• 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.

Stalker 2000?

brandon7861

Loose Wire
Nov 28, 2018
1,106
1,198
193
A friend bought a Teaberry Stalker II. It smells like a 200 year old book and it looks like the mold held water and made the metal parts of the pots rust. It don't look good. My question is for those who have a Stalker II. How good is the Stalker II compared to a cobra 148GTL? I am not sure if I should try cleaning up the board and replacing what is bad, or dropping in a 148GTL board and calling it a Stalker 2000. Any recommendations?
 

Well with any 35 plus year old radio a complete re-cap is a must. If you have water and rust damage god knows what else could need work.
 
  • Like
Reactions: brandon7861
From what little research I could be bothered to do, if it's the 40 channel version it's an 858 PLL. Not the standard board like you'd find in a Cobra 138XLR, etc but may be close to the Midland 79-893. If it's the 23 channel version then it's more closely related to the Realistic TRC-57. Since you asked about how it compares to a Cobra 148GTL I'm guessing it's the 40 channel version.

Based on your description I'd take a real close look at the board to check for mold and/or water damage. Even a little bit of green on wires where they connect to the board could be a bad sign. The corrosion you can see won't be half as bad as what you can't see. If the board is good then it might be worth saving as is, just don't take it into the backyard for the garden hose/simple green treatment certain snake oil peddlers have been known to use.

You'll need new pots either way, of course. Hopefully they haven't rusted so much that they're fused to the nuts that hold them in place.

For the smell, maybe a good scrubbing and Febreze soak of the case and leave it outside for a week weather permitting? I did that with a computer that came out of smoker's house and it seemed to work. Used it for a good five years at least after that. If you do that to any of the electronics wash it off with alcohol before powering on. I don't think Febreze leaves a conductive residue, but I haven't tested that. Radio will probably emit the Febreze smell for a while every time it gets warm.

In case it wasn't obvious, I'm recommending saving the original board if you can. Don't hesitate to change course if it's obviously not going to work.
 
  • Like
Reactions: brandon7861
Its the 23ch board. Here is a look inide. I will have to look closer at it later when I have more time. Leaving for work in a half hour or so.
 

Attachments

  • IMG_20230523_094922538.jpg
    IMG_20230523_094922538.jpg
    3.8 MB · Views: 11
Now that I've seen the inside, if you decide to gut it and throw a 148 or export board in there no one could blame you. I think it can still be saved, but it's the harder road from that pic. As in prepare your friend for not seeing the radio for a very long time. Which is probably a good idea either way.

The PLL unit kind of looks like stuff had accumulated in there and then been removed. Also, first time I've seen one of those round metal body IC's with pitting. But from your initial description of the smell, that shouldn't be a surprise. What might be deal killer for resurrection is what looks like a missing tuning can. Shouldn't be too hard to figure out what it is, but finding one may be a challenge.
 
  • Like
Reactions: brandon7861
Any time I'm asked about restoring a radio that's over 40 years old I always recommend low mileage. The less visible oxidation the better.

From the sound of it, this will be like restoring a '76 Camaro that spent the last few decades in a creek bed. By the time you make it reliable, there won't be a lot of original parts, at least not the important ones. The numerous "can" inductors, the ones with the tuning slugs are likely to cause headaches, since they tolerate moisture and humidity very poorly. Finding replacements can get tricky. A "junk" radio is frequently the only viable source. And if the parts radio was treated well enough that those parts are still good, maybe that one should get restored instead?

Just my experience, YMMV.

73
 
Any time I'm asked about restoring a radio that's over 40 years old I always recommend low mileage. The less visible oxidation the better.

From the sound of it, this will be like restoring a '76 Camaro that spent the last few decades in a creek bed. By the time you make it reliable, there won't be a lot of original parts, at least not the important ones. The numerous "can" inductors, the ones with the tuning slugs are likely to cause headaches, since they tolerate moisture and humidity very poorly. Finding replacements can get tricky. A "junk" radio is frequently the only viable source. And if the parts radio was treated well enough that those parts are still good, maybe that one should get restored instead?

Just my experience, YMMV.

73
Would I be able to use hot air to drive moisture out of the tuning cans? Maybe a lower temperature over a several minute period? I have a stand for my hot air gun and it can be set fairly low.
 
Now that I've seen the inside, if you decide to gut it and throw a 148 or export board in there no one could blame you. I think it can still be saved, but it's the harder road from that pic. As in prepare your friend for not seeing the radio for a very long time. Which is probably a good idea either way.

The PLL unit kind of looks like stuff had accumulated in there and then been removed. Also, first time I've seen one of those round metal body IC's with pitting. But from your initial description of the smell, that shouldn't be a surprise. What might be deal killer for resurrection is what looks like a missing tuning can. Shouldn't be too hard to figure out what it is, but finding one may be a challenge.
Wow, I didn't even notice that. Good eye! Every time I look at the crud inside, I just cringe and look away thinking about the board swap.

I looked at the schematic. I could be wrong, but it appears that the missing coil is part of the VCO tuning tank. I will have to look up the varactor and see what its range is (in parallel with the other capacitance) to get an idea of what coil should go there to get the 19MHz VCO signal. What a crappy deal.
 
I've decided its a parts board. Going with the board swap.

I need to think about this one for a little while now, because if its not going to be original, I may as well add a SMPS and add a PA on the back. I do have an old PA from a TS-130s. The whole amp is built into the heat sink (except the filter). I wonder what that kenwood amp takes for drive..

Thanks!
 
Would I be able to use hot air to drive moisture out of the tuning cans?
The problem with the tuneable IF/RF transformer "cans" is not the moisture, but the corrosion damage it leaves behind. There's a dirty trick inside many of them. A built-in capacitor serves to tune the coil inside to a range of frequencies. The cap isn't the dirty trick, but the way the capacitor is fabricated. A tiny hollow cylinder of ceramic has a metal coating applied in a vacuum. A wire the size of a frog hair is wrapped around one end and soldered. Just one problem. The edge of the solder, where it meets the deposited metal layer is a galvanic site. Meaning, that two chemically different metals are joined along the edge of the soldered area.

This is no big deal until moisture arrives. Might be the morning dewfall in an unheated garage, might be a radio that's cold from overnight, when a warm humid breeze blows through later in the day. Condensation is all the moisture you need to turn that capacitor's boundary-between-metals into a tiny battery. The tiny current flow eats the metal away from the junction area, leaving an open circuit. Oxides don't conduct electricity like metals. Turns that capacitor into an open circuit, and the coil's adjustment no longer behaves like it should.

Sometimes this can be remedied without replacing the tuneable can, sometimes not.

Just the same, driving out the moisture isn't the fix, keeping it out in the first place is the only true remedy.

73
 
The problem with the tuneable IF/RF transformer "cans" is not the moisture, but the corrosion damage it leaves behind. There's a dirty trick inside many of them. A built-in capacitor serves to tune the coil inside to a range of frequencies. The cap isn't the dirty trick, but the way the capacitor is fabricated. A tiny hollow cylinder of ceramic has a metal coating applied in a vacuum. A wire the size of a frog hair is wrapped around one end and soldered. Just one problem. The edge of the solder, where it meets the deposited metal layer is a galvanic site. Meaning, that two chemically different metals are joined along the edge of the soldered area.

This is no big deal until moisture arrives. Might be the morning dewfall in an unheated garage, might be a radio that's cold from overnight, when a warm humid breeze blows through later in the day. Condensation is all the moisture you need to turn that capacitor's boundary-between-metals into a tiny battery. The tiny current flow eats the metal away from the junction area, leaving an open circuit. Oxides don't conduct electricity like metals. Turns that capacitor into an open circuit, and the coil's adjustment no longer behaves like it should.

Sometimes this can be remedied without replacing the tuneable can, sometimes not.

Just the same, driving out the moisture isn't the fix, keeping it out in the first place is the only true remedy.

73
Thanks for that explanation! I will use that board for parts and try to put the 148GTL board in it sometime this summer. I am not sure what I will do about a channel display, but I might have to find an old royce knob with all 40 on it.
 
  • Like
Reactions: TM86 and Holydvr

dxChat
Help Users
  • No one is chatting at the moment.
  • dxBot:
    Tucker442 has left the room.
  • @ BJ radionut:
    LIVE 10:00 AM EST :cool:
  • @ Charles Edwards:
    I'm looking for factory settings 1 through 59 for a AT 5555 n2 or AT500 M2 I only wrote down half the values feel like a idiot I need help will be appreciated