!

 

[DTB Radio]

In my experience this is almost always a bad solder joint in the VCO/PLL circuit. In some cases, the joint is visibly cracked, in other cases I find that carefully touching up all the joints in that area does the trick. Sometimes you can isolate the part by gently moving individual parts, but you can also make the radio jump freq just from the capacitance of your fingers.

 

[TonyV225]

I remember years ago I had that problem with a Yaesu FT-747 all I had to do was bump the desk or bump the radio and it would jump allover and it turned out to be a common problem with that aswell it was the (rotary encoder switch) in the VFO it was a common problem with the 747 and I had to track down the part which was made by a company called Alps. It use to frustrate me bigtime when it would jump around so I feel your pain. Hopefully you get it figured out Im sure you will and Ide personally do what Dave suggested and just go through and retouch all those connections but becareful with the heat and solder flow

 

[longhaireddwb]

Thanks for the comments guys. I'm going to go pick it up tomorrow morning and check it out. hoping for the solder joint problem. I'll let you all know how it comes out. Thanks for the encouragement. I know I'll get it. Maybe.

 

[Carl]

+1 on pll solder joint and or pll.

 

[longhaireddwb]

I got the radio in my hands and here is what I found.

To start with I need to quit listening to how people explain the problem! Scanning my a--.

It was stuck on 17.*** frequency no matter what you did with the knobs.

I opened it up and started pushing and flexing the main board and it jumped right on to frequency and everything worked. After about 15 minutes I found a bad solder joint on TR25 which is part of the VCO 14mhz to 18mhz I believe. Anyway. An easy fix. So you all were still right with it being in the PLL section.

Thanks to all who piped up and gave me encouragement in getting this fixed. I told my buddy he's buying the beer tonight because it took me forever to find the problem. What he don't know wont hurt him.

Thanks again forum! This is the best place on the web! (Yes, the web is for more than just porn.):w00t: